JPH01261619A - Formation of circuit wiring - Google Patents

Abstract

PURPOSE:To reduce the electric resistance of the wiring of a circuit and to improve the corrosion resistance and weatherability of the circuit by forming a metallic layer of a metallic material having a relatively low electric resistance on one surface of a transparent substrate in a pattern and exposing the other surface of the substrate after a photoresist is applied to the one surface of the substrate and, forming a coating layer of a metallic material having a better corrosion resistance and weatherability than the metallic layer. CONSTITUTION:The metallic layer of a metallic material having a relatively low electric resistance is formed on one surface of a transparent substrate 12 in a pattern. The photoresist is applied to the surface of the substrate 12 and the other surface of the substrate is exposed to light so as to remove the photoresist from the vicinity of the metallic layer. The the coating layer 142 of a metallic material having a better corrosion resistance and weatherability than the metallic layer has is formed on the one surface of the substrate 12. Thereafter, the part other than the vicinity of the photoresist is removed together with the coating layer 142. Thus the circuit wiring which is low in electric resistance and excellent in corrosion resistance and weatherability can be formed easily and inexpensively.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The present invention is suitable for forming patterns of signal lines for supplying signal voltages to each pixel electrode in a liquid crystal display device driven by a multiplex method. The present invention relates to a method for forming circuit wiring, which is carried out in the following.

BACKGROUND OF THE INVENTION FIG. 5 shows the basic configuration of a matrix type liquid crystal display device 1. A plurality of pixel electrodes l1i3 are patterned in a matrix on a transparent substrate 2 made of a material such as glass. A plurality of signal lines 4 are formed along one arrangement direction of the pixel electrodes 3. The plurality of pixel electrodes 3 arranged along the one arrangement direction are each connected in parallel to the same signal line 4, and a signal voltage is supplied from this signal line 4.

A transparent electrode 6 extending parallel to the direction intersecting the signal line 4 is formed in a pattern on the surface of the transparent substrate 5 facing the transparent substrate 2 .

A space between the transparent substrates 2 and 5 is filled with, for example, twisted nematic (hereinafter referred to as rTN) liquid crystal. In such a case, a polarizing plate 7 is provided on the surface of the transparent substrate 2 opposite to the transparent substrate 5, and on the surface of the transparent substrate 5 opposite to the side on which the transparent electrode Ff16 is formed.
, 8 are arranged.

A scanning pulse is applied to the plurality of transparent electrodes 6 sequentially and cyclically. Signal voltages corresponding to video signals to be displayed are applied to the plurality of signal lines 4 in parallel. As a result, each display pixel becomes translucent or light-shielding, and an image can be displayed.

As the material for the signal line 4, tantalum and titanium are used due to issues such as etching resistance in the process after pattern formation of the signal line 4, and weather resistance, that is, resistance to changes in environmental conditions such as temperature and humidity, and resistance to aging. ,
Or use chrome etc.

However, these materials have relatively high specific resistance, and it is difficult to obtain good display characteristics in the liquid crystal display device 1.From the end portion 4a of each signal line 4, the capacitance of the pixel electrode 3 and the capacitance related to the signal line 4 cannot be obtained. , or when an active element is provided in association with each pixel electrode 3, sufficient charge must be supplied to charge the capacitance associated with this active element, but the charging time constant depends on the electrical resistance of the signal line 4. Dependent. Therefore, if the signal line 4 is formed using a material with relatively high resistivity as described above, good display quality cannot be obtained when driving a large matrix type liquid crystal display device, for example. , that is,
As liquid crystal display devices become larger, for example, the length of the signal lines 4 and the number of pixel electrodes 3 covered by each signal line 4 may increase while the width and pitch of the signal lines 4 remain unchanged, or the number of pixel electrodes 3 covered by each signal line 4 may increase. width, the length of the signal line 4, the length and width of the pixel electrode 3,
In either case, the charging time constant for each capacitive component increases as the length and width of the active elements both increase. This charging time constant increases with the resistance component of the signal line 4, so in the multiplex drive as described above, display pixels near the end 4a of the signal line 4 to which the signal voltage is supplied and display pixels far away Differences in display characteristics occur between the two.

