JP2001051259A - Production of substrate, production of optoelectronic device and the optoelectronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To thickly form inorganic insulating films which do not induce crazing, etc., from coating films of a liquid precursor. SOLUTION: An end edge 921 of an upper coating film 92 is offset with respect to an inner side from the end edge 911 of the lower coating film 91, when the surface protective films 19 covering the surface side of electrode patterns 40 are formed from the coating films of the liquid precursor applied by flexographic printing on a substrate 10 holding liquid crystals of the optoelectronic device. Then, even if build-up portions 912 and 922 of the liquid precursor are generated respectively near the end edges 911 and 921 of the upper coating film 92 and the lower coating film 91, these build-up portions 912 and 922 do not overlap on each other, and therefore, smaller maximum film thickness after coating application will be sufficient and the occurrence of the crazing is averted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a substrate having a conductive film covered with an insulating film, a method of manufacturing an electro-optical device, and an electro-optical device manufactured by the method. More specifically, the present invention relates to a technique for forming an inorganic insulating film on a surface of a substrate.

[0002]

2. Description of the Related Art Substrates in which the front surface of a conductive film is covered with an inorganic insulating film are used in various fields. A typical example thereof is for driving an electro-optical material in an electro-optical device or the like. There is a substrate on which the electrodes are formed. For example, in a liquid crystal device which is a typical electro-optical device, a pair of substrates is used to sandwich liquid crystal, and each of the pair of substrates has a liquid crystal driving electrode formed of a conductive film, The surface of this electrode is covered with a surface protection film made of an inorganic insulating film formed on substantially the entire surface of the substrate.

A substrate used in such a liquid crystal device is a substrate for a passive matrix type liquid crystal device, and an ITO film (Indi) is formed on the surface of a transparent substrate such as a glass substrate.
It is manufactured by forming an electrode pattern with a transparent conductive film such as umTin Oxide) and then forming a surface protection film made of a silicon oxide film on the surface side of the electrode pattern. An alignment film is formed on the surface of the surface protection film. Here, the surface protective film is formed for the purpose of preventing conductive foreign matter generated when an electrode pattern is formed or the like from breaking through the alignment film and short-circuiting the electrode patterns formed on each substrate. I have.

Conventionally, in manufacturing such a liquid crystal device, a surface protective film is formed by a film forming method such as a sputtering method after forming an electrode pattern on a surface of a transparent substrate. In some cases, the film is formed by a flexographic printing method. According to the flexographic printing method, high productivity can be obtained without using an expensive film forming apparatus.

In this film forming method by flexographic printing, generally, as shown in FIG. 8A, a liquid precursor for forming an inorganic insulating film made of a liquid containing a silicon composition in a solvent is formed by using a relief printing plate. After transferring and applying to form a coating film 90,
The solvent component is evaporated and removed from the coating film 90, and then UV
Irradiation and heat treatment are performed to obtain a silicon oxide film from the coating film 90.

[0006]

However, when a surface protective film is formed by a conventional flexographic printing method, there is a problem that a surface protective film having a sufficient film thickness cannot be stably formed. That is, when the liquid precursor is applied at the time of flexographic printing, as shown in FIG. 8A, the vicinity of the edge 901 of the coating film 90 rises to a film thickness that is about twice as large as the film thickness of the inner region. If the portion is too thick, cracks occur when cleaning or rubbing is performed after film formation. Such cracks are not preferable because they cause the whole surface protective film to peel off.

[0007] For example, in the method in which the liquid precursor is applied once by flexographic printing, when the bulge generated near the edge 901 becomes about 1500 angstroms, cracks are generated later. That is, when a surface protective film of about 750 angstroms is formed, about 1500
In this method, the formation of a 750 Å surface protective film is the limit, since Angstrom swelling will occur.

On the other hand, as shown in FIG.
After the liquid precursor is applied by flexographic printing to form the lower coating 91, the solvent component is evaporated and removed from the lower coating 91, and then the surface of the lower coating 91 is again coated with an inorganic insulating film. When a liquid precursor for formation is applied by flexographic printing to form an upper coating film 92 and then the upper coating film 92 and the lower coating film 91 are cured, a bulge 903 near the edge 901 is obtained. When it reaches about 2000 Angstroms, cracking occurs later. That is, when the upper protective film 92 of about 500 Å is overlaid on the lower paint film 91 of about 500 Å to form a surface protective film of about 1,000 Å, a bulge 903 of about 2,000 Å near the edge 901 occurs. Therefore, this method has a limit in forming a surface protective film of 1000 Å.

