KR100261974B1 - Structure of lcd panel and manufacturing method thereof - Google Patents

Abstract

PURPOSE: A substrate structure of LCD and manufacturing method thereof don't form an insulator layer in the boundary between a metal layer and a conductive layer. CONSTITUTION: The second metal layer of Mo, W or Ta is laminated on the first metal layer of Cr metal layer. A passivation layer(155) of SiNx, SiOx or BCB is coated in the front surface of a substrate. A contact hole is formed in the passivation layer(155) to contact a gate pad, a data pad and a drain electrode(172) of a switching element with a conductive layer of ITO. The contact hole is formed by the etching method using a plasma gas of SF6/O2 or CF4/O2. The surface of the second metal layer is exposed in the lower of the contact hole, and the second metal layer doesn't form an insulator layer because the surface is etched by the plasma gas of SF6/O2 or CF4/O2. Therefore, the ohmic contact isn't formed in the boundary between the second metal layer and the conductive layer.

Description

Structure of Substrate of LCD and Manufacturing Method Thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device using a thin film transistor (hereinafter referred to as TFT) as a switching element, and in particular, to a contact resistance of a metal film generated during a patterning process such as a metal film and an insulating film.

A substrate constituting a conventional liquid crystal display device has a pixel electrode 80 formed in an area where two adjacent gate bus lines 60 and two adjacent data bus lines 70 intersect each other, as shown in FIG. The TFT 37 in electrical contact is formed near the intersection of the gate bus line 60 and the data bus line 70.

The TFT 37 includes a gate electrode 61 branching from the gate bus line 60, a source electrode 71 branching from the data bus line 70, a drain electrode 72 disposed to face the source electrode, a semiconductor layer 90, and the like.

The portion 33 where the pixel electrode 80 and the gate bus line 60 overlap with each other serves as a storage capacitor electrode.

The manufacturing method of the board | substrate of the conventional liquid crystal display device comprised as mentioned above is demonstrated by FIG. 2 (sectional drawing cut | disconnected along the II-II line of FIG. 1).

First, a first Cr metal film is deposited on a transparent glass substrate 10 by a sputtering method, and a photoresist is coated on the first Cr metal film by spin coating. After exposing the photoresist using a mask, the photoresist is developed to a predetermined pattern, and the first Cr metal film is etched with an etchant such as CAN (ceric ammonium nitrate) according to the developed pattern to form a gate bus line and the gate bus line. After forming the gate electrode 61 branching at, the photoresist remaining on the metal film is removed with an organic solution of NMP (N-Methyl-Pyrrolidone), a mixture of alcohol and amine.

Subsequently, an inorganic insulating film made of SiN _x , SiO _x, etc. to be the gate insulating film 50, an a-Si layer serving as the semiconductor layer 90, and an a-Si layer doped with n ⁺ ions serving as the ohmic contact layer 100 were deposited by CVD. Deposition was carried out in succession, and a photoresist was applied by spin coating onto the a-Si layer doped with n ⁺ ions. After exposing the photoresist by using a mask and developing in a predetermined pattern, dry-etching or wet-etching the a-Si layer and the a-Si layer doped with n ⁺ ions simultaneously according to the developed pattern The photoresist remaining on the a-Si layer doped with n ⁺ ions is removed with an organic solution of NMP (N-Methyl-Pyrrolidone), a mixture of alcohol and amine.

Due to the etching, the semiconductor layer 90 and the ohmic contact layer 100 are formed in an island shape on the gate insulating layer of the gate electrode 61.

Subsequently, a second Cr metal film is deposited on the entire surface of the substrate on which the ohmic contact layer 100 is formed by sputtering, and a photoresist is coated on the second Cr metal film by spin coating. After exposing the photoresist using a mask, the photoresist is developed to a predetermined pattern, and the second Cr metal film is etched with an etchant such as CAN (ceric ammonium nitrate) according to the developed pattern.

A data bus line 70 is formed on the gate insulating layer 50 by the etching, and a source electrode 71 branching from the data bus line 70 and a drain electrode 72 facing the source electrode 71 are formed on the ohmic contact layer 100. A portion of the drain electrode may be formed to extend on the gate insulating layer 50.

