JPH0645483B2 - Substrate for liquid crystal display device and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION “Industrial field of application” The present invention relates to a linear pattern without using a photoresist when patterning a thin film used in a solar cell using a cheap soda glass, a liquid crystal display device or the like. The groove formation is directly drawn (pattern formation) with a laser beam.
Then, in order to prevent the leaching of impurities such as sodium ions to the outside due to the removal of the first blocking layer between the thin film and the soda glass generated for this direct writing, the second
The present invention relates to a substrate having a thin film provided with a blocking layer in the groove.

"Prior Art" A method of using a photoresist for patterning a thin film is known. This method is for patterning a conductive film such as a transparent conductive film on a soda glass substrate without damaging a blocking layer such as silicon oxide or phosphorus glass, which prevents an alkali metal element or the like from entering the outside. It has the feature that it can be performed. However, this method has a complicated step of coating a photoresist in a predetermined shape, using this resist as a mask, patterning, and then removing the photoresist.
Therefore, there is a demand for an inexpensive patterning method.

As this inexpensive method, there is known a method of directly drawing (pattern forming) by a laser processing method. As this laser processing method, a method using a YAG laser (wavelength 1.06 μm) is generally considered to be effective. This method using infrared rays has an optical energy of the laser light of 1.23 eV
(1.06 μm) only. On the other hand, a work piece formed on the glass substrate, for example, a transparent conductive film (hereinafter referred to as CTF) has an optical energy bandwidth of 3 to 4 eV. Therefore, tin oxide, indium oxide (including ITO),
CTF such as zinc oxide (ZnO) does not have sufficient light absorption for the YAG laser light, and the energy of the laser light has not been effectively used. Moreover, in the laser processing method using the Q switch oscillation of the YAG laser, the pulsed light has a high scanning speed with an average of 0.5 to 1 W (optical diameter 50 μm, focal length 40 mm, pulse frequency 3 KHz, pulse width 60 nsec). Must be added and processed at 30-60 cm / min. As a result, the CTF can be processed by this laser light, but at the same time, soda glass having a blocking layer provided on the lower side thereof causes microcracks to a depth of 10 to 50 μm and damages it. It was

Further, as irradiation light other than the YAG laser, a pulse laser having an ultraviolet light wavelength of 400 nm or less (energy is 3.1 eV or more) is irradiated, and not a beam spot of 20 to 50 μφ but a width of 2 to 200 μm (for example, 10 μm), length 10-60 cm
For example, a method is known in which a linear pattern of 30 cm is irradiated with a pulse at the same location once or several times to form a linear groove and a thin film is patterned. The YAG laser (1.06 μm) was used to measure the absorption efficiency of light energy in a transparent substance such as CTF by linearly irradiating this pulsed light with a wavelength of 400 nm or less (pulse width is extremely short, 5 to 30 nsec). More than 100 times higher, resulting in a processing speed of 10
Can be more than twice as fast.

In this case, excimer laser light is generally used as the initial light source. Therefore, the irradiation surface of the initial light has a rectangular shape, and its intensity is also substantially uniform on the irradiation surface. A so-called beam expander that widens the width for this is used to increase the rectangular area. After that, the laser beam is condensed in a slit shape by a cylindrical rod lens, that is, a cylindrical lens along one of the X or Y directions.

Thus, a linear groove having a width of 2 to 200 μm, for example, 10 μm is formed.

These methods using laser light have a feature that the manufacturing process is easy because no photoresist is used. However, there is a drawback that the blocking layer is also removed at the groove portion formed by processing with this laser light. Therefore, even if it is desired to use an inexpensive soda glass, a sufficient means cannot be found for exuding impurity ions such as sodium mixed in advance into the outside to the outside.

When solar cells, liquid crystal display devices and other electronic components are manufactured using the substrate in such a state, short circuits between electrodes due to the unevenness, disconnection, color unevenness, etc. occur, and the production yield of electronic components decreases. I was imitating.

