WO2005052891A1

WO2005052891A1 - Photomask and production method for laminated substrate using this

Info

Publication number: WO2005052891A1
Application number: PCT/JP2004/017359
Authority: WO
Inventors: Naru Usukura; Mitsuaki Morimoto
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2003-11-26
Filing date: 2004-11-22
Publication date: 2005-06-09
Also published as: TW200521551A

Abstract

A photomask(10) comprising a transparent substrate (11), a light shielding layer (12) formed on one surface of the substrate (11) so that a seal-material area is irradiated with at least a light source light, and spacers (13) formed within the light shielding layer (12) area. The photomask (10) is overlapped on and kept in contact with a laminated substrate in which a pair of substrates is laminated via a seal material containing a photocuring resin to thereby define the area of a light source light applied to the surface of the laminated substrate.

Description

Specification

Photomask and method of manufacturing bonded substrate using the same

Technical field

The present invention relates to a photomask. For example, the present invention relates to a photomask that is superimposed on a liquid crystal display panel when ultraviolet curing is performed on the ultraviolet curable sealant formed on the periphery of the liquid crystal display panel to be cured.

Background art

Among the steps of manufacturing a display device such as a liquid crystal display device, there is a step of filling a functional material such as a liquid crystal material in a panel. As a method for filling the functional material, dip type or dispenser type may be mentioned. In these methods, the bonded maza-glass substrate is divided into individual panels or strips including a plurality of panels, and the functional material is filled from the opening of the sealing material and the opening is sealed. Is taken. However, with the increase in screen size, it has become a problem that the tact time for functional material filling is long.

In recent years, a one-drop filling method (also called a drop bonding method) has been developed as another method for filling a functional material into a panel. In the one-drop filling method, a functional material is dropped in a seal pattern frame formed on one substrate before stacking without providing an opening in the seal pattern, and a pair of substrates are stacked and attached under reduced pressure. It is a method. According to the one-drop filling method, it is possible to cope with the increase in screen size, and there is an advantage that the tact time of functional material filling can be dramatically shortened.

[0004] Since it is not possible to use a sealing material that is cured by heating in view of curing time in the one-drop filling method, a sealing material that is cured by irradiation with ultraviolet light (UV) Hereinafter, a UV curable sealing material) or a sealing material cured by both UV irradiation and heating (hereinafter referred to as a heat curing combination sealing material) is used. Therefore, in the one-drop filling method, a step of curing the sealing material by UV irradiation is required.

In the UV irradiation step, a mask is usually used. As a mask alignment method, a zonal contact method in which the mask is not in contact with the laminated substrate and a contact method in which the mask is in contact with the laminated substrate can be mentioned. Three characteristics are mainly required for the mask material used in the non-contact method and the contact method. (1) High rigidity V, material to keep the distance between mask and bonded substrate constant, and (2) high dimensional stability, material to form a pattern with high accuracy, 3) It is a material that has a particularly high transmittance so that it does not lose UV light. Although quartz glass and low alkali glass are generally used as materials that satisfy these three requirements, quartz glass with a surface tension such as precision and heat absorption is widely used.

On the other hand, the size of glass for manufacturing a display device is increasing year by year, and accordingly, the size of a mask is also increasing. The mask used in the non-contact method is required to be higher in rigidity than the mask used in the contact method, and therefore, it is necessary to increase the thickness of the mask in order to prevent the mask from being warped or cracked by its own weight. For example, a mask for a 620 mm × 750 mm substrate requires a thickness of about 5 mm. In the case of a mask having such a thickness, it is necessary to use expensive quartz glass having a particularly high transmittance, so that it is difficult to reduce the manufacturing cost.

On the other hand, since the mask used in the contact method is in contact with the bonded substrate, the required rigidity is lower than that of the mask used in the non-contact method. Therefore, since the thickness of the mask can be reduced, it is possible to use a low alkali glass or the like, which has lower transmittance than quartz glass but is inexpensive. However, in the contact method, there is a risk that the pattern forming surface may be contaminated or damaged by the contact.

