JPH05273600A - Plastic substrate for thin-film laminated device and thin-film laminated device with the same - Google Patents

Abstract

PURPOSE:To provide a plastic substrate which is light in weight and low in cost, is free from film peeling, crack, substrate curl, etc., and can form the thin-film laminated device operating stably over a long period of time, the thin-film laminated device constituted by using this substrate and the liquid crystal display device constituted by using this device as a switching element. CONSTITUTION:This plastic substrate for the thin-film laminated device is constituted by forming thin films 2a, 2b consisting of an inorg. material and more particularly, the thin films 2a, 2b consisting of the inorg. material having 0.04Cal/cm.S. deg.C thermal conductivity at room temp. to 200 deg.C or >=5X10<6>/ deg.C coefft. of thermal expansion at the above-mentioned temp. on at least one surface of a plastic substrate 1 and more particularly the plastic substrate 1 which has a crystalline property and is unstretched or biaxially stretched.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thin film laminated device, and more particularly to a switching element which can be suitably used for a flat panel display for OA equipment or TV.

[0002]

2. Description of the Related Art There is a strong demand for the use of a large-area liquid crystal panel for OA equipment terminals and liquid crystal TVs. Therefore, in the active matrix system, a switch is provided for each pixel to hold a voltage (special feature). Kaisho 61-2602
19, JP-A-62-62333). On the other hand, in recent years, liquid crystal panels have been actively reduced in weight and cost, and the use of plastic as a substrate in simple matrix liquid crystal panels has been studied (Japanese Patent Laid-Open No. 1-47769).
A conventional plastic substrate for liquid crystal display uses low birefringence because polarized light is used for display. Therefore, usable plastic substrates are structurally isotropic amorphous ones, or crystalline ones are limited to polyethylene terephthalate (1-PET) films that are precisely uniaxially stretched [. T. Umeda, T .; Miyashi
ta, and F.I. Nakano, SID Symp.
Dig. Tech. Paper, P.P. 178 (198
2)]. However, the 1-PET substrate is for a simple matrix type liquid crystal display, and it is difficult to fabricate a finely processed thin film laminated device due to its structural anisotropy.
Therefore, there has been no example in which a thin film laminated device, in particular, an active element for driving a liquid crystal is manufactured on a crystalline plastic substrate. Also, on the plastic substrate,
The thin film laminated switching element formed has a problem such as deformation and curling of the plastic substrate and film peeling. For example, when a thin film laminated device is formed into a fine pattern, expansion and contraction of the substrate causes a pattern shift, which makes it difficult to collectively expose a large area. In addition, the anisotropy of substrate expansion and contraction makes pattern formation more difficult. Furthermore, when the thin film laminated device is manufactured on a plastic substrate and then driven by a predetermined method, the thin film laminated device is peeled off from the plastic substrate.
Further, when the thin film laminated device is used as a liquid crystal driving element, the problem of peeling between the thin film laminated device and the plastic substrate becomes more remarkable when the driving voltage of the liquid crystal or polymer dispersed liquid crystal is high. Furthermore, when manufacturing the thin film stack switching element, there is a photolithography step of immersing the plastic in a solution of acid, alkali, water, etc., and the acid, alkali, water, etc. remain in the plastic,
It caused the element deterioration. In order to avoid this, it is conceivable to form a thin film made of an inorganic material on at least one surface of the plastic substrate (the surface on which the thin film laminated device is formed), preferably both surfaces. As such an inorganic substance, the inventors have proposed SiOx, SiNx, SiOxNy, or a laminate thereof in view of adhesion to a plastic substrate, permeability of various solutions, etc. (Japanese Patent Application No. 2- 417313, Japanese Patent Application No. 3-18933
6). In addition, in the production of a liquid crystal display device using a plastic film substrate, it was necessary to carry out an alignment method peculiar to plastic during the alignment treatment. Therefore, it is known that by forming an SiO ₂ layer on one side of a plastic film, the alignment treatment can be performed in the same manner as a glass substrate (Japanese Patent Publication No. 1-47769).

[0003]

An object of the present invention is to solve the above-mentioned conventional problems and to provide a light-weight, low-cost substrate for a thin film laminated device having good reliability without film peeling, cracks, curl, etc., and a thin film laminated device with a substrate using the substrate. Furthermore, it is an object of the present invention to provide a liquid crystal display device using the thin film laminated device.

[0004]

