JPH08320494A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE: To decrease the contact resistance between a metal and a transparent conductive body without a complicated production process by forming a joined part having a metal/insulating material/transparent conductive material structure and applying a current on the joined part for welding. CONSTITUTION: An insulating material 9 and a transparent conductive material 10 of ITO are deposited on a metal 8 made of tantalum on a glass substrate 7 except in the area for a welding part 6. Since the surface of the metal tantalum 8 is covered with the insulating material 9 except for the welding part 6, good adhesion property with the ITO transparent conductive body 10 is obtd. A current is applied between the metal tantalum 8 and the conductive material 10 to cause breakdown in the insulating material 9 comprising Ta2 O5 and to weld the metal 8 and the conductive material 10 to produce a welding part 6 essentially comprising tantalum and indium. Thus, the electric contact between the metal tantalum 8 and the ITO transparent body 10 is made as an ohmic contact having enough low resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device using a thin film diode (hereinafter referred to as TFD) having a metal-insulator-metal structure as a switching element, and tantalum (hereinafter referred to as Ta) which is a wiring material. The present invention relates to a structure and a manufacturing method of a portion for connecting a metal film such as a film and a transparent conductor such as an indium tin oxide film (hereinafter referred to as ITO).

[0002]

2. Description of the Related Art Today, thin film transistors (TFTs), diodes, and
A switching element of a thin film diode (TFD) is used.

For the gate electrode and wiring material of thin film transistors (TFTs) and the electrode and wiring materials of thin film diodes (TFDs), tantalum films that can easily form high-quality insulating films by anodization are often used.

By the way, when ITO used as a pixel electrode and a wiring material is laminated on tantalum by a sputtering method or the like and heat-treated, the oxygen affinity of tantalum is large and oxygen diffuses from the ITO to tantalum.

Therefore, at the interface between tantalum and ITO, an insulating tantalum oxide layer is formed on the tantalum side, and the contact resistance increases. On the other hand, since oxygen is deficient near the interface on the ITO side, a deposition layer of indium or a lower oxide layer of indium is formed, and the adhesion between the tantalum film and the ITO film is reduced.

Therefore, in order to make a stable electrical connection between the tantalum wiring and the ITO wiring, another metal layer is provided as a barrier layer between the tantalum layer and the ITO layer, or tantalum oxide is processed by a method such as anodization. A tantalum layer and I
Capacitive coupling between the TO layer and the tantalum oxide layer is performed.

[0007]

However, in the method of providing another metal as a barrier layer between the tantalum film and the ITO film, the barrier layer is required to be formed and patterned, which complicates the manufacturing process. .

Further, in the method of connecting by capacitive coupling across the oxide layer, it is necessary to make the coupling capacitance of each signal line large so that the impedance is sufficiently lowered at the driving frequency, so that the wiring is compared with the display section. The area of the part must be relatively large, which is disadvantageous especially in a small display.

Further, in order to prevent display unevenness, it is necessary to make the capacitance coupling portions of the respective signal lines equal in capacitance, so that the degree of freedom in designing the capacitance coupling portions of the wiring portion is reduced.

An object of the present invention is to solve these problems and improve the adhesion between the tantalum film and the ITO film without using a complicated manufacturing process, and to provide a connecting portion for DC coupling between the tantalum wiring and the ITO wiring. Another object of the present invention is to provide a structure and a manufacturing method of the liquid crystal display device.

[0011]

In order to achieve the above object, the structure of the liquid crystal display device of the present invention and the manufacturing method thereof adopt the following means.

In the liquid crystal display device of the present invention, the connecting portion between the metal and the transparent conductor is coated with the metal made of tantalum on the substrate made of glass, the insulator made of tantalum oxide on the metal, and the metal and the insulator. It is composed of a transparent conductor, and a predetermined current is applied to the metal and the transparent conductor to cause a dielectric breakdown at a predetermined position of the insulator to weld the metal and the transparent conductor to each other through the welded portion where the metal and the transparent conductor are welded. Take a structure to obtain electrical connection.