[0009] Patent Document 1 discloses a contact method mask in which a notched surface is protected. Specifically, in the mask disclosed in Patent Document 1, a spacer with a constant thickness is provided in an empty space on the pattern formation surface of the glass mask, and this spacer is applied to the surface of the layer to be exposed. By contacting them, the not formed surface is protected.

Patent Document 1: Japanese Patent Application Laid-Open No. 61-260633

Disclosure of the invention

Problem that invention tries to solve

[0010] In order to form a pattern efficiently, it is desirable to reduce free space. However, it is difficult to provide a spacer at the central portion of the mask substrate, since practically there is almost no vacant space on the notched surface except for the outer peripheral portion of the mask substrate. . Therefore, the deflection of the mask is increased, and the distance between the mask and the layer to be exposed becomes uneven in the plane, which may lower the pattern accuracy. In addition, if the mask thickness is increased to prevent mask deflection, the advantages of the contact method are lost and it becomes impossible to use inexpensive low alkali glass. Therefore, as disclosed in Patent Document 1, it is not realistic to form a pattern! Providing a spacer in an empty space is not very practical.

An object of the present invention is to reduce the thickness of a mask while maintaining the pattern accuracy of the mask, and to reduce the manufacturing cost of the mask.

Means to solve the problem

The present invention provides a contact type photomask in which a spacer is formed in the region of the light shielding layer. Specifically, in the photomask of the present invention, the photomask is brought into contact with a bonded substrate stack in which a pair of substrates are bonded via a sealing material containing a photocurable resin, and then stacked.

And a photomask for defining a region of light source light irradiated to the surface of the bonded substrate, wherein at least the light source light irradiates a transparent substrate and the region of the sealing material. And a spacer formed in a region of the light shielding layer.

The sealing material containing a photocurable resin includes a UV-curable sealing material and a UV′-heat-curing combination-type sealing material. The seal material pattern includes a frame shape (open loop shape) having an opening which is open only in a frame shape having no opening (closed loop shape). In other words, the photo mask of the present invention can also be applied to a method in which the functional material is injected from the opening (injection port) which is only one drop filling method.

Since the light shielding layer is typically formed to shield the area other than the area of the sealing material, the occupancy rate in the plane of the photomask is high. Therefore, since spacers formed in the region of the light shielding layer can be formed at various places in the plane of the photomask, the photomask is brought into contact with the bonded substrate stack through the spacers. The distortion of the mask is significantly reduced, and the distance between the mask and the bonded substrate can be kept approximately constant. Thereby, the thickness of the mask can be reduced while maintaining the accuracy of the notch.

[0015] The spacer is made of a material having a hardness lower than that of the pair of substrates in contact with each other. Preferably, it is formed. This makes it difficult for the bonded substrate surface to be damaged.

The present invention also provides a method for producing a bonded substrate by a one-drop filling method. In detail, in the method of the present invention, a layer containing a functional material, a sealing material surrounding the functional material layer and containing a photocurable resin, and the functional material layer and the sealing material are bonded to each other. A method of manufacturing a bonded substrate having a pair of substrates, comprising the steps of: forming the sealing material in a frame shape on one substrate surface of the pair of substrates; The step of dropping the functional material, the step of bonding the pair of substrates, the step of overlapping the photomask of the present invention on the bonded substrate and bringing the spacer into contact with the bonded substrate, Curing the sealing material by irradiating the bonded substrate with a light source light through a photomask.

The functional material layer includes a layer in which the light transmittance is modulated by a potential difference between the electrodes facing each other, and a layer which emits light by a current flowing between the electrodes facing each other. For example, a liquid crystal layer, an organic or organic electorite luminescence (EL) layer, a light emitting gas layer, an electrophoresis layer, an electoric hole chromic layer, and the like. Effect of the invention

According to the present invention, it is possible to thin the mask while maintaining the pattern accuracy of the mask. Therefore, the transmittance is improved, and the loss of light source light can be suppressed. In addition, since it is possible to use low-alkali glass or the like, which has lower transmittance than quartz glass but is inexpensive, manufacturing cost can be reduced. Furthermore, since the light shielding layer does not contact the bonded substrate surface, there is no risk of the light shielding layer becoming dirty or broken.