[Structure] The structure of the present invention will be described in detail below. A first aspect of the present invention is to form a thin film made of an inorganic substance on at least one surface of the substrate, preferably one surface on the thin film lamination device side, and more preferably both surfaces, in the thin film lamination device using a plastic substrate as described above. Is essential. Such inorganic materials include SiO ₂ , SiO,
SiON, SiO: H, SiN: H, SiON: H, S
i ₃ N ₄ , TiO ₂ , ZnS, ZnO, Al ₂ O ₃ , Al
N, MgO, GeO, ZrO ₂ , Nb ₂ O ₅ , SiC, T
a ₂ O ₅ , BeO, BN, diamond, SiO: F, S
_{iO 2: F, SiOx: F} , Si 3 N 4: F, SiNx:
F, SiON: F, SiC: F, SiOx: CFy and the like can be mentioned. These inorganic substances are formed by a sputtering method, a vapor deposition method, a plasma CVD method or the like with a thickness of 300 to 15,000 Å, preferably 1,000 to 10,000 Å and a predetermined stress. The formed thin film does not necessarily need to have the same inorganic substance on both surfaces, and does not have to have the same film thickness. Furthermore, the thin film may be a laminate of two or more layers, especially layers of different kinds of inorganic substances, as in the invention previously filed by the applicant (Japanese Patent Application No. 2-417313). When the thin film layered device is used for a liquid crystal display drive element, it is preferable that the transmittance of an inorganic substance is 75% or more at a wavelength of 400 to 850 nm in order to secure display contrast. When thin films are formed on both sides of a plastic substrate, if they are formed on each side, the substrate curls immediately after forming on one side only. In addition, since it is necessary to form a thin film on each side, there are problems in productivity and cost. Therefore, it is preferable to simultaneously form the inorganic material thin films on both surfaces. Generally, the curl of the substrate is
It is determined by the internal stress of the thin film formed on the substrate. Further, the thermal stress caused by the temperature at the time of forming the thin film becomes a problem in the plastic substrate having a large linear expansion coefficient. Therefore, in order to form a thin film laminated device on a plastic substrate and obtain a flat one, a substrate structure having a stress that cancels internal stress and thermal stress generated when the thin film laminated device is manufactured is required. When using a substrate formed with a thin film made of an inorganic material on both sides of the present invention,
A thin film made of an inorganic substance having a stress as shown in the formula below is required. Stress of thin film laminated device (2, 6, 7 of FIG. 1) + stress of second inorganic material layer (2b of FIG. 1) = stress of first inorganic material layer (2a of FIG. 1) First and second inorganic When the substances are materials having the same composition and the same quality, the stress is determined by the film thickness. Therefore, it is easy to control the stress of the plastic substrate having the inorganic substance formed on both sides by controlling the film thickness of the inorganic substance. However, even when a thin film of an inorganic substance as described above is provided, the device generates Joule heat when the thin film laminated device is continuously driven under a constant driving condition. If the difference in the coefficient of thermal expansion is large, a large thermal stress is generated, and the thin film peels from the substrate. Generally, the coefficient of thermal expansion of plastics is larger than that of inorganic substances, but in order to avoid the above phenomenon, the coefficient of thermal expansion of inorganic substances is 5 × 10 ⁻⁶ / ° C. or more at room temperature to 200 ° C. Turned out to be necessary. Such a substance is A
L ₂ O ₃ , BeO, MgO, AlN, ZrO _{2 and the} like can be mentioned, but ZrO ₂ is particularly preferable in terms of process resistance, environment resistance and the like. If necessary, a thin film made of another substance may be formed on the thin film made of such a substance. Further, since the thin-film laminated device generates Joule heat as described above, even if the thermal conductivity of the thin film made of an inorganic substance provided on the plastic substrate is smaller than that of the plastic substrate, the thin film will be affected by thermal stress. Peel off the substrate. In order to avoid this, the thermal conductivity of the inorganic substance is 0.04 Cal / cm · S · ° C at room temperature to 200 ° C.
It was necessary to be above. Examples of such a material include Al ₂ O ₃ , BeO, MgO, AlN, BN, diamond and the like, and AlN and BN are particularly preferable in terms of process resistance, environment resistance, film forming property and the like. In the present invention, a thin film of an inorganic substance having a thermal conductivity of 0.04 Cal / cm · S · ° C. or higher or a thermal expansion coefficient of 5 × 10 ⁻⁶ / ° C. or higher at room temperature to 200 ° C. However, it may be composed of two or more kinds of laminated thin film layers, as in the invention previously filed (Japanese Patent Application No. 2-417313). Also, these thin film layers can be formed by depositing the above-mentioned inorganic substance to a thickness of several hundred Å to several μm by a sputtering method, a plasma CVD method, an ion plating method, a coating method or the like.

A second aspect of the present invention is the use of heat resistant polymer substrates, especially crystallized polymer substrates. The types of materials constituting the plastic substrate used in the present invention are
Although not particularly limited, polyethylene terephthalate (P
ET), polyethylene naphthalate (PEN), polyimide (PI), polyphenylene sulfide (PP)
S), polyether ether ketone (PEEK), polyether sulfone (PES), polyamide (PA), polyacrylate, and other heat resistant polymers. In particular, as a result of repeated studies, the inventors of the present invention have found that the deformation of the plastic substrate in the device manufacturing process is the biggest problem in the case of the plastic film. Furthermore, we found that the causes of deformation and curling of this plastic film were internal stress of the laminated thin film, thermal expansion and contraction of the plastic, swelling with acid, alkali, water, etc., and crystallized plastic substrate with a more dense structure. It became clear that it was effective to use. As the crystallinity, when the crystallinity is small, the elastic modulus is lowered, the thermal expansion coefficient is increased, the water absorption is increased,
This causes an increase in air permeability, which is not preferable as a substrate for thin film lamination. On the other hand, when the crystallinity is high, the impact resistance is lowered, which is also unfavorable as a thin film laminating substrate. Therefore, the crystallinity of the plastic substrate is 10
~ 90%, preferably 15-85%. The crystallinity of the plastic substrate can be controlled by the production temperature such as the melt cooling temperature. Further, as the crystallized plastic substrate, not only an unstretched one but also a stretched one,
In particular, it is also possible to use a crystallized plastic film while biaxially stretching. Further, it is desirable that the plastic having these crystalline materials is subjected to a secondary treatment with ozone, plasma, light, and heat to obtain a plastic surface suitable for a substrate for a thin film laminated device. The thickness of these plastics should be 50 μm to 2 mm, or 5
It is preferably 00 μm or less, and particularly preferably 300 μm or less.

