JP4760180B2 - Manufacturing method of liquid crystal device - Google Patents

Description

  The present invention relates to a method of manufacturing a liquid crystal device suitable for bonding small liquid crystal panels and a liquid crystal device.

  A liquid crystal device such as a liquid crystal light valve is configured by sealing liquid crystal between two substrates such as a glass substrate and a quartz substrate. In a liquid crystal device, for example, thin film transistors (hereinafter referred to as TFTs) are arranged in a matrix on one substrate, a counter electrode is arranged on the other substrate, and a liquid crystal layer sealed between both substrates is arranged. By changing the optical characteristics according to the image signal, it is possible to display an image.

  The TFT substrate on which the TFT is disposed and the counter substrate disposed to face the TFT substrate are manufactured separately. Both substrates are bonded together with high accuracy in the panel assembling process, and then liquid crystal is sealed therein.

  In the panel assembling process, first, an alignment film is formed on the opposing surfaces of the TFT substrate and the counter substrate manufactured in each substrate process, that is, the surface in contact with the liquid crystal layer of the counter substrate and the TFT substrate, and then the rubbing process. Is done.

  By forming an alignment film and performing a rubbing treatment, the alignment of liquid crystal molecules when no voltage is applied is determined. The alignment film is formed, for example, by applying polyimide with a thickness of about several tens of nanometers. By forming an alignment film on the surfaces of both substrates facing the liquid crystal layer, the liquid crystal molecules can be aligned along the substrate surface. In the rubbing process, fine grooves are formed on the surface of the alignment film to form an alignment anisotropic film, and the alignment of liquid crystal molecules can be defined by performing a rubbing process in a certain direction on the alignment film.

  Next, a sealing material serving as an adhesive is formed on the edge of one substrate. The TFT substrate and the counter substrate are bonded together using a sealing material, and are pressure-bonded and cured while being aligned. A part of the sealing material is provided with a notch, and the liquid crystal is sealed through the notch.

  By the way, in the bonding process of a board | substrate, there exists a method of hardening a thermosetting sealing material using thermosetting, and a method of hardening an ultraviolet curable sealing material using light (ultraviolet rays) hardening.

  The method of thermosetting the sealing material has an advantage of high productivity. However, an alignment error occurs due to a difference between the thermal expansion coefficient of the sealing material and the thermal expansion coefficient of the glass.

For this reason, generally, a method in which an adhesive portion (sealant) is cured by ultraviolet rays is often employed. However, ultraviolet curing requires a large amount of light of 5000 to 30000 mJ / cm ² and requires a long time for sufficient curing, so that sufficient alignment accuracy cannot be obtained. Therefore, there is also a technology to improve the alignment accuracy by irradiating the sealing material with a small amount of light in a short time to temporarily cure the adhesive, and then to fully cure the adhesive with a large amount of ultraviolet light over a sufficient amount of time later. It is disclosed. However, when the ultraviolet curable sealing material is irradiated with ultraviolet rays twice, there is a drawback that the curing rate is lowered.

  In addition, there is a problem that when the ultraviolet rays are irradiated, the alignment film is irradiated with light and deteriorates, and the pretilt angle of liquid crystal alignment is lowered.

  Therefore, recently, there is a case where a temporary curing by ultraviolet curing that cures in a short time is employed, and a sealing material that employs thermal curing is used in the main curing. Alignment accuracy is improved by short-time temporary curing, and sufficient fixing strength is obtained by thermal curing.

When the sealing material is irradiated with ultraviolet rays, a light shielding mask that shields light other than the sealing material is used in order to avoid the influence on the pixels. Patent Document 1 discloses a technique of a manufacturing method using an ultraviolet and heat combined seal material that avoids such adverse effects of ultraviolet rays.
JP 2003-270644 A

  However, a thermosetting sealing material such as an epoxy resin is a contaminant for the liquid crystal. The liquid crystal is contaminated and deteriorated by the contaminants dissolved into the liquid crystal from the sealing material. In addition, as described above, there is a problem that distortion occurs between the upper and lower substrates due to heat during thermosetting, resulting in misalignment.

  The present invention has been made in view of such problems, and prevents contamination of the liquid crystal by using an ultraviolet radical curable sealing material and a temporary fixing material, and improves alignment accuracy by using the temporary fixing material. It is another object of the present invention to provide a method of manufacturing a liquid crystal device and a liquid crystal device capable of obtaining sufficient fixing strength by curing a sealing material.

The method of manufacturing a liquid crystal device according to the present invention includes a step of forming a temporary fixing portion and a seal portion on a first substrate using an ultraviolet radical curable adhesive material, and the first substrate and the second substrate. The first and second are temporarily bonded so that the temporary fixing portion is not completely cured by irradiating the temporary fixing portion with ultraviolet rays through a mask disposed so as to be overlapped with the seal portion. A step of bonding the substrates together, and after the first and second substrates are bonded to each other, the temporary fixing portion and the sealing portion are connected to the temporary fixing portion and the seal portion via a mask disposed inside the sealing portion. And a step of curing each of the temporary fixing portion and the seal portion by irradiating ultraviolet rays having a light quantity larger than that of the ultraviolet rays for temporarily curing the adhesive.

