JPH06175117A - Sin film forming plastic substrate and mim element formed by using the substrate - Google Patents

Abstract

PURPOSE:To provide the plastic substrate and MIM element which are light in weight and low in cost and are free from film peeling, cracking or substrate curling by specifying the content of H in SiN films which are surface protective films. CONSTITUTION:The moisture permeation, etc., from the rear surface of a plastic substrate 1 is a problem in the case of production of various devices on this substrate 1. The plasma CVD SiN films 2a, 2b are formed on both surfaces in order to prevent the above-mentioned moisture permeation and to prevent the curing of the substrate in the case of the formation of the film only on the one surface of the plastic substrate 1. Removing of the H is effective in order to obtain the dense SiN films 2a, 2b by a plasma CVD method in such a case and is so executed that the content of the H in the SiN films 2a, 2b attains <=2X10<22>cm<-3>. That halogen elements, such as fluorine, chlorine, iodine and bromine, is incorporated into gaseous raw materials, is effective for removing the H at a low temp. The dense films are obtd. by the halogen-contg. plasma CVD.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plastic substrate that can be suitably used for a lightweight and small-sized flat panel display for OA equipment and TV, and an MI using the substrate.
It relates to an M switching element.

[0002]

2. Description of the Related Art There is a strong demand for the use of large-area liquid crystal panels for OA equipment terminals and liquid crystal TVs. Therefore, the active matrix method is devised so that each pixel has a switch to hold a voltage (special feature). Kaisho 61-2602
19, JP-A-62-62333). Further, in recent years, liquid crystal panels have been actively reduced in weight and cost, and the use of plastic as a substrate has been studied (Japanese Patent Laid-Open No. HEI-1).
-47769). However, when the thin film laminated switching element is formed on plastic, the plastic substrate is deformed or curled, and there is a problem such as film peeling. Further, when manufacturing a thin film stack switching element, an acid, an alkali,
There is a photolithography process in which the plastic is immersed in a solution such as water.
Water and the like remained, which caused element deterioration. 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. In the production of a liquid crystal display device using a plastic film substrate, it was necessary to perform an alignment method peculiar to plastic during the alignment treatment. So S
It is known that the physical orientation of an iO ₂ film on one side of a plastic film can be used for orientation treatment in the same manner as for glass substrates (Japanese Patent Publication No. 1-47769).
However, if the thin film is formed on only one surface of the plastic substrate (film), curling occurs according to the internal stress of the inorganic material thin film, which causes problems such as handling.
Japanese Patent Application Laid-Open No. 64-25543 discloses a technique of performing plasma treatment with an F-containing gas for the purpose of improving crack resistance and moisture resistance of the SiO ₂ film. But that is F
A surface treatment of SiO ₂ by in was not a fluorinated overall SiO ₂ film. The manufacturing method is the SOG method (Sp
Since it is a wet process based on the in-on-glass method), the shrinkage of the film is unavoidable and causes cracks. When depositing SiN on a plastic substrate, especially on a plastic film, it is advantageous in terms of cost to deposit a large area by a roll-to-roll method. In the roll-to-roll method, uniform film formation with a width of 1 m is required. In that case, the sputtering film formation requires a target having a width of 1 m or more, which increases the cost. In vapor deposition, in order to enable uniform film formation with a width of 1 m, the distance between the substrate and the evaporation source must be sufficiently large by a special material evaporation method. In addition, it is impossible to stand and form a film in the manufacturing method, and the floor area of the vapor deposition apparatus also increases. On the other hand, in the CVD method, the raw material is gas, and a uniform film can be formed in a large area. There is no increase in raw material cost due to the increase in area. However, in the CVD method, the substrate temperature must be 400 ° C. or higher in order to thermally decompose silane (SiH ₄ ) or silazane. Moreover, at a substrate temperature of 400 ° C., a porous film is formed, and in order to obtain a dense film, 700 ° C.
Substrate temperature was required. In recent years, low temperature film formation of SiN has been performed by the plasma CVD method. Still,
In order to obtain a dense SiN film, a substrate temperature of 300 ° C. or higher was required [S. Yokoyama et al. ，
J. Appl. Phys. 51, 5470 (198
0)]. In addition, in the film formation of SiN by ECR plasma, a dense film can be obtained at low temperature [Tanigawa et al., Applied Physics,
57, 121 (1988), Sugiyama et al., Optical Memory Symposium '90 Abstracts, p. 71 (1990)]. However, it was not possible to form a film on a large area with ECR plasma. As described above, a technique for forming a dense SiN film in a large area at low cost on a plastic substrate having a heat resistance of 300 ° C. or lower has not been obtained.