Using the source electrode 71 and the drain electrode 72 as a mask, the exposed ohmic contact layer is removed by dry etching, and the photoresist on the data bus line, the source electrode and the drain electrode is NMP (N-Methyl-Pyrrolidone). Remove with an organic solution of a mixture of alcohol and amine.

Subsequently, a protective film 55 made of SiN _x , SiO _X or benzocyclobutene (BCB) containing a Si group is coated on the entire surface of the substrate on which the source and drain electrodes are formed, and the photoresist is spin coated on the protective film. Apply with After exposing the photoresist using a mask, the photoresist is developed in a predetermined pattern, and the exposed passivation layer is exposed in a dry etching chamber using a plasma gas of SF ₆ / O ₂ or CF ₄ / O ₂ according to the developed pattern. Etch in

Due to the dry etching, a contact hole 30 through which a portion of the drain electrode 72 is exposed is formed.

The dry etching mechanism of the protective film will be described in more detail as follows.

The exposed protective film starts to be etched because the Si group of the exposed protective film reacts with the F group of the etching gas and turns into a volatile substance of SiF ₄ . Simultaneously with the etching, the photoresist covered on the protective film is removed by ashing with O ₂ gas.

After forming a contact hole on the protective film and removing the photoresist as described above, an ITO (Indium Tin Oxide) film is deposited on the entire surface of the protective film 55 by sputtering, and the photoresist is coated on the ITO film by spin coating. The photoresist is exposed using a mask and developed to a predetermined pattern, and the ITO film is etched with an etchant such as HCl according to the developed pattern to form a pixel electrode 80.

Through the above process, one substrate of the liquid crystal display device includes a switching element (TFT) 37 including a semiconductor layer 90, a source electrode 71, a drain electrode 72, a gate electrode 61, and the like, and a drain electrode 72 of the switching element 37. Is made to be in contact with the pixel electrode 80 via the protective film 55.

On the other hand, the cross section of the gate pad portion and the data pad portion located at the end of each gate bus line and data bus line and in contact with the tape automated bonding (TAB) of the IC has a structure as shown in FIG.

3, 92 is formed of a Cr metal film such as a metal film forming a gate bus line and a data bus line, and is connected to the gate bus line or the data bus line.

Further, 55 is a SiN _x, SiO _x or benzo cyclo butene (benzocyclobute-ne: BCB), which comprises an Si and protection film made of, such as 93 is the ITO film formed in order to facilitate contact with the IC TAB terminal.

In particular, the ITO film 93 in contact with the pad portion is in contact with the Cr metal film 92 after etching a part of the protective film 55 using a plasma gas of SF ₆ / O ₂ or CF ₄ / O ₂ .

However, in the substrate of the conventional liquid crystal display device configured as shown in FIGS. 2 and 3, the protective film 55 is SF ₆ / O ₂ or CF so that a part of the drain electrode 72 made of the Cr metal film or the Cr metal film 92 of the pad part is exposed. _In the process of etching with a plasma gas of ₄ / O ₂ , a thin insulating film 75 is formed on the surface of the Cr metal film exposed to the etching gas.

Since the thin insulating film 75 increases the contact resistance of the conductive film that is in contact with the Cr metal film, that is, the ITO film, the display quality of the liquid crystal display device may be degraded, such as raining on the screen. Cause.

The reason why the insulating film 75 is formed on the surface of the Cr metal plate is presumably because an oxide film is formed on the surface of the Cr metal film when the surface of the Cr metal film is exposed to the etching gas, but a specific cause is not known.

According to the present invention, when a protective film including a Si group is formed on the metal film as described above, the protective film is etched to expose the metal film, and a conductive film such as ITO is brought into contact with the exposed metal film. The purpose is to prevent a thin insulating film from being formed at the boundary with the metal film.

The present invention is selected from among the etchant of the protective film containing the Si group, that is, Mo, W, Ta is not formed on the surface even if exposed to the plasma gas of SF ₆ / O ₂ or CF ₄ / O ₂ to achieve the above object By forming the metal film in a stacked structure on the Cr metal film, the Cr metal film is not exposed to the etchant of the protective film.