[Object of the Invention] The present invention uses a laser beam having a wavelength of 400 μm or less to form a thin film or a laminate on a glass substrate, in particular, a soda glass (also referred to as alkali glass) provided with a blocking layer against impurities such as alkali ions. In particular, a conductive film such as a transparent conductive film or a metal film, or an insulating film such as a color filter below this, or a laminated body in which a non-single crystal semiconductor is laminated thereon When laser processing and patterning, a good work surface with no residue near the open groove of the work part is realized, and impurities such as sodium in the substrate are prevented from seeping out to the outside. The second purpose is to provide a blocking layer (2), that is, a protective film for preventing the exudation of sodium from the groove.

[Constitution of the Invention] In order to achieve the above object, a blocking layer made of silicon oxide or the like, which is doped with phosphorus, sodium, or boron in a sufficiently small amount, between a base substrate such as soda glass and a thin film to be processed ( As a first blocking layer), a thin film, particularly ITO, tin oxide, zinc oxide or a laminated body thereof, and a metal conductive film such as chromium or molybdenum are laminated thereon. Further, if necessary, it may be a laminated body having an insulator or a semiconductor provided on the lower surface or the upper surface thereof. Then, by irradiating the conductive film with a laser beam having a wavelength of 400 μm or less, the blocking layer as well as the conductive film is simultaneously irradiated and removed to form an open groove. Therefore, the exudation of impurities such as sodium from the substrate material is promoted.

Therefore, the second blocking layer is formed on all of them. The second blocking layer is made of a liquid material, which is applied, printed or coated, and the whole of them is heat-treated and cured. Then, since the open groove of the laser processing portion constitutes a concave portion, this portion can be made relatively thicker than on the thin film. And preferably 50 on the thin film
~ 300 Å thickness, for example 200 Å, 100 ~ 600 Å thickness (100 Å when 50 Å on the thin film, 60 when 300 Å
Corresponding to 0Å) For example, 400Å can be made 30% thicker. This thickness makes it possible to prevent the effect of exuding alkali ions such as sodium in the substrate to the outside.

Furthermore, after forming a laminated body together with other semiconductors, insulators, etc., which are previously formed on or under this conductive film, patterning all of these with a laser beam, and the upper surface and side surface of the laminated body formed by this It is also possible to fill the second blocking layer and form the groove as well. At this time, since the thickness of this laminated body becomes thicker, it is formed in the open groove to be thicker than the thickness of the second blocking layer on the laminated body, so that the effect of shielding impurity ions such as sodium is remarkably increased. can do.

Examples will be shown below.

Example 1 FIG. 2 shows a system diagram of laser processing of the present invention using an excimer laser. The excimer laser (1
4) (wavelength 248 nm, Eg = 5.0 eV) was used. This laser has an initial light beam (21) of 16 mm × 2 as shown in Fig. 3 (A).
Since it has 0 mm and the efficiency is 3%, it has 350 mJ (millijoule). Furthermore, this beam is expanded
The area was made longer or larger in (15). That is, 16 mm x 30
It was enlarged to 0 mm (Fig. 3 (22)). At this time, 5.6 × 10 ^-2 mJ /
mm ² was obtained in energy density.

Next, the laser beam is transmitted through a slit (16) having an interval of 2 mm × 300 mm to obtain a laser beam (23) of 2 mm × 300 mm. (FIG. 3 (C)) Furthermore, the cylindrical lens (17) made of synthetic quartz was focused (24) so that the groove width on the processed surface was 10 μm. (FIG. 3 (D)) Although the width of the slit used at this time is not particularly determined, it is necessary to narrow down the laser beam to the extent that the spherical aberration of the cylindrical lens does not affect. Further, the groove width of the workpiece can be arbitrarily selected depending on the performance of the cylindrical lens.