[0003]

An object of the present invention is to solve the above conventional problems and to provide a light weight, low cost, plastic substrate (especially large area plastic substrate) free from film peeling, cracks or substrate curl, and an MIM element and a liquid crystal display device using the same. It is intended to be provided.

[0004]

[Structure] When various devices are manufactured on a plastic substrate, moisture permeation from the back surface of the substrate becomes a problem, but this is prevented, and when formed on only one side of the plastic substrate, the substrate curls. In order to prevent this, it is effective to form the plasma CVD SiN film on both sides. When productivity is taken into consideration, it is preferable to simultaneously form the SiN film on both surfaces. As SiN of the SiN film, for example, SiNx has x = 1 to 1.5, but x in the above equation can be controlled arbitrarily. The present inventor studied a method for producing SiN on a large-area plastic substrate, and obtained the results shown in Table 1 below. Therefore, in order to achieve the above-mentioned object, a plasma CVD method is selected, which allows a large area and simultaneous film formation on both sides and obtains good film quality at a lower temperature.

[Table 1] However, as described above, when the film forming temperature is 300 ° C,
It cannot be manufactured on a plastic substrate with low heat resistance. In addition, a low temperature substrate of 200 ° C. or lower results in a porous SiN film, which is not practical. Therefore, when the present inventor investigated the relationship between the film formation temperature of the SiN film by plasma CVD and the density, refractive index, and H content, the H content decreased as the substrate temperature increased, while the density and refractive index It was found to increase with increasing substrate temperature (see Figure 1). As a result, due to the increase in substrate temperature, Si-H,
It can be seen that the bonds such as NH are decomposed to form a denser SiN film. That is, it was considered effective to remove H in order to obtain a dense SiN film by the plasma CVD method. Then, as a result of repeated research on a method of removing H at low temperature, it was found that it is effective that the source gas contains a halogen element such as fluorine, chlorine, iodine and bromine. This is because the binding energies of Si-H and N-H are 74.6 and 86 kcal / mol, and the binding energies of HF, H-Cl, and H-Br are 1 respectively.
Less than 53, 103, 87.4 kcal / mol,
Therefore, due to the halogen atom (radical), Si-H,
It is considered that H in N-H is easily eliminated as hydrogen halide. HI has a binding energy of 71 kcal
Although it is as small as / mol, this is also desorbed by ion assist. Actually, 2.0 × 10 ²² cm ⁻³ or less on a plastic substrate by halogen-containing plasma CVD,
That is, a dense film of 20 atomic% or less was obtained. As the source gas, F ₂ , Cl ₂ , Br ₂ , I ₂ , CF ₄ , CHF ₃ ,
Halogen sources such as NF ₃ , SF ₆ , CHCl ₃ , CHBr ₃ , BCl ₃ , SiH ₄ , Si ₂ H ₆ , SiH ₂ F ₂ , S
Examples thereof include silicon sources such as i ₂ F ₆ and silazane, and N sources such as N ₂ and NH ₃ . These components are used in combination depending on the intended film quality and production conditions. In order to form the plasma CVD SiN film on both surfaces of the plastic substrate, a method of applying high-frequency and low-frequency AC voltage to both electrodes of the parallel plate electrode of the plasma CVD device is effective (see FIG. 2). Further, it is effective for desorption of H to utilize an ion pumper by the sheath electric field of the cathode for lowering the temperature (FIG. 3). The SiN-coated plastic substrate produced as described above is effective for producing a lightweight and inexpensive device when used as a substrate for MIM having a hard carbon film as an insulating layer. The hard carbon film can be formed at room temperature and can be formed even on a plastic substrate having low heat resistance. Further, the MIM element manufactured on the plastic substrate is effective as a liquid crystal driving element. As a result, the LCD (PF-
(LCD) can be actively driven, and a higher-definition display can be performed as compared with the conventional simple matrix type PF-LCD. The details of the present invention will be described below. The plasma CVD SiN film of the present invention is produced by an apparatus as shown in FIGS. This is two RF of parallel plate
It has electrodes and can control plasma parameters independently. In addition, each RF power source can generate plasma with an arbitrary phase difference. In this device, the same quality Si is used on both sides of the plastic film.
An N film or a heterogeneous film of SiN having different Si / N composition ratio, H content, compactness, internal stress, etc. can be prepared. Also, roll the plastic film to
Since it can be supplied by rolls, continuous film formation is possible. In the device of FIG. 3, self-bias is generated in the cathode, and accelerated ions are incident on the plastic film. As a result, H
Can be easily desorbed, and a dense SiN film can be manufactured at a lower temperature. The plastic substrate used in the present invention includes polyethylene terephthalate, polyarylate,
Examples thereof include polyether sulfone, polycarbonate, polyethylene, polymethylmethacrylate, polypropylene and polyimide. Its thickness is 50 μm to 1
mm, preferably 75 μm to 300 μm, and if necessary, secondary treatment such as stretching treatment and plasma surface treatment is carried out. The plasma CVD SiN film is formed by using silazane, SiH ₄ , Si ₂ H ₆ , SiH ₃ X, and S as raw material gases.
iH ₂ X ₂ , SiHX ₃ , SiX ₄ , Si ₂ X ₆ , (X = F,
Cl, Br, I) or other Si supply gas, F ₂ , Cl ₂ , B
r ₂ , I ₂ , CF ₄ , CHF ₃ , NF ₃ , SF ₆ , CCl ₄ ,
Halogen supply gas such as CHCl ₃ and CHBr ₃ , N ₂ ,
This is performed by combining nitrogen supply gases such as NH ₃ according to the purpose and supplying them into the plasma at a predetermined flow rate. However, if halogen, silicon, and nitrogen can be supplied, the supply gas does not necessarily have to be a combination of three components. Other gases such as He, Ne, Ar, N ₂ and H ₂ are also used as carrier gas or reaction control gas. Plasma CV
The conditions for producing the DSiN film are as follows: pressure: 1000 Pa to 0.1 Pa, preferably 100 Pa to 1 Pa, plasma power: 0.09 to 2.0 W / cm ² , preferably 0.2 to 1.5 W / cm ² . The thickness of plasma CVD SiN is 500 to
It is 15,000Å, preferably 1,000 to 10,000Å.