In the above structure, a pattern may be formed of a single metal layer such as Mo, W, Ta, etc. without forming a laminated structure of a metal film of Mo, W, Ta, etc., and a Cr metal film. Therefore, it is preferable to form the structure laminated with the Cr metal film.

The method of patterning the stacked metal film has a method of continuously depositing a metal film selected from Mo, W, Ta, and the like on the Cr metal film by sputtering and simultaneously patterning the same, and then patterning the Cr metal film first, followed by Mo, W, There is a method of depositing a metal film selected from Ta or the like by a sputtering method and patterning the deposited metal film using the same mask as the patterning mask of the Cr metal film.

In particular, metal layers such as Mo, W, and Ta, which are laminated to prevent the formation of an insulating layer on the exposed metal film surface after etching, are exposed to the plasma gas of SF ₆ / O ₂ or CF ₄ / O ₂ . Because it reacts with and is etched, the surface is kept clean without impurities, and the insulating film is not formed.

1 is a plan view of a substrate of a conventional liquid crystal display device.

2 is a cross-sectional view taken along the line II-II of FIG.

3 is a cross-sectional view showing a conventional pad structure.

4A to 4J are sectional views of the manufacturing process of the liquid crystal display alien substrate of the present invention for explaining the first embodiment.

5 is a sectional view showing a pad structure of the present invention.

6A, 6D, 7, 8, and 9 are cross-sectional views of the manufacturing steps of the substrate of the liquid crystal display device of the present invention for explaining the second embodiment.

* Explanation of symbols for main parts of the drawings

10, 110: transparent glass substrate 33: auxiliary capacitance electrode

37: TFT 50, 150: gate insulating film

55, 155: Protective film 60: Gate bus line

61, 161: gate electrode 70, 170: data bus line

71, 171: source electrode 72, 172: drain electrode

75: insulating film 80, 180: pixel electrode

90, 190: semiconductor layer 192: pad metal layer

193, 280: ITO membrane 100, 200: ohmic contact layer

260, 261, 265: first metal film 360, 361, 365: second metal film

400: photoresist

According to an aspect of the present invention, there is provided a substrate of a liquid crystal display device having a protective film covering a portion of a metal film and a conductive film in contact with the exposed metal film, wherein the metal film includes a first metal film (Cr metal film) and a second metal. And a structure in which a layer (a metal film selected from Mo, W, and Ta) is laminated, a portion of the second metal film is exposed, and the exposed second metal film is in contact with the conductive film.

The metal film is composed of a drain electrode, a gate pad, a data pad part, or the like of the switching device, and the protective film is formed by stacking any one or more materials selected from SiN _x , SiO _x , and Benzocyclobutene including Si groups.

Meanwhile, a method of manufacturing a substrate of a liquid crystal display device configured as described above may include forming a metal film in a predetermined pattern, forming a protective film including the patterned metal film, and exposing a portion of the surface of the metal film. Etching a part of the protective film, and in particular, the metal film is formed such that a first metal film (Cr metal film) and a second metal film (metal film selected from Mo, W, and Ta) are laminated, and the protective film It is formed by stacking any one or more materials selected from SiN _x , SiO _x , and Benzocyclobutene including silver Si groups, and the etchant used in the etching process uses SF ₆ / O ₂ or CF ₄ / O ₂ gas.

Hereinafter, the manufacturing process and operation of the substrate of the liquid crystal display device of the present invention will be described in detail with reference to Examples 1 and 2.

Example 1

A first metal film 260 made of a Cr metal film and a second metal film 360 made of a metal film selected from Mo, W, and Ta are continuously deposited on the transparent glass substrate 110 by a sputtering method, and a photoresist is formed on the second metal film 360. 400 is coated by spin coating, and the photoresist 400 is exposed using a mask and developed to have a predetermined pattern (FIG. 4A).

Subsequently, the first metal film 260 and the second metal film 360 are simultaneously etched with an etchant such as CAN (ceric ammonium nitrate) according to the developed pattern, and NMP (N-Methyl-Pyrr-solidone), alcohol and amine The photoresist remaining on the second metal film 360 is removed with the mixed organic solution to form a gate bus line (not shown) and a gate electrode 161 branching from the gate bus line (FIG. 4B).