A third aspect of the present invention is the use of a MIM type element having a metal-insulator-metal structure. The thin film laminated device of the present invention includes a MIM having a metal-insulator-metal layer structure.
Type element, MSI element (Metal-Semi-Insulat) referred to in JP-A-61-275811.
or), SIS (Se of semiconductor-insulator-semiconductor layer structure)
microphone-Insulator-Sem
element, the MI of metal-insulator-metal-insulator-metal described in JP-A-64-7577.
There are MIM elements and the like. Among them, the MIM type element using a hard carbon film as an insulator is advantageous. By using the hard carbon film as the insulating film, the maximum manufacturing process temperature became 140 ° C. or lower. Further, by using a hard carbon film, a device design in a wide range is possible, and there is little variation in device characteristics, and a thin film two-terminal device with excellent threshold voltage and withstand voltage and good yield can be obtained. However, when the hard carbon film is used as the insulating layer, the plastic substrate (film) is greatly curled, so that the rigidity of the substrate is increased by forming the inorganic substance film on both surfaces of the substrate.

Next, the manufacturing method of the MIM element will be described with reference to FIGS.
This will be described in detail with reference to FIG. First, a transparent electrode material for pixel electrodes is deposited by a method such as vapor deposition and sputtering on a plastic substrate 1 having both surfaces coated with the above-mentioned inorganic substance 2a, 2b or not coated, and patterned into a predetermined pattern to form a pixel. The electrode 4 is used. Next, a conductor thin film for the lower electrode is formed by a method such as vapor deposition and sputtering,
The first conductor 7 to be a lower electrode is patterned into a predetermined pattern by wet or dry etching, and the hard carbon film 2 is coated thereon by a plasma CVD method, an ion beam method or the like, and then dry etching, wet etching or resist is applied. The second conductor that is patterned into a predetermined pattern by the lift-off method used to form an insulating film, and then is covered with a conductor thin film for a bus line by a method such as vapor deposition or sputtering and patterned into a predetermined pattern to form a bus line. 6 is formed, and finally, an unnecessary portion of the lower electrode is removed to expose the transparent electrode pattern to form the pixel electrode 4. In this case, the configuration of the MIM element is not limited to this, and after the MIM element is manufactured, a transparent electrode is provided on the uppermost layer, a transparent electrode also serves as an upper or lower electrode, and a side surface of the lower electrode. Various modifications are possible, such as the one in which the MIM element is formed. Here, the thickness of the lower electrode, the upper electrode and the transparent electrode is usually several hundred to several thousand Å,
The range is several hundred to several thousand Å and several hundred to several thousand Å. The thickness of the hard carbon film is 100 to 8000Å, preferably 200 to 6
000Å, more preferably 300 to 4000Å. Further, in the case of a plastic substrate, it has been very difficult to manufacture an active matrix device using an active element because of its heat resistance. However, a hard carbon film can be formed into a good quality film at a substrate temperature of about room temperature, and can be formed even on a plastic substrate, which is a very effective image quality improving means. Next, the material of the MIM element used in the present invention will be described in more detail. As the material of the first conductor 7 which becomes the lower electrode, Al, Ta, Cr, W, Mo, P
t, Ni, Ti, Cu, Au, W, ITO, ZnO: Al, In
Various conductors such as ₂ O ₃ and SnO ₂ are used. Next, as the material of the second conductor 6 which becomes the bus line, Al, Cr, N
i, Mo, Pt, Ag, Ti, Cu, Au, W, Ta, ITO,
Various conductors such as ZnO: Al, In ₂ O ₃ and SnO ₂ are used, but Ni, Pt, and Ag are preferable from the viewpoint that stability and reliability of IV characteristics are particularly excellent. It is understood that the MIM element using the hard carbon film 2 as the insulating film does not change the symmetry even if the type of the electrode is changed, and the pool Frenkel type conduction is obtained from the relation of lnI∝√V. Further, from this, it is understood that in the case of this type of MIM element, the upper electrode and the lower electrode may be combined in any manner. However, the device characteristics (IV characteristics) are deteriorated and changed depending on the adhesion between the hard carbon film and the electrodes and the state of the interface. Considering these, it was found that Ni, Pt, and Ag are preferable. The current-voltage characteristic of the MIM element of the present invention is shown in FIG. 4, and is approximately expressed by the following conduction equation.

[0008]

[Equation 1] I: Current V: Applied voltage κ: Conductivity coefficient β: Pool Frenkel coefficient n: Carrier density μ: Carrier mobility q: Electron charge Φ: Trap depth ρ: Specific resistance d: Hard carbon film thickness (Å) k : Boltzmann's constant T: Atmospheric temperature ε ₁ : Dielectric constant of hard carbon ε ₂ : Vacuum permittivity

Next, the hard carbon film used in the present invention will be described in detail. This film is also called a hard carbon film (i-C film, diamond-like carbon film, amorphous diamond film, diamond thin film) containing at least one of amorphous and microcrystalline with carbon and hydrogen atoms as the main texture-forming elements. ). One of the characteristics of the hard carbon film is the vapor phase growth film, so that its various physical properties can be controlled in a wide range by the film forming conditions, as will be described later. Therefore, even if it is called an insulating film, its resistance value covers the region from the semi-insulator to the insulator. In this sense, the thin film two-terminal element of the present invention is not limited to the MIM element. The MSI element (Metal-Semi-In) referred to in Japanese Patent Laid-Open No. 61-260219.
SIS (Semiconductor) and SIS (Semiconductor)
or-Insulator-Semiconductor
r) It is also positioned as an element (semiconductor-insulator-semiconductor, in which the "semiconductor" is one doped with a high concentration of impurities). An organic compound gas, particularly a hydrocarbon gas is used to form the hard carbon film. The phase state of these raw materials does not necessarily have to be a gas phase at room temperature and normal pressure, and a liquid phase or a solid phase can be used as long as it can be vaporized through melting, evaporation, sublimation, etc. by heating or pressure reduction. is there. Regarding hydrocarbon gas as a raw material gas, for example, CH ₄ , C ₂ H ₆ , C ₃
Paraffinic hydrocarbons such as H ₈ and C ₄ H ₁₀ , acetylene hydrocarbons such as C ₂ H ₂ , olefinic hydrocarbons, diolefinic hydrocarbons, and all hydrocarbons such as aromatic hydrocarbons. At least gas containing can be used. In addition to hydrocarbons, compounds containing at least a carbon element such as alcohols, ketones, ethers, esters, CO and CO ₂ can be used. As a method for forming a hard carbon film from a source gas in the present invention, a method in which a film-forming active species is formed through a plasma state generated by a plasma method using direct current, low frequency, high frequency, or microwave However, since the deposition is performed under a low pressure for the purpose of increasing the area, improving the uniformity, and forming a film at a low temperature, a method of utilizing the magnetic field effect is more preferable.
Active species can also be formed by thermal decomposition at high temperature. Besides, it may be formed through an ionic state generated by an ionization vapor deposition method, an ion beam vapor deposition method, or the like, or may be formed from neutral particles generated by a vacuum vapor deposition method, a sputtering method, or the like. However, it may be formed by a combination thereof.

