JPH04298722A - Thin film laminated device with substrate and production thereof - Google Patents

Abstract

PURPOSE:To eliminate the deformation, curling, etc., of a substrate and to reduce the cost and weight of the thin film laminated device by forming an SiNx layer having the stress to negate the deformation stress possessed by the thin film device body on at least one surface of the substrate. CONSTITUTION:The thin film 2b consisting of the SiNx (x is 0.5 to 1.2) is provided on at least one surface of the substrate 1 of the plastic substrate 1 and the thin film laminated device formed on this substrate. The thin film 2b is provided with a compsn. distribution in which x is small on the plastic substrate 1 side and large on the opposite side. In addition, the thin film 2b has the stress value which can nearly negate the stress value possessed by the thin film and the entire part of the thin film laminated device to be formed on the thin film. Further, the thin film 2b is formed on at least one surface of the substrate 1 by a CVD method in which the rf power value is set at an adequate value between 250 and 300w at the time of producing the thin film laminated device with the substrate.

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 that can be suitably used in flat panel displays for office automation equipment, TVs, and the like.

0002

[Prior Art] There is a strong demand for the use of large-area liquid crystal panels in office automation equipment terminals and liquid crystal TVs. Therefore, in the active matrix method, a switch is provided for each pixel to maintain the voltage (especially Kaisho 61-2602
19, Japanese Patent Publication No. 62-62333). Furthermore, in recent years, efforts have been made to reduce the weight and cost of liquid crystal panels, and the use of plastic for the substrates of switching elements is being considered (Japanese Patent Laid-Open No. 1-47769). However, when a thin film laminated switching element is formed on plastic, there are problems such as deformation and curling of the plastic substrate, and film peeling. In addition, when manufacturing a thin film laminated switching element, there is a step of immersing plastic in a solution of acid, alkali, water, etc., and acid, alkali, water, etc. remain in the plastic, causing element deterioration. On the other hand, in the production of a liquid crystal display device using a plastic film substrate, it is necessary to perform an alignment method unique to plastics during alignment treatment. Therefore, it is known that by forming a SiO2 layer on one side of a plastic film, alignment treatment can be performed in the same manner as for glass substrates (Japanese Patent Publication No. 1-47769). However, in a film made of SiO2,
Although it has a passivation effect, it does not solve the problem of substrate curling caused by Young's modulus mismatch between the plastic substrate and its coating film, and a new coating film material is required. As a result of our research on this point, the present inventors have found that it is desirable for the film material to be able to freely change the internal stress from the direction of elongation to the direction of contraction. We have discovered that it is preferable not only to provide a passivation effect by giving the film material a compositional distribution, but also to optimize the stress in the coating film against substrate curl.

0003

An object of the present invention is to solve the above-mentioned conventional problems and provide a thin film laminated device that is lightweight, low cost, and free from film peeling, substrate curl, etc.

0004

[Structure] The first aspect of the present invention is a plastic substrate and a thin film laminated device formed on the substrate, characterized in that the substrate has a thin film made of SiNx (x is 0.5 to 1.2) on at least one side. The present invention relates to a thin film laminated device with a substrate. The second aspect of the present invention is the SiNx (x is 0.5 to
1.2) The present invention relates to the substrate-attached thin film laminated device, characterized in that the thin film consisting of 1.2) has a composition distribution in which x is small on the plastic substrate side and x is large on the opposite side. A third aspect of the present invention is a plastic substrate and a thin film laminated device formed on the substrate.
A thin film made of iNx (x is 0.5 to 1.2) is provided, and the thin film has a stress value that can almost cancel out the stress value of the whole of the substrate and the thin film laminated device to be formed thereon. The present invention relates to the substrate-attached thin film laminated device characterized in that it has the following. A fourth aspect of the present invention is that, in manufacturing the thin film laminated device with a substrate, SiNx (x is 0.5 The present invention relates to a method for producing the thin film laminated device with a substrate, characterized in that the thin film of ~1.2) is formed.