  According to such a configuration, the temporary fixing portion and the seal portion are formed on the first substrate by the ultraviolet radical curable adhesive material. The first and second substrates are bonded together, and the temporary fixing part is cured by irradiating the temporary fixing part with ultraviolet rays. Thereby, the first and second substrates are temporarily fixed. Next, the seal portion is irradiated with ultraviolet rays to be fully cured, and the first and second substrates are fixed. Since a thermosetting adhesive material is not used for bonding the first and second substrates, there is no contamination by the adhesive material and no distortion occurs in the first and second substrates. The temporary fixing portion and the seal portion are formed of an ultraviolet radical curable adhesive material and are cured with a relatively small amount of light. Accordingly, it is possible to prevent the adverse effects of the ultraviolet rays on the first and second substrates. Moreover, since the seal portion is cured in a single curing step, sufficient fixing strength can be obtained. In this way, high-precision pasting is performed without causing deterioration of the pixels.

  The temporary fixing portion also serves as a conducting portion for conducting the first and second substrates.

  According to such a configuration, for example, conductive portions provided at four locations of the first and second substrate corners can be used as the temporary fixing portions, and the temporary fixing portions can be formed without increasing the number of steps. be able to. Further, it is not necessary to increase the area occupied by the temporary fixing portion, and the liquid crystal device can be configured in a small size.

In addition, the step of curing the temporary fixing portion may include a step of masking the seal portion .

  According to such a configuration, since the seal portion is masked when the temporary fixing portion is cured, the seal portion is cured during the main curing, and sufficient fixing accuracy is obtained.

In addition, the step of curing the temporary fixing portion and the seal portion is performed by irradiating the temporary fixing portion and the seal portion with an irradiation light amount of 500 to 5000 mJ / cm ² .

  According to such a configuration, the sealing material can be fully cured with a relatively small amount of light, and adverse effects on the first and second substrates can be suppressed.

In addition, the step of curing the seal portion may include a step of masking a display area surrounded by the seal portion .

  According to such a configuration, it is possible to prevent the display area from being irradiated with light, and to suppress adverse effects on the display area.

In addition, the method for manufacturing a liquid crystal device according to the present invention includes a step of forming a temporary fixing portion and a seal portion on a counter substrate using an ultraviolet radical curable adhesive material, and the above-described element mother substrate including a plurality of element substrates. The counter substrate on which the temporary fixing portion and the seal portion are formed is pressure-bonded on the element substrate, and the temporary fixing portion is irradiated with ultraviolet rays through a mask disposed so as to overlap the seal portion. Are temporarily cured so as not to be completely cured, and the counter substrate and the element mother substrate are bonded together, and after the plurality of counter substrates are bonded to the element mother substrate, each of the counter substrates A plurality of the temporary fixing portions by irradiating a plurality of the temporary fixing portions and the seal portions with ultraviolet rays having a light amount larger than an ultraviolet ray for temporarily curing the temporary fixing portions via a mask disposed inside the sealing portion. Characterized in that the finely the seal portion equipped and curing respectively.

  According to such a configuration, the counter substrate is temporarily fixed on the element mother substrate by the temporary fixing portion. The temporary fixing portion is formed using an ultraviolet radical curable adhesive material, and can be temporarily cured with a small amount of light in a short time. Thereby, alignment accuracy between the counter substrate and the element mother substrate can be improved. The counter substrate and the element mother substrate are fully cured by irradiating the seal portion with ultraviolet rays. The seal portion is cured by a single UV irradiation to obtain a sufficient fixing strength.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart showing a method for manufacturing a liquid crystal device according to the first embodiment of the present invention. FIG. 2 is a plan view of the liquid crystal device manufactured in the present embodiment as viewed from the counter substrate side together with the components formed thereon. FIG. 3 is a cross-sectional view of the liquid crystal device after the assembly process in which the element substrate and the counter substrate are bonded to each other and the liquid crystal is sealed is cut along the line HH ′ in FIG. FIG. 4 is an equivalent circuit diagram of various elements and wirings in a plurality of pixels constituting the pixel region of the liquid crystal device. FIG. 5 is a cross-sectional view showing the pixel structure of the liquid crystal device in detail. FIG. 6 is a flowchart showing the panel assembly process. In each of the above drawings, the scale is different for each layer and each member so that each layer and each member can be recognized in the drawing.

First, the overall configuration of the liquid crystal device manufactured in the present embodiment will be described with reference to FIGS.
As shown in FIGS. 2 and 3, the liquid crystal device includes, for example, a quartz substrate, a glass substrate, a TFT substrate 10 using a silicon substrate, and a counter substrate using a glass substrate or a quartz substrate, for example. The liquid crystal 50 is sealed between the two. The TFT substrate 10 and the counter substrate 20 that are arranged to face each other are bonded together by a sealing material 52.

  On the TFT substrate 10, pixel electrodes (ITO) 9a constituting pixels are arranged in a matrix. A counter electrode (ITO) 21 is provided on the entire surface of the counter substrate 20. On the pixel electrode 9 a of the TFT substrate 10, an alignment film 16 that has been subjected to a rubbing process is provided. On the other hand, an alignment film 22 subjected to a rubbing process is also provided on the counter electrode 21 formed over the entire surface of the counter substrate 20. The alignment films 16 and 22 are made of a transparent organic film such as a polyimide film, for example.

  FIG. 4 shows an equivalent circuit of elements on the TFT substrate 10 constituting the pixel. As shown in FIG. 4, in the pixel region, a plurality of scanning lines 11a and a plurality of data lines 6a are wired so as to cross each other, and a pixel electrode is formed in a region partitioned by the scanning lines 11a and the data lines 6a. 9a are arranged in a matrix. A TFT 30 is provided corresponding to each intersection of the scanning line 11 a and the data line 6 a, and the pixel electrode 9 a is connected to the TFT 30.