Therefore, the conventional film forming method using flexographic printing has a limit of forming a surface protective film of about 1000 Å, and in a liquid crystal device or the like, the surface protective film is thickened to, for example, about 1300 Å. If you want to more reliably prevent short circuits between boards,
The conventional film forming method by flexographic printing cannot cope.

[0010] In view of the above problems, an object of the present invention is to provide:
Provided are a method of manufacturing a substrate, a method of manufacturing an electro-optical device, and an electro-optical device manufactured by these methods, which can form an inorganic insulating film that does not cause cracks or the like from a coating film of a liquid precursor. It is in.

[0011]

In order to solve the above-mentioned problems, the present invention provides a method of forming a substrate having a surface covered with an inorganic insulating film formed from a coating film of a liquid precursor for forming an inorganic insulating film. In the manufacturing method, a liquid precursor for forming an inorganic insulating film is applied on the surface of the substrate on which the conductive film is formed to form a lower coating, and then the inorganic coating is formed on the surface of the lower coating. And forming an upper coating by applying the liquid precursor of the above, wherein the edge of the upper coating is positioned inside the edge of the lower coating when forming the upper coating. .

In the present invention, when forming the upper coating on the surface of the lower coating, the upper coating is formed in a region inside the lower coating, so that the edge of the upper coating is formed by the edge of the lower coating. It is shifted inside the edge. Therefore, even if a raised portion of the liquid precursor occurs near the edges of the upper coating and the lower coating,
These raised portions do not overlap each other. Therefore, compared to the conventional single-coating method or double-coating method in which the upper coating film is completely overlaid on the lower coating film, the maximum film thickness after coating is the same even if the liquid precursor is applied to the same thickness. It can be thin. Therefore, according to the present invention, even if the lower coating and the upper coating are formed to be thicker to increase the insulation strength, the inorganic insulating film does not crack, so that the electro-optical material such as liquid crystal is used in the electro-optical device. It is suitable for manufacturing a substrate to be held.

In the present invention, the liquid precursor for forming the lower coating and the upper coating is, for example, a liquid containing a silicon composition in a solvent. The coating film of such a liquid material is subjected to ultraviolet irradiation and heat treatment to form the inorganic insulating film made of silicon oxide.

In the present invention, it is preferable that after forming the lower coating film, a solvent component is evaporated from the lower coating film, and then the upper coating film is formed on the surface of the lower coating film.

In the present invention, it is preferable that the liquid precursor is applied by flexographic printing to both the lower coating and the upper coating.

In the present invention, when forming the upper coating film, the liquid precursor is placed so that the edge of the upper coating film is located at least about 50 μm inside the edge of the lower coating film. Apply. For example, when using the flexographic printing method, in consideration of mechanical accuracy and the like, the liquid precursor is placed such that the edge of the upper coating is about 200 μm inside the edge of the lower coating, and is located inside. It is preferable to apply.

In the case of employing such a method, if the maximum film thickness after forming the lower coating film and the upper coating film is set to 2000 Å or less, the generation of cracks can be surely prevented.

The substrate manufactured by the method according to the present invention is preferably used as at least one of a pair of substrates holding an electro-optical material in an electro-optical device. Here, if a liquid crystal is used as a representative electro-optical material, a liquid crystal device can be manufactured as the electro-optical device.

[0019]

Embodiments of the present invention will be described with reference to the accompanying drawings.

(Overall Configuration) FIG. 1 is a perspective view showing the appearance of an electro-optical device (liquid crystal device) used in the display device of the present embodiment. FIG. 2 is a sectional view of the electro-optical device taken along line AA '. FIGS. 3 and 4 are plan views of a first substrate and a second substrate, respectively, which hold liquid crystal as an electro-optical material in the electro-optical device. Note that FIG. 1 schematically shows only electrode patterns and terminals, and the details will be described with reference to FIGS. 3 and 4.

1 and 2, the electro-optical device 1 of the present embodiment is a passive matrix type liquid crystal device. In the electro-optical device 1, an electro-optical material enclosing area 35 surrounded by the sealant 30 is defined between a pair of rectangular substrates that are bonded to each other with a sealant 30 therebetween with a predetermined gap therebetween. I have. An injection port 39 is formed in the sealant 30 by the interrupted portion, and a liquid crystal as an electro-optical material is injected from the injection port 39 into the electro-optical material enclosing region 35, and after the injection, the liquid crystal is sealed with a sealing material. ing. Here, of the pair of substrates, the substrate on which the first electrode pattern 40 in the vertical direction is formed is referred to as the first substrate 10, and the second electrode pattern 50 in the horizontal direction is formed. One substrate to the second substrate 20
And In the electro-optical device 1 shown here, a polarizing plate (not shown) is attached to the outer surface of the first substrate 10 with an adhesive or the like, and the polarizing plate (see FIG. (Not shown)) is attached with an adhesive or the like. When the electro-optical device 1 is configured as a reflection type, outside the polarizing plate,
Alternatively, a reflecting plate (not shown) is attached instead of the polarizing plate.