An example of deposition conditions for the hard carbon film thus produced is as follows in the case of the plasma CVD method. RF output: 0.1 to 50 W / cm ² Pressure: 10 ^{−3 to} 10 Torr Deposition temperature: Room temperature to 350 ° C., preferably room temperature to 250 ° C. This plasma state causes the source gas to decompose into radicals and ions to react. By the carbon atom C on the substrate
A hard carbon film containing at least one of amorphous and microcrystalline (the crystal size is several tens of .mu.m to several .mu.m) composed of and hydrogen atoms H is deposited. Table 1 shows various characteristics of the hard carbon film.

[0011]

[Table 1] Note) Measurement method; Specific resistance (ρ): Determined from the IV characteristics of a coplanar cell. Optical bandgap (Egopt): Absorption coefficient (α) is obtained from the spectral characteristics, and is determined from the relationship of Equation 2.

[0012]

[Equation 2] Amount of hydrogen in film [C (H)]: 29 from infrared absorption spectrum
The peak near 00 / cm is integrated, and it is determined by multiplying by the absorption cross section A. That is, [C (H)] = A · ∫α (ν) / ν · dν SP ³ / SP ² ratio: infrared absorption spectrum of SP ³ , SP ²
It is decomposed into the Gaussian functions respectively assigned to, and calculated from the area ratio. Vickers hardness (H): By micro Vickers meter. Refractive index (n): By ellipsometer. Defect density: According to ESR.