Formation of a SiNx thin film on a plastic substrate is important in order to solve problems such as peeling of thin film laminated devices fabricated thereon. If only a plastic substrate is used, the thin film deposited on top of the substrate will curl due to the internal stress, causing problems in handling. In order to avoid this, it is necessary to form a buffer layer on a plastic substrate under appropriate conditions. In order to fabricate the thin film laminated device of the present invention, first, SiN (x is 0.5
~1.2) is formed by sputtering, vapor deposition, plasma CVD, or the like. A thin film made of this material, namely SiNx
As a result of research conducted by the present inventors, it was found that a thin film of (x is 0.5 to 1.2) is a material that has excellent adhesion to a plastic substrate and has low permeability. This material has a lower permeability than oxide-based materials, and the film forming conditions (r.
By changing the f power), a film with a small etching rate and high density can be produced. Furthermore, as can be seen in Figure 4, which shows the dependence of SiNx internal stress on rf power, rf
By varying the power value between 250 and 300 W, the stress value can be changed from the direction of elongation (upward arrow in Figure 5) to the direction of contraction (
There is an advantage that an arbitrary value can be set for the arrow (downward arrow in FIG. 5). In order to fully utilize these advantages, it is desirable to provide a stress distribution that acts in a direction that suppresses curling by changing the film forming conditions and changing the film composition as shown in FIG. This film can be formed by vapor deposition, sputtering, C
It is formed by a method such as VD. As mentioned above, in the region where x in SiNx is in the range of 0.5 to 1.2, the density of the SiNx layer is high, and therefore a high density and a high passivation effect can be expected. Furthermore, it is possible to cope with changes in the internal stress of the device layer due to changes in the manufacturing conditions of the device layer provided on the top of the SiNx layer, etc. by arbitrarily varying the internal stress. In addition, the stress in the SiNx layer can be set from the elongation direction to the contraction direction, so when providing SiNx layers on both sides of the substrate, the device internal stress is contractionary, so the device side SiNx layer should have stress in the elongation direction, and vice versa. The SiNx layer on the surface has the advantage that it can be made to have stress in the direction of contraction, thereby suppressing stress mismatch between the substrate and the entire device. The thickness of the plastic board is 5
Use 0 μm to 2 mm, but 500 μm or less,
In particular, a thickness of 300 μm or less is desirable. A thin film laminated device is formed on the plastic substrate on which the SiNx thin film is formed on at least one side in this manner. As a thin film stacked device, MIM consisting of a metal-insulator-metal layer structure is used.
(Metal-Insulator-Metal) element, MS as referred to in Japanese Patent Application Laid-Open No. 61-275811
I (Metal-Semi-Insulator) element, SIS (S
emiconductor-Insulator-Se
microconductor) element, JP-A-64-7577
There is a MIMIM element having a metal-insulator-metal-insulator-metal layer structure described in the above publication. Among these, an MIM element using a hard carbon film as an insulator is advantageous for a switching element for liquid crystal display. When a hard carbon film is used as an insulating layer, the plastic substrate curls significantly, so at least one side of the substrate is covered with Si, which acts to cancel out the internal stress.
This is handled by forming an Nx thin film. in particular,
By changing the RF power, the Si of the SINx layer
/N ratio was changed from 0.8 to 1.0, and the refractive index was changed to 2.0.
~2.2, resulting in a stress distribution and suppressing yellowing of the coat film. The Si/N ratio can be determined from the IR spectrum, and the refractive index distribution can be determined by observing the Neutling interference effect. Next, a method for manufacturing the MIM element using the present invention will be described in detail. As shown in FIGS. 1 to 3, a film (2b or 2a, 2b) made of SiNx with excellent adhesion to the plastic substrate is deposited on at least one side to a thickness of several hundred to several thousand angstroms. A transparent electrode material that will become a pixel is deposited thereon by a method such as vapor deposition sputtering and formed into a predetermined pattern to form a pixel electrode 4. Next, a conductor thin film for the lower electrode is formed by a method such as vapor deposition or sputtering, and patterned into a predetermined pattern by wet or dry etching to form the first conductor 7 that will become the lower electrode. After coating the hard carbon film 2 by a method such as a dry etching method, it is patterned into a predetermined pattern by dry etching, wet etching, or a lift-off method using a resist to form an insulating film, and then a bus line conductor is formed on the insulating film by a method such as vapor deposition or sputtering. coated with a thin film,
A second conductor 6 that will become a bus line is formed by patterning into a predetermined pattern, and finally, an unnecessary portion of the lower electrode is removed to expose a transparent electrode pattern to form a pixel electrode 6. In this case, the configuration of the MIM element is not limited to this, and after the MIM element is created, a transparent electrode is provided on the top 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 one in which an MIM element is formed on the top. Here, the thickness of the lower electrode, upper electrode, and transparent electrode is usually several hundred to several thousand Å, and several hundred to several thousand Å, respectively.
, in the range of several hundred to several thousand Å. The thickness of the hard carbon film is 1
The thickness is in the range of 00 to 8000 Å, preferably 200 to 6000 Å, and more preferably 300 to 4000 Å. Furthermore, in the case of plastic substrates, it has been extremely difficult to fabricate active matrix devices using active elements due to their heat resistance. However, a hard carbon film can be produced at a substrate temperature of about room temperature, and can also be produced on a plastic substrate, making it a very effective means for improving image quality.