The second configuration of the electro-optical device 1 configured as described above
As shown in FIG. 2, a window frame 60 such as an exterior case in which a rectangular window 61 for defining an image display area in the electro-optical device 1 is formed on the substrate 20 side.

(Structure of Substrate) In FIGS. 3 and 4,
In the electro-optical device 1 of the present embodiment, both the signal input from the outside and the conduction between the substrates are applied to the substrate sides 10 located in the same direction on the first substrate 10 and the second substrate 20.
1, 201 (lower side), the terminal formation region 1 formed on each of the first substrate 10 and the second substrate 20
This is performed in steps 1 and 21. Therefore, the first substrate 10 is
The terminal formation region 11 is formed on the surface of the side of the substrate 20 opposite to the second substrate 20 so that the end protrudes outward from the substrate side 201. Substantially the entire surface of the terminal forming region 11 is in an open state (not facing the second substrate 20), and a flexible substrate (not shown) is provided for external input terminals 81 and 82 formed there. .) Are electrically connected.

In addition, at both ends of the terminal forming region 11 of the first substrate 10 shown in FIG. 3, the portion located on the side of the electro-optical material enclosing region 35 is connected to the side of the second substrate 20 via a conductive material. Since conduction (conductive connection) between the substrates is performed, the external terminals 8
From 2, the inter-substrate conduction terminals 60 extend to a position overlapping the second substrate 20.

A plurality of rows of first electrode patterns 40 are formed on the first substrate 10 from the central region of the terminal forming region 11 in the direction of the substrate side 102 facing the substrate side 101 of the same substrate. Extending. In FIG. 3, the position where the image display area is cut off by the inner periphery of the window frame 60 (the outer periphery of the window 61) shown in FIG. 2 is indicated by a solid line L2.
The region where the sealant 30 is formed is indicated by a double line L1.

On the other hand, the second substrate 20 shown in FIG.
Then, a wiring pattern is formed from the inter-substrate conduction terminal 60 so as to go around the area corresponding to both sides of the formation area of the first electrode pattern 40 shown in FIG. First substrate 1 in region 35
A plurality of rows of pixel driving second electrode patterns 50 extending so as to intersect the first electrode patterns 40 formed in the plane 0 in a plane are formed. In FIG. 4, the position where the image display area is cut off by the inner periphery of the window frame 60 (the outer periphery of the window 61) shown in FIG. 2 is indicated by a solid line L <b> 2, and the sealant 30 is formed. Double line L for area
It is indicated by 1.

(Manufacturing Method of Liquid Crystal Device 1) In manufacturing the electro-optical device 1 having such a configuration, first, as shown in FIGS. Electrode pattern 4 on second substrate 20
0, 50 and terminals are formed.

Next, as shown in FIG.
Surface protective films 19 and 29 are formed so as to completely cover 0 and 50. Here, the surface insulating films 19 and 29 are
It is formed up to a region where the end portion overlaps with 0.

Next, alignment films 18, 28 made of polyimide resin or the like are formed on the surfaces of the surface protection films 19, 29.

Next, after the surfaces of the alignment films 18 and 28 are subjected to a rubbing treatment, the first substrate 10 and the second substrate 20 are bonded via a sealant 30 containing a gap material and a conductive material. Match. This conductive material (conductive particles) is N
i, metal particles such as solder, spherical or rod-shaped plastic or glass plated with metal, or, for example, particles obtained by plating the surface of elastically deformable plastic beads having a particle size of about 6 0.6 μm. On the other hand, the particle size of the gap material contained in the sealant 30 is about 5.6 μm. Therefore, when the sealant 30 is melted and cured while applying a force to narrow the gap in a state where the first substrate 10 and the second substrate 20 are overlapped, the sealant 30 spreads from the application area, The conductive material conducts predetermined terminals between the first substrate 10 and the second substrate 20 in a crushed state.