  The TFT 30 is turned on by the ON signal of the scanning line 11a, whereby the image signal supplied to the data line 6a is supplied to the pixel electrode 9a. A voltage between the pixel electrode 9 a and the counter electrode 21 provided on the counter substrate 20 is applied to the liquid crystal 50. In addition, a storage capacitor 70 is provided in parallel with the pixel electrode 9a, and the storage capacitor 70 makes it possible to hold the voltage of the pixel electrode 9a for a time that is, for example, three orders of magnitude longer than the time when the source voltage is applied. The storage capacitor 70 improves the voltage holding characteristic and enables image display with a high contrast ratio.

  FIG. 5 is a schematic cross-sectional view of a liquid crystal device focusing on one pixel.

  A plurality of pixel electrodes 9a are provided in a matrix on the TFT substrate 10, and data lines 6a and scanning lines 11a are provided along the vertical and horizontal boundaries of the pixel electrodes 9a. As will be described later, the data line 6a has a laminated structure including an aluminum film, and the scanning line 11a is made of, for example, a conductive polysilicon film. The scanning line 11a is electrically connected to the gate electrode 3a facing the channel region 1a 'in the semiconductor layer 1a. That is, the pixel switching TFT 30 is configured by disposing the gate electrode 3a and the channel region 1a 'connected to the scanning line 11a so as to face each other at the intersection of the scanning line 11a and the data line 6a.

  On the TFT substrate 10, in addition to the TFT 30 and the pixel electrode 9a, various configurations including these are provided in a laminated structure. As shown in FIG. 5, this stacked structure includes, in order from the bottom, the first layer including the scanning line 11a, the second layer including the TFT 30 including the gate electrode 3a, the third layer including the storage capacitor 70, and the data line 6a. And the like, the fifth layer including the shield layer 400 and the like, and the sixth layer including the pixel electrode 9a and the alignment film 16 and the like. Further, the base insulating film 12 is provided between the first layer and the second layer, the first interlayer insulating film 41 is provided between the second layer and the third layer, and the second interlayer insulating film 42 is provided between the third layer and the fourth layer. A third interlayer insulating film 43 is provided between the fourth layer and the fifth layer, and a fourth interlayer insulating film 44 is provided between the fifth layer and the sixth layer, so that the above-described elements are short-circuited. Is preventing. Further, these various insulating films 12, 41, 42, 43 and 44 are also provided with, for example, a contact hole for electrically connecting the high concentration source region 1d in the semiconductor layer 1a of the TFT 30 and the data line 6a. It has been.

Hereinafter, each of these elements will be described in order from the bottom.
The first layer includes, for example, a simple metal, an alloy containing at least one of refractory metals such as Ti (titanium), Cr (chromium), W (tungsten), Ta (tantalum), and Mo (molybdenum). A scanning line 11a made of metal silicide, polysilicide, a laminate of these, or conductive polysilicon is provided. The scanning line 11a has a function of simultaneously controlling ON / OFF of the TFTs 30 existing in the same row. The scanning line 11a is formed so as to substantially fill a region where the pixel electrode 9a is not formed, and also has a function of blocking light entering the TFT 30 from below. Thereby, generation of light leakage current in the semiconductor layer 1a of the TFT 30 is suppressed, and high-quality image display without flicker or the like is possible.

  In the second layer, the TFT 30 including the gate electrode 3a is provided. As shown in FIG. 5, the TFT 30 has an LDD (Lightly Doped Drain) structure, and includes the above-described gate electrode 3a, for example, a polysilicon film, and a channel formed by an electric field from the gate electrode 3a. The channel region 1a ′ of the semiconductor layer 1a to be formed, the insulating film 2 including a gate insulating film that insulates the gate electrode 3a from the semiconductor layer 1a, the low concentration source region 1b and the low concentration drain region 1c in the semiconductor layer 1a, and the high concentration. A source region 1d and a high concentration drain region 1e are provided.

  In the second layer, a relay electrode 719 is formed as the same film as the gate electrode 3a described above. The relay electrode 719 is formed in an island shape so as to be positioned approximately at the center of one side of each pixel electrode 9a when seen in a plan view. Since the relay electrode 719 and the gate electrode 3a are formed as the same film, when the latter is made of a conductive polysilicon film or the like, the former is also made of a conductive polysilicon film or the like.

  The above-described TFT 30 preferably has an LDD structure as shown in FIG. 5, but may have an offset structure in which impurities are not implanted into the low-concentration source region 1b and the low-concentration drain region 1c. A self-aligned TFT that implants impurities at a high concentration as a mask and forms a high concentration source region and a high concentration drain region in a self-aligning manner may be used. In the present embodiment, only one gate electrode of the pixel switching TFT 30 is disposed between the high-concentration source region 1d and the high-concentration drain region 1e. However, two or more gates are interposed between these gate electrodes. An electrode may be arranged. If the TFT is configured with dual gates or triple gates or more in this way, leakage current at the junction between the channel and the source and drain regions can be prevented, and the off-time current can be reduced. Further, the semiconductor layer 1a constituting the TFT 30 may be a non-single crystal layer or a single crystal layer. A known method such as a bonding method can be used for forming the single crystal layer. By making the semiconductor layer 1a a single crystal layer, it is possible to improve the performance of peripheral circuits in particular.

