JPH10293326A - Manufacture of liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a new liquid crystal display by which display failure is not caused even if patterning failure is caused in a pattern structure formed on a base board in the manufacturing method of the liquid crystal display. SOLUTION: A backing layer 11 composed of a Ta oxide is formed on a surface of a glass substrate 10, and a wiring layer 12 and an MIM(metal- insulator metal) element connected to this, are formed on this backing layer 11, and this MIM element is also connected to a transparent electrode 16. A residual part removing process of preventing the remainder of a film between patterns by performing etching processing on unformed areas A, B and C of these pattern structures, is arranged in a manufacturing process of the pattern structures. This process is desirably performed simultaneously with a process of patterning a connecting layer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly to a process for a pattern structure on an inner surface of a substrate constituting a liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, as a schematic structure of a liquid crystal display device, two substrates made of glass or the like having a surface structure formed of wirings, pixel electrodes, etc. formed on the surface of a translucent substrate are fixed to each other. In most cases, they are bonded at intervals and a liquid crystal is sealed between liquid crystal substrates. As the structure of the liquid crystal substrate,
Active elements such as TFTs (thin film transistors) and TFDs (thin film diodes) are arranged on the surface of the light-transmitting substrate such that the surface structures corresponding to the pixel regions are arranged in a matrix on the surface of the transparent substrate. And a wiring layer connected to a pixel electrode via an active element.

In various liquid crystal display devices, a wiring layer is formed on the inner surface of a substrate, and a pixel electrode connected to the wiring layer is provided for each pixel region. In an active matrix type liquid crystal display device provided with an active element as described above, for example, the active element is connected between a wiring layer and a pixel electrode, and the potential applied from the wiring layer to the pixel electrode by the characteristics of the active element. Is configured to be controlled.

[0004]

In the above-mentioned various liquid crystal display devices, it is necessary to form a pattern structure on the inner surface of the substrate for forming a wiring layer, a pixel electrode, an active element and the like. When a structure is formed, a so-called film residue that originally leaves a film in a region where a predetermined pattern portion is not formed due to a patterning defect occurs, and this film residue causes an electrical short circuit, resulting in a display defect. There is a problem.

[0005] Such display defects are rapidly increasing with the recent increase in the definition and size of the liquid crystal display device or the number of pixels, and this is one of the causes for lowering the yield of the liquid crystal display device. Has become.

SUMMARY OF THE INVENTION Accordingly, the present invention is to solve the above-mentioned problem, and an object of the present invention is to cause a display failure even if a pattern failure occurs in a pattern structure formed on a substrate in a method of manufacturing a liquid crystal display device. It is an object of the present invention to provide a new method of manufacturing a liquid crystal display device without any problem.

[0007]

Means taken to solve the above-mentioned problem is a structure in which a liquid crystal layer is sandwiched between two substrates having a pattern structure including a wiring layer and a pixel electrode on an inner surface thereof. In the method for manufacturing a liquid crystal display device having the above, there is provided a residue removing step for removing a pattern residue that may occur due to a shape defect of the pattern structure in a region where the pattern structure is not formed.

According to this means, since the remaining portion removing step for removing the remaining portion of the pattern (remaining portion of the film) generated in the non-formed region of the pattern structure is provided, it is possible to prevent a short circuit between the patterns. Since display defects can be reduced, the yield of products can be increased.

In the residual portion removing step, a step of forming a mask for processing the non-formation region of the pattern structure is performed, and an etching process of the non-formation region of the pattern in the state where the mask is formed is performed. And a performing step.

According to this means, since a mask for processing the non-formed region is formed and the etching process is performed through this mask, the main part of the pattern structure is not affected without affecting the pattern structure. After the patterning of the portion, it is possible to process at an appropriate point in the manufacturing process.

[0011] In this case, further, a mask pattern that enables processing of a portion other than the non-formation region is formed at the stage of forming the mask, and the pattern structure is formed together with the non-formation region at the stage of performing the etching process. Is desirably patterned.

According to this means, in the remaining portion removing step, the patterning of the portion other than the non-formation region can be simultaneously performed using the common mask, so that the manufacturing process can be simplified and the increase in the manufacturing cost can be suppressed. can do.

A step of forming a conductive pattern including a first conductor on the substrate, and forming an insulating film by anodic oxidation on the surface of the first conductor by supplying power through the conductive pattern; A step of forming a second conductor and a third conductor on the surface of the insulating film; and a step of removing at least a part of the conductive pattern after the step of forming the insulating film. Between the wiring layer and the pixel electrode by the first conductor, the insulating film and the second conductor, and the first conductor, the insulating film and the third conductor. Forming a two-terminal non-linear element having a pair of electrode-insulator-electrode structures connected in series to the substrate, etching the non-formation region of the pattern structure to remove the remaining pattern, and the conductive pattern Little It is preferred that also serves as a step for Ku and also remove some.