Next, a method of manufacturing an MIM element having a hard carbon film as an insulating layer will be described in detail with reference to FIGS. First, plasma CVD SiN film is coated on both sides (2a, 2
A transparent electrode material for pixel electrodes is deposited on the plastic substrate 1) b) by a method such as vapor deposition and sputtering, and patterned into a predetermined pattern to form pixel electrodes 4. Next, a conductor thin film for the lower electrode is formed by a method such as vapor deposition and sputtering, and is patterned into a predetermined pattern by wet or dry etching to form a first conductor 7 to serve as the lower electrode. After coating the hard carbon film 2 by a dry etching method, a wet etching method, or a lift-off method using a resist, patterning into a predetermined pattern to form an insulating film, and then a conductor for a bus line by a method such as vapor deposition or sputtering. The thin film is covered and patterned into a predetermined pattern to form the second conductor 6 which becomes the bus line. Finally, unnecessary portions of the lower electrode are removed to expose the transparent electrode pattern,
The pixel electrode 4 is used. In this case, the structure 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 thicknesses of the lower electrode, the upper electrode and the transparent electrode are usually in the range of several hundred to several thousand Å, several hundred to several thousand Å and several hundred to several thousand Å, respectively. The thickness of the hard carbon film is 100 to 8000Å, preferably 20
0-6000Å, more preferably 300-4000Å
Is the range. 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, Pt, N
i, Ti, Cu, Au, W, ITO, ZnO: Al, In ₂ O ₃ ,
Various conductors such as SnO ₂ are used. Next, as the material of the second conductor 6 which becomes the bus line, Al, Cr, Ni, M
o, Pt, Ag, Ti, Cu, Au, W, Ta, ITO, Zn
O: Al, but In ₂ O _3, SnO ₂ and the like various conductors are used, Ni from the viewpoint of stability and reliability of the I-V characteristic is particularly excellent, Pt, Ag is preferable. 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 conductivity is obtained from the relation of 1nI∝√v. From this fact, it can be seen 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 (I
(-V characteristic) is deteriorated and changed. Considering these, it was found that Ni, Pt, and Ag are preferable. M of the present invention
The current-voltage characteristic of the IM element is shown in FIG. 6, and is approximately expressed by the following conduction equation.

[0007]

[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 constant T: Atmospheric temperature ε ₁ : Hard carbon Dielectric constant ε ₂ : Vacuum dielectric constant

The hard carbon film used in the MIM element of the device of the present invention will be described in detail. 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 may be a liquid phase or a solid phase as long as it can be vaporized through melting, evaporation, sublimation, etc. by heating or pressure reduction. is there. For the hydrocarbon gas as the raw material gas, for example, CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₄
A gas containing at least all hydrocarbons such as paraffinic hydrocarbons such as H ₁₀ , acetylene hydrocarbons such as C ₂ H ₂ , olefinic hydrocarbons, diolefinic hydrocarbons, and aromatic hydrocarbons is used. It is possible. 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,
The 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 250 ° C., preferably room temperature to 200 ° 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 (crystal size is several tens of .mu.m to several .mu.m) consisting of hydrogen atoms and hydrogen atoms H is deposited. Table 2 shows various characteristics of the hard carbon film.