In order to solve this problem, as shown in FIG. 6, the signal line 4 is connected to a lower signal line 41 made of a metal material with low electrical resistance and an upper signal line 41 made of a metal material with high corrosion resistance and weather resistance. A structure composed of a line 42 has also been proposed.

In forming the pattern of the signal line 4, a metal thin film made of the material of the lower signal line 41 is formed over the entire surface of the transparent substrate 2 facing the liquid crystal layer, and then the above-mentioned thin film is continuously formed on this metal thin film. A thin metal film made of the material of the upper signal line 42 is formed, and then patterned, for example, by etching. As a result, the lower signal line 41 has an exposed portion, which is insufficient in terms of corrosion resistance and weather resistance.

In order to solve this problem, it is conceivable to configure the signal line 4 as shown in FIG. 7, for example. That is, the signal line 4 is made up of a core wire 41a made of a metal material with relatively low electrical resistance, and a patterned coating layer 42a covering the core ti41a and having relatively high corrosion resistance and weather resistance. By doing so, the core wire 41a is not affected by changes in the external environment, so that the corrosion resistance and weather resistance of the signal wire 4 are significantly improved.

A general method for forming such a signal line 4 on the transparent substrate 2 is shown in FIG.

On one surface of the transparent substrate 2, a pattern of core wires 41a is formed. In this state, a metal material film 42b made of the metal material of the coating layer 42a is formed covering one surface of the transparent substrate 2, and a positive photoresist 43 is applied thereon.

Such a state is shown in FIG. 8 (1), and in this state, a light shielding member 45 etc. is printed on a transparent substrate 44 and a pattern is formed by interposing the transparent substrate 44 through a two-dimensional mask 46. Light is emitted from the one surface side of 2 in the direction of the 8121st arrow 1'f47.

Thereafter, by performing development, the state shown in FIG. 8(2) is obtained. By performing etching in this state, patterning of the metal material B42b is performed,
Thereafter, by removing the photoresist 43, the signal line 4 shown in FIG. 7 can be obtained.

Problem to be Solved by the Invention However, when forming the signal line 4 in this manner, it is necessary to newly use a photomask 46, and furthermore, the pattern of the light shielding member 45 of this photomask 46 and the pattern of the core wire 41a are different from each other. In order to obtain alignment, the position between the photomask 46 and the transparent substrate 2 must be adjusted.

Furthermore, when patterning a resist by screen printing or patterning a metal material film by mask evaporation, for example, it is necessary to newly install equipment for photoringer fibroprocessing that allows the core wire 41a to match the pattern with high precision. This inevitably increases production costs.

An object of the present invention is to provide a method for forming circuit wiring that can easily and inexpensively form circuit wiring that has low electrical resistance and good corrosion resistance and weather resistance. be.

Means for Solving the Problems The present invention involves patterning a metal layer made of a metal material with relatively low electrical resistance on one surface of a transparent substrate, applying a photoresist to one surface of the transparent substrate, and applying a photoresist to the other surface of the transparent substrate. Exposure is performed from the surface side to remove the portion of the photoresist layer near the metal layer, and a coating layer made of a metal material with better corrosion resistance and weather resistance than the metal layer is formed thereon, thereby removing the photoresist layer. This method of forming circuit wiring is characterized in that the remaining portion other than the above-mentioned vicinity is removed together with the overlying coating layer.

Function In the present invention, a metal layer made of a metal material with relatively low electrical resistance is patterned on one surface of a transparent substrate.

A photoresist is coated on one surface of this transparent substrate, and further, exposure is performed from the other surface side of the transparent substrate. As a result, the portion of the photoresist layer near the metal layer is removed.

A coating layer made of a metal material having better corrosion resistance and weather resistance than the metal layer is formed on this, and after that, the remaining portion of the photoresist other than the above-mentioned neighboring portion is covered with a coating formed thereon. removed along with the layer. In this way, circuit wiring consisting of the metal layer and the coating layer is formed.