Next, the material of the MIM element used in the present invention will be explained in more detail. The material of the first conductor 7 serving as the lower electrode includes Al, Ta, Cr, W, Mo, and Pt.
, Ni, Ti, Cu, Au, W, ITO, ZnO:Al
, In2O3, SnO2, etc. are used. Next, the material for the second conductor 6, which will become the bus line, is Al.
, Cr, Ni, Mo, Pt, Ag, Ti, Cu, Au,
W, Ta, ITO, ZnO: Al, In2O3, SnO
Although various conductors such as No. 2 can be used, Ni, Pt, and Ag are preferred because they have particularly excellent stability and reliability of IV characteristics. In the MIM device using the hard carbon film 2 as an insulating film, the symmetry does not change even if the type of electrode is changed, and ln
From the relationship I∝√v, it can be seen that Poole-Frenkel type conduction is occurring. Further, 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 (IV characteristics) deteriorate and change depending on the adhesion between the hard carbon film and the electrode and the state of the interface. Considering these, it was found that Ni, Pt, and Ag are good. The current-voltage characteristics of the MIM element of the present invention are shown in FIG. 5, and are approximately expressed by the conduction equation shown below.

[0007]

[Math 1]

I: Current V: Applied voltage κ: Conductivity coefficient
β: Poole-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: Ambient temperature ε
1: Dielectric constant of hard carbon ε2: Vacuum dielectric constant

The hard carbon film in the present invention will be explained in detail. An organic compound gas, especially a hydrocarbon gas, is used to form a hard carbon film. The phase state of these raw materials does not necessarily have to be a gas phase at normal temperature and pressure; they can be used in either a liquid or solid phase as long as they can be vaporized through melting, evaporation, sublimation, etc. by heating or reduced pressure. be. Regarding the hydrocarbon gas as the raw material gas, for example, paraffinic hydrocarbons such as CH4, C2H6, C3H8, C4H10, acetylenic hydrocarbons such as C2H4,
Gases containing at least all hydrocarbons such as olefinic hydrocarbons, diolefinic hydrocarbons, and even aromatic hydrocarbons can be used. Furthermore, other than hydrocarbons, compounds containing at least the carbon element can be used, such as alcohols, ketones, ethers, esters, CO, and CO2. In the method of forming a hard carbon film from a raw material gas in the present invention, the film-forming active species is
It is preferable to use a plasma state generated by a plasma method using direct current, low frequency, high frequency, microwave, etc., but for the purpose of increasing the area, improving uniformity, and forming a film at a low temperature, A method using a magnetic field effect is more preferable. Active species can also be formed by thermal decomposition at high temperatures. In addition, it may be formed through an ion state generated by an ionization vapor deposition method, an ion beam vapor deposition method, etc., or a vacuum vapor deposition method,
Alternatively, it may be formed from neutral particles produced by a sputtering method or the like, or may be formed from a combination of these. An example of the deposition conditions for the hard carbon film produced in this manner is as follows in the case of the plasma CVD method. RF output: 0.1 to 50 W/cm2 Pressure: 1/103 to 10 Torr Deposition temperature: Room temperature to 350°C Due to this plasma state, the raw material gas is decomposed into radicals and ions and reacts, thereby forming carbon atoms C on the substrate.
A hard carbon film containing at least one of amorphous (amorphous) and microcrystalline (crystal size is several tens of angstroms to several μm) is deposited. Further, Table 1 shows various properties of the hard carbon film.