The hard carbon film thus formed is analyzed by Raman spectroscopy and IR absorption, and the results are shown in FIGS.
And as shown in 7 and 7, hybrid orbitals with carbon atoms of SP ³ and SP ²
It has been clarified that the interatomic bonds forming the mixed orbitals of are mixed. The ratio of SP ³ bond to SP ² bond can be roughly estimated by separating peaks in the IR spectrum. IR spectrum shows 2800 to 3150 cm ^-1
The spectra of many modes are overlapped and are measured,
The attribution of the peaks corresponding to the respective wave numbers has been clarified. As shown in FIG. 5, the peaks are separated by the Gaussian distribution, the respective peak areas are calculated, and the ratio is calculated to obtain S.
It is possible to know the P ³ / SP ^2. Further, it has been found by X-ray and electron diffraction analysis that it is in an amorphous state (a-C: H) and / or in an amorphous state containing fine crystal grains of about 50Å to several µm. Generally, in the case of the plasma CVD method suitable for mass production, the smaller the RF output, the more the specific resistance value and hardness of the film increase, and the lower the pressure, the longer the life of active species. The area can be made uniform, and the specific resistance and hardness tend to increase. Furthermore, at low pressure the plasma density decreases,
The method utilizing the magnetic field confinement effect is particularly effective for increasing the specific resistance. Furthermore, this method is also suitable for lowering the temperature of the MIM element manufacturing process because it has the characteristic that a good quality hard carbon film can be formed even under relatively low temperature conditions of room temperature to 150 ° C. Therefore, the degree of freedom in selecting the substrate material to be used is widened, and since the substrate temperature can be easily controlled, a uniform film can be obtained in a large area. Further, as shown in Table 1, the structure and physical properties of the hard carbon film can be controlled in a wide range, so that there is also an advantage that the device characteristics can be freely designed. Furthermore, the relative permittivity of the film is 2 to 6, which is Ta ₂ used in the conventional MIM element.
For O _5, Al ₂ O _3, small compared with SiNx, when making elements having the same capacitance, since the need to increase the element size, without the need for much fine processing, yield is improved (driving condition Therefore, the capacitance ratio between the LCD and the MIM element needs to be about C (LCD) / C (MIM) = 10: 1). Since the element steepness is β∝1 / √ε · √d, the steepness increases as the relative permittivity ε decreases.
A large ratio of the on-current Ion and the off-current Ioff can be taken. Therefore, the LCD can be driven with a lower duty ratio, and a high-density LCD can be realized. Further, since the hardness of the film is high, there is little damage due to the rubbing process when the liquid crystal material is filled, and the yield is improved also from this point. In consideration of the above points, by using a hard carbon film, low cost, gradation (colorization), and high density LCD can be realized.
Furthermore, this hard carbon film has carbon atoms and hydrogen atoms,
Group III elements, Group IV elements, Group V elements of the periodic table,
Alkali metal elements, alkaline earth metal elements, nitrogen atoms,
An oxygen element, a chalcogen element, or a halogen atom may be included as a constituent element. Those in which a Group III element of the periodic table, a Group V element, an alkali metal element, an alkaline earth metal element, a nitrogen atom or an oxygen atom is introduced as one of the constituent elements is a non-doped hard carbon film. It is possible to make the thickness about 2 to 3 times larger than that of the above, and by this, it is possible to prevent the occurrence of pinholes at the time of manufacturing the element and to dramatically improve the mechanical strength of the element. Further, in the case of a nitrogen atom or an oxygen atom, the periodic table IV as described below is used.
It has the same effect as in the case of group elements. Similarly, the periodic table
Introducing a group IV element, a chalcogen-based element, or a halogen element dramatically improves the stability of the hard carbon film and also improves the hardness of the film, so that a highly reliable element can be manufactured. These effects are obtained because the active double bond existing in the hard carbon film is reduced in the case of the group IV element and the chalcogen element, and in the case of the halogen element, 1) the abstraction to hydrogen The reaction accelerates the decomposition of the raw material gas to reduce the dangling bonds in the film, and 2) during the film formation process, the halogen element X abstracts out hydrogen in the C—H bond and replaces it with C—X bond. This is because it enters into the film and the binding energy increases (the binding energy between C-H and between C-X is larger between C-X). In order to use these elements as constituent elements of the film, in addition to hydrocarbon gas and hydrogen as source gas, a group III element, a group IV element and a group V element of the periodic table are contained in the film as dopants. In order to contain an element, an alkali metal element, an alkaline earth metal element, a nitrogen atom, an oxygen atom, a chalcogen element or a halogen element, a compound (or molecule) containing these elements or atoms (hereinafter, these are referred to as `` other Sometimes referred to as "compound") gas is used. Examples of the compound containing a Group III element of the periodic table include B (OC ₂ H
₅ ) ₃ , B ₂ H ₆ , BCl ₃ , BBr ₃ , BF ₃ , Al (O-
_{i-C 3 H 7) 3} , (CH 3) 3 Al, (C 2 H 5) 3 Al,
_{(I-C 4 H 9)} 3 Al, AlCl 3, Ga (O-i-C 3
H ₇ ) ₃ , (CH ₃ ) ₃ Ga, (C ₂ H ₅ ) ₃ Ga, GaC
_{l 3, GaBr 3, (O} -i-C 3 H 7) 3 In, (C
₂ H ₅ ) ₃ In and the like. Examples of the compound containing a Group IV element of the periodic table include Si ₂ H ₆ , (C ₂ H ₅ ) ₃ SiH,
SiF ₄ , SiH ₂ Cl ₂ , SiCl ₄ , Si (OC
_{H 3) 4, Si (OC} 2 H 5) 4, Si (OC 3 H 7) 4, Ge
Cl ₄ , GeH ₄ , Ge (OC ₂ H ₅ ) ₄ , Ge (C
₂ H ₅ ) ₄ , (CH ₃ ) ₄ Sn, (C ₂ H ₅ ) ₄ Sn, SnCl
There is ₄ mag. Examples of the compound containing a Group V element of the periodic table include PH ₃ , PF ₃ , PF ₅ , PCl ₂ F ₃ and PC.
l ₃ , PCl ₂ F, PBr ₃ , PO (OCH ₃ ) ₃ , P (C _{2
H 5) 3, POCl 3,} AsH 3, AsCl 3, AsBr 3,
_{AsF 3, AsF 5, AsCl 3} , SbH 3, SbF 3, S
bCl ₃ , Sb (OC ₂ H ₅ ) _{3 and the} like. As the compound containing an alkali metal atom, for example _{LiO-i-C 3 H 7} ,
_{NaO-i-C 3 H 7} , there is KO-i-C ₃ H ₇ or the like. Examples of the compound containing an alkaline earth metal atom include Ca
(OC ₂ H ₅ ) ₃ , Mg (OC ₂ H ₅ ) ₂ , (C ₂ H ₅ ) ₂ Mg
Etc. Examples of the compound containing a nitrogen atom include an inorganic compound such as nitrogen gas and ammonia, an organic compound having a functional group such as an amino group and a cyano group, and a heterocycle containing nitrogen. Examples of the compound containing an oxygen atom include oxygen gas, ozone, water (water vapor), hydrogen peroxide, carbon monoxide,
Inorganic compounds such as carbon dioxide, carbon suboxide, nitric oxide, nitrogen dioxide, dinitrogen trioxide, dinitrogen pentoxide, nitric oxide, hydroxyl group, aldehyde group, acyl group, ketone group, nitro group, nitroso group, sulfone Examples thereof include organic compounds having functional groups or bonds such as groups, ether bonds, ester bonds, peptide bonds, oxygen-containing heterocycles, and metal alkoxides. Examples of the compound containing a chalcogen-based element include H ₂ S, (CH ₃ ) (CH ₂ ) ₄ S (CH ₂ ) ₄ CH ₃ ,
CH ₂ = CHCH ₂ SCH ₂ CH = CH ₂ , C ₂ H ₅ SC
₂ H ₅ , C ₂ H ₅ SCH ₃ , thiophene, H ₂ Se, (C ₂ H ₅ ) ₂
Se, H ₂ Te, etc. are available. Examples of the compound containing a halogen element include fluorine, chlorine, bromine, iodine, hydrogen fluoride,
Carbon fluoride, chlorine fluoride, bromine fluoride, iodine fluoride, hydrogen chloride,
Inorganic compounds such as bromine chloride, iodine chloride, hydrogen bromide, iodine bromide and hydrogen iodide, and organic compounds such as alkyl halides, aryl halides, styrene halides, polymethylene halides and haloforms are used. Liquid crystal drive MIM
A hard carbon film suitable as an element has a film thickness of 1 depending on driving conditions.
It is advantageous that the specific resistance is from 00 to 8000Å and the specific resistance is from 10 ⁶ to 10 ¹³ Ω · cm. The film thickness is 200Å considering the margin between the driving voltage and the breakdown voltage (dielectric breakdown voltage).
It is desirable that the thickness be 6000Å or less in order to prevent color unevenness due to a step (cell gap difference) between the pixel portion and the thin film two-terminal element portion from becoming a practical problem. Therefore, the hard carbon film has a film thickness of 200 to 6000Å and a specific resistance of 5 × 10 ⁶ to 10 ¹³ Ω · c.
More preferably m. The number of defects in the device due to pinholes in the hard carbon film increases as the film thickness decreases,
It becomes particularly remarkable below 300 Å (defect rate exceeds 1%), and it becomes impossible to secure the uniformity of the in-plane distribution of film thickness (and thus the uniformity of device characteristics) (the accuracy of film thickness control is about 30 Å However, since the variation of the film thickness exceeds 10%), it is more preferable that the film thickness is 300 Å or more. Further, in order to prevent the hard carbon film from peeling off due to stress and to drive at a lower duty ratio (desirably 1/1000 or less), the film thickness is 40
It is more desirable that it is less than 00Å. Taking these factors into consideration, the thickness of the hard carbon film is 300 to 4000.
Å, It is more preferable that the specific resistance is 10 ⁷ to 10 ¹¹ Ω · cm.