The circuit wiring thus formed has sufficiently low electrical resistance, and the corrosion resistance and weather resistance of the circuit wiring are improved due to the action of the coating layer covering the metal layer.

Embodiment No. 111J is a liquid crystal display device 1 according to an embodiment of the present invention.
FIG. 1 is a perspective view showing the basic configuration of FIG. For example, on one surface of the transparent substrate 12 made of a material such as glass,
A plurality of pixel electrodes 13 are arranged in rows and columns. A plurality of signal lines 14, which are circuit wiring for supplying a signal voltage corresponding to a video signal to each pixel electrode 13, are patterned along one arrangement direction of the plurality of pixel electrodes 13.

A transparent substrate 15 is arranged opposite to the surface of the transparent substrate 12 on which the pixel electrodes 13 and the like are formed.

On the surface of the transparent substrate 15 facing the transparent substrate 12,
A plurality of transparent electrodes 16 extending in a direction intersecting the plurality of signal lines 14 are formed in a pattern. Transparent substrate 12.
15 is filled with, for example, twisted nematic (hereinafter referred to as rTNJ) type liquid crystal (not shown). In this case, a polarizing plate 17.18 is provided on the surface of the transparent substrate 12.15 opposite to the liquid crystal layer.

In the transparent substrates 12 and 15, an alignment film (not shown) is formed to cover the surface facing each liquid crystal layer, and an alignment process is performed, for example, so as to make an angle of 90 degrees with each other. As a result, the liquid crystal molecules constituting the liquid crystal layer are twisted at 90 degrees between the alignment films. In such a case, for example, polarizing plates 17, 18
are arranged so that the directions of their respective polarization axes are parallel or perpendicular to each other.

Scanning pulses are applied to the plurality of transparent electrodes 16 sequentially and cyclically. Furthermore, signal voltages based on video signals corresponding to the transparent electrodes 16 to which scanning pulses are applied are applied in parallel from one end 14a of the plurality of signal lines 14. In this way, in the liquid crystal display device 11, a plurality of pixel electrodes 13 corresponding to each transparent electrode 16 are driven in a so-called time-division manner, that is, a so-called multiplex method, and display driving is performed to display an image.

2nd [21] is a perspective view showing the structure of the signal line 14 in an enlarged manner. The signal line 14 is formed by covering a core wire 141 made of, for example, aluminum, gold, silver, or an alloy containing these materials, and is made of titanium, tantalum, chromium, or an alloy containing these materials. It is composed of a covering layer 142. Aluminum, gold, silver, or alloys containing these have sufficiently low electrical resistance, and titanium, tantalum, chromium, or alloys containing these have good resistance to etching solutions such as acids and alkalis. It also has good resistance to changes in temperature, humidity, and aging, that is, it has good weather resistance. Therefore, the signal line 14 configured as described above is formed to have a relatively low electrical resistance, and is not susceptible to damage or changes in properties during the manufacturing process of the liquid crystal display device. .

FIG. 3 is a cross-sectional view showing the process of patterning the signal line 14 according to an embodiment of the present invention.

A core wire 141 made of aluminum, for example, is patterned on one surface of the transparent substrate 12 .

In such a state 1, a negative resist 20 is applied to the entire surface of the transparent substrate 12 on the side where the core wires 1 and 11 are to be patterned. In this situation, 3rd U! U
(1). From this state, light is irradiated from the back side of the transparent substrate 12, that is, from the side opposite to the side where the core wire 141 is patterned, in the direction of the arrow 21 in FIG. 3(1) [2I].

Next, the exposed negative photoresist 20 is developed. At this time, the development time or development (I?, 'f1 degree) is increased from normal, and the resist removal width is increased by 2 due to overdevelopment.
2 (see Fig. 3 (2)) is adjusted so that the width 23 of the core wires 1 and 11 is larger than the width 23 of the core wires 1 and 11. (The state after the elephant is the third
This is shown in Figure (2).