A method of manufacturing a liquid crystal display device according to the present invention comprises a step of forming a metal made of tantalum on a substrate made of glass, a step of patterning the metal by photoetching, and anodization to insulate the element part. A step of forming a body, a step of forming a transparent conductor, a step of patterning the transparent conductor by photoetching, and a predetermined position of the insulator by applying a predetermined current to the metal and the transparent conductor. Dielectric breakdown to form a welded portion in which a metal and a transparent conductor are welded.

[0014]

In the active substrate of the liquid crystal display device, the display area and the driving semiconductor device are electrically connected through the wiring. A large number of signal lines, switching elements, and pixel electrodes are formed in the display area.

In the present invention, the signal line is connected to the driving semiconductor device through a connecting TFD element that performs DC coupling.

The connecting TFD element has a TFD structure in which a transparent conductor, which is a wiring for connecting to a semiconductor device, is laminated on a signal line made of metal and an insulator.

In the embodiment of the present invention, tantalum is used as a metal, a tantalum oxide (Ta2 O5) film formed by anodic oxidation is used as an insulator, and indium tin oxide (ITO) is used as a transparent conductor.

When a current is applied to this connecting TFD element by a constant current source, tantalum oxide (Ta2 O5) as an insulator is formed.
Joule heat is generated in the film. Generated heat is TFD for connection
Run around the element.

When a lamp current is applied to gradually increase the current value, the temperature gradient in the central portion of the connecting TFD element plane becomes highest.

In the connecting TFD element having a temperature gradient, the current is concentrated in the central portion of the element where the temperature is high, and when a predetermined current value is reached, Ta2O5 of the insulating film undergoes dielectric breakdown.

This is because the conductivity of the connecting TFD element has a positive temperature characteristic, so that the central portion where heat does not easily escape has the lowest resistance.

Since this dielectric breakdown occurs thermally, after the dielectric breakdown, metal tantalum and ITO of the transparent conductor are welded at the welded portion where Ta2O5 of the insulating film is dielectrically broken, and the electrical connection becomes ohmic contact. .

When a constant current source is used as the power source and the current value at the time of dielectric breakdown is maintained, the welded portion becomes the main path of current after welding, but the resistance is low, so the temperature of the connecting TFD element drops sharply and the reaction occurs. Does not proceed and stable DC coupling is obtained.

In the DC coupling portion formed by applying the lamp current by the constant current source, the mechanical coupling is Ta / Ta2 because the area of the connecting TFD element is sufficiently larger than that of the welding portion.
Since it is held by the O5 / ITO structure, the adhesion is also good.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a liquid crystal display device and its manufacturing method according to embodiments of the present invention will be described below with reference to the drawings.

First, the structure of a liquid crystal display device according to an embodiment of the present invention will be described with reference to the drawings. The structure of the liquid crystal display device will be described with reference to FIG. FIG. 3 is a plan view showing an active substrate of a liquid crystal display device according to an embodiment of the present invention.

Display area 1 of the area surrounded by the chain double-dashed line of element 3
2 is provided with a large number of signal lines, switching elements, and pixel electrodes. This signal line is connected to the active substrate 1 by the wiring 2.
1 is connected to the driving semiconductor device 14 mounted on the semiconductor device 1.

In FIG. 3, a chip-on-glass (hereinafter referred to as COG) structure is used in which the driving semiconductor device 14 is directly mounted on the active substrate 11.

Here, the COG mounting structure is a mounting means for directly bonding the driving semiconductor device 14 onto the active substrate 11, which is a glass substrate, using a wire bonding method, solder or a conductive adhesive.

Next, the structure of the signal line wiring connection portion will be described with reference to FIG. FIG. 1 is an enlarged plan view showing a signal line wiring connection portion 13 in the area near the wiring 2 in the display area 12 of FIG.

As shown in FIG. 1, the signal line 3 is a metal having an insulating layer formed on its surface. In the embodiment of the present invention, tantalum is used as the material, and the display TFD element 4 in the area surrounded by the broken line is interposed. Then, the pixel electrode 5 is connected to the transparent conductor.
In the embodiment of the present invention, indium tin oxide (ITO) is used as the material of the pixel electrode 5.

In the embodiment of the present invention, the Ta / ITO connecting portion of the connecting TFD element 1 has the structure shown in the sectional view of FIG.