According to this means, by forming a two-terminal non-linear element having a pair of electrode-insulator-electrode structure connected in series between the wiring layer and the pixel electrode, the voltage / current of the nonlinear element can be increased. In the case where the asymmetry of the characteristics is reduced, the step of removing the remaining pattern and the step of removing at least a part of the conductive pattern can be performed at the same time. The increase can be suppressed.

[0015] In this case, the residual portion removing step may be performed simultaneously with the step of removing at least a part of the conductive pattern, and removes a pattern residual portion formed of substantially the same material as the first conductor. And a step of removing a remaining pattern formed of substantially the same material as the second conductor and the third conductor.

According to this means, the residue removing step includes a step of removing a pattern residue formed of substantially the same material as the first conductor, and a step of removing the second conductor and the third conductor. The method includes a step of removing a pattern residue formed of substantially the same material, and a step of removing the pattern residue formed of substantially the same material as the first conductor.
By performing the process at the same time as the step of removing at least a part of the conductive pattern, the processing can be efficiently performed for each material of the conductor.

[0017]

Next, an embodiment according to the present invention will be described with reference to the accompanying drawings.

(First Embodiment) FIGS. 1 and 2 are a plan view and a sectional view, respectively, showing the surface structure of an element-side substrate of a liquid crystal display device according to a first embodiment. A thickness of 800 to 1000 made of Ta oxide on the surface of the transparent glass substrate 10
An underlayer 11 having a thickness of about Å is formed, and a wiring layer 12 having a two-layer structure of a conductive layer made of Ta and having a thickness of about 2,000 被覆 and a covering layer made of Cr and the like having a thickness of about 1500 に is formed on the surface thereof.
Are formed. Further, as shown in FIG.
The connection layer 13 made of Ta is also formed on the surface of the substrate 1.

On the surface of the connection layer 13, a thin insulating film having a thickness of about 200 to 600 ° is formed by an anodic oxidation method described later. First electrode portion 12 formed by extending a layer
a and are in conductive contact with each other. Also, connection layer 1
On the surface of the insulating film on the other end side of 3, a second electrode portion 15 a extended from an electrode layer 15 made of Cr or the like is coated, and is in conductive contact.

In the above structure, the MIM (metal-insulator-metal) element is formed by joining the first electrode portion 12a and the connection layer 13 via the insulating film. Further, since the connection layer 13 and the second electrode portion 15a are joined via an insulating film, a similar MIM element is configured. In these structures, when viewed from the wiring layer 12 side, an MIM element stacked in the order of Cr, insulating film, and Ta and an MIM element stacked in the order of Ta, the insulating film, and Cr are connected in series. Things. The reason why the pair of MIM elements is connected in series is to eliminate the asymmetry based on the polarity of the non-linearity in the current-voltage characteristics of the MIM element and improve the element characteristics.

The electrode layer 15 is conductively connected to a transparent electrode 16 made of ITO (indium tin oxide) or the like having a plane shape substantially corresponding to the pixel region. As a result, two MIM elements are connected in series between the wiring layer 12 and the transparent electrode 16.

In such a pattern structure, there is a risk that a film residue may occur in the non-formation regions A, B and C of the pattern shown in FIG. 1 when patterning each pattern portion included in the pattern structure. If this film residue is left untouched, the pattern portions are short-circuited, and a display defect occurs in the pixel. This display defect causes a white or black point defect in the liquid crystal display.

Next, a method for manufacturing the liquid crystal substrate according to the present embodiment will be described with reference to FIGS.
3 and 4 show cross sections cut along the line IV-IV shown in FIG.

First, as shown in FIG. 3A, Ta is deposited on the surface of a glass substrate 10 by a sputtering method or the like, and a base layer 11 is formed by thermal oxidation. The underlayer 11 can also be formed by directly sputtering Ta oxide. The underlayer 11 is formed to enhance the adhesion between the upper wiring layer, the MIM element, the transparent electrode, and the like, and also prevents contamination of Na and the like contained in the glass substrate 10. In some cases. Furthermore, in some cases, it is provided to protect the glass substrate 10 from an etchant used when forming the upper layer structure.

