JP2006293046A - Active matrix liquid crystal display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active matrix liquid crystal display wherein the occurrence of a display defect is prevented by providing preventing means of destruction of a pixel and a TFT due to static electricity and to provide its manufacturing method. <P>SOLUTION: In the active matrix liquid crystal display 10 wherein a plurality of signa lines Y1, Y2, ..., Ym and a plurality of scanning lines X1, X2, ..., Xn are wired in a matrix shape on a light transmissive substrate, display regions are formed by regions enclosed by the plurality of signal lines and the plurality of scanning lines and wire lines for connecting the signal lines and the scanning lines to connection terminal for connecting an external part are formed at peripheral edge parts of the display regions, scanning line wiring lines 401, 402, ..., 40n respectively connected to the plurality of scanning lines and signal line wiring lines respectively connected to the plurality of signal lines are electrically connected to each other via a connection wiring line 30 and then the scanning lines and the signal lines are electrically disconnected one another from the connection wiring line 30 at a plurality of points. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an active matrix liquid crystal display device and a method for manufacturing the same, and more particularly to an active matrix liquid crystal display device using a thin film transistor (hereinafter referred to as “TFT”) as a semiconductor switching element. The present invention relates to an active matrix liquid crystal display device provided with prevention means and a method for manufacturing the same.

  In general, liquid crystal display devices are characterized by thinness, light weight and low power consumption. In particular, thin film transistor type active matrix liquid crystal display devices are widely used from mobile phones and portable terminals to large televisions.

First, a general configuration of a conventional active matrix type liquid crystal display device is shown in FIG. 3 which is a plan view of several pixel portions, and a schematic equivalent circuit diagram corresponding to several pixels of FIG. 4 and FIG. This will be briefly described with reference to FIG. The conventional liquid crystal display panel 10A includes a region surrounded by scanning lines X1, X2,..., Xn and signal lines Y1, Y2,. pixel electrodes 12 are provided, the pixel electrode 12 are equivalently represented by a liquid crystal capacitance C _LC in FIG. 4 for each. Usually the liquid crystal capacitance C _LC auxiliary capacitance Cs formed by the auxiliary capacitance electrodes 13 are connected in parallel. One end of the liquid crystal capacitance C _LC is connected to the pixel transistor 14 for driving, the other end is connected to a counter electrode 16 provided through the color filter layer CF to the second light-transmitting substrate 15 a predetermined Common potential Vc is applied.

The pixel transistor 14 is formed of an insulated gate field effect type thin film transistor TFT (Thin Film Transistor), and its source electrode S is connected to signal lines Y1, Y2,. electrode D is connected to one end of the liquid crystal capacitance C _LC, i.e., the pixel electrode 12. Further, the gate electrode G of the pixel transistor 14 is connected to the scanning lines X1, X2,..., Xn so that a gate pulse Vg having a predetermined voltage is applied.

In addition, an alignment film (not shown) is provided on the surface of each of the pixel electrode 12 and the counter electrode 16, and between the first translucent substrate 11 and the second translucent substrate 15. Liquid crystal 17 is enclosed. Reference numerals 18 and 19 denote insulating films made of SiO ₂ or SiN, respectively, and reference numeral 20 denotes an a-Si layer. A plurality of scanning lines X1, X2,..., Xn and signal lines Y1, Y2,..., Ym are drawn out in two directions or one direction of the frame portion of the substrate (peripheral portion of the substrate). A scanning line input terminal portion 21 and a signal line input terminal portion 22 are provided in the portion.

  The active matrix liquid crystal display device having such a structure has been manufactured from a small size to a large size of about 40 inches (about 102 cm) to 50 inches (about 127 cm) diagonal. Especially in small and medium-sized models, static defects are more likely to occur as high definition progresses, and various countermeasures have been taken. One of the problems is that static electricity is applied to each electrode during the manufacturing process. Accumulation and electrostatic breakdown may occur.

  In the liquid crystal display device, when static electricity enters the display area in the manufacturing process, a display defect occurs when the liquid crystal display device is completed. Static electricity is generated only by contact with other objects in the manufacturing process and when the panel is transported. Further, when the alignment film is rubbed, static electricity is most likely to occur due to friction. Therefore, in the manufacturing technical field of liquid crystal display devices, it is particularly urgent to prevent display defects due to static electricity.