  A base insulating film 12 made of, for example, a TEOS film is provided on the scanning line 11 a described above and below the TFT 30. In addition to the function of insulating the scanning line 11a and the TFT 30, the base insulating film 12 is formed on the entire surface of the TFT substrate 10 so that pixel switching due to roughness during polishing of the surface of the TFT substrate 10 or dirt remaining after cleaning is performed. The TFT 30 has a function of preventing characteristic changes.

  In the base insulating film 12, grooves (contact holes) 12cv having the same width as the channel length of the semiconductor layer 1a extending along the data line 6a described later are dug on both sides of the semiconductor layer 1a in plan view. Corresponding to the groove 12cv, the gate electrode 3a stacked above includes a portion formed in a concave shape on the lower side. Further, since the gate electrode 3a is formed so as to fill the entire groove 12cv, a side wall portion 3b formed integrally with the gate electrode 3a is extended. Yes. As a result, the semiconductor layer 1a of the TFT 30 is covered from the side as viewed in a plan view, and at least light from this portion is prevented from entering.

  Further, the side wall 3b is formed so as to fill the groove 12cv and so that the lower end thereof is in contact with the scanning line 11a. Accordingly, the scanning line 11a and the gate electrode 3a in the same row have the same potential. A structure in which another scanning line including the gate electrode 3a is formed so as to be parallel to the scanning line 11a may be employed. In this case, the scanning line 11a and the other scanning line have a redundant wiring structure. Thereby, for example, even when a part of the scanning line 11a has some defect and normal energization is impossible, another scanning line in the same row as the scanning line 11a is not present. As long as it is sound, the operation control of the TFT 30 can still be normally performed through the soundness.

  In the third layer, a storage capacitor 70 is provided. The storage capacitor 70 includes a lower electrode 71 as a pixel potential side capacitor electrode connected to the high concentration drain region 1e of the TFT 30 and the pixel electrode 9a, and a capacitor electrode 300 as a fixed potential side capacitor electrode. It is formed by arrange | positioning through. According to the storage capacitor 70, it is possible to remarkably improve the potential holding characteristic in the pixel electrode 9a. Further, since the storage capacitor 70 is formed so as not to reach the light transmission region substantially corresponding to the formation region of the pixel electrode 9a (in other words, formed so as to be within the light shielding region), The pixel aperture ratio of the entire electro-optical device is kept relatively large, and thus a brighter image can be displayed.

  More specifically, the lower electrode 71 is made of, for example, a conductive polysilicon film and functions as a pixel potential side capacitor electrode. However, the lower electrode 71 may be composed of a single layer film or a multilayer film containing a metal or an alloy. In addition to the function as a pixel potential side capacitor electrode, the lower electrode 71 has a function of relay-connecting the pixel electrode 9a and the high concentration drain region 1e of the TFT 30. This relay connection is made via a relay electrode 719 as will be described later.

  The capacitor electrode 300 functions as a fixed potential side capacitor electrode of the storage capacitor 70. In order to set the capacitor electrode 300 to a fixed potential, the capacitor electrode 300 is electrically connected to a shield layer 400 described later, which is set to a fixed potential.

  The capacitor electrode 300 is formed in an island shape on the TFT substrate 10 so as to correspond to each pixel, and the lower electrode 71 is formed to have substantially the same shape as the capacitor electrode 300. . As a result, the storage capacitor 70 does not have a wasteful spread in a plane, that is, without decreasing the pixel aperture ratio, and can achieve the maximum capacitance value under the circumstances. That is, the storage capacitor 70 has a smaller area and a larger capacitance value.

  As shown in FIG. 5, the dielectric film 75 is, for example, a relatively thin silicon oxide film such as an HTO (High Telperature oxide) film, an LTO (Low Telperature oxide) film, or a silicon nitride film having a thickness of about 5 to 200 nm. Consists of From the viewpoint of increasing the storage capacitor 70, the thinner the dielectric film 75 is, the better as long as the reliability of the film is sufficiently obtained. As shown in FIG. 5, the dielectric film 75 has a two-layer structure including a silicon oxide film 75a in the lower layer and a silicon nitride film 75b in the upper layer. The presence of the silicon nitride film 75b having a relatively large dielectric constant makes it possible to increase the capacitance value of the storage capacitor 70, and the presence of the silicon oxide film 75a reduces the pressure resistance of the storage capacitor 70. I will not let you down. Thus, by making the dielectric film 75 have a two-layer structure, it is possible to enjoy two conflicting effects.

  In addition, the presence of the silicon nitride film 75b makes it possible to prevent water from entering the TFT 30 in advance. As a result, a situation in which the threshold voltage of the TFT 30 rises is not caused, and a relatively long-term apparatus operation is possible. In the present embodiment, the dielectric film 75 has a two-layer structure. However, the dielectric film 75 has a three-layer structure such as a silicon oxide film, a silicon nitride film, and a silicon oxide film, or more. You may comprise so that it may have the laminated structure of these.

  A first interlayer insulating film 41 is formed on the TFT 30 to the gate electrode 3 a and the relay electrode 719 described above and below the storage capacitor 70. In the first interlayer insulating film 41, a contact hole 81 that electrically connects the high-concentration source region 1d of the TFT 30 and a data line 6a described later opens while penetrating the second interlayer insulating film 42 described later. It is holed. The first interlayer insulating film 41 is provided with a contact hole 83 that electrically connects the high-concentration drain region 1 e of the TFT 30 and the lower electrode 71 constituting the storage capacitor 70.