Subsequently, an inorganic insulating film made of SiN _x , SiO _x, etc., serving as a gate insulating film 150, an a-Si layer serving as a semiconductor layer 190, and an a-Si layer doped with n ⁺ ions serving as an ohmic contact layer 200 were deposited by CVD. After the deposition, the photoresist 400 was spin-coated on the n ⁺ ion-doped a-Si layer, and the photoresist 400 was exposed using a mask and developed in a predetermined pattern (FIG. 4C). .

Subsequently, the a-Si layer and the a-Si layer doped with n ⁺ ions are dry-etched or wet-etched simultaneously according to the developed pattern, and a mixture of NMP (N-Methyl-Pyrrolidone), an alcohol, and an amine is used. and removing the n ⁺ ions remain on the doped a-Si layer 400 on the photoresist by organic solvents. Due to the etching, the semiconductor layer 190 and the ohmic contact layer 200 are formed in an island shape on the gate insulating film 150 of the gate electrode 161 (FIG. 4D).

Subsequently, a first metal film 265 made of a Cr metal film and a second metal film 365 made of a metal film selected from Mo, W, and Ta are continuously deposited by sputtering on the entire surface of the substrate on which the ohmic contact layer 200 is formed. The photoresist 400 is coated on the second metal film 365 by spin coating, and the photoresist 400 is exposed using a mask and developed to have a predetermined pattern (FIG. 4E).

Subsequently, the first metal film 265 and the second metal film 365 are simultaneously etched with an etchant such as CAN (ceric ammonium nitrate) according to the developed pattern, and the ohmic contact layer exposed by the etching is subjected to dry etching or the like method. And a photoresist remaining on the second metal layer 365 by using an organic solution of NMP (N-Methyl-Pyrrolidone), a mixture of alcohol and amine, and a source electrode 171 branching from the data bus line 170 and the data bus line. And a drain electrode 172 (FIG. 4F).

The structure of FIG. 4F is formed on the substrate of the liquid crystal display device, thereby completing a switching element including a gate electrode 161, an ohmic contact layer 190, a semiconductor layer 200, a source electrode 171, a drain electrode 172, and the like.

Subsequently, a protective film 155 made of SiN _x , SiO _x, or benzocyclobutene (BCB) containing Si groups is coated on the entire surface of the substrate on which the source and drain electrodes are formed, and the photoresist 400 is spin coated on the protective film. It applies by the method, and exposes the said photoresist using a mask, and develops in a predetermined pattern (FIG. 4G).

Subsequently, according to the developed pattern, the exposed protective film is etched in a chamber with a plasma gas of SF ₆ / O ₂ or CF ₄ / O ₂ to form a part of the drain electrode 172, that is, a second metal film constituting the drain electrode. A partially exposed contact hole 300 is formed.

Since the F group of the SF ₆ / O ₂ or CF ₄ / O ₂ plasma group and the Si group of the protective layer react with each other to form a volatile substance of SiF ₄ , the exposed protective layer starts to be removed, and at the same time, the O ₂ gas forms a photoresist 400. Start by removing it by ashing. The exposed protective film is removed, and the drain electrode 172 of the lower layer, that is, Mo. When the second metal film of W, Ta, etc. is exposed, the exposed surface of the second metal film is etched by reaction with the remaining etching gas, so that the surface of the second metal film is cleaned without forming impurities such as an insulating film. It is effective to always maintain a clean surface (FIG. 4H).

In addition, when the drain electrode is exposed, the remaining portion of the photoresist 400 is not etched and removed with an organic solution of NMP (N-Methyl-Pyrrolidone), a mixture of alcohol and amine.

Subsequently, a conductive film 280 made of an indium tin oxide (ITO) film is deposited on the entire surface of the protective film 155 by sputtering, a photoresist 400 is coated on the conductive film by spin coating, and the photoresist is applied using a mask. After exposure, development is carried out to form a predetermined pattern (Fig. 4I).