That is, as shown in FIG. 2, the glass substrate 7
The tantalum of the metal 8 above the ITO layer is laminated with the ITO of the transparent conductor 10 via the insulator 9 except for the welded portion 6.

According to the structure shown in FIG. 2, since the surface of tantalum of metal 8 excluding the welded portion 6 is covered with the insulator 9, the adhesion of the transparent conductor 10 to ITO is improved. .

Further, tantalum of metal 8 and transparent conductor 1
For electrical connection with ITO of 0, a current is applied between tantalum of metal 8 and ITO of transparent conductor 10 to produce Ta 2 O.
The insulator 9 made of 5 is subjected to dielectric breakdown, and the metal 8 and the transparent conductor 10 are heat-welded to each other by the welded portion 6 containing tantalum and In as main components to obtain ohmic contact with sufficiently low resistance.

Next, a manufacturing method for obtaining the structure shown in FIGS. 1 to 3 will be described. The display TFD element 4 will be described with reference to the sectional views in the order of steps of the display TFD element 4 in FIGS. 4 to 7, and the connection TFD element 1 will be described in connection with the connection TFD element 1 in FIGS. This will be described with reference to the sequential sectional views.

First, as shown in FIGS. 4 and 8, tantalum as the metal 8 is formed to a thickness of 100 nm on the glass substrate 7 forming the active substrate 11 by the sputtering method.

Next, as shown in FIGS. 5 and 9, the metal 8 is subjected to a normal photolithography process and a reactive ion etching (hereinafter abbreviated as RIE) process using sulfur hexafluoride (SF6) as an etching gas. Pattern the tantalum.

Next, as shown in FIGS. 6 and 10, a voltage of 40 V is applied in a 0.1% aqueous solution of citric acid to perform anodic oxidation, and Ta 2 O 5 of the insulator 9 is thickened on the surface of the metal 8. To a thickness of 70 nm.

Next, as shown in FIGS. 7 and 11, ITO is used as the transparent conductor 10 by sputtering to a thickness of 10
After being formed to a thickness of 0 nm, heat treatment is performed, and the ITO is patterned by ordinary photolithography and wet etching using ferric chloride and hydrochloric acid as etchants.

With the above description, the display TFD element 4 shown in the plan view of FIG. 1 can be completed.

Next, the metal 8 and the transparent conductor 10 shown in FIG.
A current is applied by a constant current source during. At this time, the welding characteristics 6 of the connecting TFD element can be formed by locally heating and welding the insulator 9 by applying a predetermined current to the element characteristics, the area, and the thickness of the insulator 9.

This welded portion 6 can be an ohmic junction having a low resistance, and T of the connecting TFD element 1 shown in FIG.
An a / ITO connection can be formed.

The welding mechanism of the welded portion 6 which forms the low resistance ohmic junction is considered as follows.

T for connecting Ta / Ta2 O5 / ITO structure
The current flowing through the FD element 1 is T of the insulator 9 that becomes the active layer.
It is mainly governed by the conduction properties of the a2 O5 layer.

Approximately, the pool Frenkel conduction is explained as the conduction mechanism. Regarding the temperature dependence, the current value increases with increasing temperature when the same bias voltage is applied. That is, the conductivity has a positive coefficient with respect to temperature.

Consider a case where a constant current source supplies a current to the connecting TFD element 1 made of a thin film formed on the glass substrate 7. Here, it is assumed that the formed insulator 9 of the connecting TFD element 1 is free of in-plane defects that are homogeneous and partially have high conductivity.

When the current value flowing in the connecting TFD element 1 is small, the heat generated in the insulator 9 is the heat generated in the insulating TFD element 1.
Of the glass substrate, the temperature of the glass substrate is almost constant in the plane of the element, and the current value flowing in the connecting TFD element 1 settles in an equilibrium state mainly determined by pool Frenkel conduction according to the applied electric field.

However, if the current density is increased, the insulator 9
The Joule heat generated inside is locally connected to the TFD element 1
The glass substrate is heated with a temperature gradient in the direction of the normal line.

Further, even in the plane of the connecting TFD element 1, the peripheral portion of the connecting TFD element 1 where the heat easily escapes is low, and the connecting TF
The temperature gradient becomes high at the center of the D element 1.