From such a state, the core wires 1 and 41 of the transparent substrate 12 and the photoresist 20 are formed. A film of material 24 is applied. Such a situation is shown in FIG. 3(3).

From this state, apply the negative photoresist 20! II.5 coating layer 142 by the so-called lift-off method.
is patterned. Such a condition is the 3113th
(It is shown in page 4.

As described above, in this embodiment, after the core wire 141 is patterned on one surface of the transparent substrate 12, the saw-through type photoresist 20 is applied. In this state, light is irradiated from the surface side of the transparent substrate 12. In the subsequent development process, the negative type of the portion near the core wire 141)
<l-The resist 20 can be removed in a width larger than the width of the core line 141. In this state, the portion exposed on the one surface side of the transparent substrate 12 is covered with a metal material film 24 made of the material of the coating layer 142, and the photoresist 20 is further removed by using a so-called lift-off technique. 142 is patterned and the core wire 141 and ? A signal line 14 consisting of *7WN142 is obtained.

Therefore, in forming the signal line 14, there is no need to use a photomask, for example, and in addition, the core wire]1
No new equipment is required to form a resist that is precisely arranged in the 11 patterns. This allows the liquid crystal display device 11 to have good display characteristics and lower production costs. - will be realized without being unnecessarily increased.

40, a method for patterning the wire wire 14 on the transparent substrate 12 according to another embodiment of the present invention is shown. That is, in a state where the core wires 141 are patterned on the transparent substrate 12, the core wires 141 of the transparent substrate 12 are
The side surface where is formed? Then, a negative photoresist 20 is applied, and in this state, light is irradiated in the direction of arrow 25 from the back side of the transparent substrate 12, that is, the side opposite to the side where the core wire 141 is patterned. Ru. At this time, a light scattering plate 26 is arranged on the opposite side of the transparent substrate 12 from the core wires 1 and 41. As a result, the amount of exposure in the vicinity of the core wire 141 can be relatively reduced, so there is no need to perform overdevelopment as described above in the subsequent development process.

Effects of the Invention As described above, according to the present invention, circuit wiring having low electrical resistance and excellent corrosion resistance and weather resistance can be easily formed at low cost. When such circuit wiring is used as a signal line to supply signal voltage to each pixel electrode in a liquid crystal display device driven by a multiplex method, for example, the display characteristics of the liquid crystal display device can be significantly improved. In addition, such a liquid crystal display device can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the basic configuration of a liquid crystal display A 11 according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view showing the configuration of a signal line 14, and FIG. A cross-sectional view for explaining a method of forming the signal line 14 according to one embodiment,
FIG. 4 is a cross-sectional view for explaining a method of forming the signal line 14 according to another embodiment of the present invention, FIG. 5 is a perspective view showing the basic configuration of the conventional liquid crystal display device 1, and FIG. 2I is a perspective view showing another configuration example of the signal line 4, and FIG. 7 is the signal line 1.
FIG. 8 is a cross-sectional view showing still another example of the structure of FIG. 1. FIG. 8 is a cross-sectional view for explaining a method of forming the signal line 4 shown in FIG. 11...Liquid crystal display device, 12.15...Transparent substrate,
13... Pixel electrode, 14... Signal line, 16... Transparent electrode 17.18... Polarizing plate, 20... Negative photoresist, 24... Metal material film, 26... Light Scatter plate, 141...Core wire, 142...Coating layer agent Patent attorney Number of strokes Keiichi Figure 1 Z Figure 2 Figure 3 Figure 4 Figure 5 Figure 2' □6D Figure 7 Figure 8 Prisoner

Claims (1)

[Claims] A metal layer made of a metal material with relatively low electrical resistance is patterned on one surface of a transparent substrate, a photoresist is applied to one surface of the transparent substrate, and light is exposed from the other surface of the transparent substrate. remove the portion of the photoresist layer near the metal layer, form a covering layer made of a metal material with better corrosion resistance and weather resistance than the metal layer, and remove the remaining portion of the photoresist layer other than the area near the metal layer. 1. A method for forming circuit wiring, characterized in that the portion is removed together with the covering layer thereon.