Brief description of the drawings

FIG. 1 is a plan view schematically showing a photomask of an embodiment.

[FIG. 2] FIG. 2 is a plan view of a bonded liquid crystal substrate on which the photomasks of the embodiments are superimposed.

[FIG. 3] FIG. 3 is a cross-sectional view of a bonded liquid crystal substrate on which the photomasks of the embodiments are stacked.

[Fig. 4] Fig. 4 schematically shows the state in which the bonded liquid crystal substrate 1 and the photomask 10 are superimposed. It is a sectional view showing.

Explanation of sign

1 Bonded liquid crystal substrate

2, 3 board

4 Sealant around

5 Liquid crystal layer

6 Transparent electrode

7 pixel transparent electrode

8 terminals

10 Photo mask

11 Transparent substrate

12 Light shielding layer

13 Spacer

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a bonded liquid crystal substrate is described as an example of a bonded substrate, but the bonded substrate in the present invention is capable of displaying an image shift panel for shifting pixels optically sequentially and a three-dimensional image. It can also be applied to the lux-no rear panel. The image shift panel has at least one combination of a liquid crystal panel that modulates the polarization state of light and a birefringence element that shifts the optical path according to the polarization state of light emitted from the liquid crystal panel. In addition, the parallax panel can display a stereoscopic video by combining it with a video display element having a pixel for the left eye and a pixel for the right eye.

FIG. 1 is a plan view schematically showing a photomask of the present embodiment. FIG. 2 is a plan view of a bonded liquid crystal substrate on which the photomasks of the present embodiment are superimposed, and FIG. 3 is a cross-sectional view thereof. The bonded liquid crystal substrates shown in FIGS. 2 and 3 are divided into four liquid crystal display panels.

First, the configuration of the bonded liquid crystal substrate will be described with reference to FIGS. 2 and 3. The bonded liquid crystal substrate 1 is a peripheral seal sandwiched between a pair of substrates 2 and 3 and both substrates 2 and 3 A material 4 and a liquid crystal layer 5 surrounded by both substrates 2 and 3 and surrounded by a peripheral sealing material 4 are provided. One of the substrates 2 is a color filter substrate, and a color filter layer (not shown), a transparent electrode 6 such as ITO (indium stannic acid oxide) and the like, and a liquid crystal alignment film which is treated such as polyimide and rubbed Not shown).

The other substrate 3 is a TFT (Thin Film Transistor) substrate, and includes a plurality of gate bus lines (not shown) extending in the row direction and a plurality of source bus lines (not shown) extending across the gate bus lines. And a TFT (not shown) provided near the intersection of the gate bus line and the source bus line, and a pixel arranged in a matrix, connected to the source bus line (not shown) via the TFT. It has a transparent electrode 7 and a liquid crystal alignment film (not shown) covering the pixel transparent electrode 7. Further, on the other substrate 3, terminals 8 for inputting signals to the gate bus line and the source bus line are formed outside the frame-shaped peripheral sealing material 4.

Examples of the material of the substrates 2 and 3 include glass such as quartz glass, soda lime glass, borosilicate glass, low alkali glass, non-alkali glass, and plastics such as polyester and polyimide.

The peripheral sealing material 4 contains a UV curable resin such as atarilate resin or epoxy resin, and is cured by UV light irradiated with a UV light source. The photomask of the present embodiment defines a region of UV light to be irradiated to the surface of the bonded liquid crystal substrate 1 by bringing the bonded liquid crystal substrate 1 into contact and overlapping. Specifically, by overlapping the photomask, the area of the peripheral sealing material 4 is irradiated, and the other area of the bonded liquid crystal substrate 1, for example, the display area of the bonded liquid crystal substrate 1 is shielded.

The configuration of the photomask of the present embodiment will be described with reference to FIG. In the photomask 10 of the present embodiment, the transparent substrate 11, the light shielding layer 12 formed on one surface of the transparent substrate 11 so that UV irradiates the region of the peripheral sealing material 4, and the light shielding layer 12. And a spacer 13 having a predetermined thickness formed thereon.