  Further, the first interlayer insulating film 41 is provided with a contact hole 881 for electrically connecting the lower electrode 71 serving as a pixel potential side capacitor electrode constituting the storage capacitor 70 and the relay electrode 719. . In addition, a contact hole 882 that electrically connects the relay electrode 719 and a second relay electrode 6a2 described later is formed in the first interlayer insulating film 41 while penetrating the second interlayer insulating film 42 described later. Has been.

  As shown in FIG. 5, the contact hole 882 is formed in a region other than the storage capacitor 70, and the lower electrode 71 is once detoured to the lower relay electrode 719 and drawn out to the upper layer through the contact hole 882. Therefore, even when the lower electrode 71 is connected to the upper pixel electrode 9 a, it is not necessary to form the lower electrode 71 wider than the dielectric film 75 and the capacitor electrode 300. Therefore, the lower electrode 71, the dielectric film 75, and the capacitor electrode 300 can be simultaneously patterned in one etching process. As a result, the etching rates of the lower electrode 71, the dielectric film 75, and the capacitor electrode 300 can be easily controlled, and the degree of freedom in design such as film thickness can be increased.

  In addition, since the dielectric film 75 is formed in the same shape as the lower electrode 71 and the capacitor electrode 300 and does not have a spread, in the case of performing a hydrogenation process on the semiconductor layer 1 a of the TFT 30, It is also possible to obtain an effect that it is possible to easily reach the semiconductor layer 1a through the opening around the storage capacitor 70.

  A data line 6a is provided in the fourth layer. The data line 6 a is formed in a stripe shape so as to coincide with the extending direction of the semiconductor layer 1 a of the TFT 30. As shown in FIG. 5, the data line 6a includes, in order from the lower layer, a layer made of aluminum (reference numeral 41A in FIG. 5), a layer made of titanium nitride (see reference numeral 41TN in FIG. 5), and a layer made of a silicon nitride film (see FIG. The film is formed as a film having a three-layer structure 401) in FIG. The silicon nitride film is patterned to a slightly larger size so as to cover the lower aluminum layer and titanium nitride layer. Of these, the data line 6a contains aluminum, which is a relatively low resistance material, so that the supply of image signals to the TFT 30 and the pixel electrode 9a can be realized without delay. On the other hand, the formation of a silicon nitride film that is relatively excellent in preventing moisture from entering on the data line 6a can improve the moisture resistance of the TFT 30, and can achieve a long life. The silicon nitride film is preferably a plasma silicon nitride film.

  In addition, a shield layer relay layer 6a1 and a second relay electrode 6a2 are formed on the fourth layer as the same film as the data line 6a. These are not formed so as to have a planar shape continuous with the data line 6a when viewed in plan, but are formed so as to be divided by patterning. The shield layer relay layer 6a1 and the second relay electrode 6a2 are in the same process as the data line 6a, and have a three-layer structure of an aluminum layer, a titanium nitride layer, and a plasma nitride film layer in order from the lower layer. It is formed as. The plasma nitride film is patterned to a slightly larger size so as to cover the lower aluminum layer and titanium nitride layer. The titanium nitride layer functions as a barrier metal for preventing etching through of the contact holes 803 and 804 formed for the shield layer relay layer 6a1 and the second relay electrode 6a2. Further, by forming a plasma nitride film that is relatively excellent in the action of blocking moisture ingress on the shield layer relay layer 6a1 and the second relay electrode 6a2, the moisture resistance of the TFT 30 can be improved. Longer service life can be realized. The plasma nitride film is preferably a plasma silicon nitride film.

  A second interlayer insulating film 42 is formed on the storage capacitor 70 and below the data line 6a. In the second interlayer insulating film 42, a contact hole 81 for electrically connecting the high concentration source region 1d of the TFT 30 and the data line 6a is opened, and the shield layer relay layer 6a1 and the storage capacitor 70 are formed. A contact hole 801 is formed to electrically connect the capacitor electrode 300, which is the upper electrode. Further, a contact hole 882 for electrically connecting the second relay electrode 6a2 and the relay electrode 719 is formed in the second interlayer insulating film.

  A shield layer 400 is formed on the fifth layer. The shield layer 400 is formed in a lattice shape in plan view. The shield layer 400 extends from the image display region 10a in which the pixel electrode 9a is disposed to the periphery thereof, and is electrically connected to a constant potential source to have a fixed potential. The constant potential source may be a positive potential source or a negative potential constant source supplied to the data line driving circuit 101 described later, or a constant potential source supplied to the counter electrode 21 of the counter substrate 20.

  Further, a third relay electrode 402 as a relay layer is formed on the fifth layer as the same film as the shield layer 400. The third relay electrode 402 has a function of relaying an electrical connection between the second relay electrode 6a2 and the pixel electrode 9a through a contact hole 89 described later. The shield layer 400 and the third relay electrode 402 are not continuously formed in a planar shape, but are formed so as to be separated by patterning.

  On the other hand, the shield layer 400 and the third relay electrode 402 described above have a two-layer structure in which a lower layer is made of aluminum and an upper layer is made of titanium nitride. In the third relay electrode 402, the lower layer made of aluminum is connected to the second relay electrode 6a2, and the upper layer made of titanium nitride is connected to the pixel electrode 9a made of ITO or the like. Yes. When aluminum and ITO are directly connected, electric corrosion occurs between the two, and preferable electrical connection cannot be realized due to disconnection of aluminum or insulation due to formation of alumina. On the other hand, since titanium nitride and ITO are connected, contact resistance is low and good connectivity is obtained.