Next, Ta is entirely deposited on the surface of the underlayer 11 by a sputtering method or the like, and is subjected to predetermined patterning to form a conductive pattern 12A. This conductive pattern 12A is a plane pattern as shown in FIG. 5, and is formed in a plurality of parallel and parallel in a region on the substrate corresponding to the liquid crystal display region, and becomes a conductive layer constituting a lower layer of the wiring layer 12. Wiring pattern section 12A-1
And an electrode pattern portion 12A-2 which is formed in the extension direction of the wiring pattern portion 12A-1 and is provided in a shape bent at a right angle, protruding from the middle of the wiring pattern portion, and a plurality of wiring pattern portions 12A-1. And a connection pattern portion 12A-3 connected to the end. Each wiring pattern portion 12A-1 and electrode pattern portion 12A-2 of the conductive pattern 12A are conductively connected to each other by a connection pattern 12A-3.

Next, the liquid crystal substrate is immersed in a predetermined electrolytic solution, and a predetermined voltage is applied between the conductive pattern 12A and the electrolytic solution to thereby form an electrode pattern portion 1 of the conductive pattern 12A.
Anodize the surface of 2A-2. By this anodic oxidation, a thin insulating film 14 made of Ta oxide is formed as shown in FIG. The insulating film 14 is subjected to a heat treatment after being formed and cooled under predetermined conditions, thereby removing pinholes and stabilizing the film quality.

Next, as shown in FIG. 3C, Cr is deposited on the above structure by a sputtering method or the like to form a wiring pattern portion 12B on the wiring pattern portion 12A-1 of the conductive pattern 12A. , Electrode pattern 12
The electrode layer 15 is formed on the end of A-2. As shown in FIG. 6, the wiring pattern portion 12B
2A-1 and the wiring pattern portion 12A-
The first electrode portion 12a is formed so as to protrude from the first electrode portion and partially overlap the electrode pattern portion 12A-2.

Next, as shown in FIG. 4A, the base of the electrode pattern portion 12A-2 is removed by etching.
The connection layer 13 separated from the wiring pattern portion 12A-1 is formed. In this etching step, the connection pattern portion 12A-3 is also removed at the same time.

In the present embodiment, in the etching step, a mask having openings in the non-formed areas A, B, and C shown in FIG. 1 is formed together with the base of the electrode pattern section 12A-2. The non-forming region is also subjected to the etching process. The plane pattern of the region to be etched in this step is shown by oblique lines in FIG. 7 and corresponds to the opening D of the mask.

A mask having a shape having an opening D indicated by a hatched portion in FIG. 7 is formed by applying a photosensitive resist by a usual photolithography method, exposing the resist in a desired pattern, and developing it. The portion other than the hatched portion 7 is covered with the resist layer. At the stage of forming the mask, a Ta pattern portion made of Ta or its oxide insulating film and a Cr pattern portion made of Cr are formed on the glass substrate 10.

Actually, as described later, first, wet etching for selectively etching and removing Cr is performed using a mask shown in FIG. In this etching, for example, an aqueous solution obtained by mixing ceric ammonium and nitric acid is used. However, it is also possible to carry out by dry etching. Next, etching is performed to remove Ta and Ta oxide by etching. In this etching, for example, dry etching such as plasma etching or reactive ion etching is performed using an etching gas obtained by mixing SF4 or CF4 with oxygen.

Finally, as shown in FIG. 4B, a transparent electrode 16 is formed by a sputtering method or the like so as to partially cover the electrode layer 15.

FIG. 8 shows a schematic procedure of the patterning step in this embodiment. First, the above-described conduction pattern 1
A Ta-sputtering step, a Ta-photolithography step, and a Ta-etching step for patterning 2A are sequentially performed, and thereafter, an anodic oxidation step for anodizing Ta is performed. Next, Cr for patterning the wiring layer 12 and the electrode layer 15 is used.
A sputtering process, a Cr-photolithography process and a Cr-etching process are performed sequentially.

Next, an additional photolithography step for forming the above-described mask is performed to form a mask having an opening D shown in FIG. 7 on the glass substrate 10, and a Cr-etching step and a Ta etching step are performed. Perform sequentially. Thereafter, an ITO sputtering step, an ITO photolithography step, and an ITO etching step for forming the pixel electrode 16 are performed to finally form a planar pattern structure shown in FIG.

In this embodiment, Ta oxide and Ta are removed by etching in the patterning step of the MIM element shown in FIG. 4A.
The non-forming regions A, B, and C are etched to remove the film residue, thereby preventing a short circuit between the patterns. Therefore, display failure can be reliably prevented by adding only the Cr-etching step after the additional photolithography step, and an increase in manufacturing cost can be suppressed.