As the transparent substrate 11, a plate glass used for a general photomask can be used. As described later, according to the photomask of the present embodiment, since the thickness of the transparent substrate 11 can be reduced, inexpensive low alkali glass made of quartz glass alone can be used. It can be used. It is also possible to use other glasses such as soda lime glass, borosilicate glass, alkali-free glass, and plastics such as polyester.

The light shielding layer 12 is formed so that the region of the peripheral sealing material 4 of the bonded liquid crystal substrate 1 is irradiated and the other region of the bonded liquid crystal substrate 1 is shielded from light. Specifically, as shown in FIG. 1, the light shielding layer 12 is formed in the area excluding the area 1 la corresponding to the peripheral sealing material 4 and the peripheral area 1 lb of the transparent substrate 11. Typically, the transmission area 1 la (the area of the light shielding layer 12) formed so as to be irradiated with the area of the peripheral sealing material 4 is approximately equal in width to the area of the peripheral sealing material 4, but the peripheral seal The width may be wider than the area of the material 4. The photomask for curing the peripheral sealing material 4 does not require strict pattern accuracy as compared with the photomask used in the photolithography method.

The light shielding layer 12 is patterned using a film having a light shielding property with respect to the UV to be irradiated.

For example, a light shielding layer 12 having a predetermined mask pattern is formed by a photolithography method, a printing method, or the like using a chromium single layer film, a laminated film of a chromium film and a chromium oxide film, and an emulsion film containing a silver salt gelatin emulsion. can do.

The spacers 13 are formed at a plurality of locations in the region of the light shielding layer 12. Since the light shielding layer 12 is formed in the area 11 a corresponding to the peripheral seal material 4 and the area excluding the peripheral area l ib of the transparent substrate 11, the occupancy rate in the plane of the transparent substrate 11 is high. Therefore, the spacers 13 can be formed at various places in the plane of the transparent substrate 11 where the options for forming the spacers 13 are wide.

Any material can be used as the material of the spacer 13 as long as it has appropriate dimensional stability or has flexibility to follow expansion and contraction of the mask. However, also in order not to damage the substrate 2 which is the surface layer of the bonded liquid crystal substrate 1, it is preferable to use a material whose hardness is lower than that of the substrate 2. For example, cemented PTFE (polytetrafluoroethylene) tape can be used to form the spacer 13.

[0033] As a method of forming the spacer 13, the material having the above-mentioned characteristics is cylindrical, and the film thickness is preferably 20 to 500 μm, and more preferably 50 to 200 μm. As a degree, a method of bonding with a UV curing type or thermosetting type adhesive can be mentioned. In the present embodiment, the shape of the spacer 13 is cylindrical, and the shape of the force spacer 13 is not particularly limited. It is not decided. For example, it may be in the shape of a bump or a band.

In the photomask 10 of the present embodiment, since the spacers 13 are formed in the area of the light shielding layer 12, the spacers 13 may be scattered at various places in the plane of the transparent substrate 11. Can. Therefore, by bonding the photomask 10 to the liquid crystal substrate 1 by the contact method, the deflection of the photomask 10 is significantly reduced, and the distance between the photomask 10 and the liquid crystal substrate 1 can be kept approximately constant. it can. Thereby, the thickness of the transparent substrate 11 can be reduced while maintaining the pattern accuracy. However, when the photomask 10 is bonded and is not in contact with the liquid crystal substrate 1, it is preferable that the thickness be such that it does not break by its own weight. For example, in the case of a low alkali glass substrate having a size of 620 mm × 750 mm, it is appropriate to set the thickness to about 0.7 mm.

Next, steps of manufacturing a liquid crystal display panel using the photomask 10 of the present embodiment will be described. First, a color filter layer, a transparent electrode 6 and a liquid crystal alignment film subjected to rubbing treatment are sequentially formed on one substrate 2 by a sputtering method, a printing method or the like. In addition, after forming various lines, insulating films, TFTs, and pixel transparent electrodes 7 on the other substrate 3 by photolithography or printing, etc., a rubbed liquid crystal alignment film covering the pixel transparent electrodes 7 is formed. Form.