In FIG. 1, a substrate is irradiated with slit-shaped pulsed light to form a plurality of open grooves (6-1, 6-2, 6-3, ... N). That is, as shown in FIG. 1 (A), a blocking layer (2) (100%) is formed on soda glass (also called soda lime glass).
Thickness of up to 1500Å) For example, a substrate having a thickness of 200Å of silicon oxide is used. Further, a conductive film (4), for example, indium tin oxide or chromium is formed on this to a thickness of 1000 to 3000Å. As shown in FIG. 1 (B), these were irradiated with laser light using the optical system shown in FIGS. 2 and 3.

The pulsed light was 248 nm light from a KrF excimer laser. Because the optical energy bandwidth of the light is 5.
Because it is 0 eV, the work piece absorbs light sufficiently and only the conductive film can be selectively processed.

Pulse width 20 ns, repetition frequency 1-100 Hz, eg 10H
Light irradiation was performed at z.

Then, the open grooves (6-1), (6-2), (6-3) ... Are obtained. At this time, the protrusion (5-2) is formed on the patterned conductive film (4) and the residue (5-1) inside the groove. These are dissolved with diluted hydrofluoric acid (diluted with water to 1/10), and further ultrasonically washed with acetone and pure water.

Then, as shown in FIG. 1 (C), the open grooves (6-1), (6-2), (6-3) had only grooves, and all the residues could be removed.

However, in this groove, the blocking layer (2) was also removed at the same time, and part of the upper part of the soda glass substrate (0.
It has been scooped out and exposed (to a depth of 3 to 1 μm). For this reason, when a liquid crystal display device is manufactured using only the structure shown in FIG. 1 (C), the substrate material is directly contacted with the liquid crystal that requires ultra-high purity, and sodium is contained in the liquid crystal during long-term use. There is a risk of exudation.

If it is used as it is for image sensors, solar cells, etc.,
Sodium bleeds into the amorphous semiconductor from this portion, which promotes the photodegradation effect and the semiconducting N-type conductivity.

For this reason, in the present invention, the upper surface of FIG.
As shown in (D), a second blocking layer was formed.

This blocking layer is preferably an organic resin such as polyimide that blocks sodium, or an inorganic material such as silicon oxide. These have a liquid state in the raw material state (non-polymerized state or liquid state of an organosilicide liquid such as silazane), and the raw material has a thickness of 50 to 250 Å as a whole, for example, 300 Å on the conductive film, open groove part. Apply a coating thickness of about 500Å.
This coating coat may use a spinner, or a printing method, a coater method, or a spray method.

Then, since these have a surface coated with a liquid, a larger amount can be applied to the open grooves (6-1), (6-2) ... Constituting the concave portion, and the groove can be formed thicker.

Further, these liquid raw materials were heat-cured. For example, the polyimide solution is heated and baked at 230 ° C. for 2 hours. Also in the method using a liquid organosilicon compound, heating and oxidation were performed in the atmosphere or oxygen to transform the blocking layer of solid silicon oxide.

Thus, as shown in FIG. 1 (D), the solvent was vaporized, and the volume contracted and became dense due to the heating reaction, and it was possible to completely prevent the alkali ions and the like from seeping out to the outside. Then, the seepage from the lower side of the organic substance into the conductive film was blocked by the blocking layer (2) (first blocking layer). Then, the permeation of pure material into the conductive film or the laminate (7) from the periphery and the upper surface of the side was blocked by the second blocking layer (8).

Further, in the liquid crystal display device, it is effective that the second blocking layer also functions as an alignment film by lapping the surface thereof as necessary.

Further, the second blocking layer may be subjected to a CVD method or a vacuum vapor deposition method. However, such a method has a drawback in that the thickness of the concave portion forming the open groove becomes smaller than the thickness on the conductive film. In addition, the thickness of the groove of the recess is likely to be uneven. Ideally, it is required that all of the recesses be filled so that the top surface of the recesses is substantially aligned with the top surface of the conductive film, and that local electric field concentration at the ends of the conductive film is prevented. Therefore, it is more preferable that the liquid raw material is applied and formed, and then cured.