Once a temperature gradient is generated in the plane, the temperature coefficient of the conductivity of the insulator 9 is positive and the temperature dependence is large, so that the current value in the central portion of the TFD element for connection 1 having a high temperature becomes large,
Further, positive feedback is given that the temperature of the central portion of the connecting TFD element 1 is concentrated and rises.

This is because the temperature distribution can be made in the surface of the connecting TFD element 1 while the potentials of both electrodes of the metal 8 and the transparent conductor 10 are constant in the surface of the connecting TFD element 1.

Eventually, a kind of thermal runaway causes dielectric breakdown in the central portion of the insulator 9, and tantalum and indium (In)
A filament-shaped initial welded portion made of a metal whose main component is is formed.

When a constant current source is used as the power source, the total current concentrates on the initial welded portion after the dielectric breakdown, but the constant current value is maintained by the action of the power source. Then, the initial welded portion grows into a welded portion 6 having stable and low resistance.

Since the welded portion 6 that has grown has a low resistance, the Joule heat that is generated decreases rapidly, and further destruction does not proceed unless the current value is significantly increased. The above is the reason why a stable ohmic junction can be obtained by current application welding of the welded portion 6.

T formed by anodic oxidation as the insulator 9
When a2 O5 is used, an insulator 9 film with almost no pinholes can be obtained.
It was possible to stably perform current welding in the central portion of the connecting TFD element 1 for an element of about m square.

In the connecting TFD element 1 having a size of 6 μm square according to the example of the present invention, the welded portion 6 became the central portion of the connecting TFD element 1 with good reproducibility. 6 in the graph of FIG.
The voltage-current characteristic at the time of carrying out heat welding by applying a current using a constant current source to the connecting TFD element 1 having a μm square Ta / ITO laminated structure is shown. The vertical axis represents the applied current, and the horizontal axis is the voltage across the connecting TFD element 1 at that time.

T / Ta 2 O 5 / T for connecting the ITO structure
The FD element 1 has an asymmetrical characteristic in which the voltage-current characteristic changes depending on the current application direction, but in the example of FIG.
The measurement was performed in the direction in which O became the positive electrode.

In the experimental example shown in FIG. 13, the applied current is 1 × 1.
When gradually increasing from 0 ^-11 A, 2 × 10 ^-5
When A, the terminal voltage across the connecting TFD element 1 is the first
The voltage 35 of the second voltage suddenly decreased to the second voltage 36. At this time,
The central portion of the connecting TFD element 1 was welded at the welding portion 6 in FIG.

The voltage-current characteristics of the connecting TFD element 1 after welding are shown in the graph of FIG. The area of the welded portion 6 at this time was 1 μm or less in diameter, but the contact resistance was as shown in FIG.
As can be seen from FIG. 4, the ohmic connection in which the applied voltage and the current are proportional to each other was obtained, and the resistance value was about 2 kΩ, which was a sufficiently low value.

Therefore, it can be seen that the structure of the present invention provided with the welded portion 6 is effective for the direct current low resistance connection of Ta / ITO.

Here, the peeling load of the ITO at the Ta / ITO connecting portion having the same structure as the connecting TFD element 1 of the embodiment of the present invention was measured by the scratch tester SST-101 (manufactured by Shimadzu Corporation).
It was determined by a scratch test using the.

In this scratch test, the connection TFD element 1 used for the evaluation of the electrical connection of the embodiment of the present invention.
Since the area of Ta / ITO connection part of 6 was as small as 6 μm square, it could not be evaluated, so that it was evaluated by forming a film having a laminated structure of Ta / Ta 2 O 5 / ITO on a glass substrate of 10 × 15 mm. The test was conducted under the conditions described below.

Tantalum film thickness: 200 nm Ta2 O5 film thickness: 70 nm ITO film thickness: 200 nm Test method: Constant speed load test Cartridge tip diameter: 15 μm Load speed: 1 μm / s Amplitude: 50 μm Feed speed: 20 μm / s

As a result of this scratch measurement, Ta / O formed through Ta2O5 of the insulator 9 formed by the anodic oxidation method was used.
The peeling load of the ITO connection part is 40 [gf] or more, and the tantalum film thickness is 250 nm and the ITO film thickness is 200 nm.
A significant improvement in the adhesive force of 80 times or more was observed in comparison with the peeling load of 0.5 [gf] under the same measurement conditions for the sample in which a / ITO was directly laminated.

