JP4954447B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a liquid crystal display device and a manufacturing method thereof. For example, the present invention relates to an electro-optical device typified by a liquid crystal display panel having a circuit formed of a thin film transistor (hereinafter referred to as TFT) and an electronic apparatus in which such an electro-optical device is mounted as a component.

In recent years, a technique for forming a thin film transistor (TFT) using a semiconductor thin film (having a thickness of about several to several hundred nm) formed on a substrate having an insulating surface has attracted attention. Thin film transistors are widely applied to electronic devices such as ICs and electro-optical devices, and development of switching devices for image display devices is urgently required.

  Conventionally, a liquid crystal display device is known as an image display device. Active matrix liquid crystal display devices are often used because high-definition images can be obtained compared to passive liquid crystal display devices. In an active matrix liquid crystal display device, a display pattern is formed on a screen by driving pixel electrodes arranged in a matrix. Specifically, by applying a voltage between the selected pixel electrode and the counter electrode corresponding to the pixel electrode, optical modulation of the liquid crystal layer disposed between the pixel electrode and the counter electrode is performed. The optical modulation is recognized by the observer as a display pattern.

  Applications of such an active matrix electro-optical device are expanding, and the demand for higher definition, higher aperture ratio, and higher reliability is increasing as the screen size increases. At the same time, demands for improved productivity and lower costs are increasing.

The present applicant has also proposed Patent Document 1 in which liquid crystal is dropped.
USP 4,691,995

  It is an object of the present invention to provide a flexible liquid crystal display device that has high liquid crystal material utilization efficiency and high reliability. As the panel size increases, the cost of the materials used increases. In particular, the liquid crystal material disposed between the pixel electrode and the counter electrode is expensive.

  The present invention is applicable to a large area substrate having a substrate size of 320 mm × 400 mm, 370 mm × 470 mm, 550 mm × 650 mm, 600 mm × 720 mm, 680 mm × 880 mm, 1000 mm × 1200 mm, 1100 mm × 1250 mm, 1150 mm × 1300 mm, for example. The present invention provides a method for efficiently manufacturing a liquid crystal display device. Furthermore, a method for manufacturing a liquid crystal display device suitable for mass production using a large-area substrate having a substrate size of 1500 mm × 1800 mm, 1800 mm × 2000 mm, 2000 mm × 2100 mm, 2200 mm × 2600 mm, 2600 mm × 3100 mm is provided.

Further, in order to seal the liquid crystal, complicated processes such as seal drawing, bonding of the counter substrate, division, liquid crystal injection, and liquid crystal injection port sealing are required. In particular, when the panel size becomes large, it becomes difficult to perform liquid crystal injection using a capillary phenomenon and fill the liquid crystal into the region (including at least the pixel portion) surrounded by the seal.

In addition, the two substrates are bonded and divided, and the liquid crystal material is injected from the liquid crystal injection port formed in the divided cross section, and the passage of the liquid crystal material extending from the liquid crystal injection port to the pixel region The part will be filled with liquid crystal. In the case where the driver circuit portion is provided over the same substrate as the pixel portion, the liquid crystal may be filled not only in the pixel portion region but also in a portion overlapping with the driver circuit portion. As described above, the liquid crystal material is also filled in an extra portion other than the region to be the display portion.

  In addition, the passage of the liquid crystal material extending from the liquid crystal injection port to the pixel region, particularly the vicinity of the liquid crystal injection port, is a portion through which a larger amount of liquid crystal passes than other parts of the panel, and friction occurs during the injection. As a result, the surface of the alignment film changes, and as a result, the alignment of the liquid crystal may be disturbed.

  In addition, various applications using a liquid crystal display device are expected, but the application to mobile devices has attracted attention. Currently, many glass substrates and quartz substrates are used, but they have the disadvantage of being easily broken and heavy. Further, in mass production, it is difficult to increase the size of a glass substrate or a quartz substrate, which is not suitable. Therefore, attempts have been made to form a liquid crystal display device using a flexible substrate, typically a flexible plastic film.

  However, the plastic film has a weaker blocking effect against impurities such as moisture and alkali metal than the glass substrate, and the reliability as a liquid crystal display device is lowered. Therefore, a high-performance liquid crystal display device using a plastic film has not been realized.

In the present invention, a protective film is provided over the counter substrate (first flexible substrate), a sealing material is drawn, and a liquid crystal material is dropped on the counter substrate in a vacuum (under reduced pressure). Provided is a liquid crystal display device manufactured by bonding to a second flexible substrate provided with a columnar spacer. It is preferable that the pair of flexible substrates be bonded together under reduced pressure while keeping the spacing between the columnar spacers uniform.

  In addition, a dispenser device or an ink jet device may be used for drawing the sealing material. The drawing of the sealing material may be performed under reduced pressure or in an inert atmosphere under atmospheric pressure. Since a solvent may be added to the sealing material to adjust the viscosity, when drawing a seal under reduced pressure, use a sealing material that contains a solvent that is difficult to volatilize so that the sealing material does not deteriorate or harden. Is preferred.

  Note that the sealing material is drawn in a closed pattern so as to surround the pixel portion, and the space of the closed pattern is filled with a liquid crystal material.

Further, both the seal drawing and the liquid crystal dropping may be performed on the substrate provided with the pixel portion. Alternatively, a protective film may be provided over a flexible substrate, and a liquid crystal material may be dropped (under reduced pressure) only on the pixel electrode, that is, on the pixel portion in a vacuum, and then bonded to the counter substrate provided with a seal. Good.

Further, the protective film in the present invention is preferably a single layer film of a silicon nitride film formed by a high frequency sputtering method using silicon as a target or a laminated film with a silicon oxide film.

In addition, a dense silicon nitride film obtained by RF sputtering using a silicon target is made of an alkali metal or alkaline earth metal such as sodium, lithium, magnesium, etc. TFT (polysilicon TFT, amorphous silicon TFT, organic TFT, etc.). Contamination effectively prevents threshold voltage fluctuations and the like, and has a very high blocking effect on moisture and oxygen. In order to enhance the blocking effect, the oxygen and hydrogen contents in the silicon nitride film are 10 atomic% or less, preferably 1 atomic% or less.

Specific sputtering conditions include nitrogen gas or a mixed gas of nitrogen and rare gas, pressure of 0.1 to 1.5 Pa, frequency of 13 MHz to 40 MHz, power of 5 to 20 W / cm ² , and substrate temperature of room temperature to room temperature. The distance between the silicon target (1 to 10 Ωcm) and the substrate is 350 mm to 200 mm, and the back pressure is 1 × 10 ⁻³ Pa or less. Further, a heated rare gas may be sprayed on the back surface of the substrate. For example, the flow rate ratio is Ar: N ₂ = 20 sccm: 20 sccm, the pressure is 0.8 Pa, the frequency is 13.56 MHz, the power is 16.5 W / cm ² , the substrate temperature is 200 ° C., and the distance between the silicon target and the substrate is A dense silicon nitride film obtained at 60 mm and a back pressure of 3 × 10 ⁻⁵ Pa has an etching rate of 9 nm or less (referred to as an etching rate when etched at 20 ° C. using LAL500; the same applies hereinafter). Preferably, the hydrogen concentration is as low as 0.5 to 3.5 nm or less, and the hydrogen concentration is as low as 1 × 10 ²¹ atoms / cm ⁻³ or less (preferably 5 × 10 ²⁰ atoms / cm ⁻³ or less). ing. “LAL500” is “LAL500 SA buffered hydrofluoric acid” manufactured by Hashimoto Kasei Co., Ltd., which is an aqueous solution of NH ₄ HF ₂ (7.13%) and NH ₄ F (15.4%).

Further, the relative dielectric constant of the silicon nitride film formed by the sputtering method is 7.02 to 9.3, the refractive index is 1.91 to 2.13, the internal stress is 4.17 × 10 ⁸ dyn / cm ² , and the etching rate is 0.77 to 1.31 nm / min. Further, the sign of the numerical value of the internal stress changes depending on the compressive stress or the tensile stress, but only the absolute value is handled here. Further, the Si concentration obtained by RBS of the silicon nitride film by the sputtering method is 37.3 atomic%, and the N concentration is 55.9 atomic%. Further, the sputtering hydrogen concentration by SIMS of the silicon nitride film by the ^{4 × 10 20 atoms / cm -3} , the oxygen concentration of ^{8 × 10 20 atoms / cm -3} , carbon ^{concentration, 1 × 10 19 atoms / cm} - ³ . Further, the silicon nitride film formed by the sputtering method has a transmittance of 80% or more in the visible light region. The SIMS measurement result of the silicon nitride film (thickness 130 nm) is shown in FIG.

Further, FIG. 6 shows the result of performing SIMS measurement by stacking a silicon nitride film (film thickness 30 nm) and a silicon oxide film (film thickness 20 nm). This silicon nitride film has an argon concentration of 1 × 10 ²⁰ to 1 × 10 ²¹ cm ⁻³ . Table 1 shows an example of typical film forming conditions for the silicon oxide film and the silicon nitride film.

  As described above, the present invention functions as a protective film that can effectively prevent intrusion of impurities such as moisture by including a large amount of inert gas such as argon or nitrogen in the film.