In the above-described embodiment, the etching of Cr and the etching of Ta are sequentially performed using the mask formed in the additional photolithography process. However, the effect of the present invention can be obtained with only one of them.
For example, when only the etching process of Ta (and Ta oxide) is performed simultaneously with the patterning of the connection layer 13 using the mask, no additional process is required, and the connection layer 13 is not required.
This can be dealt with only by changing the shape of the mask pattern at the time of patterning, so that an increase in manufacturing cost can be avoided.

The order of the Cr-etching step and the Ta-etching step after the formation of the mask is as follows.
It is preferable to perform etching on Cr first as described above. One reason is that since the Cr pattern is formed after the Ta pattern, the order of etching is such that the C pattern formed on the surface side (formed later) is formed.
Unless r is removed first, if the remaining portions of Cr and Ta overlap, the two cannot be reliably removed. Another reason is that wet etching (C
By performing r-etching first, the effect due to the weak point of wet etching, which cannot be etched if something adheres to the surface, is reduced, and the etching is caused by damage (damage) of the mask (resist) due to dry etching. This is to avoid possible etching defects in wet etching.

The opening D shown in FIG. 7 may be formed, for example, in a slit shape only in a portion where a short circuit between the patterns is likely to occur. In particular, the non-forming regions A, B, and C shown in FIG.
A slit-shaped opening along the area may be provided for each portion indicated by. The width of the opening D and the width of the slit-shaped opening may be appropriate, and the planar shape of these openings may be any appropriate shape as long as short-circuiting between patterns can be effectively prevented.

(Second Embodiment) FIG. 9 shows a schematic procedure in a second embodiment different from the first embodiment for forming the same pattern structure shown in FIG. 1 as the first embodiment. In this embodiment, after performing the above-described anodic oxidation process, the process is exactly the same as that of the first embodiment until a Cr-sputtering process is performed. However, without performing Cr patterning thereafter, as shown in FIG. An additional photolithography step of forming a mask having an opening D is performed, and the same Cr-etching step and Ta-etching step as described above are performed. In this Ta-etching step, an island-shaped connection layer 13 is formed as described above.

Thereafter, a Cr-photolithography step and a Cr-etching step for forming the wiring layer 12 and the electrode layer 15 similar to those in the first embodiment are sequentially performed. Finally, an ITO sputtering process, an ITO photolithography process, and an ITO etching process are sequentially performed.

In this embodiment, although the order of the steps is different from that of the first embodiment, the remaining of the non-formed regions A, B, and C can be prevented in the same number of steps as in the first embodiment.

(Third Embodiment) FIG. 10 shows a schematic procedure in a further different third embodiment. Also in this embodiment, a pattern structure similar to that shown in FIG. 1 is formed. In this embodiment, a conductive pattern 12A forming step, Ta-sputtering step, Ta-photolithography step and Ta-etching step, anodizing step, a forming step of the wiring layer 12 and the electrode layer 15, C
After performing the r-sputtering step, the Cr-photolithography step, and the Cr-etching step,
A sputtering process, an ITO photolithography process, and an ITO etching process are sequentially performed.

Thereafter, a mask having an opening substantially similar to the opening D shown in FIG. 7 is formed by an additional photolithography process. Here, the opening edge of the opening around the pixel electrode forming position in the mask is set so as to be arranged slightly outside the outer edge of the pixel electrode 16 shown in FIG. Is done.

Next, an ITO etching step, a Cr-etching step, and a Ta-etching step are sequentially performed through the mask. This ITO etching step is performed by wet etching of aqua regia or hydrofluoric acid or the like, similarly to the patterning of the pixel electrode 16. Note that this Ta
-In the etching step, the connection layer 13 is formed as in the above embodiment.

In this embodiment, after all of the pattern structure shown in FIG. 1 is completed, the non-formed regions A, B, and C are etched, and a film of an ITO pattern for forming the pixel electrode 16 is formed. The rest can be prevented.

In each of the above embodiments, it is most preferable to remove all the film residues of the three patterns of Ta (Ta oxide), Cr, and ITO which form the pattern structure, but any one of these three patterns is preferable. A great effect can be obtained only by removing one or two film residues.

In the above embodiment, a part of the step of removing the film residue (the step of removing Ta and Ta oxide) is performed simultaneously with the patterning step (the step of forming the connection layer 13) which has existed conventionally. The process of removing the remaining film may be newly provided in the conventional manufacturing process as long as the number of processes may be increased.

The region for removing the film residue may be only a part of the non-formed region, or only the portion where the film residue is likely to occur.
Alternatively, the effect can be obtained even if the processing is performed only on the portion that is likely to be short-circuited.

When the film residue is removed by a plurality of removal steps, the removal step for the material existing in the upper layer (material formed later) is performed first on the material existing in the lower layer (material formed earlier). It is more preferable to perform the removal step afterward in order to perform the reliable removal.