  Furthermore, since the shield layer 400 and the third relay electrode 402 include aluminum that is relatively excellent in light reflection performance and include titanium nitride that is relatively excellent in light absorption performance, the shield layer 400 and the third relay electrode 402 can function as a light shielding layer. That is, according to these, it is possible to block the progress of incident light (see FIG. 5) on the semiconductor layer 1a of the TFT 30 on the upper side. Such a light shielding function can be similarly applied to the capacitor electrode 300 and the data line 6a described above. The shield layer 400, the third relay electrode 402, the capacitor electrode 300, and the data line 6 a form an upper light-shielding film that blocks light incident on the TFT 30 from the upper side while forming a part of the laminated structure constructed on the TFT substrate 10 Function.

  A third interlayer insulating film 43 is formed on the data line 6 a and below the shield layer 400. In the third interlayer insulating film 43, a contact hole 803 for electrically connecting the shield layer 400 and the shield layer relay layer 6a1, and a third relay electrode 402 and the second relay electrode 6a2 are electrically connected. Contact holes 804 for connecting to each are opened.

  In the sixth layer, the pixel electrodes 9a are formed in a matrix as described above, and the alignment film 16 is formed on the pixel electrodes 9a. A fourth interlayer insulating film 44 is formed under the pixel electrode 9a. In the fourth interlayer insulating film 44, a contact hole 89 for electrically connecting the pixel electrode 9a and the third relay electrode 402 is opened.

  The surfaces of the third and fourth interlayer insulating films 43 and 44 are planarized by a CMP (Chemical Mechanical Polishing) process or the like. Alignment defects of the liquid crystal layer 50 due to steps due to various wirings, elements, etc. existing below the planarized interlayer insulating films 43 and 44 are reduced. However, instead of or in addition to performing the planarization process on the third and fourth interlayer insulating films 43 and 44 in this way, the TFT substrate 10, the base insulating film 12, the first interlayer insulating film 41, and the second interlayer A planarization process may be performed by digging a groove in at least one of the insulating film 42 and the third interlayer insulating film 43 and embedding a wiring such as the data line 6a or the TFT 30 or the like.

  In addition, the storage capacitor 70 has a three-layer structure of a pixel potential side capacitor electrode, a dielectric film, and a fixed potential side capacitor electrode in order from the bottom, but may have a structure opposite to this. .

  As shown in FIGS. 2 and 3, the counter substrate 20 is provided with a light shielding film 53 as a frame for partitioning the display area. As described above, a transparent conductive film such as ITO is formed on the entire surface of the counter substrate 20 as the counter electrode 21, and a polyimide-based alignment film 22 is formed on the entire surface of the counter electrode 21. The alignment film 22 is rubbed in a predetermined direction so as to give a predetermined pretilt angle to the liquid crystal molecules.

  In a region outside the light shielding film 53, a sealing material 52 that encloses liquid crystal is formed between the TFT substrate 10 and the counter substrate 20. The sealing material 52 is disposed so as to substantially match the contour shape of the counter substrate 20, and fixes the TFT substrate 10 and the counter substrate 20 to each other. The sealing material 52 is missing in a part of one side of the TFT substrate 10, and a liquid crystal injection port 108 for injecting the liquid crystal 50 is formed. Liquid crystal is injected from the liquid crystal injection port 108 into the gap between the element substrate 10 and the counter substrate 20 bonded together. After the liquid crystal injection, the liquid crystal injection port 108 is sealed with a sealing material 109.

  In an area outside the sealing material 52, an image signal is supplied to the data line 6a at a predetermined timing to drive the data line 6a and an external connection terminal 102 for connection to an external circuit. Are provided along one side of the TFT substrate 10. A scanning line driving circuit 104 that drives the gate electrode 3a by supplying a scanning signal to the scanning line 11a and the gate electrode 3a at a predetermined timing is provided along two sides adjacent to the one side. The scanning line driving circuit 104 is formed on the TFT substrate 10 at a position facing the light shielding film 53 inside the sealing material 52. Further, on the TFT substrate 10, wiring 105 for connecting the data line driving circuit 101, the scanning line driving circuit 104, and the external connection terminal 102 is provided to face the three sides of the light shielding film 53.

  Conductive portions 106 are formed outside the four corner portions of the sealing material 52. The conducting portion 106 includes an adhesive material and a conducting material amount, and can establish electrical continuity between the TFT substrate 10 and the counter substrate 20. Note that the conductive portion 106 may be provided at any position outside the display area as long as it is an area other than the area where the sealing material 52 is formed.

  In the present embodiment, the conductive portion 106 also functions as a temporary fixing portion. The conductive portion 106 is formed of an ultraviolet (UV) radical curable adhesive material. A UV radical curing material is a material that cures with a relatively low amount of light. In the present embodiment, the sealing material 52 is also formed of a UV radical curable adhesive material.

The conductive portion 106 is hardened with a low light amount of, for example, about 50 mJ / cm ² . Further, the sealing material 52 is hardened by a single UV irradiation with a relatively low light amount of, for example, about 3000 mJ / cm ² .

  Next, the assembly process will be described with reference to FIGS. 1 and 6 to 8.

  The liquid crystal device described above is assembled by, for example, a panel assembly process shown in FIG. The element substrate 10 (TFT substrate) and the counter substrate 20 are manufactured separately. In the next steps S2 and S6, polyimide (PI) to be the alignment films 16 and 22 is applied to the TFT substrate and the counter substrate 20 prepared in steps S1 and S5, respectively. Next, in steps S3 and S7, a rubbing process is performed on the alignment film 16 on the surface of the element substrate 10 and the alignment film 22 on the surface of the counter substrate 20.