  As a method for preventing such display defects due to static electricity, there is a method for manufacturing a liquid crystal substrate described in Patent Document 1 below. The method of manufacturing the liquid crystal substrate includes a step of forming a short circuit that commonly connects the source / drain electrodes and the gate electrode of the scanning circuit unit TFT, a processing step of performing a treatment in a plasma atmosphere furnace, and the short circuit later. And a separation step of electrically separating each electrode by removing the circuit. Then, a short circuit is formed in advance between the source / drain electrodes and the gate electrode of the scanning circuit unit TFT, and after passing through a process that easily accepts damage due to static electricity, the short circuit is removed to electrically connect each electrode. Since the separation is performed, generation of a potential difference that causes electrostatic breakdown or the like can be suppressed between the two.

In particular, a step of forming a short circuit for commonly connecting at least a pair of electrodes of a source electrode, a drain electrode and a gate electrode of the pixel transistor portion TFT, a processing step of performing a treatment in a plasma atmosphere furnace, and the short circuit later And a separation step of electrically separating each electrode by removing the circuit. Then, a short circuit is formed on at least a pair of the source electrode, the drain electrode, and the gate electrode of the pixel transistor portion TFT, and after passing through a process that easily accepts damage due to static electricity, the short circuit is removed to electrically connect each electrode. Therefore, damage due to static electricity or the like can be avoided.
JP-A-8-1114815 (paragraphs [0015] and [0016])

  However, in the method of manufacturing a liquid crystal substrate disclosed in Patent Document 1, a scanning circuit unit TFT different from the pixel transistor TFT, that is, a gate driver IC or a source / drain electrode of the source driver IC and a gate electrode with a short circuit. By connecting, the short circuit can accept damage caused by static electricity generated in the processing process in the plasma atmosphere furnace, but the source / drain electrodes and gate electrodes are not necessarily avoided by the short circuit. If the potential is the same, there is no need to provide such a short circuit.

  Therefore, the inventors of the present application have conducted various experiments to examine a configuration that can achieve the prevention of destruction of pixels and TFTs due to intrusion of static electricity from the outside that is effective even in the initial manufacturing process of the active matrix substrate. Pixels due to intrusion of static electricity from the outside by removing all shorting means simultaneously with other processes in the second half of the manufacturing process by connecting all the scanning lines and signal lines of the substrate to the same connection wiring. The present inventors have found that the TFT can be prevented from being destroyed, and have achieved the present invention.

  That is, an object of the present invention is to provide an active matrix liquid crystal display device that prevents the occurrence of display defects by providing a means for preventing destruction of pixels and TFTs due to static electricity, and a method for manufacturing the same. It is.

In order to achieve the above object, an active matrix type liquid crystal display device according to claim 1 of the present invention is characterized in that a plurality of signal lines and scanning lines are wired in a matrix on a light-transmitting substrate. An active matrix type liquid crystal in which a region surrounded by the signal lines and the scanning lines forms a display region, and wiring for connecting the signal lines and the scanning lines to the connection terminals for external connection is formed in the peripheral portion of the display region A display device,
After the scanning line wiring connected to each of the plurality of scanning lines and the signal line wiring connected to each of the plurality of signal lines are electrically connected to each other via the connection wiring, each scanning line wiring and Each of the signal line wirings is electrically disconnected from the connection wiring at a plurality of locations.

  According to a second aspect of the present invention, there is provided the active matrix liquid crystal display device according to the first aspect, wherein each of the plurality of signal line wirings and scanning line wirings includes an electrostatic protection element and the electrostatic protection element. It has a detour wiring arranged so as to detour, and the detour wiring is electrically disconnected at a plurality of locations.

  According to a third aspect of the invention, there is provided the active matrix type liquid crystal display device according to the second aspect, wherein the bypass wiring is made of aluminum or an aluminum alloy.

According to a fourth aspect of the present invention, there is provided a method of manufacturing an active matrix liquid crystal display device, wherein a plurality of signal lines and scanning lines are arranged in a matrix on a translucent substrate, and the plurality of signal lines and scanning lines are externally connected. Forming a wiring connected to the connection terminal for use;
Electrically connecting the scanning line wiring respectively connected to the plurality of scanning lines and the signal line wiring respectively connected to the plurality of signal lines via a connection wiring;
Electrically cutting the scanning line wiring and the signal line wiring at a plurality of locations in the vicinity of the connection wiring, respectively, in a subsequent process;
It is characterized by including.