On the surface of either one of the two substrates 2 and 3, a UV curable peripheral sealing material 4 containing epoxy resin is formed by a screen printing method or a dispenser method. The pattern of the peripheral sealing material 4 has a closed loop shape without an opening serving as a liquid crystal injection port. For example, a nematic liquid crystal material is dropped in the pattern frame of the peripheral sealing material 4. The liquid crystal layer 5 is enclosed in each liquid crystal display panel by overlapping the two substrates 2 and 3 in the vacuum chamber.

FIG. 4 is a cross-sectional view schematically showing a state in which the bonded liquid crystal substrate 1 and the photomask 10 of the present embodiment are superimposed. As shown in FIG. 4, the photomask 10 is laminated on the liquid crystal substrate 1 and the spacer 13 of the photomask 10 is laminated and brought into contact with one surface of the liquid crystal substrate 1. Since spacers 13 having a predetermined thickness are scattered at various places in the plane of the transparent substrate 11, the photomask 10 is bonded by a contact method and superimposed on the liquid crystal substrate 1 to obtain a photomask. 10 and bonded liquid crystal substrate 1 The spacing can be kept approximately constant.

By irradiating the bonded liquid crystal substrate 1 with UV light through the photomask 10, only the area of the peripheral sealing material 4 in the surface of the bonded liquid crystal substrate 1 is exposed, and the peripheral sealing material 4 is Cure. Furthermore, the bonded liquid crystal substrate 1 is divided into individual panels, and after passing through a chamfering process and a polarizing plate bonding process, the driver IC is connected to the terminal 8. The liquid crystal display panel of the present embodiment is manufactured through the above steps.

In the photomask 10 of the present embodiment, the light shielding layer 12 is formed on one side of the transparent substrate 11, and the spacer 13 is formed on the light shielding layer 12. The light shielding layer 12 is a transparent substrate The spacer 13 may be formed on one side of the transparent substrate 11, and the spacer 13 may be formed on the other side of the transparent substrate 11. In the liquid crystal display panel of the present embodiment, TFTs are used as liquid crystal drive elements, but other active drive elements such as MIM (Metal Insulator Metal) may be used, or passive elements without drive elements may be used. Plex) may be driven. The liquid crystal display panel may be any of a transmissive type, a reflective type, and a transmissive / reflective type.

In the present embodiment, a liquid crystal panel is illustrated as a target to be irradiated with UV through the photomask 10, but the bonded substrate to be a target is not limited to the liquid crystal panel. For example, a PDP (Plasma Display Panel), an organic or inorganic EL (Electro Luminescence) display panel, an aperture-chromic display panel, and the like can also be targets.

The embodiments of the present invention have been described above, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is understood by those skilled in the art that the above-described embodiment is an exemplification, and various modifications can be made by variously changing the respective constituent elements, and such modifications are also within the technical scope of the present invention.

The contents disclosed in the specification, drawings and claims of Japanese Patent Application No. 2003-395952 filed on Nov. 26, 2003 are incorporated in their entirety into the present specification by reference.

Industrial applicability

The photo mask of the present invention can be used as a photo mask for a contact system for curing a photosensitive sealing material sandwiched between a pair of substrates.

Claims

The scope of the claims

[1] A region of light source irradiated to the surface of the bonded substrate is brought into contact by superposing on a bonded substrate with a pair of substrates bonded together via a sealing material containing a photocurable resin. Is a specified photomask,

A transparent substrate, a light shielding layer formed on one surface of the transparent substrate so that at least the light source light irradiates the area of the sealing material, and a spacer formed in the area of the light shielding layer Have a photo mask.

[2] The photomask according to claim 1, wherein the spacer is formed of a material having a hardness lower than that of the pair of substrates in contact with each other.

[3] Affixing having a layer containing a functional material, a sealing material surrounding the functional material layer and containing a photocurable resin, and a pair of substrates bonded via the functional material layer and the sealing material A method of manufacturing a laminated substrate,

Forming the sealing material in a frame shape on one of the pair of substrates, and dropping the functional material into the sealing material frame.

Bonding the pair of substrates together;

Placing the photomask according to claim 1 on the laminated substrate and bringing the spacer into contact with the laminated substrate;

Curing the sealing material by irradiating the laminated substrate with light source light through the photomask.