0010

[Table 1]

Note) Measuring method: Specific resistance (ρ): Obtained from the IV characteristics using a coplanar cell. Optical bandgap (Egopt): Obtain the absorption coefficient (α) from the spectral characteristics and determine from the relationship shown in Equation 2.

0012

[Math 2]

Amount of hydrogen in the film [C(H)]: Obtained by integrating the peak near 2900/cm from the infrared absorption spectrum and multiplying it by the absorption cross section A. That is, [C(H)]=A・∫α(v)/v・dvSP3/SP
2 ratio: The infrared absorption spectrum is decomposed into Gaussian functions assigned to SP3 and SP2, respectively, and determined from the area ratio. Vickers hardness (H): Based on a micro Vickers meter. Refractive index (n): By ellipsometer. Defect density: Based on ESR. The hard carbon film thus formed was measured using Raman spectroscopy and IR spectroscopy.
As a result of analysis by an absorption method, it has been revealed that interatomic bonds in which carbon atoms form SP3 hybrid orbitals and SP2 hybrid orbitals coexist, as shown in FIGS. 6 and 7, respectively. The ratio of SP3 bonds to SP2 bonds can be approximately estimated by peak-separating the IR spectrum. In the IR spectrum, many mode spectra from 2800 to 3150/cm are measured to overlap, but the attribution of the peak corresponding to each wavenumber has been clarified, and peak separation can be performed using a Gaussian distribution as shown in Figure 8. SP3/SP2 can be found by calculating the area of each peak and finding the ratio. Also, according to X-ray and electron diffraction analysis, it is in an amorphous state (a-C:H) and/or about 50
It is known that it is in an amorphous state containing microcrystalline grains of about Å to several μm in size. In the case of the plasma CVD method, which is generally suitable for mass production, the lower the RF output, the higher the specific resistance and hardness of the film, and the lower the pressure, the longer the life of active species, so lowering the substrate temperature and increasing the The area can be made uniform, and the specific resistance and hardness tend to increase. Furthermore, since the plasma density decreases at low pressures, methods using magnetic field confinement effects are particularly effective in increasing resistivity. Furthermore, this method has the characteristic that it can form a hard carbon film of good quality even under relatively low temperature conditions of about room temperature to 150° C., so it is optimal for lowering the temperature of the MIM element manufacturing process. Therefore, the degree of freedom in selecting the substrate material to be used is increased, and the substrate temperature can be easily controlled, so that a uniform film can be obtained over a large area. Furthermore, as shown in Table 1, the structure and physical properties of the hard carbon film can be controlled over a wide range, so there is an advantage that device characteristics can be designed freely. Furthermore, the dielectric constant of the film is 2 to 6, which is the amount of Ta2O5 and Al2O used in conventional MIM devices.
3. It is smaller than SiNx, so if you want to make an element with the same capacitance, the element size will only need to be larger.
It does not require much microfabrication, and the yield improves (Due to the driving conditions, the capacitance ratio of the LCD and MIM element is C(L
(CD)/C(MIM) = approximately 10:1 is required). Also, since the element steepness β∝1/√ε・√d, the smaller the dielectric constant ε, the greater the steepness, and the on-current Ion
The ratio of the off current Ioff to the off current Ioff can be increased. Therefore, it becomes possible to drive the LCD at a lower duty ratio, and a high-density LCD can be realized. Furthermore, since the film has high hardness, there is less damage caused by the rubbing process during encapsulation of the liquid crystal material, which also improves the yield. Considering the above points, by using a hard carbon film, it is possible to achieve low cost and gradation (
Colorization) and high-density LCDs can be realized. Furthermore, this hard carbon film contains carbon atoms, hydrogen atoms, and
It may contain a group II element, a group IV element, a group V element, an alkali metal element, an alkaline earth metal element, a nitrogen atom, an oxygen element, a chalcogen element, or a halogen atom as a constituent element. Periodic table III as one of the constituent elements
Group elements, also Group V elements, alkali metal elements, alkaline earth metal elements, nitrogen atoms, or oxygen atoms introduced, have a hard carbon film thickness of about 2 to 30% compared to non-doped ones.
It is possible to increase the thickness by three times, thereby preventing the occurrence of pinholes during device fabrication, and dramatically improving the mechanical strength of the device. Further, in the case of a nitrogen atom or an oxygen atom, the same effect as in the case of a group IV element of the periodic table as described below can be obtained. Similarly, periodic table I