Subsequently, the conductive layer 280 is etched with an etchant such as HCl to form a pixel electrode 180 according to the developed pattern, and the photoresist remaining on the pixel electrode is mixed with NMP (N-Methyl-Pyrrolidone), alcohol and amine. Remove with an organic solution (FIG. 4J).

By constructing the substrate of the liquid crystal display device as described above, no contact resistance is formed in the contact portion between the pixel electrode 180 and the drain electrode 172 which are contacted through the contact hole 300 formed in the protective film.

On the other hand, at each end of the gate bus line and each end of the data bus line, a pad portion for contacting the tape automated bonding (TAB) of the IC is formed.

The pad part is simultaneously patterned when the gate bus line and the data bus line are patterned, and undergoes an etching process such as forming a contact hole of a switching element to expose the metal film of the pad part. Further, in order to facilitate contact with the terminal of the TAB of the IC, it is formed in contact with the metal film of the pad of a conductive film such as ITO.

It will be readily understood that the pad is a cross-sectional structure of FIG.

In FIG. 5, the pad metal film 192 has a lamination structure of a first metal film made of a Cr metal film and a second metal film made of a metal film selected from Mo, W, and Ta, and made of the second metal film and ITO. The conductive film 193 is in contact with the insulating film 155.

Also in the above structure, since the protective film is etched by the etching method described in Example 1 and the exposed metal film and the conductive film 193 are in contact, no contact resistance occurs at the contact portion of the metal film.

Example 2

This second embodiment is almost the same as that of the first embodiment, and the method of only patterning the first metal film and the second metal film is different.

That is, in the first embodiment, as shown in FIGS. 4A and 4E, the first metal film and the second metal film are sequentially deposited and the metal film is patterned at the same time to form a gate bus line and a data bus line. After the metal film is patterned, the second metal film is patterned.

As an example, a process of forming a gate bus line and a gate electrode branching from the gate bus line will be described. First, a first metal film 260 made of a Cr metal film is deposited on a transparent glass substrate 110 by a sputtering method. The photoresist 400 is coated on the one metal film 260 by spin coating, and the photoresist 400 is exposed using a mask and developed to have a predetermined pattern (FIG. 6A).

Subsequently, the first metal layer 260 is etched with an etchant such as CAN (ceric ammonium nitrate) according to the developed pattern, and the first metal is an organic solution of a mixture of N-Methyl-Pyrrolidone (NMP) and an alcohol and an amine. The photoresist remaining on the film 260 is removed to form a gate bus line (not shown) and an underlayer 261 of the gate electrode 161 branching from the gate bus line (FIG. 6B).

Subsequently, a second metal film 360 made of a metal film selected from Mo, W, and Ta is deposited on the transparent glass substrate 110 by a sputtering method, and a photoresist 400 is coated on the second metal film 360 by spin coating, and a mask is applied. The photoresist 400 is exposed to light and then developed to form a predetermined pattern. The mask may be a mask used when patterning the underlayer 261 of the gate electrode (FIG. 6C).

Subsequently, the second metal film is etched using a plasma gas of SF ₆ / O ₂ or SF ₄ / O ₂ according to the developed pattern, and at the same time, the photoresist 400 is etched by O ₂ contained in the plasma gas. ashing). The unresisted photoresist is removed with an organic solution of NMP (N-Methyl-Pyrrolidone), a mixture of alcohol and amine, and a gate bus line (not shown) and an upper layer of the gate electrode 161 branching from the gate bus line. A film 361 is formed (FIG. 6D).

The metal film of each pad portion may be formed using the same method as the method of forming the gate bus line and the gate electrode, and the data bus line, the source electrode, and the drain electrode may be configured. That is, even though the first metal film made of Cr metal film and the second metal film made of metal film selected from Mo, W, and Ta are formed to be stacked as described above, the surface of the first metal film is SF ₆ / O _2. Alternatively, the insulating film is not formed on the surface of the first metal film because it is not exposed to the plasma gas of CF ₄ / O ₂ .

Therefore, the method according to Example 2 can obtain the same effects as the method according to Example 1.