Next, a method of manufacturing a liquid crystal display device will be described with reference to FIG. First, on the insulating substrate 1 ', a transparent conductor for the common electrode 4', such as ITO, ZnO: Al, ZnO: Si, Sn.
Sputtering O _2, In ₂ O _3, etc., it is several μm deposited from several hundred Å by vapor deposition or the like, and patterned into a stripe shape and the common electrode 4 '. Substrate 1'provided with this common electrode 4 '
Then, an alignment material 8 such as polyimide is attached to each surface of the substrate 1 on which MIM elements are previously provided in a matrix, a rubbing process is performed, a sealing material is attached, and a gap material 9 is inserted to make the gap constant, 3 is enclosed to form a liquid crystal display device. In this way, a liquid crystal display device is obtained. When a polymer-liquid crystal composite is used for the liquid crystal 3 and a light scattering mode display is formed, it is not necessary to provide the alignment film 8. As the polymer material in the polymer-liquid crystal composite,
Polymethylmethacrylate, polystyrene, polyfumarate, polyethylene oxide and the like can be used. Of these, polyfumarate, which is a rigid polymer, is preferable. As a liquid crystal material, T which has been used for conventional liquid crystal displays
N liquid crystal or the like can be used. The structure of the polymer-liquid crystal composite includes a system in which liquid crystal is dispersed in a droplet form in the polymer and a system in which liquid crystal forms a continuous phase in the polymer. Either system can be used in the present invention. These composite layers can be prepared by casting a polymer-liquid crystal solution using chloroform as a solvent. It can also be prepared by a method in which a monomer and a liquid crystal are mixed and then photopolymerized.

[0015]

EXAMPLES Examples of the present invention are shown below, but the present invention is not limited to these. Example 1 A ZrO ₂ film was formed on a PET substrate by sputtering.
000Å accumulated. Next, the thin film two-terminal element shown in FIG. 2 was produced as follows. First, ITO was deposited to a thickness of 700 Å by a sputtering method and then patterned to form the pixel electrode 4. Then, Al was deposited to a volume of 1000 Å by a vapor deposition method and then patterned to form a lower conductor 7. A hard carbon film was deposited thereon as an insulating film 2 by a plasma CVD method for 1100 Å, and then patterned by dry etching. Further, Ni was deposited thereon to a thickness of 1000 Å by EB vapor deposition and then patterned to form the upper conductor 6. At this time, the conditions for forming the hard carbon film are as follows. Pressure: 0.035 Torr CH ₄ Flow rate: 10 SCCM RF power: 0.3 W / cm ²

Example 2 ZrO was sputtered on a polyarylate substrate.
After depositing ₂ 3,000 liters of film, sputter the Si
An Nx film was deposited at 1500Å. Next, the thin film two-terminal element shown in FIG. 9 was produced as follows. First, ITO was deposited to a thickness of 700 Å by a sputtering method and then patterned to form the pixel electrode 4. Next, Al is deposited by vapor deposition to 60
After being deposited to a thickness of 0Å, the lower conductor 1 was formed by patterning. A hard carbon film is formed thereon by plasma CVD 15
After depositing 00Å, Ni is 1000 by EB evaporation.
Å Deposited. The Ni and the hard carbon film were sequentially etched to form the upper conductor 3 and the insulating film 2. At this time, the conditions for forming the hard carbon film are as follows. Pressure: 0.035 Torr CH ₄ Flow rate: 10 SCCM RF power: 0.6 W / cm ²

Example 3 AlN was formed on a polyarylate substrate by a sputtering method.
After depositing 2000 Å film, sputter method
The x film was deposited at 3000Å. Next, the thin film two-terminal element shown in FIG. 9 was produced in the same manner as in Example 2.