When the first substrate 10 and the second substrate 20 are attached to each other, pixels are formed in a matrix at intersections between the first electrode pattern 40 and the second electrode pattern 50. Therefore, when an image signal and a scanning signal are input from the outside, these signals cause the first electrode pattern 40 and the second electrode pattern 50 in each pixel.
Since the alignment state of the liquid crystal (electro-optical material) positioned between the two can be controlled, a predetermined image can be displayed.

(Step of Forming Surface Protective Film) In manufacturing the electro-optical device 1 in this manner, the surface protective film 1 is formed.
When bonding the first substrate 10 and the second substrate 20, the sealing agent 30 is melted and cured while applying a force to narrow the gap between the first substrate 10 and the second substrate 20.
It is formed in order to prevent conductive foreign matter generated when forming 0 and 50 from breaking through the alignment films 18 and 28 and short-circuiting the electrode patterns 40 and 50. Therefore, the surface protection films 19 and 29 need to have a predetermined insulation strength.

FIG. 5A shows the first insulation strength.
As shown schematically in FIG.
The tip of the pin terminal 100 connected to the electrode pattern 40 of the substrate 10 via the ohmmeter 101 is pressed against the surface protection film 19 formed on the surface of the first substrate 10 as shown by arrow C. When the load is increased, the load when the value of the resistance meter 101 falls below a predetermined value is measured as insulation strength.

In the measurement results, there is a relationship shown in FIG. 5B between the insulation strength and the thickness of the surface protection film 19. As is apparent from this figure, the insulation strength increases as the film thickness of the surface protection film 19 increases. For example, if an insulation strength of 2000 g or more is to be obtained, the film thickness of the surface protection film 19 is 1300. Angstroms or more is required, and cannot be handled by the conventional method.

Therefore, in this embodiment, as a method of forming the insulating film, a liquid precursor for forming an inorganic insulating film is applied to the substrate side by an application method such as flexographic printing, and the application conditions at that time are changed. Set as follows. Here, the liquid precursor for forming the inorganic insulating film is composed of a liquid material containing a small amount of titanium oxide or zirconia together with an organic silicon composition or silicon oxide in a solvent such as methyl carbitol. After evaporation and removal, UV irradiation is performed to form a silicon oxide film.

With reference to FIGS. 6A, 6B, and 6C, the main part of the flexographic printing press and its printing operation will be described. In addition, the coating process in this flexographic printing machine and FIG.
The steps of forming an insulating film described with reference to (A) and (B) are performed in the same manner on both the first substrate 10 and the second substrate 20, and therefore, in order to avoid redundant description, Only the step of forming the insulating film on the first substrate 10 will be described, and the description of the step of forming the insulating film on the second substrate 20 will be omitted.

As shown in FIG. 6A, in the flexographic printing press 800, the doctor roller 801 and the anilox roller 802 are configured to rotate in opposite directions.
A liquid precursor for the inorganic insulating film is supplied from between the rollers 801 and 802 to the roller 804 on which the relief 803 is formed, as shown in FIG.
As shown in (C), the liquid precursor held by the relief 803 of the roller 804 is transferred to the first substrate 10.
At this time, since the first substrate 10 is held on the surface plate 805 that moves horizontally in conjunction with the rotation of the roller 804, the liquid precursor held by the relief plate 803 is placed on the first substrate 10 Is applied to a predetermined area of the solid.

In the flexographic printing machine 800, the relief printing plate 80
If only 3 is changed, the liquid precursor can be applied to an arbitrary region of the first substrate 10. Therefore, in this embodiment,
As described below with reference to FIGS. 7A and 7B,
A liquid precursor is applied on the first substrate 10 to form a thick surface insulating film 19 with good film quality.

FIGS. 7A and 7B are process cross-sectional views showing the state of the process of forming an insulating film in the method of manufacturing a substrate to which the present invention is applied.

In this embodiment, first, as shown in FIG. 7A, a predetermined area on the surface side of the first substrate 10 on which the electrode pattern 40 is formed is inorganic-insulated by a flexographic printing machine. A liquid precursor for forming a film is printed and applied in a solid state, and the lower coating film 91 having a thickness of about 650 Å is formed.
To form At this time, a bulge 912 having a film thickness (1300 angstroms) that is about twice the film thickness of the inner region occurs near the edge 911 of the lower coating film.

Next, a pre-bake is performed for about 10 minutes at a temperature of 100 ° C. to evaporate the solvent component from the lower coating film 91, and then the wavelength is 360 nm and the energy intensity is 60.
The lower coating layer 91 is irradiated with UV light of 00 mJ to react organic components in the liquid composition.