  Next, a cleaning process is performed in steps S4 and S8. This cleaning process is for removing dust generated by the rubbing process. When the cleaning process is completed, the element substrate 10 and the counter substrate 20 are bonded together in step S10. In this case, the conductive portion 106 and the sealing material 52 (see FIG. 2) are formed, and are subjected to pressure bonding while performing alignment in step S11, and the conductive portion 106 and the sealing material 52 are cured. In step S <b> 12, liquid crystal is sealed from the liquid crystal inlet 108 provided in a part of the sealing material 52, and the liquid crystal inlet 108 is closed to seal the liquid crystal.

  In this embodiment, an example of a sealing method in which liquid crystal is sealed from a liquid crystal injection port will be described as an example. However, a region where liquid crystal is interposed is surrounded by a sealing material, and a dropping method in which liquid crystal is dropped therein is similarly applied. Applicable.

  FIG. 1 specifically shows the bonding step and the alignment / compression curing step of FIG. FIG. 7 is a perspective view showing a state in the middle of the bonding process.

  This embodiment shows an example applied to a case where a liquid crystal device is manufactured by an array manufacturing method having excellent productivity. In the array manufacturing method, a plurality of element (TFT) substrates (active matrix substrates) are cut out from one mother glass substrate (element mother substrate). In other words, the film formation and photolithography steps are repeated without dividing the element mother substrate that was input at the time of manufacture. Thus, each element for a plurality of active matrix substrates is simultaneously formed on the element mother substrate to obtain an element substrate array. Then, each active matrix substrate is obtained by dividing the element mother substrate.

  From the viewpoint of productivity and yield, each active matrix substrate arranged in the state of an element mother substrate is bonded to each active matrix substrate, and each active matrix substrate is sealed after liquid crystal is sealed. The chip mount method is used to obtain a single liquid crystal device.

  In addition, although the example which employ | adopts the chip | tip mount system of an array manufacture is demonstrated as a bonding system, this Embodiment is not limited to this system. For example, a large plate assembly method in which an element mother substrate on which a large number of element substrates are formed and an opposing mother substrate on which a large number of counter substrates are formed may be used. Alternatively, a single element substrate and a counter substrate may be bonded to each other. You may employ | adopt the method to match.

  Although an example in which the sealing material is formed on the counter substrate side will be described, the sealing material may be formed on the element substrate side, or the sealing material may be formed on both the element substrate and the counter substrate.

  In steps S20 and S21 in FIG. 1, the TFT substrate and the counter substrate after the rubbing process are loaded, respectively. The TFT substrate is input in the state of an element mother substrate, and the counter substrate is input in the state of a single substrate. In steps S22 and S23, the sealing material 52 and the conductive portion 106 are formed on the surface of the counter substrate by, for example, a dispensing method. The sealing material 52 is formed at the edge of the pixel region, and the conductive portions 106 are formed at the four corners of the counter substrate 20. Both the conducting part 106 and the sealing material 52 are made of UV radical curing material.

  In the next step S24, the TFT substrate and the counter substrate are bonded together. In FIG. 7, each section of the element mother substrate 110 indicates each TFT substrate 111. Each TFT substrate 111 corresponds to the TFT substrate 10 of FIGS. A plate-like member on the element mother substrate 110 in FIG. 7 indicates each counter substrate 112. Each counter substrate 112 corresponds to the counter substrate 20 of FIGS.

  In the example of FIG. 7, a state is shown in which a plurality of counter substrates 112 are bonded onto the element mother substrate 110, but actually, the counter substrates 112 are bonded one by one. In a state where the counter substrate 112 is bonded to the element mother substrate 110, first, the conductive portion 106 is temporarily cured using an ultraviolet irradiation device (not shown) (step S11). The ultraviolet irradiation apparatus can perform exposure only on a portion other than the mask by using a mask.

  FIG. 8 is an explanatory view showing a mask region of the ultraviolet irradiation device. The hatched portion in FIG. 8 shows a mask region for each active matrix substrate, and this region is not irradiated with ultraviolet rays. FIG. 8A shows a mask area at the time of exposure of the conductive portion 106 in step S25. As shown in FIG. 8A, when the conductive portion 106 is cured, a mask is formed on the region (display region) surrounded by the sealing material 52 and the sealing material 52, and this portion is irradiated with ultraviolet rays. Not done.

In the exposure in step S25, for example, exposure with a small light amount such as 50 mJ / cm ² is performed. At the time of exposure, alignment is performed, and the conductive portion 106 is temporarily fixed at a predetermined position. Note that the conductive portion 106 is cured with a relatively small amount of light, but the conductive portion 106 only needs to be cured to an extent necessary for alignment, and does not necessarily need to be completely cured.

Thereafter, similarly, the conductive substrate 106 is cured while aligning each counter substrate 112 on the element mother substrate 110, whereby the counter substrate 112 is temporarily fixed on the element mother substrate 110. When all the counter substrates 112 are temporarily fixed, the process proceeds from step S26 to step S27, and the sealing material 52 is fully cured. That is, as shown in FIG. 7, ultraviolet rays are irradiated using the mask shown in FIG. 8B in a state where all the counter substrates 112 are temporarily fixed on the element mother substrate 110. As shown in FIG. 8B, in the main curing, only the display area is masked and the sealing material 52 is exposed. In the exposure in step S27, exposure is performed with a small light amount in the range of 500 to 5000 mJ / cm ² , preferably, for example, 3000 mJ / cm ² or less. The sealing material 52 is a UV radical curing material and can be cured with a relatively small amount of light. In addition, since the sealing material 52 is not exposed when the conductive portion 106 is temporarily cured, the sealing material 52 is cured only in one exposure process of step S27.