Example 4 An AlN film was formed on a PET substrate by sputtering with a mixed gas of Ar and N ₂ to form an AlN film of 4000 Å.
Deposited. Next, the thin film two-terminal element shown in FIG. 2 was produced as follows. First, ITO is sputtered
After being deposited to a thickness of 00Å, the pixel electrode 4 was formed by patterning. Then, Al was deposited to a volume of 1000 Å by a vapor deposition method and then patterned to form a lower conductor 7. A hard carbon film as an insulating film 2 is formed thereon by a plasma CVD method 1100.
Å After depositing, patterning was performed by dry etching. Further, Ni is deposited thereon by EB vapor deposition to 1000
After being deposited to a thickness of Å, the upper conductor 6 was formed by patterning. At this time, the conditions for forming the hard carbon film are as follows. Pressure: 0.035 Torr CH ₄ Flow rate: 10 SCCM RF power: 0.3 W / cm ²

Example 5 A BN film was deposited on a polyarylate substrate by an ion plating method in an amount of 3000 liters. Next, the thin film two-terminal element shown in FIG. 9 was produced as follows. First, ITO was deposited to a thickness of 700 Å by a sputtering method and then patterned to form the pixel electrode 4. Next, Al is deposited by vapor deposition to 60
After being deposited to a thickness of 0Å, the lower conductor 1 was formed by patterning. A hard carbon film is formed thereon by plasma CVD 15
After depositing 00Å, Ni is 1000 by EB evaporation.
Å Deposited. The Ni and the hard carbon film were sequentially etched to form the upper conductor 3 and the insulating film 2. At this time, the conditions for forming the hard carbon film are as follows. Pressure: 0.035 Torr CH ₄ Flow rate: 10 SCCM RF power: 0.6 W / cm ²

Example 6 SiO was sputtered on a polyarylate substrate.
After depositing the x film at 4000Å, the AlN film was deposited at 2000Å. Next, the thin film two-terminal element shown in FIG. 9 was manufactured in the same manner as in Example 5.

Example 7 As shown in FIG. 1, a SiO ₂ thin film (2a, 2b) having a thickness of about 2000 Å was formed on both sides of a biaxially stretched polyethylene naphthalate film 1 having a thickness of 100 μm by a sputtering method. Next, an ITO thin film was deposited on SiO ₂ to a thickness of about 1000 Å by a sputtering method and then patterned to form a pixel electrode. Next, the MIM element was provided as follows. First, Al is deposited to a thickness of about 1000 Å by vapor deposition and then patterned to form a lower electrode 7, and then,
As the insulating layer 2, a hard carbon film was deposited to a thickness of about 1000 Å by the plasma CVD method and then patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr CH ₄ Flow rate: 10 SCCM RF power: 0.2 W / cm ² Ni was further deposited thereon by EB evaporation to a thickness of about 1000 Å and patterned to form the upper electrode 6.

Example 8 As shown in FIG. 1, Si ₃ was deposited on both sides of a 150 μm thick polyetheretherketone film 1 (crystallinity 45%).
N ₄ is sputtered to form S with a thickness of about 1500Å
An i ₃ N ₄ layer (2a, 2b) was formed. Next, ITO was deposited on Si ₃ N ₄ to a thickness of about 1000 Å by sputtering and then patterned to form a pixel electrode. Next, MIM
The device was provided as follows. First, Al is deposited to a thickness of about 1000 Å by vapor deposition and then patterned to form a lower electrode 7, and a hard carbon film is deposited as an insulating layer 2 thereon to a thickness of about 1000 Å by a plasma CVD method.
It was patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr CH ₄ Flow rate: 10 SCCM RF power: 0.2 W / cm ² Ni was further deposited thereon by EB evaporation to a thickness of about 1000 Å and patterned to form the upper electrode 6.

Example 9 As shown in FIG. 1, a biaxially stretched polyphenylene sulfide film 1 having a thickness of 100 μm was formed with Si ₃ N ₄ thin films (2a, 2b) having a thickness of about 1500Å on both sides. Next, Si ₃ N ₄
Approximately 1000Å ITO thin film on top by sputtering method
After thickly depositing, it was patterned to form a pixel electrode. Next, the MIM element was provided as follows. First, Al is deposited to a thickness of about 1000 Å by vapor deposition and then patterned to form a lower electrode 7, and a hard carbon film as an insulating layer 2 is formed thereon by a plasma CVD method under the same conditions as in Example 1 to a thickness of about 1000 Å. And then patterned by dry etching. Further, Ni was deposited thereon by EB vapor deposition to a thickness of about 1000 Å and patterned to form the upper electrode 6.

Example 10 As shown in FIG. 1, a biaxially stretched polyethylene terephthalate film 1 having a thickness of 100 μm was provided with a SiO ₂ thin film (2b) having a thickness of about 6000Å on one side and about 7,000Å on the other side.
A thick SiO ₂ thin film (2a) was formed by the sputtering method. Next, an ITO thin film was deposited on SiO ₂ to a thickness of about 1000 Å by a sputtering method and then patterned to form a pixel electrode. Next, the MIM element was provided as follows. First, Al is deposited to a thickness of about 1000 Å by vapor deposition and then patterned to form a lower electrode 7, and a hard carbon film as an insulating layer 2 is formed thereon by a plasma CVD method under the same conditions as in Example 1 to a thickness of about 1000 Å. And then patterned by dry etching. Furthermore on this N
i was deposited by EB vapor deposition to a thickness of about 1000 Å and then patterned to form the upper electrode 6. In the MIM element according to each of the above-described examples, film peeling, substrate deformation and substrate curl were not observed. No deterioration of the element was observed even after continuous driving for 200 hours.

Example 11 As shown in FIG. 1, an unstretched polyimide film 1 having a thickness of 300 μm was coated with a SiO ₂ thin film (2
a, 2b) was formed. Next, an ITO thin film was deposited on SiO ₂ to a thickness of about 1000 Å by a sputtering method and then patterned to form a pixel electrode. Next, the MIM element was provided as follows. First, about 10 Al is vapor-deposited.
After depositing to a thickness of 00Å, patterning is performed to form the lower electrode 7,
On top of that, a hard carbon film is formed as a plasma CV as an insulating layer 2.
After being deposited to a thickness of about 1000Å by the D method, it was patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr CH ₄ Flow rate: 10 SCCM RF power: 0.2 W / cm ² Ni was further deposited thereon by EB evaporation to a thickness of about 1000 Å and patterned to form the upper electrode 6.