According to a fifth aspect of the present invention, there is provided the method of manufacturing the active matrix liquid crystal display device according to the fourth aspect, wherein the electrostatic protection element is formed on the wiring connected to the signal line and the scanning line. When,
Forming a bypass wiring so as to bypass the electrostatic protection element formed on the wiring connected to the scanning line;
The bypass line is electrically disconnected in the step of electrically disconnecting the scanning line wiring and the signal line wiring at a plurality of locations in the vicinity of the connection wiring.

  According to a sixth aspect of the present invention, there is provided an active matrix liquid crystal display device manufacturing method according to the fifth aspect, wherein the bypass wiring is formed of aluminum or an aluminum alloy, and the scanning line wiring and the signal line are formed. The step of electrically cutting each of the wirings at a plurality of locations in the vicinity of the connection wiring includes the detour wiring in a wet etching process of a transparent electrode material made of IZO (Indium Zinc Oxide) formed on the translucent substrate. Are simultaneously cut.

  By providing the above configuration, the present invention has the following excellent effects. That is, according to the first aspect of the present invention, the scanning line wiring and the signal line wiring connected to each of the plurality of scanning lines and signal lines are connected to the connection wiring at the time of manufacture, and each scanning line is connected before the completion. Since the wiring and the signal line wiring are cut from each other at a plurality of locations, even if there is static electricity that has entered from the outside during manufacturing, each wiring is at the same potential. By cutting the scanning line wiring and the signal line wiring at a plurality of locations in the manufacturing process, it is possible to provide an active matrix liquid crystal display device in which display defects are unlikely to occur. In addition, since the scanning line wiring and the signal line wiring are cut at a plurality of locations, they can be cut reliably.

  According to the invention of claim 2, even when the electrostatic protection element is provided on the scanning line wiring and the signal line wiring, the scanning line and the signal line are set to the same potential by forming the bypass electrode. If the bypass electrode is electrically cut in a later manufacturing process, even if static electricity enters before this cutting process, the active matrix type liquid crystal is less likely to cause display defects without causing electrostatic breakdown. A display device can be provided.

  According to a third aspect of the present invention, when the bypass wiring is made of aluminum or an aluminum alloy and the transparent electrode provided on the translucent substrate is formed of IZO, the transparent electrode is formed. In this etching process, the bypass wiring can be cut simultaneously by etching, and it is not necessary to provide a separate etching process for the bypass wiring, thereby simplifying the manufacturing process.

  According to the invention of claim 4, the active matrix type liquid crystal display device having the effect of claim 1 can be manufactured by a simple manufacturing method.

  Moreover, according to the invention of Claim 5 and 6, the manufacturing method of the active-matrix liquid crystal display device which has the effect of Claim 2 and 3 can be provided, respectively.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies an active matrix type liquid crystal display device and a manufacturing method thereof for embodying the technical idea of the present invention. It is not intended to be specific to manufacturing methods, and other embodiments within the scope of the claims are equally applicable.

  FIG. 1 is an enlarged plan view showing a part of the liquid crystal display device of the present invention in an enlarged manner, and FIG. 2 is an enlarged view of a portion B in FIG.

  The active matrix liquid crystal display device 10 according to the embodiment includes scanning lines X1, X2,..., Xn and signal lines Y1, Y2 provided in a matrix on one of a pair of translucent substrates. ,..., Ym are provided. Among these, the area surrounded by the scanning lines X1, X2,..., Xn and the signal lines Y1, Y2,..., Ym is a display area. Various wirings that connect to connection terminals (not shown) to which signals and the like are supplied are provided.

  In this effective display area, pixel electrodes 12 that contribute to display are provided for each area surrounded by each scanning line and signal line. The switching transistor 14 is made of a TFT, and its source electrode S is connected to the signal lines Y1, Y2,..., Ym, the gate electrode G is connected to the scanning lines X1, X2,. The drain electrode D is connected to the pixel electrode 12. Further, an auxiliary capacitance electrode 13 is provided below the drain electrode D in parallel with the scanning lines X1, X2,. The specific configuration and operation principle of the display area of these liquid crystal display devices 10 are the same as those of the conventional example shown in FIGS. 3 to 5, and will be described with reference to FIGS. 3 to 5 as necessary. I decided to.