In the embodiment of the present invention, the welded portion is 1 with respect to the 6 μm square of the Ta / ITO connecting portion of the connecting TFD element 1.
Since the area ratio is 36: 1 or more at μm ² or less, the mechanical adhesion strength between tantalum and ITO is almost Ta / Ta 2 O 5 / IT.
Determined by the O stack part.

Therefore, the structure of the present invention is based on Ta / ITO.
It can be seen that it is also effective for improving the adhesion of the connection part.

When current is applied between the metal 8 and the transparent conductor 10 during current welding in FIG. 11, an insulator 9 is coated on the tantalum wiring of the metal 8 and is electrically connected to the welding current source. When connecting, the insulating film 9 on the metal 8 is shaved. It may be considered necessary to prepare to create a non-anodized region on the extension of metal 8.

However, FIG. 15 shows an active substrate structure in which signal lines, wirings, and semiconductor device pad portions are welded.
Then, by patterning the liquid crystal panel structure as shown in FIG. 16, welding can be easily performed.

The common electrode 18 for anodization shown in FIG.
Is used when the metal 8 is anodized. Transparent conductor 1
A constant current source is connected between the first semiconductor device pad 15 and the second semiconductor device pad 16 formed of 0, and the first connecting TFD element 19 and the second connecting TFD element 20 are back-to-back connected. To be done.

Here, the back-to-back connection means that two TFD elements for connection are connected to each other by metal 8 or transparent conductor 1.
It means to connect in series so as to connect 0s.

Next, a lower current that causes welding between the first semiconductor device connection pad 15 and the second semiconductor device connection pad 16 is supplied by the constant current source.

Next, welding is performed by gradually increasing the current value. In the examples of the present invention, since the 6 μm square element was used, the welding conditions are as follows.

Welding current: 2 × 10 ^-5 A Maximum terminal voltage during welding: ITO is the positive electrode. ． ． 22V ITO is the negative electrode. ． ． 25V Treatment temperature: Room temperature

In the case of the connection shown in FIG. 15, in one set of back-to-back connection TFD elements, if one is the ITO positive electrode and the other is the negative electrode, the maximum terminal voltage immediately before welding is different, but the insulation breakdown during welding is insulation. Since it occurs in the Ta2 O5 layer of body 9, the welding currents are almost equal. Therefore, it is possible to simultaneously weld two connecting TFD elements at one time.

This is the nth semiconductor device connection pad 17
By repeating until, TFD for connection of all signal lines 3
A welded connection with the element 1 can be formed.

Next, as shown in FIG. 16, the active substrate 11 is formed on the active-side glass substrate 24 and laminated with the counter substrate 25 to form a panel.

Next, on the active side glass substrate 24 shown in FIG. 16, a break process is performed along the first scribe line 21, the second scribe line 22 and the third scribe line 23 to form a liquid crystal panel. Complete.

Here, the anodizing common electrode 18 is cut off by the first scribe line 21 shown in FIG. 15 to obtain an independent signal line 3.

In the embodiment described above, the welded portion 6
The connection resistance of is 2 kΩ and the wiring resistance of the wiring part including the signal line 3 and the wiring 2 is 1/10 of the value of about 20 kΩ, so it is possible to perform sufficient DC coupling without affecting the display quality. is there.

When the mounting method of the driving semiconductor device 14 shown in FIG. 3 is the COG mounting method, the connecting TFD element 1 shown in FIG. 1 is completed as described above.

Next, as another embodiment of the liquid crystal display device according to the present invention, the wiring 2 is formed by tape automated bonding (hereinafter referred to as TAB) to the driving semiconductor device 1.
The structure of the connecting TFD element 1 in the case of connecting to 4 will be described.

Here, TAB means that a driving semiconductor device is bonded to a film tape made of polyimide,
This is a mounting method in which the film tape is connected to a glass substrate. The plan view of FIG. 19 shows a liquid crystal display device adopting the TAB mounting configuration.