The configuration of the invention disclosed in this specification is as follows.
A first flexible substrate, a second flexible substrate, and a liquid crystal held between a pair of substrates composed of the first flexible substrate and the second flexible substrate. A liquid crystal display device comprising
An inorganic insulating film on the first substrate or the second substrate;
A columnar spacer for keeping the distance between the pair of substrates constant;
In the liquid crystal display device, the pair of substrates are bonded to each other with a sealing material having a closed pattern shape.

In the above structure, the silicon nitride film has an argon concentration of 1 × 10 ²⁰ to 1 × 10 ²¹ cm ⁻³ . In the above structure, the inorganic insulating film is a silicon nitride film having a hydrogen concentration of 1 × 10 ²¹ cm ⁻³ or less. In the above structure, the inorganic insulating film is a silicon nitride film having a hydrogen concentration of 1 × 10 ²¹ cm ⁻³ or less and an oxygen concentration of 5 × 10 ^{18 to} 5 × 10 ²¹ cm ^−3. Yes.

Further, in order to relieve stress, the protective film may be a multilayer film of a silicon nitride film and a silicon oxide film.
A first flexible substrate, a second flexible substrate, and a liquid crystal held between a pair of substrates composed of the first flexible substrate and the second flexible substrate. A liquid crystal display device comprising
An inorganic insulating film comprising a multilayer film of a silicon nitride film and a silicon oxide film on the first substrate or the second substrate;
A columnar spacer for keeping the distance between the pair of substrates constant;
In the liquid crystal display device, the pair of substrates are bonded to each other with a sealing material having a closed pattern shape.

In the above structure, the silicon nitride film has an argon concentration of 1 × 10 ²⁰ to 1 × 10 ²¹ cm ⁻³ .

In addition, as the flexible substrate in the present invention, that is, the film-like plastic substrate, for example, polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polycarbonate (PC), nylon, poly Ether ether ketone (PEEK), polysulfone (PSF), polyetherimide (PEI), polyarylate (PAR), polybutylene terephthalate (PBT), polypropylene, polypropylene sulfide, polyphenylene sulfide, polyphenylene oxide, polyphthalamide, polyimide, etc. A plastic substrate made of an organic resin is preferred. Alternatively, a plastic substrate (ARTON made of norbornene resin with a polar group: manufactured by JSR) may be used.

  The liquid crystal may be dropped by using a dispenser device or an ink jet device. It is important to stabilize the amount of dripping accurately in the closed seal pattern. Note that the ink jet method is a method in which a small amount of liquid crystal is ejected (or dropped) toward a pixel electrode. By using the inkjet method, the amount of a small amount of liquid crystal can be freely adjusted by the number of discharges or the number of discharge points.

  Moreover, it is preferable to perform dripping (or jetting) of liquid crystal under reduced pressure so that impurities are not mixed. The liquid crystal does not change or harden even when dropped under reduced pressure. When liquid crystal is dropped (or jetted) under reduced pressure, a liquid crystal that has been depressurized and defoamed in advance may be used. Further, while dropping (or jetting) the liquid crystal, the substrate is heated to degas the liquid crystal and the viscosity of the liquid crystal is lowered. Further, if necessary, the film thickness may be made uniform by spinning after dropping the liquid crystal. Moreover, it is preferable to perform the bonding operation under reduced pressure so that bubbles do not enter when bonding.

In addition, the configuration of the invention related to the manufacturing method for obtaining the above configuration is as follows.
A liquid crystal display device comprising: a first substrate; a second substrate; and a liquid crystal held between a pair of substrates including the first substrate and the second substrate.
Forming an inorganic insulating film on the first substrate or the second substrate by a high-frequency sputtering method;
Forming a pixel electrode on the first substrate;
Forming a counter electrode on the second substrate;
Forming a columnar spacer on the first substrate for keeping the distance between the pair of substrates constant;
Drawing and temporarily fixing a sealing material on the second substrate;
Dropping a liquid crystal material under reduced pressure on a region surrounded by the sealing material on the second substrate;
Heating and degassing the liquid crystal material under reduced pressure;
Bonding the first substrate and the second substrate under reduced pressure;
And a step of fixing the sealing material. A method for manufacturing a liquid crystal display device.

In addition, in the case of bonding to an element substrate provided with a seal, the configuration of another invention is as follows:
A liquid crystal display device comprising: a first substrate; a second substrate; and a liquid crystal held between a pair of substrates including the first substrate and the second substrate.
Forming an inorganic insulating film on the first substrate or the second substrate by a high-frequency sputtering method;
Forming a pixel electrode on the first substrate;
Forming a counter electrode on the second substrate;
Forming a columnar spacer on the first substrate for keeping the distance between the pair of substrates constant;
Drawing and temporarily fixing a sealing material on the first substrate;
Dropping a liquid crystal material under reduced pressure on a region surrounded by the sealing material on the first substrate;
Heating and degassing the liquid crystal material under reduced pressure;
Bonding the first substrate and the second substrate under reduced pressure;
And a step of fixing the sealing material. A method for manufacturing a liquid crystal display device.

In each structure related to the manufacturing method, the first substrate or the second substrate is a flexible plastic substrate. In each of the above structures, the inorganic insulating film is a silicon nitride film manufactured by a high frequency sputtering method using silicon as a target. The inorganic insulating film is produced by sputtering a single crystal silicon target with N ₂ gas or a mixed gas of N ₂ and rare gas using a turbo molecular pump or a cryopump with a back pressure of 1 × 10 ⁻³ Pa or less. It is characterized by being a silicon nitride film.

  According to the present invention, since a necessary amount of liquid crystal is dropped only at a necessary portion, there is no material loss. Further, since the seal pattern is a closed loop, the liquid crystal injection port and the passage seal pattern are not required. Accordingly, defects (for example, alignment defects) that occur during liquid crystal injection are eliminated.

  Further, the liquid crystal is not particularly limited as long as it can be dropped, and a liquid crystal material may be mixed with a photocuring material, a thermosetting material, or the like to increase the adhesive strength between the pair of substrates after dropping.

  As the alignment mode of the liquid crystal, a TN mode in which the alignment of liquid crystal molecules is twisted by 90 ° from the incident light to the emitted light is often used. In the case of manufacturing a TN mode liquid crystal display device, alignment films are formed on both substrates, and after rubbing treatment, the substrates are bonded so that the rubbing directions are orthogonal to each other.

Further, as the sealing material, it is preferable to select a material that does not dissolve in the liquid crystal even when it comes into contact with the liquid crystal. In addition, a second seal may be provided so as to surround the pixel portion and further surround the first seal that is in contact with the liquid crystal so as to be doubled. In addition, when bonding is performed under reduced pressure, it is preferable to fill a filler that is not a liquid crystal, for example, a resin, between the first seal and the second seal.

Alternatively, the liquid crystal may be dropped (or jetted) on both substrates so that bubbles do not enter when the substrates are bonded, and then bonded together.

  Moreover, what is necessary is just to maintain a pair of board | substrate space | interval by forming the columnar spacer which consists of resin, or making a sealing material contain a filler. The columnar spacer is made of an organic resin material mainly containing at least one of acrylic, polyimide, polyimide amide, and epoxy, or any one of silicon oxide, silicon nitride, and silicon oxynitride, or a laminated film thereof. It is characterized by being an inorganic material.

  Moreover, in this invention, after bonding substrates together, it will parting.

Further, in the present invention, in the case of one-side chamfering, the dividing step can be omitted by pasting a counter substrate that has been cut in advance. Conventionally, in order to provide the liquid crystal injection port on the end surface, the liquid crystal injection port is formed on the end surface by dividing after bonding.

  In each of the above structures, the step of bonding the pair of substrates is performed under an atmospheric pressure that is an inert atmosphere or under a reduced pressure. In order to shorten the process, it is preferable to spray a plurality of liquid crystals under reduced pressure and to bond the pair of substrates together without touching the atmosphere under reduced pressure.

In each of the above-mentioned configurations, the reduced pressure is characterized by being in an inert atmosphere of 1 × 10 ² to 2 × 10 ⁴ Pa or in a vacuum of 1 to 5 × 10 ⁴ Pa.

Under reduced pressure (also referred to as vacuum) refers to a pressure lower than atmospheric pressure, and 1 × in an atmosphere filled with nitrogen, a rare gas, or other inert gas (hereinafter referred to as an inert atmosphere). It may be 10 ^{2 to} 2 × 10 ⁴ Pa (preferably 5 × 10 ^{2 to} 5 × 10 ³ Pa).

  In each of the above configurations, the liquid crystal material can be intermittently attached by appropriately setting the conditions for dropping the liquid crystal and the liquid crystal material. Further, the liquid crystal material can be continuously adhered.

In each of the above structures, when the liquid crystal is dropped, the substrate may be heated to room temperature (typically 20 ° C.) to 200 ° C. (however, the plastic substrate itself does not deteriorate). The liquid crystal material is degassed by heating.

  In addition, there are two types of liquid crystal display devices, a passive type (simple matrix type) and an active type (active matrix type), and the present invention can be applied to both types.