When group V elements, chalcogen elements, or halogen elements are introduced, the stability of the hard carbon film is dramatically improved, and the hardness of the film is also improved, making it possible to produce highly reliable elements. These effects can be obtained because Group IV elements and chalcogen elements reduce the active double bonds present in the hard carbon film, and in the case of halogen elements, 1) abstraction for hydrogen The reaction promotes the decomposition of the raw material gas and reduces dangling bonds in the film, and 2) during the film formation process, the halogen element X pulls out hydrogen in the C-H bond and replaces it, forming a C-X bond. enters the film and increases the bond energy (C-H and C-
This is because the bond energy between X is larger between C and X). In order to use these elements as constituent elements of the film, in addition to hydrocarbon gas and hydrogen as raw material gases, group III elements, group IV elements, and group V elements of the periodic table must be added as dopants to the film. In order to contain elements, alkali metal elements, alkaline earth metal elements, nitrogen atoms, oxygen atoms, chalcogen elements, or halogen elements, compounds (or molecules) containing these elements or atoms (hereinafter referred to as "other gases (sometimes referred to as "compounds") are used. Here, as a compound containing a group III element of the periodic table, for example, B
(OC2H5)3,B2H6,BCl3,BBr3,B
F3, Al(O-i-C3H7)3, (CH3)3Al
, (C2H5)3Al, (i-C4H9)3Al, Al
Cl3, Ga(O-i-C3H7)3, (CH3)3G
a, (C2H5)3Ga, GaCl3, GaBr3, (
Examples include O-i-C3H7)3In and (C2H5)3In. Examples of compounds containing Group IV elements of the periodic table include Si3H6, (C2H5)3SiH, SiF4, Si
H2Cl2, SiCl4, Si(OCH3)4, Si(
OC2H5)4, Si(OC3H7)4, GeCl4,
GeH4, Ge(OC2H5)4, Ge(C2H5)4
, (CH3)4Sn, (C2H5)4Sn, SnCl4
etc. Compounds containing Group V elements of the periodic table include:
For example, PH3, PF3, PF5, PCl2F3, PCl
3, PCl2F, PBr3, PO(OCH3)3, P(
C2H5)3, POCl3, AsH3, AsCl3, A
sBr3, AsF3, AsF5, AsCl3, SbH3
, SbF3, SbCl3, Sb(OC2H5)3, etc. As a compound containing an alkali metal atom, for example, L
iO-i-C3H7, NaO-i-C3H7, KO-i
-C3H7 etc. Examples of compounds containing alkaline earth metal atoms include Ca(OC2H5)3, Mg(OC
2H5)2, (C2H5)2Mg, etc. Examples of compounds containing nitrogen atoms include nitrogen gas, inorganic compounds such as ammonia, organic compounds having functional groups such as amino groups and cyano groups, and nitrogen-containing heterocycles. Examples of compounds containing oxygen atoms include oxygen gas, ozone, water (steam), hydrogen peroxide, carbon monoxide, carbon dioxide, suboxide, nitrogen monoxide, nitrogen dioxide, dinitrogen trioxide, and dinitrogen pentoxide. , inorganic compounds such as nitrogen trioxide, hydroxyl groups, aldehyde groups, acyl groups, ketone groups, nitro groups, nitroso groups, sulfone groups, ether bonds, ester bonds, peptide bonds,
Examples include organic compounds having a functional group or bond such as a heterocycle containing oxygen, and metal alkoxides. Examples of compounds containing chalcogen elements include H2S, (C
H3)(CH2)4S(CH2)4CH3,CH2=C
HCH2SCH2CH=CH2, C2H5SC2H5,
C2H5SCH3, thiophene, H2Se, (C2H5
)2Se, H2Te, etc. Examples of compounds containing halogen elements include fluorine, chlorine, bromine, iodine, hydrogen fluoride, carbon fluoride, chlorine fluoride, bromine fluoride, iodine fluoride, hydrogen chloride, bromine chloride, iodine chloride, and hydrogen bromide. , inorganic compounds such as iodine bromide and hydrogen iodide, and organic compounds such as alkyl halides, aryl halides, halogenated styrene, halogenated polymethylene, and haloform. A hard carbon film suitable as a liquid crystal driving MIM element has a film thickness of 100 to 8000 Å and a specific resistance of 106 to 1013 Ω depending on the driving conditions.
Advantageously in the cm range. In addition, considering the margin between drive voltage and withstand voltage (dielectric breakdown voltage), it is desirable that the film thickness be 200 Å or more, and color unevenness due to the step difference (cell gap difference) between the pixel part and the thin film two-terminal element part should be avoided. In order to prevent this from becoming a practical problem, the film thickness should be 6.
Since it is desirable that the thickness is 000 Å or less, the thickness of the hard carbon film is 200 to 6000 Å, and the specific resistance is 5 × 10 6 to
More preferably, it is 1013 Ω·cm. The number of device defects due to pinholes in hard carbon films increases as the film thickness decreases, and becomes especially noticeable below 300 Å (
The defect rate exceeds 1%), and the uniformity of the in-plane distribution of film thickness (and thus the uniformity of device characteristics) cannot be ensured (
The accuracy of film thickness control is limited to about 30 Å, and the variation in film thickness exceeds 10%), so it is more desirable 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 (preferably 1/1000 or less), the film thickness is more preferably 4000 Å or less. Taking all of these into consideration, the thickness of the hard carbon film is 30
0~4000Å, specific resistivity 107~1011Ω・cm
It is more preferable that