Example 12 Next, using the liquid crystal drive element manufactured in the above example, FIG.
The liquid crystal display device shown in 1 was manufactured as follows. First,
A transparent conductor for the common electrode 4 ', ITO, is deposited on the insulating substrate 1'by 700 Å by sputtering and patterned into a stripe shape to form the common electrode 4'. Next, MI
A polymer-liquid crystal composite layer 10 was formed by casting a solution of polyfumarate and a liquid crystal E8 in chloroform on a substrate 1 on which M elements were provided in a matrix (a substrate for a liquid crystal drive element manufactured in Examples 1 to 4) and by a solvent evaporation method. Provided. Next, a sealing material was attached, and it was bonded to the common electrode insulating substrate 1 ', and then the reflective layer 11 was provided on the back surface of the MIM element substrate 1 to form a liquid crystal display device. The liquid crystal display device manufactured in this way is
Bright and high-definition display can be obtained without a backlight.
Moreover, since it is lightweight and thin, it has excellent impact resistance and flexibility.

[0027]

[Effect] The thin film laminated device with a substrate of the present invention uses, as a substrate, an unstretched or biaxially stretched plastic substrate having a crystal and / or a substrate on which a coating film of an inorganic substance is formed, There is no deformation or curl of the substrate, low cost and light weight can be achieved. Furthermore, when the thin film laminated device is made into the MIM type element using the hard carbon film as the insulating layer, the hard carbon film becomes 1) plasma CVD method. Since it is manufactured by a vapor phase synthesis method such as, the physical properties can be controlled widely depending on the film forming conditions, and therefore there is a large degree of freedom in device design. 2) It is hard and can be made a thick film, so it is less susceptible to mechanical damage. Also, it can be expected to reduce pinholes by thickening the film. 3) There is no restriction on the substrate material because a good film can be formed even at low temperatures near room temperature. 4) Excellent uniformity of film thickness and film quality. For It is suitable for thin film devices. 5) It has a low dielectric constant, so it does not require high-level microfabrication technology and is therefore advantageous for increasing the area of the device. Furthermore, the low dielectric constant makes the device steep. Since the Ion / Ioff ratio can be obtained, it can be driven at a low duty ratio, and so on. Therefore, a particularly reliable switching element for liquid crystal display is provided, which is extremely useful in industry.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the structure of a thin film device with a substrate of the present invention.

FIG. 2 is an explanatory view of a main part of an example of the MIM element of the present invention.

FIG. 3 is a partial cross-sectional perspective view of a liquid crystal display device incorporating the thin film device with a substrate of the present invention.

4A and 4B are graphs respectively showing an IV characteristic curve and an lnI-√V characteristic curve of a MIM element.

FIG. 5 shows a Gaussian distribution of IR spectrum of a hard carbon film used as an insulating layer of the MIM element of the present invention.

FIG. 6 is a spectrum diagram showing an analysis result of a hard carbon film used as an insulating layer of the MIM element of the present invention, which is separated by a Raman spectrum method.

FIG. 7 is a spectrum diagram showing an analysis result obtained by analyzing a hard carbon film used as an insulating layer of the MIM element of the present invention by an IR absorption method.

FIG. 8 is an explanatory diagram of a liquid crystal display device using a liquid crystal driving element manufactured in an example of the present invention.

FIG. 9 is an explanatory view of a main part of another example of the MIM element of the present invention.

[Explanation of symbols]

 1 plastic substrate 1'plastic substrate 2 hard carbon film 2a inorganic substance layer 2b inorganic substance layer 3 liquid crystal 4 pixel electrode 4'common electrode 5 active element (MIM element) 6 second conductor (bus line) (upper electrode) 7 1st Conductor (lower electrode) 8 Alignment film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuyuki Yamada 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Kenji Kameyama 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Company Ricoh

Claims (7)

[Claims] 1. A thin film laminated device with a substrate, comprising a thin film laminated device on a substrate having a film of an inorganic substance formed on both surfaces or one surface (a surface on which the thin film laminated device is formed) of a plastic substrate. 2. The thin film laminated device with a substrate according to claim 1, wherein the plastic substrate is crystalline and is unstretched or biaxially stretched. 3. The crystallinity of the plastic substrate is 10-9.
It is 0%, The thin film laminated device with a substrate of Claim 2. 4. A thin film of an inorganic material having a thermal conductivity of 0.04 Cal / cm · S · ° C. or more at room temperature to 200 ° C. or a thermal expansion coefficient of 5 × 10 ⁻⁶ / ° C. or more at the temperature. A thin film laminated device with a substrate according to claim 1, 2 or 3. 5. The thin film laminated device with a substrate according to claim 1, wherein the thin film laminated device is a thin film two-terminal element comprising a first conductor layer-insulating layer (hard carbon film) -second conductor layer. device. 6. A plastic substrate having a thermal conductivity of 0.04 Cal / cm · S · ° C. or more at room temperature to 200 ° C. on both sides or one side (the side on which a thin film device is formed),
Alternatively, the coefficient of thermal expansion at the above temperature is 5 × 10 ⁻⁶ / ° C.
A plastic substrate for a thin-film laminated device, which is formed with a thin film of the above-mentioned inorganic material. 7. A liquid crystal display device using the thin film laminated device with a substrate according to claim 1, 2, 3, 4 or 5.