Next, as shown in FIG. 7B, in the flexographic printing machine, the relief plate 2 when the lower coating film 91 was formed was formed.
03, using a relief plate different from the above, the liquid precursor for forming the inorganic insulating film is again applied on the surface of the lower coating film 91, and applied.
An upper coating 92 having a thickness of about 650 Å is formed. At this time, the upper coating film 91 is formed such that the edge 921 of the upper coating film 92 is located about 200 μm inward from the edge 911 of the lower coating film 91. As a result, near the edge 921 of the upper coating film 92, a bulge 922 having a thickness (1300 angstroms) which is about twice the thickness of the inner region is generated. However, since the bulge 922 is located about 200 μm inside when viewed from the position where the bulge 912 of the lower coating 92 occurs,
The two bumps 912 and 922 do not overlap. Therefore, as shown in FIG. 7B, in the state where the coating is completed, the sum of the film thicknesses of the lower coating film 91 and the upper coating film 92 is the largest (where the bulge 922 occurs). Even so, the thickness of this part is about 1950 Å, which is less than 2000 Å.

Next, pre-baking is performed again at a temperature of 100 ° C. for about 10 minutes to evaporate the solvent component from the upper coating film 92. Then, UV light having a wavelength of 360 nm and an energy intensity of 6000 mJ is irradiated on the upper side. By irradiating the coating film 92, an organic component reacts in the liquid composition.

Thereafter, the baking is performed for about 30 minutes at a temperature of 300 ° C. to cure the lower coating 91 and the upper coating 92, and is made of a silicon oxide film having a thickness of about 1300 angstroms. The surface protection film 19 is formed.

(Effect of this Embodiment) When the first substrate 10 is manufactured under such film forming conditions, the surface protective film 19 having a thickness of about 1300 angstroms can be formed. Also in this case, since the upper coating film 91 is formed such that the edge 921 of the upper coating film 92 is located on the inner side by about 200 μm as viewed from the edge 911 of the lower coating film 91, the bulge generated in each coating film 912 and 922 do not overlap. Accordingly, even after the lower coating film 91 and the upper coating film 92 have been formed, even if the sum of the film thicknesses is the maximum (the portion where the bulge 922 occurs), the film thickness in this portion is About 1
It is only 950 angstroms. Therefore, even when these coating films are heated and converted into the surface protective film 19, the surface protective film 19 does not crack.

Therefore, the first substrate 10 on which the surface protection film 19 is formed in this manner and the second substrate 20 on which the surface protection film 29 is formed in the same manner as the surface protection film 19 are formed.
When the electro-optical device 1 is manufactured by bonding
Both the substrate 10 and the second substrate 20 have a film thickness of 1300 angstroms and thus have an insulation strength of 2000
g and the high surface protection films 19 and 29 are formed,
Even if the conductive foreign matter remains when the electrode patterns 40 and 50 are formed, the conductive foreign matter does not break through the surface protection films 19 and 29 and short-circuit the electrode patterns 40 and 50. Therefore, in the electro-optical device 1, a high yield can be maintained even when the display quality is improved by reducing the distance between the substrates (cell gap).

In this embodiment, the surface protection films 19 and 29 are used.
The thickness of the film formed when is formed is suppressed to 2000 angstroms or less, which is the upper limit at which cracks occur, even at the raised portions 912 and 922 at which the maximum film thickness is formed. Therefore, after the surface protection films 19 and 29 are formed, no cracks occur in the surface protection films 19 and 29 in the cleaning step or the rubbing step.

(Other Embodiments) In the above embodiment, when the liquid precursor for forming the inorganic insulating film is applied, the upper coating is performed in consideration of the mechanical accuracy of the flexographic printing machine 800. The dimension for shifting the edge 921 of the film 92 inward from the edge 911 of the lower coating 91 was set to about 200 μm.
When the experiment was performed by changing the displacement size to 30 μm, 40 μm, and 50 μm, no crack occurred at about 50 μm. Therefore, the edge 921 of the upper coating 92 was shifted from the edge 911 of the lower coating 91. The size to be shifted inward may be about 50 μm or more.

In the above embodiment, the method of forming an insulating film to which the present invention is applied is based on the first substrate 10 and the second substrate 20.
Although the thick surface protection films 19 and 29 are formed on both of them, the present invention may be applied to only one of the substrates.

Further, the present invention is not limited to the substrate for the electro-optical device 1, but may be applied to a substrate used for other electronic devices as long as a surface protective film requiring an insulating strength is formed thereon. Can also be applied.