As shown in FIG. 19, the wiring 2 is formed on the active substrate 11 superposed on the counter substrate 25, and the film 38 to which the driving semiconductor device 14 is bonded is connected to the wiring 2 to form a liquid crystal panel. To do.

Next, a method of manufacturing the connecting TFD element 1 of the embodiment of the present invention shown in FIG. 19 will be described. In this embodiment, the active side glass substrate has the structure shown in FIGS.

The display TFD element 4 and the connecting TFD element 1 are formed by the same process steps as those in the first embodiment.

Next, as shown in FIG. 18, the active side glass substrate 24 having the active substrate 11 formed thereon is superposed on the counter substrate 25 to form a liquid crystal panel.

Next, a scribe process is performed along the welding element forming scribe line 28 shown in FIG. 18 to cut off the anodizing common electrode 18. Here, since the common electrode 18 for anodic oxidation has the structure shown in FIG. 17, after the common electrode 18 for anodic oxidation is cut off, two adjacent signal lines 3
The set is short-circuited.

Therefore, the active side glass substrate 24
Has a structure in which the first connecting TFD element 19 and the second connecting TFD element 20 are connected in series by back-to-back connection to the first current terminal 34 shown in FIG.

The second connecting TFD element 20 is further connected to the next connecting TFD element via the welding common electrode 33 formed of the transparent conductor 10. Therefore, by repeating the structure of the present invention, n connecting TFD elements are connected in series back to back up to the nth connecting TFD element between the first current terminal 31 and the second current terminal 32. You can

Next, a current source is connected between the first current terminal 31 and the second current terminal 32 to weld n points at once. Here, since a back-to-back configuration is formed by a set of the (n-1) th TFD element 26 and the nth TFD element 27, it is desirable that the number of connecting TFD elements connected at one time is an even number.

In the second embodiment, since a constant current source having a withstand voltage of 1 kV is used and the area of the connecting TFD element is set to 6 μm, the number of connectable elements (the number of lines) is 1000 V / (22V + 25V) = 21.3. As it was, 21 sets, or 42 sets. Here, the terminal voltage of the TFD element for connection at the time of welding changes depending on the element size.
It is 15V for the m-square element.

Therefore, if the withstand voltage of the current sources is the same and the area of the wiring portion can be made large, the number of lines that can be connected at one time can be made larger by increasing the area of the connecting TFD element 1.

Even if there are several hundred lines or more,
This can be dealt with by repeating the welding process for a necessary number of groups with a group of series connection between the first current terminal 31 and the second current terminal 32 as shown in FIG. 17 as one unit.

Next, a scribe process is performed along the TAB terminal forming scribe line 29 shown in FIG. 18, and a break process is further performed to cut off the welding common electrode 33 shown in FIG. The enclosed TAB connection terminal array 30 is formed.

Next, scribe is performed along the first scribe line 21 to form an independent signal line 3, and the connection TFD element 1 is completed.

Next, the second scribe line 22 and the third scribe line 22
The scribe process and the break process are performed along the scribe line 23 of FIG. 18 and TAB mounting is performed on the TAB connection terminal array 30 shown by the dotted line in FIG.
The liquid crystal panel for AB mounting is completed.

In the manufacturing process described in the above embodiment,
In addition to tantalum, the metal may be nitrogen-added tantalum, tantalum nitride, or an alloy of tantalum and another metal.
Further, it is also effective when a metal having a large oxygen affinity, such as Nb, is used in addition to tantalum. The production method of the present invention is also effective when an oxide such as In2 O3, SnO2, ZnO, etc. is used as the transparent conductor in addition to ITO. Furthermore, it becomes possible to form a programmable array on the active substrate by applying a predetermined current.

[0099]

As is apparent from the above description, according to the present invention, in the formation of the driving element and the wiring of the liquid crystal display device, the connection portion of the metal / insulator / transparent conductor structure is formed,
An electric current is applied to this and welding is performed to reduce the contact resistance between the metal and the transparent conductor without complicating the manufacturing process.
Furthermore, since an insulator is present on the bonding surface between the metal and the transparent conductor other than the welded part, the adhesion between the two is greatly improved, and an active matrix liquid crystal display device with excellent display quality can be obtained. To be

[Brief description of drawings]

FIG. 1 is a plan view showing a display TFD element and a connection TFD element formed on a glass substrate of a liquid crystal display device according to an example of the present invention.