  In the case of an active liquid crystal display device, a TFT used as a switching element is not particularly limited, and a polysilicon TFT having a crystalline semiconductor film as an active layer or a semiconductor film having an amorphous structure is activated. An amorphous TFT having a layer and an organic TFT having an organic semiconductor film as an active layer can be used. Further, the active layer of the TFT is a semiconductor having an intermediate structure between an amorphous structure and a crystal structure (including single crystal and polycrystal) and having a third state that is stable in terms of free energy, and has a short distance. A semi-amorphous semiconductor film (also referred to as a microcrystalline semiconductor film or a microcrystal semiconductor film) including a crystalline region having order and lattice strain can be used.

  The present invention can be applied regardless of the TFT structure. For example, a top gate TFT, a bottom gate (reverse staggered) TFT, or a forward staggered TFT can be used. The present invention is particularly useful for the active type, and by using a single layer film of a silicon nitride film formed by a high frequency sputtering method using silicon as a target or a laminated film with a silicon oxide film as a protective film. Deterioration can be suppressed and reliability can be improved.

According to the present invention, it is possible to realize a flexible liquid crystal display device with high utilization efficiency of a liquid crystal material and high reliability.

  Embodiments of the present invention will be described below.

(Embodiment 1)
Here, an example of performing seal drawing and liquid crystal dropping on the counter substrate side will be described. The flow of panel production will be described below.

  First, a second substrate 120 serving as a counter substrate and a first substrate 110 provided with a TFT (not shown) in advance are prepared. The first substrate 110 and the second substrate 120 are flexible substrates and are not particularly limited as long as they are light-transmitting substrates. Typically, plastic substrates are used. As TFTs, TFTs using polysilicon as an active layer (also called polysilicon TFTs), TFTs using amorphous silicon as active layers (also called amorphous silicon TFTs), TFTs using organic semiconductor materials as active layers (also called organic TFTs) ) May be used.

  The plastic substrate has the advantages of being lightweight and thin, but has a weak effect of blocking moisture and the like, and therefore, in the present invention, a protective film is formed on one side or both sides of the plastic substrate. Here, a silicon nitride film is formed on only one side by sputtering. A dense silicon nitride film obtained by RF sputtering using a silicon target effectively prevents fluctuations in threshold voltage due to contamination of TFT by alkali metal or alkaline earth metal such as sodium, lithium and magnesium. In addition, it has a very high blocking effect against moisture and oxygen. In order to enhance the blocking effect, the oxygen and hydrogen contents in the silicon nitride film are 10 atomic% or less, preferably 1 atomic% or less.

Specific sputtering conditions include nitrogen gas or a mixed gas of nitrogen and rare gas, pressure of 0.1 to 1.5 Pa, frequency of 13 MHz to 40 MHz, power of 5 to 20 W / cm ² , and substrate temperature of room temperature to room temperature. The distance between the silicon target (1 to 10 Ωcm) and the substrate is 350 mm to 200 mm, and the back pressure is 1 × 10 ⁻³ Pa or less. Further, a heated rare gas may be sprayed on the back surface of the substrate.

  As shown in FIG. 1A, a protective film 123 is formed on the second substrate 120 which is a counter substrate, and a protective film 113 is also formed on the first substrate 110. Although a TFT or the like is not illustrated on the first substrate, at least one silicon nitride film may be provided as a base insulating film, an interlayer insulating film, or a protective film of the TFT.

  Next, a counter electrode 122 made of a transparent conductive film is formed over the second substrate 120. In addition, a pixel electrode 111 made of a transparent conductive film is formed on the first substrate 110. Further, columnar spacers 115 made of an insulator for maintaining the distance between the substrates are formed on the first substrate 110. (FIG. 1B) An alignment film (not shown) is formed on both substrates, and a rubbing process is performed.

  Next, the sealing material 112 is drawn on the second substrate 120. As the sealing material 112, an acrylic photo-curing resin or an acrylic thermosetting resin may be used. The sealing material 112 includes a filler (diameter 6 μm to 24 μm) and a viscosity of 40 to 400 Pa · s. It is preferable to select a sealing material that does not dissolve in the liquid crystal that comes into contact later. This sealing material 112 forms a closed loop and surrounds the display area. Here, the sealing material is temporarily fired. (Figure 1 (C))

  Next, the liquid crystal 113 is dropped by the liquid crystal dispenser 118 under a reduced pressure into a region surrounded by the sealing material 112. (FIG. 1D) As the liquid crystal 113, a known liquid crystal material having a droppable viscosity may be used. The liquid crystal dispenser can hold a necessary amount of the liquid crystal 113 in a region surrounded by the sealing material 112 without waste. Alternatively, liquid crystal may be dropped using an inkjet method.

  Next, the liquid crystal is degassed by heating under reduced pressure. (Figure 1 (E))

  Next, the first substrate 110 provided with the pixel portion and the second substrate 120 provided with the counter electrode 122 and the alignment film are bonded together under reduced pressure so that bubbles do not enter. (Fig. 1 (F))

  Next, the sealing material 112 is cured by performing ultraviolet irradiation or heat treatment. (FIG. 1G) In addition to ultraviolet irradiation, heat treatment may be performed.

  When pasted together under reduced pressure, gradually return to atmospheric pressure. Moreover, you may return to atmospheric pressure gradually in the state which pressurized a pair of board | substrate. Alternatively, after bonding under reduced pressure, the sealing material may be cured by performing ultraviolet irradiation or heat treatment while pressing the pair of substrates.

  Through the above steps, the liquid crystal is held between the pair of substrates. In this embodiment mode, liquid crystal dropping, heat degassing, and bonding steps are continuously performed under reduced pressure. Furthermore, the sealing material may be drawn under reduced pressure.

(Embodiment 2)
Here, an example of performing seal drawing and liquid crystal dropping on the TFT substrate side will be described.

  First, similarly to Embodiment Mode 1, a second substrate 220 which is a counter substrate and a first substrate 210 on which a TFT (not shown) is provided in advance are prepared. The first substrate 210 and the second substrate 220 are flexible substrates and are not particularly limited as long as they are light-transmitting substrates. Typically, plastic substrates are used.

  Next, in the same manner as in Embodiment Mode 1, the protective film 213 is formed on the second substrate 220 which is the counter substrate, and the protective film 223 is also formed on the first substrate 210. (FIG. 2A) Although a TFT or the like is not shown in the first substrate, at least one silicon nitride film may be provided as a base insulating film, an interlayer insulating film, or a protective film of the TFT.

  Next, a pixel electrode 211 made of a transparent conductive film is formed over the first substrate 210. Further, columnar spacers 215 made of an insulating material for maintaining the distance between the substrates are formed on the first substrate 210. In addition, a counter electrode 222 made of a transparent conductive film is formed over the second substrate 220. (FIG. 2B) Further, an alignment film (not shown) is formed on both substrates, and a rubbing treatment is performed.

Next, the sealing material 212 is drawn on the first substrate 210 by a dispenser device or an inkjet device. As the sealant 212, an acrylic photo-curing resin or an acrylic thermosetting resin may be used. The sealant 212 includes a filler (diameter: 6 μm to 24 μm) and a viscosity of 40 to 400 Pa · s. It is preferable to select a sealing material that does not dissolve in the liquid crystal that comes into contact later. This sealing material 212 forms a closed loop and surrounds the display area. Here, the sealing material is temporarily fired. (Fig. 2 (C))

  Next, the liquid crystal 213 is dropped into the region surrounded by the sealing material 212 under reduced pressure by the liquid crystal dispenser 218. (FIG. 2D) As the liquid crystal 213, a known liquid crystal material having a droppable viscosity may be used. The liquid crystal dispenser can hold a necessary amount of the liquid crystal 213 in a region surrounded by the sealant 212 without waste. Alternatively, liquid crystal may be dropped using an inkjet method.

FIG. 3 shows an example of manufacturing four panels. FIG. 3A is a cross-sectional view in the middle of liquid crystal layer formation by the liquid crystal dispenser 318. The liquid crystal material 314 is dropped from the liquid crystal dispenser 318 so as to cover the pixel portion 311 surrounded by the sealant 312. It is discharged. The liquid crystal dispenser 318 may be moved, or the liquid crystal layer may be formed by fixing the liquid crystal dispenser 318 and moving the substrate. Alternatively, a plurality of liquid crystal dispensers 318 may be installed to drop liquid crystal at a time.

  FIG. 3B is a perspective view. The liquid crystal material 314 is selectively dropped or discharged only in the region surrounded by the seal 312.

  3C is an enlarged cross-sectional view of a portion 319 surrounded by a dotted line in FIG. The liquid crystal material is dropped as shown in FIG.

  In FIG. 3C, 320 indicates an inverted staggered TFT, 321 indicates a pixel electrode, 322 indicates a columnar spacer, 323 indicates an alignment film, 324 indicates a protective film (here, a silicon nitride film formed by RF sputtering). Yes. The pixel portion 311 includes pixel electrodes arranged in a matrix, switching elements connected to the pixel electrodes, here inverted staggered TFTs, and a storage capacitor (not shown).

  Next, the liquid crystal is degassed by heating under reduced pressure. (FIG. 2 (E)) Heating is performed to lower the viscosity of the liquid crystal layer to make the film thickness uniform.