  As shown in FIG. 5, the liquid crystal display device 10 includes scanning lines X1, X2,..., Xn and scanning lines formed of aluminum or an aluminum alloy on an optically transparent substrate 11 with an insulating film 11 ′ interposed therebetween. Each auxiliary capacitance electrode 13 is formed in parallel with the first electrode.

  The scanning lines X1, X2,..., Xn and the signal lines Y1, Y2,..., Ym are connected to scanning lines 401, 402,. 40n and signal line wiring (not shown) are connected, and the scanning line wirings 401, 402,..., 40n and signal line wiring are electrically connected via the connection wiring 30. 1 shows a connection portion between the connection wiring 30 and the scanning line wirings 401, 402,..., 40n, and the connection structure between the connection wiring 30 and the signal line wiring is shown in FIG. The description thereof will be omitted, and only the structure around the scanning line wirings 401, 402,..., 40n shown in FIG.

  The scanning line wirings 401, 402,..., 40n are extended from the scanning lines X1, X2,..., Xn to the outside of the display area. Connected. On the scanning line wirings 401, 402,..., 40n, electrostatic protection elements 31 are provided that prevent static electricity from entering the scanning lines X1, X2,. As shown in FIG. 2, the electrostatic protection element 31 is an element that does not conduct at a voltage applied to a scanning line or a signal line, and shorts all wiring when a high voltage such as static electricity is applied. For example, it is an electrostatic protection element in which a pair of diode-connected TFTs are connected in antiparallel, and the scanning line wirings 41n, 41n and 401, 402,..., 40n are connected via the contact holes 32. Has been.

  Since the electrostatic protection element 31 having such a configuration does not conduct at a voltage normally applied to the scanning line or the signal line, the scanning line wiring 401, 402,. Even if wiring is connected, the same potential cannot be maintained. In order to prevent the electrostatic protection element 31 from interfering with the connection of the respective wirings, a bypass wiring is provided between the scanning line wirings 401, 402,..., 40n and 41n so as to bypass the electrostatic protection element 31. 42 is provided. By providing this bypass wiring 42, the scanning lines X1, X2,..., Xn are connected to the connection wiring 30 through the scanning line wirings 401, 402,. Similarly, since the signal line is connected to the connection wiring 30 via the signal line wiring and the bypass wiring, both wirings can be kept at the same potential.

  The bypass wiring 42 is made of aluminum or an aluminum alloy, and preferably the scanning line wirings 401, 402,..., 40n and the scanning lines X1, X2,. The A plurality of cutting regions 341, 342,..., 34n are formed on the bypass wiring 42, and the cutting regions 341, 342,. The insulating film 18 is not covered on 34n, and the wiring is exposed. These cutting regions 341, 342,..., 34n are preferably cut at a plurality of portions in order to cut more reliably.

  In this state, various subsequent processes are performed. At this time, even if the substrate comes into contact with other objects and static electricity enters the electrodes, the signal lines and scanning lines are at the same potential. The TFT or the like does not cause electrostatic breakdown due to static electricity.

  Further, when the detour electrode 42 is cut at the cutting regions 341, 342,..., 34n, it is performed by a predetermined etching process, and the transparent electrode formed on the translucent substrate is made of IZO (Indium Zinc Oxide). If formed, the cutting regions 341, 342,..., 34n can be simultaneously etched during the transparent electrode etching process, and the bypass electrode 42 can be cut without additional processing steps. . In addition, when forming a transparent electrode by ITO (Indium Tin Oxide) currently widely used as a transparent electrode material, the cutting process of this bypass electrode 42 is needed separately. This cutting step is preferably performed after the patterning of the transparent electrode. If the bypass electrode 42 is cut at this timing, the metal layer (layer on which the metal wiring is formed) excluding a part of the bypass electrode 42 is formed. The transparent electrode made of ITO is formed, and other wirings that are not desired to be cut other than the bypass electrode 42 can be protected in the cutting process. As described above, the step of cutting the bypass electrode 42 is performed in the latter half of the entire manufacturing process, whereby electrostatic breakdown at the initial stage of the manufacturing process can be satisfactorily prevented.