[0014]

[Example] Example 1 As shown in Fig. 2, r
A SiNx film was deposited to a thickness of 2000 Å using the f-plasma CVD method. When the device was formed, the stress of the insulating layer against the substrate was in the direction of contraction, so the SiNx film (2b) was formed on the top surface of the substrate (the side in contact with the device) with stress in the direction of expansion. A SiNx film (2a) was formed on the lower surface of the substrate by changing the stress value in the direction of contraction. During actual film formation, the RF power was changed (1.5 to 3 W/cm2).
, the SiNx film was grown at the optimum value to satisfy the above stress value and to deal with substrate curl. On top of this, the MIM element shown in FIG. 3 was fabricated as follows. First, ITO was deposited to a thickness of 700 Å by sputtering, and then patterned to form the pixel electrode 4. Next, Al was applied to 6
After depositing to a thickness of 0.00 Å, the lower conductor 7 was formed by patterning. On top of that, a hard carbon film is applied as an insulating film 2 by plasma CV.
A thickness of 1100 Å was deposited by the D method, and then Ni was deposited to a thickness of 1000 Å by the EB evaporation method, and then patterned by etching to form an upper conductor (also serving as a scanning electrode) 6. Finally, the hard carbon film was patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr CH4 flow rate
:10 sccm RF power: 0.2 W/cm2 Example 2 As shown in FIG. 2, a 2000 Å SiNx film was deposited on both sides of a polyarylate substrate by sputtering under the following conditions. Target: Si3N4 sintered body Sputtering gas: N2/Ar (ratio 5 to 20 vol%) Pressure: 5 x 1/104 to 5 x 1/102
TorrRF power: 2 to 8 W/cm2 This will deal with substrate curl and
A device was produced in the same manner as in Example 1. Example 3 As shown in FIG. 2, a 2000 Å SiNx film having a gradient distribution in the film thickness direction was deposited on both sides of a polyacrylate substrate by RF plasma CVD. When an element is formed into a film, the stress caused by the device layer on the substrate is in the direction of contraction. As shown in Figure 9 (the vertical axis shows the change in The stress of the coat film was distributed in the direction of elongation, so that the stress of the coat film as a whole was lowered with respect to the lower substrate, and the adhesion to the substrate was improved. The SiNx film was grown at an optimal value to satisfy the above stress value and to deal with substrate curl. On top of this, the MIM element shown in FIG. 3 was fabricated as follows. First I
After depositing TO to a thickness of 700 Å by sputtering, it was patterned to form the pixel electrode 4. Next, Al was deposited to a thickness of 600 Å by vapor deposition, and then patterned to form the lower conductor 7.
was formed. A hard carbon film with a thickness of 1100 Å is deposited thereon as an insulating film 2 by plasma CVD, and then Ni is deposited with a thickness of 1000 Å by EB evaporation, and patterned by etching to form an upper conductor (also serving as a scanning electrode) 6.
was formed. Finally, the hard carbon film was patterned by dry etching. The conditions for forming the hard carbon film at this time are as follows. Pressure: 0.035 Torr CH4 flow rate
:10 sccm RF power: 0.2 W/cm2