  Next, the first substrate 210 provided with the pixel portion and the second substrate 220 provided with the counter electrode 222 and the alignment film are bonded together under reduced pressure so that bubbles do not enter. (Fig. 2 (F))

FIG. 4 shows an example of a bonding apparatus capable of performing ultraviolet irradiation or heat treatment at the time of bonding or after bonding.

  In FIG. 4, 41 is a first substrate support, 42 is a second substrate support, 44 is a window, 48 is a lower surface plate, and 49 is a light source.

  The lower surface plate 48 has a built-in heater, and can cure the sealing material and reduce the viscosity of the liquid crystal material. Further, the second substrate support is provided with a window 44 so that ultraviolet light from the light source 49 can pass therethrough. Although not shown here, the substrate is aligned through the window 44. In addition, the second substrate 31 serving as the counter substrate is cut into a desired size in advance and fixed to the table 42 with a vacuum chuck or the like. FIG. 4A shows a state before bonding.

  At the time of bonding, after the first substrate support base and the second substrate support base are lowered, the first substrate 35 and the second substrate 31 are bonded together by applying pressure, and then temporarily cured by irradiating ultraviolet light as it is. . The state after pasting is shown in FIG.

  Next, ultraviolet ray irradiation or heat treatment is performed to fully cure the sealing material 212. (FIG. 2G) In addition to ultraviolet irradiation, heat treatment may be performed.

  When pasted together under reduced pressure, gradually return to atmospheric pressure. Moreover, you may return to atmospheric pressure gradually in the state which pressurized a pair of board | substrate. Alternatively, after bonding together under reduced pressure, ultraviolet irradiation or heat treatment may be performed with the pair of substrates being pressurized to cure the sealing material, and then gradually returned to atmospheric pressure.

  Through the above steps, the liquid crystal is held between the pair of substrates. In this embodiment mode, liquid crystal dropping, heat degassing, and bonding steps are continuously performed under reduced pressure. Furthermore, the sealing material may be drawn under reduced pressure.

  Further, in the case where four panels are manufactured from a single substrate as shown in FIG. 3, after bonding, the first substrate is cut using a cutting device such as a scriber device or a roll cutter or a breaker device. Thus, four panels can be manufactured from one substrate.

  The present invention having the above-described configuration will be described in more detail with the following examples.

  In this embodiment, a manufacturing process of an active matrix liquid crystal display device is described below with reference to FIGS.

  First, an active matrix substrate is manufactured using a light-transmitting substrate 600. Substrate sizes are 600mm x 720mm, 680mm x 880mm, 1000mm x 1200mm, 1100mm x 1250mm, 1150mm x 1300mm, 1500mm x 1800mm, 1800mm x 2000mm, 2000mm x 2100mm, 2200mm x 2600mm, or 2600mm x 3100mm It is preferable to use a substrate and reduce manufacturing costs. As a substrate that can be used, a glass substrate such as barium borosilicate glass or aluminoborosilicate glass represented by Corning # 7059 glass or # 1737 glass can be used. Furthermore, a light-transmitting substrate such as a quartz substrate or a plastic substrate can be used as another substrate.

  First, after a conductive layer is formed over the entire surface of the substrate 600 having an insulating surface by sputtering, a first photolithography process is performed, a resist mask is formed, and unnecessary portions are removed by etching to form a wiring. And electrodes (eg, a gate electrode, a storage capacitor wiring, and a terminal) are formed. Note that a base insulating film is formed over the substrate 600 if necessary.

  The wiring and electrode materials are made of an element selected from Ti, Ta, W, Mo, Cr, and Nd, an alloy containing the element as a component, or a nitride containing the element as a component. Further, a plurality of elements selected from Ti, Ta, W, Mo, Cr, and Nd, an alloy containing the element as a component, or a nitride containing the element as a component can be selected and stacked.

  In addition, when the screen size is increased, the length of each wiring increases, which causes a problem that the wiring resistance increases, resulting in an increase in power consumption. Therefore, Cu, Al, Ag, Au, Cr, Fe, Ni, Pt, or an alloy thereof can be used as the material for the wiring and electrodes in order to reduce the wiring resistance and realize low power consumption. . In addition, the above-described wiring and the above-mentioned wiring and An electrode may be formed.

  Next, a gate insulating film is formed on the entire surface by PCVD. The gate insulating film is a stacked layer of a silicon nitride film and a silicon oxide film and has a thickness of 50 to 200 nm, preferably 150 nm. Note that the gate insulating film is not limited to a stacked layer, and an insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a tantalum oxide film can also be used.

  Next, a first amorphous semiconductor film with a thickness of 50 to 200 nm, preferably 100 to 150 nm, is formed over the entire surface of the gate insulating film by a known method such as a plasma CVD method or a sputtering method. Typically, an amorphous silicon (a-Si) film is formed with a thickness of 100 nm. Note that when a film is formed on a large-area substrate, the chamber is also enlarged, so that it takes a long time to process the chamber and a large amount of film forming gas is required. Therefore, a linear plasma CVD apparatus is used at atmospheric pressure. Further, an amorphous silicon (a-Si) film may be formed to further reduce the cost.

  Next, a second amorphous semiconductor film containing an impurity element of one conductivity type (n-type or p-type) is formed to a thickness of 20 to 80 nm. The second amorphous semiconductor film containing an impurity element imparting one conductivity type (n-type or p-type) is formed over the entire surface by a known method such as a plasma CVD method or a sputtering method. In this embodiment, a second amorphous semiconductor film containing an n-type impurity element is formed using a silicon target to which phosphorus is added.

  Next, a resist mask is formed by a second photolithography step, unnecessary portions are removed by etching, and an island-shaped first amorphous semiconductor film and an island-shaped second amorphous semiconductor film are formed. Form. As an etching method at this time, wet etching or dry etching is used.

Next, after a conductive layer covering the island-shaped second amorphous semiconductor film is formed by a sputtering method, a third photolithography step is performed, a resist mask is formed, and unnecessary portions are removed by etching. A wiring and an electrode (a source wiring, a drain electrode, a storage capacitor electrode, and the like) are formed. As a material for the wiring and the electrode, an element selected from Al, Ti, Ta, W, Mo, Cr, Nd, Cu, Ag, Au, Cr, Fe, Ni, and Pt, or the above element as a component is used. Made of alloy. In addition, the above-described wiring and the above-mentioned wiring and An electrode may be formed. If the wiring and the electrodes are formed by an ink jet method, a photolithography process is not necessary, and further cost reduction can be realized.

  Next, a resist mask is formed by a fourth photolithography process, and unnecessary portions are removed by etching to form a source wiring, a drain electrode, and a capacitor electrode. As an etching method at this time, wet etching or dry etching is used. At this stage, a storage capacitor having an insulating film made of the same material as the gate insulating film as a dielectric is formed. Then, a part of the second amorphous semiconductor film is removed in a self-aligning manner using the source wiring and the drain electrode as a mask, and a part of the first amorphous semiconductor film is further thinned. The thinned region becomes a TFT channel formation region.

 Next, a first protective film made of a silicon nitride film with a thickness of 150 nm and a first interlayer insulating film made of a silicon oxynitride film with a thickness of 150 nm are formed over the entire surface by plasma CVD. Note that when a film is formed on a large-area substrate, the chamber is also enlarged, so that it takes a long time to process the chamber and a large amount of film forming gas is required. Therefore, a linear plasma CVD apparatus is used at atmospheric pressure. Thus, a protective film made of a silicon nitride film may be formed to further reduce the cost. Thereafter, hydrogenation is performed, and a channel etch type TFT is manufactured.

 In this embodiment, a channel etch type is shown as the TFT structure, but the TFT structure is not particularly limited, and may be a channel stopper type TFT, a top gate type TFT, or a forward stagger type TFT.

Next, a second protective film 619 is formed by RF sputtering. This second protective film 619 is sputtered by using a turbo molecular pump or a cryopump with a back pressure of 1 × 10 ⁻³ Pa or less and a single crystal silicon target with N ₂ gas or a mixed gas of N ₂ and a rare gas. This is a silicon nitride film manufactured in this way. This dense silicon nitride film effectively prevents threshold voltage fluctuations due to contamination of TFT by alkali metal or alkaline earth metal such as sodium, lithium and magnesium, and is extremely resistant to moisture and oxygen. Has a high blocking effect. In order to enhance the blocking effect, the oxygen and hydrogen contents in the silicon nitride film are 10 atomic% or less, preferably 1 atomic% or less.

 Next, a fifth photolithography step is performed to form a resist mask, and then a contact hole reaching the drain electrode and the storage capacitor electrode is formed by a dry etching step. At the same time, a contact hole (not shown) for electrically connecting the gate wiring and the terminal portion is formed in the terminal portion, and a metal wiring (not shown) for electrically connecting the gate wiring and the terminal portion is formed. Also good. At the same time, a contact hole (not shown) reaching the source wiring may be formed, and a metal wiring for drawing out from the source wiring may be formed. After these metal wirings are formed, pixel electrodes such as ITO may be formed, or these metal wirings may be formed after pixel electrodes such as ITO are formed.