  As described above, in the present invention, the scanning line and the signal line are maintained at the same potential by providing the bypass line in the scanning line wiring and the signal line wiring and connecting to the connection wiring. In addition, even when static electricity enters the various electrodes, it is possible to prevent electrostatic breakdown or the like from occurring due to this static electricity.

  In the above embodiment, the transmissive liquid crystal display device has been described. However, the present invention is not limited to this. For example, the transmissive liquid crystal display device can also be applied to a transflective liquid crystal display device. Thus, even when static electricity enters the reflective electrode, electrostatic breakdown due to the static electricity can be prevented.

FIG. 1 is an enlarged plan view showing an enlarged part of a liquid crystal display device of the present invention, 2 is an enlarged view of part B of FIG. FIG. 3 is a plan view of several pixel portions of a conventional liquid crystal display device. 4 is a schematic equivalent circuit diagram for several pixels of the liquid crystal display device of FIG. 5 is a cross-sectional view taken along the line AA in FIG.

Explanation of symbols

10, 10A Liquid crystal display device 12 Pixel electrode 13 Auxiliary capacitance electrode 14 Pixel transistor 16 Counter electrode 17 Liquid crystal 11 ′, 18, 19 Insulating film 20, 36 a-Si layer 30 Connection wiring 31 Electrostatic protection element 32 Contact hole 35 Transistor 341 ,..., 34n Cutting region 401,..., 40n, 41n Scanning line wiring 42 Detour wiring X1, X2, ..., Xn Scanning line Y1, Y2, ..., Ym Signal line

Claims (6)

A plurality of signal lines and scanning lines are arranged in a matrix on a light-transmitting substrate, a region surrounded by the plurality of signal lines and scanning lines forms a display region, and the signal lines are formed at a peripheral portion of the display region. And an active matrix liquid crystal display device in which a wiring for connecting the scanning line to the connection terminal for external connection is formed,
After the scanning line wiring connected to each of the plurality of scanning lines and the signal line wiring connected to each of the plurality of signal lines are electrically connected to each other via the connection wiring, each scanning line wiring and An active matrix liquid crystal display device, wherein each of the signal line wirings is electrically disconnected from the connection wiring at a plurality of locations.   Each of the plurality of signal line wirings and scanning line wirings has an electrostatic protection element and a bypass wiring arranged to bypass the electrostatic protection element, and the bypass wiring is electrically disconnected at a plurality of locations. The active matrix liquid crystal display device according to claim 1, wherein the liquid crystal display device is an active matrix liquid crystal display device.   3. The active matrix liquid crystal display device according to claim 2, wherein the bypass wiring is made of aluminum or an aluminum alloy. Forming a plurality of signal lines and scanning lines on a light-transmitting substrate in a matrix and forming a wiring for connecting the plurality of signal lines and scanning lines to an external connection terminal;
Electrically connecting the scanning line wiring respectively connected to the plurality of scanning lines and the signal line wiring respectively connected to the plurality of signal lines via a connection wiring;
Electrically cutting the scanning line wiring and the signal line wiring at a plurality of locations in the vicinity of the connection wiring, respectively, in a subsequent process;
A method of manufacturing an active matrix liquid crystal display device comprising: Forming an electrostatic protection element on the wiring connected to the signal line and the scanning line;
Forming a bypass wiring so as to bypass the electrostatic protection element formed on the wiring connected to the scanning line;
5. The step of electrically disconnecting the scanning line wiring and the signal line wiring at a plurality of locations in the vicinity of the connection wiring, respectively, wherein the bypass wiring is electrically disconnected. Of manufacturing an active matrix liquid crystal display device.   The bypass wiring is formed of aluminum or an aluminum alloy, and the step of electrically cutting the scanning line wiring and the signal line wiring at a plurality of locations in the vicinity of the connection wiring is formed on the translucent substrate. 6. The method of manufacturing an active matrix liquid crystal display device according to claim 5, wherein the bypass wiring is simultaneously cut in a wet etching process of a transparent electrode material made of indium zinc oxide (IZO).

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