FIG. 2 is a cross-sectional view showing a structure of a connecting TFD element of a liquid crystal display device in an example of the present invention.

FIG. 3 is a plan view showing a liquid crystal display device using an active substrate of the liquid crystal display device according to the embodiment of the invention.

FIG. 4 is a cross-sectional view showing a method of manufacturing a display TFD element of a liquid crystal display device according to an example of the present invention.

FIG. 5 is a cross-sectional view showing the method of manufacturing the display TFD element of the liquid crystal display device according to the example of the present invention.

FIG. 6 is a cross-sectional view showing the method of manufacturing the display TFD element of the liquid crystal display device according to the example of the present invention.

FIG. 7 is a cross-sectional view showing a method of manufacturing a display TFD element of a liquid crystal display device according to an example of the present invention.

FIG. 8 is a cross-sectional view showing the method of manufacturing the display TFD element of the liquid crystal display device according to the example of the present invention.

FIG. 9 is a cross-sectional view showing the method of manufacturing the display TFD element of the liquid crystal display device according to the example of the present invention.

FIG. 10 is a cross-sectional view showing the method of manufacturing the display TFD element of the liquid crystal display device in the example of the present invention.

FIG. 11 is a cross-sectional view showing the method of manufacturing the display TFD element of the liquid crystal display device in the example of the present invention.

FIG. 12 is a cross-sectional view showing the method of manufacturing the display TFD element of the liquid crystal display device in the example of the present invention.

FIG. 13 is a graph showing the relationship between the welding process current and the terminal voltage of the connecting TFD element in the method of manufacturing a liquid crystal display device according to the example of the present invention.

FIG. 14 is a graph showing the relationship between the current and voltage of the connecting TFD element after welding in the method for manufacturing a liquid crystal display device in the example of the present invention.

FIG. 15 is a view showing CO of a liquid crystal display device according to an embodiment of the present invention.
It is a top view which shows the manufacturing process of the TFD element for connection of G mounting.

FIG. 16 shows CO of the liquid crystal display device in the example of the present invention.
It is a top view which shows the manufacturing process of the liquid crystal panel for G mounting.

FIG. 17 is a TA of a liquid crystal display device according to an embodiment of the present invention.
It is a top view showing a manufacturing process of a connecting TFD element array part of an active substrate for B connection.

FIG. 18: TA of a liquid crystal display device in an example of the present invention
It is a top view which shows the manufacturing process of the liquid crystal panel for B mounting.

FIG. 19 is a TA of a liquid crystal display device in an example of the present invention.
It is a schematic diagram showing composition of a B mounting liquid crystal panel.

[Explanation of symbols]

 1 TFD Element for Connection 2 Wiring 3 Signal Line 4 TFD Element for Display 5 Pixel Electrode 6 Welding Part 7 Glass Substrate 8 Metal 9 Insulator 10 Transparent Conductor 11 Active Substrate 12 Display Area

Claims (2)

[Claims] 1. A connection portion between a metal and a transparent conductor is constituted by a metal made of tantalum on a substrate made of glass, an insulator made of tantalum oxide on the metal, and a transparent conductor covering the metal and the insulator. Then, by applying a predetermined current to the metal and the transparent conductor, dielectric breakdown occurs at a predetermined position of the insulator, and an electrical connection between the metal and the transparent conductor is obtained through the welded portion where the metal and the transparent conductor are welded. A liquid crystal display device characterized by the above. 2. A step of forming a metal made of tantalum on a substrate made of glass, a step of patterning the metal by photoetching, a step of anodizing to form an insulator in the element portion, and a transparent conductive film. A step of forming a body, a step of patterning a transparent conductor by a photoetching process, and a predetermined current of the metal and the transparent conductor is applied to cause dielectric breakdown at a predetermined position of the insulator and the metal and the transparent conductor. A method for manufacturing a liquid crystal display element, comprising the step of forming a welded portion obtained by welding