Next, a transparent electrode film made of ITO (indium tin oxide alloy), indium oxide zinc oxide alloy (In ₂ O ₃ —ZnO), zinc oxide (ZnO) or the like is formed to a thickness of 110 nm. Thereafter, a pixel electrode 601 is formed by performing a sixth photolithography process and an etching process.

  As described above, in the pixel portion, an active matrix substrate including the source wiring, the TFT and the storage capacitor of the inverted staggered pixel portion, and the terminal portion can be manufactured through six photolithography processes.

  Next, an alignment film 623 is formed over the active matrix substrate and a rubbing process is performed. In this embodiment, before the alignment film 623 is formed, a columnar spacer 602 for maintaining the substrate interval is formed at a desired position by patterning an organic resin film such as an acrylic resin film. Further, instead of the columnar spacers, spherical spacers may be scattered over the entire surface of the substrate.

  Next, a counter substrate is prepared. The counter substrate is provided with a color filter 620 in which a colored layer and a light shielding layer are arranged corresponding to each pixel. Further, a flattening film is provided to cover the color filter and the light shielding layer. Next, a counter electrode 621 made of a transparent conductive film is formed on the planarizing film at a position overlapping the pixel portion, an alignment film 622 is formed on the entire surface of the counter substrate, and a rubbing process is performed.

  Then, according to the second embodiment, a sealant is drawn with a dispenser device or an inkjet device so as to surround the pixel portion of the active matrix substrate. After drawing the sealing material, the liquid crystal is dropped by a liquid crystal dispenser device in a region surrounded by the sealing material under reduced pressure. Next, the active matrix substrate and the counter substrate are attached to each other with a sealant 607 under reduced pressure without being exposed to the air. A filler (not shown) is mixed in the sealing material 607, and two substrates are bonded to each other with a uniform interval by the filler and the columnar spacer 602. By using a method of dropping liquid crystal, the amount of liquid crystal used in the manufacturing process can be reduced. In particular, when a large-area substrate is used, significant cost reduction can be realized.

  In this way, an active matrix liquid crystal display device is completed. If necessary, the active matrix substrate or the counter substrate is divided into a desired shape. Furthermore, an optical film such as a polarizing plate 603 and a color filter is appropriately provided using a known technique. Then, the FPC is pasted using a known technique.

  If the liquid crystal module obtained by the above steps is provided with a backlight 604 and a light guide plate 605 and covered with a cover 606, an active matrix liquid crystal display device (transmission type) as shown in FIG. ) Is completed. The cover and the liquid crystal module are fixed using an adhesive or an organic resin. Further, since it is a transmissive type, the polarizing plate 603 is attached to both the active matrix substrate and the counter substrate.

  Although this embodiment shows a transmissive type, it is not particularly limited, and a reflective or semi-transmissive liquid crystal display device can also be manufactured. In the case of obtaining a reflective liquid crystal display device, a metal film with high light reflectivity, typically a material film containing aluminum or silver as a main component, or a laminated film thereof may be used as the pixel electrode.

Further, this embodiment can be freely combined with Embodiment Mode 1 or Embodiment Mode 2.

In this embodiment, a top view of the liquid crystal module obtained in Embodiment 1 is shown in FIG. 8A, and a top view of a liquid crystal module different from that in Embodiment 1 is shown in FIG.

A TFT in which an active layer is formed of an amorphous semiconductor film obtained in Example 1 has a small field-effect mobility and only about 1 cm ² / Vsec. Therefore, a driving circuit for displaying an image is formed by an IC chip, and is mounted by a TAB (Tape Automated Bonding) method or a COG (Chip on glass) method.

  In FIG. 8A, reference numeral 701 denotes an active matrix substrate, 706 denotes a counter substrate, 704 denotes a pixel portion, 707 denotes a sealant, and 705 denotes an FPC. Note that liquid crystal is dropped by a dispenser device or an inkjet device under reduced pressure, and the pair of substrates 701 and 706 are bonded to each other with a sealant 707.

  Although the TFT obtained in Example 1 has a small field effect mobility, when mass-produced using a large-area substrate, it is a low-temperature process and can reduce the cost of the manufacturing process. According to the present invention in which liquid crystal is dropped by a dispenser device or an ink jet device under reduced pressure and a pair of substrates is bonded, the liquid crystal can be held between the pair of substrates regardless of the substrate size. A display device including a liquid crystal panel having a large inch screen can be manufactured.

In addition, when a known crystallization process is performed to crystallize an amorphous semiconductor film to form an active layer of a semiconductor film having a crystal structure, typically a polysilicon film, a TFT having a high field effect mobility is obtained. Therefore, not only the pixel portion but also a driver circuit having a CMOS circuit can be manufactured over the same substrate. In addition to the driver circuit, a CPU or the like can be manufactured over the same substrate.

  When a TFT having an active layer made of a polysilicon film is used, a liquid crystal module as shown in FIG. 8B can be manufactured.

  8B, reference numeral 711 denotes an active matrix substrate, 716 denotes a counter substrate, 712 denotes a source signal line driver circuit, 713 denotes a gate signal line driver circuit, 714 denotes a pixel portion, 717 denotes a first sealant, and 715 denotes an FPC. It is. Note that the liquid crystal is dropped by a dispenser device or an inkjet device under reduced pressure, and the pair of substrates 711 and 716 are bonded to each other with the first sealant 717 and the second sealant. Since the driving circuit portions 712 and 713 do not require liquid crystal, only the pixel portion 714 holds the liquid crystal, and the second sealant 718 is provided to reinforce the entire panel.

Further, this embodiment can be freely combined with Embodiment Mode 1, Embodiment Mode 2, or Embodiment 1.

In Example 1 and Example 2, an example is shown in which an active matrix substrate in which a switching element is directly formed on a plastic substrate which is a flexible substrate is manufactured. However, in this example, an element formed on a glass substrate is peeled off. An example of transferring to a flexible substrate will be described.

  First, as shown in FIG. 9A, a metal film 11 is formed over the first substrate 10. Note that the first substrate only needs to have rigidity enough to withstand a subsequent peeling step. For example, a glass substrate, a quartz substrate, a ceramic substrate, a silicon substrate, a metal substrate, or a stainless steel substrate can be used. As the metal film, an element selected from W, Ti, Ta, Mo, Nd, Ni, Co, Zr, Zn, Ru, Rh, Pd, Os, and Ir, or an alloy material or a compound material containing the element as a main component A single layer made of the above or a laminate of these can be used. For example, the metal film may be formed by a sputtering method using a metal target. Note that the metal film may be formed to have a thickness of 10 nm to 200 nm, preferably 50 nm to 75 nm.

Instead of the metal film, a film in which the metal is nitrided (for example, tungsten nitride or molybdenum nitride) may be used. Instead of the metal film, an alloy film of the above metal (for example, an alloy of W and Mo: W _x Mo _1-X ) may be used. In this case, a plurality of targets such as a first metal (W) and a second metal (Mo) are used in the film forming chamber, or an alloy target of the first metal (W) and the second metal (Mo). What is necessary is just to form by the sputtering method using this. Furthermore, nitrogen or oxygen may be added to the metal film. For example, nitrogen or oxygen may be ion-implanted into the metal film, or a film formation chamber may be formed by sputtering in a nitrogen or oxygen atmosphere. At this time, metal nitride may be used as a target.

  When a metal film is formed using a sputtering method, the film thickness at the peripheral edge of the substrate may be nonuniform. Therefore, it is preferable to remove the peripheral film by dry etching. At this time, since the first substrate is not etched, silicon nitride oxide (SiON or SiNO) is interposed between the first substrate 10 and the metal film 11. ) An insulating film containing nitrogen such as a film may be formed to a thickness of about 100 nm.

  Thus, by appropriately setting the metal film forming method, the peeling process can be controlled, and the process margin is widened. That is, for example, when a metal alloy is used, the peeling process can be controlled by controlling the composition ratio of each metal of the alloy. Specifically, it is possible to control the heating temperature for peeling and the necessity of heat treatment.

  Thereafter, a layer to be peeled 12 is formed on the metal film 11. This peeled layer has an oxide film containing silicon and a semiconductor film, and may have an antenna in the case of a non-contact type IC. In order to prevent intrusion of impurities and dust from the metal film and the substrate, an insulating film having nitrogen such as a silicon nitride (SiN) film or a silicon nitride oxide (SiON or SiNO) film on the lower surface of the peeled layer 12, particularly the semiconductor film. It is preferable to provide it as a base film.

  As the oxide film containing silicon, silicon oxide, silicon oxynitride, or the like may be formed by a sputtering method or a CVD method. Note that the thickness of the oxide film containing silicon is preferably about twice or more that of the metal film. In this embodiment, the silicon oxide film is formed to a thickness of 150 to 200 nm by a sputtering method using a silicon target.

    When the oxide film containing silicon is formed, an oxide (metal oxide) 13 containing the metal is formed on the metal film. The metal oxide is an aqueous solution containing sulfuric acid, hydrochloric acid or nitric acid, an aqueous solution in which sulfuric acid, hydrochloric acid or nitric acid is mixed with hydrogen peroxide, or a thin metal oxide formed on the surface of the metal film by treatment with ozone water. Can also be used. Further, as another method, plasma treatment in an oxygen atmosphere or oxidation treatment may be performed by generating ozone by irradiating ultraviolet rays in an oxygen-containing atmosphere, and heating to about 200 to 350 ° C. using a clean oven. May be formed.