[0011]

[Table 2]

Note) Measurement method: Specific resistance (ρ): Determined from IV characteristics of a coplanar cell. Optical bandgap (Egopt): From absorption characteristics to absorption coefficient
(α) is calculated and determined from the relationship of Equation 2.

[0013]

[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. A hard carbon film suitable as a liquid crystal driving MIM element has a film thickness of 100 to 8000Å and a specific resistance of 10 ⁶ to 10 ⁶ depending on driving conditions.
Advantageously, it is in the range of 10 ¹³ Ω · cm. In consideration of the margin between the driving voltage and the breakdown voltage (dielectric breakdown voltage), the film thickness is preferably 200 Å or more, and color unevenness caused by a step (cell gap difference) between the pixel portion and the thin film two-terminal element portion Since it is desirable that the film thickness be 6000 Å or less so as not to be a practical problem, the hard carbon film has a film thickness of 200 to 6000 Å and a specific resistance of 5 × 10 ⁶ to 10 ¹³ Ω · cm. It is preferable.
The number of defects in the device due to pinholes in the hard carbon film increases as the film thickness decreases, and becomes particularly noticeable below 300 Å (the defect rate exceeds 1%), and the in-plane distribution of the film thickness is uniform. Since it is not possible to secure the characteristics (and eventually the uniformity of the device characteristics) (the accuracy of film thickness control is limited to about 30Å, the variation in film thickness exceeds 10%), the film thickness is 300Å
The above is more preferable. Further, the film thickness is more preferably 4000 Å or less in order to prevent the hard carbon film from peeling off due to stress and to drive with a lower duty ratio (desirably 1/1000 or less). Taking these factors into consideration, the thickness of the hard carbon film is 300 to 4000Å and the specific resistance is 10 ⁷ to 10 10.
^More preferably, it is ¹¹ Ω · cm.

Next, a method of manufacturing a liquid crystal display device will be described with reference to FIG. First, a transparent conductor for the common electrode 9, for example, ITO, ZnO: Al, ZnO: Si, Sn is formed on the insulating substrate 10.
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 an alignment material.
As the polymer material in the polymer-liquid crystal composite, polymethylmethacrylate, polystyrene, polyfumarate,
Polyethylene oxide or the like can be used. Of these, polyfumarate, which is a rigid polymer, is preferable. As the liquid crystal material, TN liquid crystal or the like which has been used for the conventional liquid crystal display can be used. The structure of the polymer-liquid crystal complex is
There are systems in which liquid crystals are dispersed in the form of droplets in a polymer and systems in which liquid crystals form 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 produced by a method in which a monomer and liquid crystal are mixed and then light is aggregated.

[0015]

EXAMPLES Examples of the present invention will be described, but the present invention is not limited to these examples. Example 1 A SiN film of 4000 Å was formed on both sides of a 100 μm thick polyarylate film by using the plasma CVD apparatus of FIG. The SiN production conditions were: Si source: SiH ₄ 10 SCCM halogen source: NF ₃ 10 SCCM N source: N ₂ 100 SCCM Film temperature: Room temperature Pressure: 13 Pa Plasma power: 1.0 W / cm ² . H of SiN film produced on Si substrate under the same conditions
As a result of obtaining the content by FTIR, 1.8 × 10 ²²
It was cm ^-3 . The FTIR results showed that SiH absorption was not observed and only a small amount of NH was observed. Next, ITO was deposited on SiN to a thickness of 1400 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 1000Å by a vapor deposition method and then patterned to form a lower electrode, and a hard carbon film as an insulating layer 2 is formed thereon by a plasma CVD method to a thickness of about 1000Å.
After thick deposition, 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 Further, Ni was deposited thereon to a thickness of about 1000 Å by an EB vapor deposition method and patterned to form an upper electrode. Next, a transparent conductor for common electrode, ITO, is deposited on the insulating substrate by sputtering for 1400 Å and patterned into a stripe shape to form a common electrode. Next, the polyfumarate and the liquid crystal E8 are formed on the substrate 1 on which MIM elements are provided in a matrix.
The chloroform solution was cast and a polymer-liquid crystal composite layer was provided by a solvent evaporation method. Next, a sealing material was attached, and it was bonded to the common electrode insulating substrate, and then a reflective layer was provided on the back surface of the MIM element substrate to obtain a liquid crystal display device. The liquid crystal display device manufactured in this manner is bright and has high definition display without a backlight, and since it is lightweight and thin, it has excellent impact resistance and flexibility.