Especially, the width of this groove is 20μm, 10μm, 5μm from 50μ,
In order to make the inside of the groove thicker in addition to making it as small as 3 μm, it is preferable to apply a liquid raw material using surface tension and to perform the curing step.

Thus, for example, the substrates of the vertical sectional view shown in FIG. 1 (D) are spaced apart from each other by a width of 2 μm, arranged in a matrix configuration, and filled with a liquid crystal material between them.
A liquid crystal display device capable of matrix display could be made.

In this case, one substrate side was made of silicon oxide to form the second blocking layer, and the other substrate was made of polyimide organic resin to form the second blocking layer. Then, the organic resin side was rubbed. By doing so, even if this alignment film was subjected to high temperature treatment at 50 ° C. for 1000 hours, the contrast of the display portion was 20, and the value was not deteriorated at all.

In Fig. 1 (D), the ITO (4-
A DC voltage of 50 V was applied between 1) and (4-2), and the current flowing between ITO was measured at 100 locations. All were 1 to 2 × 10 ^-9 A
The values are in the range of (leakage current between open grooves with a length of 30 cm and a width of 10 μm). Since the second blocking layer also prevents surface leakage, the obtained values show a constant value and are practically used. There was no hindrance.

[Effect] According to the present invention, since the conductive film and the outer periphery of the laminated body are all covered with the blocking layer in the laser processing, it is possible to further reduce the leakage between adjacent conductors.

According to the present invention, a good surface to be processed was obtained without any residue or the like remaining around the existing processing grooves which were present in the conventional method.

As a result, there is no short circuit between electrodes or disconnection, and the ITO
I was able to get enough insulation between them.

In the present invention, the conductive film may be made of ITO, SiO ₂ , ZnO, or a multilayer film of these, or metal such as chromium or molybdenum.

Further, it is effective to stack an insulating film having a function of a color filter on the upper side or the lower side of these conductive films so that the conductive films have the same shape.

Further, it is effective to stack a non-single-crystal semiconductor on the upper side of this conductive film and further form another conductive film on it to use it for an image sensor.

In the present invention, the second blocking layer is provided so as to cover all of these laminated bodies to achieve high reliability, and high reliability can be obtained even when an inexpensive soda glass substrate is used.

In the present invention, the case where the width between the open grooves (the area to be left without processing) is large is described. However, it is also possible to make the remaining surface 20 μm and the removed portion 400 μm, for example, by concatenating the light irradiations side by side.

[Brief description of drawings]

FIG. 1 shows a method for manufacturing a substrate having a conductive film of the present invention. FIG. 2 shows an outline of the laser processing system used in the present invention. FIG. 3 shows the beam shape of the laser light.

Claims (4)

[Claims] 1. A multilayer film comprising: a substrate containing a sodium, a first blocking layer for preventing the sodium from exuding to the outside, and a conductive film on the first blocking layer. When the conductive film is patterned, a second blocking layer for preventing the sodium from exuding to the outside is formed in the removed groove of the conductive film around the side, and the second blocking layer is The thin film is provided so as to cover the conductive film, and the thickness of the second blocking layer in the groove is larger than that on the conductive film. Substrate for liquid crystal display device. 2. The substrate for a liquid crystal display device according to claim 1, wherein the second blocking layer is made of an inorganic material such as silicon oxide, silicon nitride or alumina, or an organic resin material such as polyimide. . 3. The substrate for a liquid crystal display device according to claim 1, wherein the conductive film is a translucent conductive film and the second blocking layer is a liquid crystal alignment film. 4. A laminate is formed by forming a first blocking layer on a glass substrate, forming a conductive film on the blocking layer, and providing a semiconductor or an insulator on the upper surface or the lower surface of the conductive film. A step of patterning the laminated body with a laser beam to selectively remove the laminated body to form an opening groove; a step of coating, printing or coating a liquid material covering the laminated body, and further heating Second by curing by processing
Forming a blocking layer of the liquid crystal display, wherein the thickness of the second blocking layer in the groove is thicker than the thickness on the laminate. A method for manufacturing a device substrate.