[0050]

As described above, according to the present invention, the following effects can be obtained.

According to the first aspect, since the remaining portion removing step for removing the remaining portion of the pattern (the remaining portion of the film) generated in the non-formed region of the pattern structure is provided, it is possible to prevent a short circuit between the patterns. In addition, since display defects can be reduced, the yield of products can be increased.

According to the second aspect, a mask for processing the non-formed region is formed, and the etching process is performed through this mask, so that the pattern structure is not affected. After patterning the main part, it is possible to process at an appropriate point in the manufacturing process.

According to the third aspect, in the remaining portion removing step, the patterning of the portion other than the non-formation region can be simultaneously performed by the common mask, so that the manufacturing process can be simplified and the manufacturing cost can be increased. Can be suppressed.

According to the fourth aspect, when a pair of MIM elements connected in series between the wiring layer and the pixel electrode is formed, the asymmetry of the voltage-current characteristics of the MIM element is reduced. In addition, at least a part of the residue removing step can be performed simultaneously with the step of removing at least a part of the conduction pattern, and an increase in the number of steps due to the addition of the residue removing step can be suppressed.

According to the fifth aspect, the remaining portion removing step includes a step of removing a pattern remaining portion formed of substantially the same material as the first conductor, and a step of removing the second conductor and the third conductor. And a step of removing a pattern residue formed of substantially the same material as the first conductor.
By performing the process at the same time as the step of removing at least a part of the conductive pattern, the processing can be efficiently performed for each material of the conductor.

[Brief description of the drawings]

FIG. 1 is a plan view showing a surface structure of a liquid crystal substrate on an element side for showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view showing a state cut along the line II-II in FIG.

3A to 3C are process cross-sectional views illustrating a first embodiment of a method for manufacturing a liquid crystal display device according to the present invention.

FIGS. 4A and 4B are process cross-sectional views showing the same embodiment.
It is.

FIG. 5 is a process plan view showing the same embodiment.

FIG. 6 is a process plan view showing the same embodiment.

FIG. 7 is a process plan view showing the same embodiment.

FIG. 8 is a process explanatory view showing the same embodiment.

FIG. 9 is a process explanatory view showing a second embodiment.

FIG. 10 is a process explanatory view showing a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Glass substrate 11 Underlayer 12 Wiring layer 12A Conductive pattern 12A-1 Wiring pattern part 12A-2 Electrode pattern part 12A-3 Connecting pattern part 13 Connection layer 14 Insulating film 15 Electrode layer 16 Transparent electrode A, B, C non-forming area D opening

Claims (5)

[Claims] 1. A method for manufacturing a liquid crystal display device having a structure in which a liquid crystal layer is sandwiched between two substrates having a pattern structure including a wiring layer and a pixel electrode on an inner surface thereof, wherein the pattern structure is formed in a non-formation region. A method for manufacturing a liquid crystal display device, comprising a residual portion removing step for removing a residual portion of a pattern which may occur due to a defective shape of a pattern structure. 2. The non-forming region according to claim 1, wherein in the remaining portion removing step, a mask for processing a non-forming region of the pattern structure is formed, and the non-forming region of the pattern is formed in a state where the mask is formed. Carrying out an etching process of the liquid crystal display device. 3. The method according to claim 2, wherein a mask pattern that enables processing of a portion other than the non-formation region is formed in the step of forming the mask, and the pattern is formed together with the non-formation region in the stage of performing the etching process. A method for manufacturing a liquid crystal display device, comprising patterning a part of a structure. 4. A step of forming a conductive pattern including a first conductor on a substrate, and forming an insulating film by anodic oxidation on a surface of the first conductor by supplying power through the conductive pattern. A step of forming a second conductor and a third conductor on the surface of the insulating film; and a step of removing at least a part of the conductive pattern after the step of forming the insulating film. Having the first conductor,
A pair of electrodes connected in series between the wiring layer and the pixel electrode by the insulating film, the second conductor, the first conductor, the insulating film, and the third conductor; Forming a two-terminal non-linear element having a body-electrode structure, and performing both the step of removing the remaining part of the pattern by etching the non-formed area of the pattern structure and the step of removing at least a part of the conductive pattern; A method for manufacturing a liquid crystal display device, comprising: 5. The pattern removing step according to claim 4, wherein the step of removing the remaining portion is performed simultaneously with the step of removing at least a part of the conductive pattern, and removes a pattern remaining portion formed of substantially the same material as the first conductor. And a step of removing a remaining pattern formed of substantially the same material as that of the second conductor and the third conductor.