    The thickness of the metal oxide may be 0.1 nm to 1 μm, preferably 0.1 nm to 100 nm, and more preferably 0.1 nm to 5 nm.

 Note that an oxide film including silicon, a base film, and the like provided between the semiconductor film and the metal film are collectively referred to as an insulating film. That is, a metal film, a metal oxide, an insulating film, and a semiconductor film are stacked, that is, a semiconductor film is provided on one surface of the insulating film, and a metal oxide and a metal film are provided on the other surface. It is sufficient that the structure is a

  A predetermined manufacturing process is performed on the semiconductor film to form a semiconductor element such as a thin film transistor (TFT), an organic TFT, a thin film diode, or the like. These semiconductor elements constitute a CPU, a memory and the like of the thin film integrated circuit. In order to protect the semiconductor element, a protective film having carbon such as DLC or carbon nitride (CN) or a protective film having nitrogen such as silicon nitride (SiN) or silicon nitride oxide (SiNO or SiON) is provided on the semiconductor element. Is preferably provided.

After forming the layer to be peeled 12 as described above, specifically, after forming the metal oxide, heat treatment is appropriately performed to crystallize the metal oxide. For example, when W (tungsten) is used for the metal film, if heat treatment is performed at 400 ° C. or higher, the metal oxide of WO ₂ or WO ₃ becomes a crystalline state. Further, when heating is performed after the semiconductor film included in the layer to be peeled 12 is formed, hydrogen in the semiconductor film can be diffused. The hydrogen may change the valence of the metal oxide. Such heat treatment may be performed by determining the temperature and necessity depending on the metal film selected. That is, in order to perform peeling easily, a metal oxide may be crystallized as necessary.

  Further, the heat treatment may be combined with manufacturing a semiconductor element to reduce the number of steps. For example, heat treatment can be performed using a heating furnace or laser irradiation in the case of forming a crystalline semiconductor film.

  Next, as illustrated in FIG. 9B, the layer to be peeled 12 is attached to the second substrate 14 with the first adhesive 15. The second substrate 14 is preferably a substrate having higher rigidity than the first substrate 10. As the first adhesive 15, a peelable adhesive, for example, an ultraviolet peeling type that peels off by ultraviolet rays, a thermal peeling type that peels off by heat, a water-soluble adhesive that peels off by water, or a double-sided tape may be used.

  Then, the first substrate 10 provided with the metal film 11 is peeled off using physical means (FIG. 9C). Although the drawing is a schematic diagram, it is not described, but the crystallized metal oxide layer or the boundary (interface) between both sides of the metal oxide, that is, the interface between the metal oxide and the metal film or the metal oxide And peeled off at the interface between the layer to be peeled off. In this way, the layer to be peeled 12 can be peeled from the first substrate 10.

  At this time, in order to perform peeling easily, a part of the substrate may be cut and scratched with a cutter or the like near the peeling interface on the cut surface, that is, near the interface between the metal film and the metal oxide.

  Next, as shown in FIG. 9D, the peeled off layer 12 is attached to a third substrate (for example, label) 17 serving as a transfer body with the second adhesive 16. As the second adhesive 15, an ultraviolet curable resin, specifically, an adhesive such as an epoxy resin adhesive or a resin additive, a double-sided tape, or the like may be used. Further, when the third substrate has adhesiveness, the second adhesive is not necessary.

  As a material for the third substrate, a substrate having flexibility (denoted as a film substrate) such as paper or a plastic material such as polyethylene terephthalate, polycarbonate, polyarylate, or polyether sulfone can be used. Moreover, the unevenness | corrugation of the film substrate surface may be reduced by coating etc., and hardness, tolerance, and stability may be improved.

  Next, the first adhesive 15 is removed, and the second substrate 14 is peeled off (FIG. 9E). Specifically, irradiation with ultraviolet light, heating, or washing with water may be performed in order to remove the first adhesive.

  Note that the removal of the first adhesive and the curing of the second adhesive may be performed in one step. For example, the first adhesive and the second adhesive are removed by one heating or ultraviolet irradiation when using a heat-peelable resin and a thermosetting resin, or an ultraviolet-peelable resin and an ultraviolet-curable resin, respectively. And curing. Note that the practitioner appropriately selects an adhesive in consideration of the translucency of the third substrate.

  As described above, a thin film integrated circuit is completed on the flexible substrate. According to this embodiment, an active matrix substrate in which a switching element having high electrical characteristics formed on a glass substrate is peeled off and transferred to a plastic substrate is completed.

  Note that the metal oxide 13 may be completely removed from the thin film integrated circuit, or a part or most of the metal oxide 13 may be scattered (residual) on the lower surface of the layer to be peeled. If metal oxide remains, it may be removed by etching or the like. Further, at this time, the oxide film containing silicon may be removed.

  In the subsequent steps, a liquid crystal display device can be manufactured according to Embodiment 1 or Embodiment 2.

In this embodiment, a layer to be peeled including a CPU and a memory is formed on a substrate having an insulating surface (typically, a glass substrate or a quartz substrate), and transferred to a plastic substrate using the peeling transfer technique of Embodiment 3. An example will be described with reference to FIG.

  In FIG. 10A, 1001 is a central processing unit (also called CPU), 1002 is a control unit, 1003 is a calculation unit, 1004 is a storage unit (also called memory), 1005 is an input unit, and 1006 is an output unit (display unit). Etc.).

The central processing unit 1001 is a combination of the arithmetic unit 1003 and the control unit 1002, and the arithmetic unit 1003 performs arithmetic operations such as addition and subtraction, and logical operations such as AND, OR, and NOT (arithmetic). logic unit (ALU), various registers for temporarily storing operation data and results, and a counter for counting the number of input ones. A circuit that constitutes the arithmetic unit 1003, for example, an AND circuit, an OR circuit, a NOT circuit, a buffer circuit, or a register circuit can be formed using a TFT, and in order to obtain high field-effect mobility, a continuous wave laser beam A semiconductor film that has been crystallized by using a TFT may be formed as an active layer of a TFT.

  First, a tungsten film and a silicon oxide film are formed on a substrate by sputtering, a base insulating film (silicon oxide film, silicon nitride film, or silicon oxynitride film) is formed thereon, and an amorphous silicon film is formed thereon. Form. Note that separation is performed in a later step using a tungsten oxide layer formed at the interface between the tungsten film and the silicon oxide film.

  As a crystallization method, a method may be used in which after adding a metal element as a catalyst to an amorphous silicon film, a polysilicon film is obtained by heating and then a polysilicon film irradiated with a pulsed laser beam is obtained. Alternatively, a method of obtaining a polysilicon film by irradiating the amorphous silicon film with a continuous wave laser beam may be used, or a continuous wave laser beam may be applied after heating the amorphous silicon film to obtain a polysilicon film. A method of obtaining a polysilicon film by irradiation may be used, or after adding a metal element as a catalyst to an amorphous silicon film, heating to obtain a polysilicon film, and then irradiating a continuous oscillation type laser beam A method for obtaining a polysilicon film may be used. Note that in the case of using continuous wave laser light, it is preferable to align the channel length direction of the TFTs included in the arithmetic unit 1003, the control unit 1002, or the storage unit 1004 with the scanning direction of the laser beam.

  In addition, the control unit 1002 plays a role of executing an instruction stored in the storage unit 1004 and controlling the overall operation. The control unit 1002 includes a program counter, an instruction register, and a control signal generation unit. Further, the control portion 1002 can also be formed of a TFT, and a crystallized semiconductor film may be manufactured as an active layer of the TFT.

  The storage unit 1004 is a place for storing data and instructions for calculation, and stores data and programs that are frequently executed by the CPU. The storage unit 1004 includes a main memory, an address register, and a data register. Further, a cache memory may be used in addition to the main memory. These memories may be formed by SRAM, DRAM, flash memory, or the like. In the case where the memory portion 1004 is also formed using a TFT, a crystallized semiconductor film can be manufactured as an active layer of the TFT.

  An input unit 1005 is a device that takes in data and programs from the outside. The output unit 1006 is a device for displaying the result, typically a display device.

  The layer to be peeled including the CPU (including terminal electrodes and lead wirings) thus obtained is peeled from the substrate and transferred to a plastic substrate.

  In addition to the CPU, a current circuit, a display portion, and a drive circuit portion can be manufactured together. For example, a card having a non-contact type thin film integrated circuit can be manufactured.

FIG. 10B is a diagram of a non-contact thin film integrated circuit.

  FIG. 10B shows a top view of a specific structure of a non-contact thin film integrated circuit. The display unit, the antenna 31, the current circuit 32, and the integrated circuit unit 35 including the CPU 33, the memory 34, and the like are provided, and the antenna is connected to the IC through the current circuit. The current circuit 32 may be configured to have, for example, a diode and a capacitor, and has a function of converting the AC frequency received by the antenna into DC. The antenna 31 can also be formed in the same process as the integrated circuit.