(Margin below)

[0015]

[Effects] The substrate and thin film laminated device of the present invention have a SiNx layer having a stress that cancels the deformation stress formed on at least one side of the substrate, so there is no deformation or curling of the substrate, and the cost and weight can be reduced. It can be achieved. Further, when the thin film stacked device is made into an MIM element using a hard carbon film as an insulating layer, it has the following characteristics. 1) Since it is produced by a vapor phase synthesis method such as a plasma CVD method, its physical properties can be controlled over a wide range depending on the film formation conditions, and therefore there is a large degree of freedom in device design. 2) Since it is hard and can be made into a thick film, it is less susceptible to mechanical damage, and it is expected that pinholes will be reduced by making the film thicker. 3) Since high-quality films can be formed even at low temperatures near room temperature, there are no restrictions on the substrate material. 4) Excellent uniformity in film thickness and film quality, making it suitable for thin film devices. 5) Since the dielectric constant is low, advanced microfabrication technology is not required, which is advantageous for increasing the area of the device. 6) Furthermore, since the dielectric constant is low, the steepness of the element can be increased, and higher duty driving is possible. Therefore, an MIM element using such an insulating layer is suitable as a switching element for liquid crystal display.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a specific structure of a thin film laminated device with a substrate according to the present invention.

FIG. 2 is a sectional view showing another specific structure of the substrate-attached thin film laminated device of the present invention.

FIG. 3 is an explanatory diagram of a main part of an MIM element configured by a thin film laminated device with a substrate according to the present invention.

[Figure 4] The horizontal axis represents the rf power (W) in the CVD method.
The vertical axis represents the stress (
arb. unit), and the rf power is approximately 1.5 ~
It is a graph showing that the stress of the SiNx film changes from the direction of elongation to the direction of contraction when the stress is varied between 3 W/cm2.

5A and 5B are graphs showing an IV characteristic curve and an lnI-√v characteristic curve, respectively, of the MIM element; FIG.

FIG. 6 is a spectrum diagram showing the results of Raman spectroscopy analysis of the hard carbon film used as the insulating layer of the MIM element of the present invention.

FIG. 7 is a spectrum diagram showing the results of spectroscopic analysis of the hard carbon film used for the insulating layer of the MIM element of the present invention using an IR absorption method.

FIG. 8 shows the glass distribution of the IR spectrum of the hard carbon film used as the insulating layer of the MIM device of the present invention.

FIG. 9 is a graph showing the relationship between elongation and contraction (solid line), the relationship with Si/N ratio (dashed line), and the relationship with refractive index (dotted line) corresponding to changes in x of SiNx.

[Explanation of symbols]

1 Plastic substrate 1' Plastic substrate 2 Hard carbon film 2a SiNx layer 2b SiNx layer 3 Liquid crystal 4 Pixel electrode 4' Common electrode 5 Active element (MIM element) 6 Second conductor (bus line) (upper electrode) 7
First conductor (lower electrode)

Claims (4)

[Claims] 1. A plastic substrate and a thin film laminated device formed on the substrate, characterized in that the substrate has a thin film made of SiNx (x is 0.5 to 1.2) on at least one side of the substrate. Thin film stacked device. 2. A claim characterized in that the thin film made of SiNx (x is 0.5 to 1.2) has a composition distribution in which x is small on the plastic substrate side and x is large on the opposite side. 1. The thin film laminated device with a substrate according to 1. 3. In a plastic substrate and a thin film laminated device formed on the substrate, a thin film made of SiNx (x is 0.5 to 1.2) is provided on at least one side of the substrate, and the thin film is formed on the substrate. and a stress value that can substantially cancel out the stress value of the entire thin film laminated device to be formed thereon.
A thin film laminated device with a substrate as described above. 4. In manufacturing the substrate-attached thin film laminated device according to claim 1, 2 or 3, SiN (x is 0.5 to 1
．． Claims 1 and 2 characterized in that the thin film of 2) is formed.
Or the method for manufacturing a thin film laminated device with a substrate according to 3.