Example 2 A SiN film of 5000 Å was formed on both sides of a 100 μm thick polycarbonate film by using the plasma CVD apparatus shown in FIG. The conditions for producing SiN are as follows: Si source: SiH ₂ F ₂ 20 SCCM N source: NH ₃ 50 SCCM, N ₂
100 SCCM film temperature: room temperature pressure: 1.3 Pa plasma power: 1.0 W / cm ² self-bias: −300V. H of SiN film produced on Si substrate under the same conditions
As a result of obtaining the content by FTIR, 1.3 × 10 ²²
It was cm ^-3 . Next, in the same manner as in Example 1, a MIM element having a hard carbon film as an insulating layer was produced, and a liquid crystal display device was produced as follows. A transparent conductor ITO for a common electrode is deposited on an insulating substrate by using a sputtering device in an amount of 1400 Å and patterned into stripes to form a common electrode.
The insulating substrate provided with the common electrode and the substrate provided with the MIM elements in a matrix form are rubbed with an aligning material such as polyimide on each surface, and a sealing material is attached and a gap material is added to make the gap constant. Then, a liquid crystal was sealed by filling the liquid crystal. This liquid crystal display is lightweight,
In addition, it is highly flexible and enables the production of high-definition displays even on curved surfaces that were previously difficult to use.

[0017]

【effect】

1. According to the present invention, a plastic substrate in which a SiN film having a low H content is formed on at least one side, and a SiN film having a low hydrogen content and a high passivation effect are simultaneously formed on both sides of the substrate (especially a large-area substrate) at a low temperature. A method of manufacturing a SiN film-formed plastic substrate that can be formed by 2. By using the above-mentioned 1 plastic substrate as a substrate for a MIM element having a hard carbon film as an insulating layer, a lightweight, low-cost and highly flexible MIM element is provided.

[Brief description of drawings]

FIG. 1 is a diagram showing the substrate temperature dependence of the characteristics of a SiN film formed by a plasma CVD method.

FIG. 2 is a diagram showing a double-sided film-forming plasma CVD apparatus capable of applying an AC voltage to both electrodes of a parallel plate electrode.

FIG. 3 is a view showing a self-bias film-forming double-sided film-forming plasma CVD apparatus.

FIG. 4 is a diagram schematically showing a structure of a MIM element with a substrate of the present invention.

FIG. 5 is a perspective view schematically showing a main part of an MIM element.

6A and 6B are IVs of the MIM element, respectively.
It is a figure which shows a characteristic curve and an lnI-√v characteristic curve.

FIG. 7 is a partial cross-sectional perspective view of a liquid crystal display device incorporating the MIM element with a substrate of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic substrate 1'Plastic substrate 2 Hard carbon film 2a SiN film 2b SiN film 3 Liquid crystal 4 Pixel electrode 4'Common electrode 5 MIM element 6 Second conductor (bus line) (upper electrode) 7 First conductor (lower electrode) 8 Alignment film 9 Gap material 11 Film roll 21 Plastic film 31 Gas inlet 41 Cathode cover 51 Sheath electric field P pump

Claims (6)

[Claims] 1. A plastic substrate having a SiN film formed by a plasma CVD method on at least one surface as a surface protection film, wherein the HN content in the SiN film is 2 × 10.
A plastic substrate having a size of ²² cm ^-3 or less. 2. A gas mixture containing a halogen supply component, a silicon supply component and a nitrogen supply component is used as a source gas, and a plasma CVD method is used to produce Si on at least one surface of a plastic substrate at a substrate temperature of 300 ° C. or lower.
The method for producing a plastic substrate according to claim 1, wherein an N film is formed. 3. The same or different SiN on both sides of the substrate
The method for manufacturing a plastic substrate according to claim 2, wherein the film is simultaneously formed. 4. SiN is formed by a plasma CVD method in which an AC voltage is applied to both plate-shaped electrodes arranged in parallel.
The method for manufacturing a plastic substrate according to claim 2, wherein a film is formed. 5. The continuous production method for a plastic substrate according to claim 2, 3 or 4, wherein a plastic film is used as the plastic substrate and the film is supplied in a roll to roll system. 6. The plastic substrate according to claim 1,
An MIM element comprising a MIM element having a hard carbon film as an insulating film.