  The non-contact type IC is characterized in that the electric power is generated by the electromagnetic induction effect (electromagnetic induction method), mutual induction effect (electromagnetic coupling method) or static induction effect (electrostatic coupling method) of the coiled antenna. It is a point to be supplied. By controlling the number of turns of the antenna, the height of the frequency to be received can be selected.

  The frequency is generally microwave for remote type, 13.56 MHz for proximity type and proximity type, and 4.91 MHz for close contact type, but the number of antenna turns can be reduced by increasing the frequency and shortening the wavelength. it can.

  Compared with the contact type thin film integrated circuit, the non-contact type thin film integrated circuit is not in contact with the reader / writer and performs power supply and information communication without contact, so it is not damaged and has high durability, static electricity, etc. There is no worry about errors. Furthermore, the configuration of the reader / writer itself does not become complicated, and the thin film integrated circuit only needs to be held over the reader / writer, so that handling is easy.

The non-contact type integrated circuit includes a CPU, a memory, an I / O port, and a coprocessor, and exchanges data through a path. Further, the IC has an RF (wireless) interface and a non-contact interface. The reader / writer, which is a reading means, has a non-contact interface and an interface circuit. The IC is held over the reader / writer, and information is transmitted and exchanged between the non-contact interfaces by communication or radio waves. Information is exchanged and exchanged with the host computer by the interface circuit of the reader / writer. Of course, the host computer may have reader / writer means.

  FIG. 10C is an external view of a plastic card corresponding to FIG. In FIG. 10C, 1010 is a plastic card body, 1011 is a reflective liquid crystal display unit, 1012 is a storage unit, and 1013 is a CPU. When the authentication card is used, the card is lightweight and flexible. When the authentication card becomes unnecessary, it can be easily cut and subdivided, and the information in the storage unit can be completely unreadable or counterfeited.

  FIG. 11 shows examples of various modes for reading card information. A card 72 containing a thin film integrated circuit is held over a sensor portion 71 of a reader / writer main body 70 as shown in FIG.

Further, as shown in FIG. 11B, a portable information terminal owned by an individual, for example, a mobile phone main body 80 is equipped with a reader function, and a thin film integrated circuit is incorporated in a sensor portion 81 provided in a part of the main body. Hold the card 82 to display information on the display unit 83.

  Further, as shown in FIG. 11C, a sensor unit 91 of a portable reader 90 owned by an individual is held over a card 92 containing a thin film integrated circuit, and information is displayed on a display unit 93.

  In this embodiment, a non-contact type reader / writer has been described. However, information may be displayed on a display unit even in a contact type. Further, a display unit may be provided on a card itself incorporating a non-contact type or contact type thin film integrated circuit to display information.

  FIG. 10D illustrates an example of a portable information terminal including a plurality of liquid crystal display portions.

  The apparatus illustrated in FIG. 10D can be folded by the bending movable portion 1023, and can have a business card size. Since the plastic 1020 is a main body, the plastic 1020 is lightweight and has a left display portion 1021 and a right display portion 1022. Further, an integrated circuit such as a CPU may be provided in the plastic 1020.

In addition, this embodiment can be freely combined with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode 1, Embodiment Mode 2, or Embodiment Mode 3.

In this embodiment, a method for manufacturing an organic TFT formed using an organic material will be described with reference to FIGS.

  As shown in FIG. 12A, a substrate 901 having an insulating surface is prepared. The substrate 901 may be any substrate having flexibility and translucency, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), polyimide, and the like. Selected. The practical thickness of the substrate 901 is 10 to 200 μm.

  Then, a barrier layer 902 is formed over the substrate 901. The barrier layer 902 is preferably formed using silicon nitride not containing hydrogen formed by a high-frequency sputtering method or a multilayer film including the silicon nitride and a silicon oxide film. This barrier layer 902 becomes a barrier layer of water vapor or organic gas entering from the external environment, and can prevent the organic semiconductor material or the like from being deteriorated by water vapor or organic gas.

  Then, a first conductive film functioning as a gate electrode 903 of the TFT is formed over the barrier layer 902 using a conductive paste. As the conductive paste, conductive carbon paste, conductive silver paste, conductive copper paste, conductive nickel, or the like is used, and a predetermined pattern is formed by a screen printing method, a roll coater method, or an inkjet method. After the conductive paste is formed into a predetermined pattern, it is cured at 100 to 200 ° C. after leveling and drying.

  Next, as illustrated in FIG. 12B, a first insulating film functioning as the gate insulating film 904 is formed over the gate electrode 903. Note that the first insulating film is formed using a roll coater method, a spray method, or the like to which an acrylic resin, a polyimide resin, a polyamide resin, a phenoxy resin, a non-aromatic polyfunctional isocyanate, or a melamine resin is added. . The gate insulating film is preferably formed to a thickness of about 100 to 200 nm in consideration of the gate voltage.

  After that, as illustrated in FIG. 12C, a second conductive film functioning as the source electrode 905a or the drain electrode 905b is formed over the gate insulating film 904. As a material of the second conductive film, since a material that transports charges in many organic semiconductor materials is a p-type semiconductor that transports holes as carriers, a work function is required to make ohmic contact with the semiconductor layer. It is desirable to use a large metal. Specifically, a conductive paste containing a metal or an alloy material such as gold, platinum, chromium, palladium, aluminum, indium, molybdenum, or nickel is formed by a printing method or a roll coater method.

 Then, as illustrated in FIG. 12D, a second insulating film provided as a bank 906 is formed over the source electrode 905a or the drain electrode 905b. The second insulating film is an acrylic resin, a polyimide resin, a polyamide resin, a phenoxy resin, a non-fragrance, and the like using a screen printing method so that an opening is formed above the gate electrode in order to inject an organic semiconductor film. A polyfunctional isocyanate and a melamine resin are added. Further, the source electrode and the drain electrode may be formed after the bank is formed.

 Thereafter, an organic semiconductor film is formed. In the case of using a polymer material among the organic semiconductor films, a dipping method, a casting method, a bar coating method, a spin coating method, a spray method, an ink jet method, or a printing method may be used as appropriate. As the organic semiconductor material, an organic molecular crystal or an organic polymer compound material may be used. Specific organic molecular crystals include polycyclic aromatic compounds, conjugated double bond compounds, carotenes, macrocyclic compounds or complexes thereof, phthalocyanines, electromigration complexes, tetrathiofulvalene: TCNQ complexes, free radicals, diphenylpicryls. A hydrazyl, a pigment | dye, or protein is mentioned. Specific examples of the organic polymer compound material include polymers such as π-conjugated polymers, CT complexes, polyvinyl pyridine, iodine, and phthalocyanine metal complexes. In particular, polyacetylene, polyaniline, polypyrrole, polythienylene, polythiophene derivatives, poly (3-hexylthiophene) [P3HT; a flexible alkyl group at the 3-position of polythiophene, which is a π-conjugated polymer whose skeleton is composed of conjugated double bonds Polymers in which the alkyl group of the polythiophene derivative is a hexyl group], poly (3 alkylthiophene), poly (3docosylthiophene), a polyparaphenylene derivative, or a polyparaphenylene vinylene derivative are preferably used.

 An organic semiconductor film using a low molecular material may be formed by an evaporation method. For example, a thiophene oligomer film (polymerization degree 6) or a pentacene film may be formed by vapor deposition.

 In particular, in the case of a large substrate or when the first substrate and the second substrate are highly flexible, it is preferable to form the organic semiconductor film by a method of dropping a solution. Then, as shown in FIG. 12E, the organic semiconductor film 907 is formed by removing the solvent by natural standing or baking.

 Next, as shown in FIG. 12F, a passivation film 908 is formed. The passivation film may be formed using an insulating material containing silicon such as a silicon nitride film or a silicon oxynitride film by an RF sputtering method.

 Thereafter, the source electrode, the drain electrode, the gate electrode, and each wiring (not shown in FIG. 12) are contacted and connected between the element substrate and the TFT to form a semiconductor element. A liquid crystal material may be dropped according to Embodiment 2 to complete a liquid crystal display device (liquid crystal display module).

 As described above, the organic TFT formed entirely of an organic compound material is light and a flexible semiconductor device (specifically, a liquid crystal display device) can be obtained. In addition, the cost of the semiconductor device can be reduced because the organic material can be formed using an inexpensive organic material and the material to be discarded is very small.

 In particular, the organic TFT as in this embodiment is a system that integrates all of a pixel unit that visually displays information on a single panel, a communication function that transmits and receives various types of information, and a computer function that stores or processes information.・ It becomes possible to adapt to on-panel.

Further, this embodiment can be freely combined with Embodiment Mode 1, Embodiment Mode 2, Embodiment 1, Embodiment 2, Embodiment 3, or Embodiment 4.

An electronic device can be manufactured by incorporating a liquid crystal display device obtained by implementing the present invention into a display portion. Electronic devices include video cameras, digital cameras, goggle-type displays (head-mounted displays), navigation systems, sound playback devices (car audio, audio components, etc.), notebook-type personal computers, game devices, and portable information terminals (mobile computers, A mobile phone, a portable game machine, an electronic book, or the like), an image playback device including a recording medium (specifically, a display capable of playing back a recording medium such as a digital versatile disc (DVD) and displaying the image) Apparatus). Specific examples of these electronic devices are shown in FIGS.