[0051]

As described above, according to the present invention, when the liquid precursor for forming the inorganic insulating film is applied, the edge of the upper coating is shifted inward from the edge of the lower coating. . Therefore, even if swelling portions of the liquid precursor occur near the edges of the upper coating film and the lower coating film, these swelling portions do not overlap. Compared to the double coating method in which the film is completely overlaid, even if the liquid precursor is applied to the same thickness, the maximum film thickness after application can be reduced. Therefore, according to the present invention, even if the lower coating and the upper coating are formed to be thicker to increase the insulation strength, the inorganic insulating film does not crack, so that the electro-optical material such as liquid crystal is used in the electro-optical device. It is suitable for manufacturing a substrate to be held.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance of an electro-optical device to which the present invention is applied.

FIG. 2 is a cross-sectional view taken along line AA 'of FIG.

FIG. 3 is a plan view showing electrode patterns and terminals formed on a first substrate of the electro-optical device shown in FIG.

FIG. 4 is a plan view showing electrode patterns and terminals formed on a second substrate of the electro-optical device shown in FIG.

FIGS. 5A and 5B are explanatory diagrams showing a method of measuring the insulation strength of a surface protective film (inorganic insulating film), and the insulation strength measured by this method and the film thickness of the surface protective film, respectively. 6 is a graph showing the relationship of.

FIG. 6 is an explanatory diagram showing a main part of the flexographic printing press.

FIGS. 7A and 7B are process cross-sectional views showing a step of forming a surface inorganic insulating film on a surface of a substrate in a method for manufacturing a substrate to which the present invention is applied.

FIGS. 8A and 8B are a process sectional view showing a conventional once-coating method for forming a surface inorganic insulating film on the surface of a substrate, and a process sectional view showing a conventional double-coating method, respectively. It is.

[Explanation of symbols]

 Reference Signs List 1 electro-optical device 10 first substrate 19, 29 surface protective film (inorganic insulating film) 20 second substrate 30 sealant 35 electro-optical material enclosing region 40 first electrode pattern (conductive film) 50 second electrode pattern (Conductive film) 91 Lower coating film 92 Upper coating film 911 Edge of lower coating film 912 Ridge generated in lower coating film 921 Edge of upper coating film 922 Ridge generated in upper coating film 800 Flexo printing machine

Claims (10)

[Claims] 1. A method of manufacturing a substrate in which the surface of a conductive film is covered with an inorganic insulating film formed from a coating film of a liquid precursor for forming an inorganic insulating film, wherein the surface of the substrate on which the conductive film is formed is After forming a lower coating by applying a liquid precursor for forming an inorganic insulating film, and applying a liquid precursor for forming an inorganic insulating film on the surface of the lower coating to form an upper coating A method for manufacturing a substrate, comprising: forming the upper coating film such that an edge of the upper coating film is positioned inside an edge of the lower coating film. 2. The liquid precursor for forming the lower coating film and the upper coating film according to claim 1,
A liquid material containing a silicon composition in a solvent, wherein the inorganic insulating film made of silicon oxide is formed by performing ultraviolet irradiation and heat treatment on a coating film of the liquid material. Substrate manufacturing method. 3. The method according to claim 2, wherein after forming the lower coating film, a solvent component is evaporated from the lower coating film, and then the upper coating film is formed on the surface of the lower coating film. A method for manufacturing a substrate, comprising: 4. The method according to claim 1, wherein
A method for manufacturing a substrate, wherein the liquid precursor is applied by flexographic printing when forming either the lower coating film or the upper coating film. 5. The method according to claim 1, wherein
When forming the upper coating, the liquid precursor is applied such that the edge of the upper coating is about 50 μm or more than the edge of the lower coating, and is located inside. Substrate manufacturing method. 6. The liquid precursor according to claim 4, wherein the upper coating is formed such that an edge of the upper coating is positioned about 200 μm inside the edge of the lower coating. A method for manufacturing a substrate, comprising applying a body. 7. The method according to claim 1, wherein
A method of manufacturing a substrate, wherein a maximum film thickness after forming the lower coating film and the upper coating film is 2,000 angstroms or less. 8. A method for manufacturing an electro-optical device, comprising using at least one substrate on which the inorganic insulating film is formed by the method according to claim 1, and holding an electro-optical material between the substrates. Method. 9. The method according to claim 8, wherein the electro-optical material is a liquid crystal. 10. An electro-optical device manufactured by the method defined in claim 8 or 9.