  When the sealing material 52 is cured, the conductive portion 106 is further cured by being irradiated with ultraviolet rays. If the conductive portion 106 is sufficiently cured during the temporary curing of the conductive portion 106, it is not necessary to cure the conductive portion 106 when the sealing material 52 is cured.

  As described above, in the present embodiment, a thermosetting sealing material is not employed when the counter substrate 20 and the TFT substrate 10 are bonded to each other. Thereby, the liquid crystal is not contaminated by the contaminant contained in the thermosetting sealing material, and the upper and lower substrates are not distorted by heat and the alignment is not distorted.

  In addition, the conductive portion 106, which is a temporary fixing portion, is cured in a short time with a low light amount, and the alignment accuracy is excellent. Further, when the conductive portion 106 is cured, the sealing material is masked, and the sealing material is cured by a single UV irradiation. Thereby, sufficient fixing strength can be obtained.

  The electro-optical device of the present invention is not limited to a passive matrix type liquid crystal display panel but an active matrix type liquid crystal panel (for example, a liquid crystal display panel including a TFT (thin film transistor) or a TFD (thin film diode) as a switching element). It is possible to apply to the same. In addition to liquid crystal display panels, electroluminescence devices, organic electroluminescence devices, plasma display devices, electrophoretic display devices, devices using electron emission (such as Field Emission Display and Surface-Conduction Electron-Emitter Display), DPL ( The present invention can be similarly applied to various electro-optical devices such as Digital Light Processing (aka DMD: Digital Micromirror Device).

  The present invention is also applicable to display devices that form elements on a semiconductor substrate, such as LCOS (Liquid Crystal On Silicon).

  In LCOS, a single crystal silicon substrate is used as an element substrate, and a transistor is formed on a single crystal silicon substrate as a switching element used for a pixel or a peripheral circuit. In addition, a reflective pixel electrode is used for the pixel, and each element of the pixel is formed under the pixel electrode.

4 is a flowchart showing a method for manufacturing the liquid crystal device according to the first embodiment of the invention. The top view which looked at the liquid crystal device manufactured in this Embodiment from the counter substrate side with each component formed on it. FIG. 3 is a cross-sectional view of the liquid crystal device after the assembly process in which the element substrate and the counter substrate are bonded to each other and the liquid crystal is sealed is cut along a line HH ′ in FIG. FIG. 6 is an equivalent circuit diagram of various elements, wirings, and the like in a plurality of pixels constituting a pixel region of the liquid crystal device. FIG. 4 is a cross-sectional view illustrating a pixel structure of a liquid crystal device in detail. The flowchart which shows a panel assembly process. The perspective view which shows the state in the middle of the bonding process. Explanatory drawing which shows the mask area | region of an ultraviolet irradiation device.

Explanation of symbols

    S22 ... Sealing material forming step, S23 ... Conducting portion forming step, S24 ... Bonding step, S25 ... Alignment / conducting portion temporary curing step, S27 ... Sealing material main curing step.

Claims (5)

Forming a temporary fixing portion and a seal portion on the first substrate using an ultraviolet radical curable adhesive material;
The first substrate and the second substrate are pressure-bonded, and the temporary fixing portion is not completely cured by irradiating the temporary fixing portion with ultraviolet rays through a mask disposed so as to overlap the seal portion. Pre-curing and bonding the first and second substrates together;
After the first and second substrates are bonded to each other, the amount of light is higher than the ultraviolet light that temporarily cures the temporary fixing portion to the temporary fixing portion and the seal portion via a mask disposed inside the sealing portion. And a step of curing the temporary fixing portion and the seal portion, respectively, by irradiating with a large ultraviolet ray.   The method for manufacturing a liquid crystal device according to claim 1, wherein the temporary fixing portion also serves as a conducting portion for conducting the first and second substrates. The step of curing the temporary fixing part and the seal part, respectively, is performed by irradiating the temporary fixing part and the seal part with an irradiation light amount of 500 to 5000 mJ / cm ^2. Liquid crystal device manufacturing method. Forming a temporary fixing portion and a seal portion on the opposite substrate using an ultraviolet radical curable adhesive material;
A counter substrate on which the temporary fixing portion and the seal portion are formed is pressure-bonded to the element substrate on an element mother substrate including a plurality of element substrates, and the temporary substrate is interposed through a mask disposed so as to overlap the seal portion. Irradiating the stopper part with ultraviolet rays to temporarily cure the temporary stopper part so as not to be completely cured , and bonding the counter substrate and the element mother substrate together;
After the plurality of counter substrates are bonded to the element mother substrate, the temporary fixing to the plurality of temporary fixing portions and the seal portion through a mask disposed inside each seal portion of the plurality of counter substrates. And a step of curing each of the plurality of temporary fixing portions and the sealing portion by irradiating ultraviolet rays having a light amount larger than that of the ultraviolet rays for temporarily curing the portions.   The method for manufacturing a liquid crystal device according to claim 4, wherein the temporary fixing portion also serves as a conducting portion for conducting between the element substrate and the counter substrate.

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