  FIG. 13A illustrates a television which includes a housing 2001, a support base 2002, a display portion 2003, a speaker portion 2004, a video input terminal 2005, and the like. The present invention can be applied to the display portion 2003. Note that all information display televisions such as a personal computer, a TV broadcast reception, and an advertisement display are included.

  FIG. 13B illustrates a digital camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103, operation keys 2104, an external connection port 2105, a shutter 2106, and the like. The present invention can be applied to the display portion 2102.

  FIG. 13C illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. The present invention can be applied to the display portion 2203.

  FIG. 13D illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. The present invention can be applied to the display portion 2302.

  FIG. 13E shows a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion A2403, a display portion B2404, a recording medium (DVD, etc.). A reading unit 2405, operation keys 2406, a speaker unit 2407, and the like are included. Although the display portion A 2403 mainly displays image information and the display portion B 2404 mainly displays character information, the present invention can be applied to the display portions A, B 2403, and 2404. Note that an image reproducing device provided with a recording medium includes a home game machine and the like.

  FIG. 13F shows a game machine, which includes a main body 2501, a display portion 2505, operation switches 2504, and the like.

  FIG. 13G illustrates a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control receiving portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, and the like. . The present invention can be applied to the display portion 2602.

  FIG. 13H illustrates a mobile phone, which includes a main body 2701, a housing 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. The present invention can be applied to the display portion 2703. Note that the display portion 2703 can suppress current consumption of the mobile phone by displaying white characters on a black background.

  As described above, the display device obtained by implementing the present invention may be used as a display unit of any electronic device. Note that a liquid crystal display device manufactured using any one of Embodiment Modes 1, 2, and Examples 1 to 5 may be used for the electronic device of this example.

According to the present invention, it is possible to mass-produce flexible liquid crystal display devices with high use efficiency of liquid crystal materials and high reliability.

FIG. 3 shows Embodiment Mode 1; FIG. 5 shows Embodiment Mode 2. FIG. 5 shows Embodiment Mode 2. FIG. 5 shows Embodiment Mode 2. The SIMS measurement result which shows C, N, O, and H density | concentration in a silicon nitride film. The SIMS measurement result which shows Ar density | concentration in a silicon nitride film. FIG. 6 is a cross-sectional structure diagram of an active matrix liquid crystal display device. Example 1 The top view of a liquid crystal module. (Example 2) Peeling process step diagram. (Example 3) The figure which shows a card-type semiconductor device. Example 4 The figure which shows a reader / writer. Example 4 The figure which shows the preparation process of organic TFT. (Example 5) FIG. 14 illustrates an example of an electronic device. (Example 6)

Explanation of symbols

110: First substrate 114: Liquid crystal material 115: Columnar spacer 120: Second substrate

Claims (19)

A first flexible substrate, a second flexible substrate, and a liquid crystal held between a pair of substrates composed of the first flexible substrate and the second flexible substrate. A method of manufacturing a liquid crystal display device provided,
Forming an inorganic insulating film only on one side of the first flexible substrate, and forming an inorganic insulating film only on one side of the second flexible substrate;
Forming a pixel electrode on the inorganic insulating film of the first flexible substrate and forming a counter electrode on the inorganic insulating film of the second flexible substrate;
Forming a columnar spacer on the inorganic insulating film of the first flexible substrate to maintain a constant distance between the pair of substrates;
Drawing a sealing material on the inorganic insulating film of the second flexible substrate, temporarily firing and temporarily fixing,
A liquid crystal material is dropped under reduced pressure on the counter electrode and in a region surrounded by the sealing material,
The liquid crystal material dropped is heated and degassed under reduced pressure,
Bonding the first flexible substrate and the second flexible substrate under reduced pressure,
A method for manufacturing a liquid crystal display device, wherein the sealing material is fixed. A first flexible substrate, a second flexible substrate, and a liquid crystal held between a pair of substrates composed of the first flexible substrate and the second flexible substrate. A method of manufacturing a liquid crystal display device provided,
Forming an inorganic insulating film only on one side of the first flexible substrate, and forming an inorganic insulating film only on one side of the second flexible substrate;
Forming a pixel electrode on the inorganic insulating film of the first flexible substrate and forming a counter electrode on the inorganic insulating film of the second flexible substrate;
Forming a columnar spacer on the inorganic insulating film of the first flexible substrate to maintain a constant distance between the pair of substrates;
Drawing a sealing material on the inorganic insulating film of the first flexible substrate, temporarily firing and temporarily fixing,
A liquid crystal material is dropped under reduced pressure on the pixel electrode and in a region surrounded by the sealing material,
The liquid crystal material dropped is heated and degassed under reduced pressure,
Bonding the first flexible substrate and the second flexible substrate under reduced pressure,
A method for manufacturing a liquid crystal display device, wherein the sealing material is fixed. In claim 1 or 2,
The columnar spacer is made of an organic resin material containing at least one of acrylic, polyimide, polyimide amide, and epoxy as a main component, or any one of silicon oxide, silicon nitride, and silicon oxynitride, or a laminated film thereof. A method for manufacturing a liquid crystal display device, which is an inorganic material. In any one of Claims 1 thru | or 3,
The method for manufacturing a liquid crystal display, wherein the inorganic insulating film is formed by a high-frequency sputtering method. In any one of Claims 1 thru | or 4,
The method for manufacturing a liquid crystal display, wherein the inorganic insulating film is a silicon nitride film. In any one of Claims 1 thru | or 5,
The method for manufacturing a liquid crystal display device, wherein the inorganic insulating film is a silicon nitride film manufactured by a high-frequency sputtering method using silicon as a target. In any one of Claims 1 thru | or 6,
The inorganic insulating film is prepared by sputtering a single crystal silicon target with N ₂ gas or a mixed gas of N ₂ and a rare gas using a turbo molecular pump or a cryopump with a back pressure of 1 × 10 ⁻³ Pa or less. A method for manufacturing a liquid crystal display device, which is a silicon nitride film. In any one of Claims 1 thru | or 7,
The method for manufacturing a liquid crystal display device, wherein the inorganic insulating film is a silicon nitride film having an argon concentration of 1 × 10 ²⁰ to 1 × 10 ²¹ cm ⁻³ . A first flexible substrate, a second flexible substrate, and a liquid crystal held between a pair of substrates composed of the first flexible substrate and the second flexible substrate. A liquid crystal display device comprising
An inorganic insulating film provided only on one side of the first flexible substrate; and an inorganic insulating film provided only on one side of the second flexible substrate;
A pixel electrode provided on the inorganic insulating film of the first flexible substrate, and a counter electrode provided under the inorganic insulating film of the second flexible substrate,
A columnar spacer for keeping the distance between the pair of substrates constant,
The liquid crystal display device, wherein the pair of substrates are bonded together with a sealing material having a closed pattern shape. In claim 9,
The liquid crystal display device, wherein the inorganic insulating film is a silicon nitride film having an argon concentration of 1 × 10 ²⁰ to 1 × 10 ²¹ cm ⁻³ . In claim 9 or claim 10,
The liquid crystal display device, wherein the inorganic insulating film is a silicon nitride film having a hydrogen concentration of 1 × 10 ²¹ cm ⁻³ or less. In claim 9 or claim 10,
The liquid crystal display device, wherein the inorganic insulating film is a silicon nitride film having a hydrogen concentration of 1 × 10 ²¹ cm ⁻³ or less and an oxygen concentration of 5 × 10 ^{18 to} 5 × 10 ²¹ cm ⁻³ . A first flexible substrate, a second flexible substrate, and a liquid crystal held between a pair of substrates composed of the first flexible substrate and the second flexible substrate. A liquid crystal display device comprising
An inorganic insulating film made of a multilayer film of a silicon nitride film and a silicon oxide film provided only on one side of the first flexible substrate, and provided only on one side of the second flexible substrate An inorganic insulating film composed of a multilayer film of a silicon nitride film and a silicon oxide film,
A pixel electrode provided on the inorganic insulating film of the first flexible substrate, and a counter electrode provided under the inorganic insulating film of the second flexible substrate,
A columnar spacer for keeping the distance between the pair of substrates constant,
The liquid crystal display device, wherein the pair of substrates are bonded together with a sealing material having a closed pattern shape. In claim 13,
The silicon nitride film has an argon concentration of 1 × 10 ²⁰ to 1 × 10 ²¹ cm ⁻³ . In claim 13 or claim 14,
2. The liquid crystal display device according to claim 1, wherein the silicon nitride film has a hydrogen concentration of 1 × 10 ²¹ cm ⁻³ or less. In claim 13 or claim 14,
The liquid crystal display device, wherein the silicon nitride film has a hydrogen concentration of 1 × 10 ²¹ cm ⁻³ or less and an oxygen concentration of 5 × 10 ^{18 to} 5 × 10 ²¹ cm ⁻³ . In any one of Claims 9 thru | or 16,
The liquid crystal display device is of an active matrix type. In any one of Claims 9 thru | or 16,
The liquid crystal display device is a passive type liquid crystal display device. In any one of claims 9 to 18,
The liquid crystal display device is a video camera, a digital camera, a display, a car navigation system, a personal computer, or a portable information terminal.

Images