The metal film laminated by the method according to Example 2 may be formed such that the upper layer film 361 is located in the region of the lower layer film 261 as shown in FIG. 7. In addition, as shown in FIG. 8, the upper layer film 361 may be formed to be inclined to the lower layer film 261, and the range A of the upper layer film 361 deviating from the region of 261 of the lower layer film is preferably 2 μm or less. In addition, as shown in FIG. 9, the upper layer film 361 may be formed to cover the lower layer film 261 completely, and the upper layer film 361 outside the 261 region of the lower layer film may have a range B + C of 2 μm or less.

The present invention is a Cr metal due to the contact of the etching gas in the process of etching the protective film with a plasma gas of SF ₆ / O ₂ or CF ₄ / O ₂ so that a part of the surface of the Cr metal film is covered with a protective film containing a Si group This is to solve the conventional problem of forming a thin insulating film (presumably an oxide film) on the film surface.

According to the present invention for solving the above problems, a pattern of a metal film is formed by stacking a second metal film selected from Mo, W, and Ta on a first metal film made of a Cr metal film, and covers the Si group so as to cover the metal film. A protective film containing is formed.

A contact hole is formed in the passivation layer so as to contact a conductive film such as ITO, such as the gate pad part, the data pad part, and the drain electrode part of the switching element formed of the stacked metal film, and the contact hole is SF ₆ / O ₂ or CF. _It is formed by an etching method using a plasma gas of ₄ / O ₂ .

At the bottom of the contact hole, a surface of a second metal film made of Mo, W, Ta, or the like is exposed, and the second metal film reacts with the plasma gas even when exposed to a plasma gas of SF ₆ / O ₂ or CF ₄ / O ₂ . Since this is etched, impurities are removed and no insulating film is formed.

Therefore, the substrate of the liquid crystal display device of the present invention is formed by stacking a second metal film so that the Cr metal film is not exposed to the etching gas, and there is no contact resistance at the boundary with the conductive film in contact with the second metal film. When the liquid crystal display device is constructed using the substrate of the liquid crystal display device, there is an effect that the display quality is stabilized without raining phenomenon or the like on the screen.

Claims (16)

A substrate; A metal film formed on the substrate, wherein the first and second metal layers are laminated; A protective film having a contact hole exposing a portion of the second metal of the metal film on the metal film; And a conductive layer in contact with the second metal through the contact hole, wherein the second metal is selected from a metal consisting of molybdenum, tungsten, and tantalum. The liquid crystal display array substrate of claim 1, wherein the metal film is formed of at least one terminal of a switching element. The liquid crystal display array substrate of claim 1, wherein the metal layer comprises at least a gate pad portion or a data pad portion. The liquid crystal display array substrate of claim 1, wherein the passivation layer is a material selected from a group consisting of a silicon nitride film, a silicon oxide film, and BCB. The liquid crystal display array substrate of claim 1, wherein the first metal is chromium (Cr). The liquid crystal display array substrate of claim 1, wherein the conductive layer is formed on the passivation layer. The liquid crystal display array substrate of claim 1, wherein the conductive film is ITO. Providing a substrate; Depositing and patterning first and second metals on the substrate to form a metal film; Forming a protective film over an entire surface of the patterned metal film and the substrate; Forming a contact hole by etching the passivation layer to expose a portion of the second metal of the metal layer to the passivation layer; A method of manufacturing a liquid crystal display array substrate, the method comprising: forming a conductive film to contact the second metal exposed through the contact hole, wherein the second metal is selected from a group consisting of molybdenum, tungsten, and tantalum. The etching gas used for etching of SF ₆ , CF ₄ comprising a liquid crystal display array substrate manufacturing method. 10. The method of claim 8, wherein the metal film comprises at least one terminal of a switching element. The method of claim 8, wherein the metal layer comprises at least a gate pad portion or a data pad portion. The method of claim 8, wherein the passivation layer is a material selected from a group consisting of a silicon nitride film, a silicon oxide film, and BCB. The method of claim 8, wherein the first metal is chromium (Cr). The method of claim 8, wherein the conductive layer is formed on the passivation layer. The method of claim 8, wherein the conductive film is ITO. The method of claim 8, wherein the forming of the metal film comprises: sequentially stacking the first and second metals; And simultaneously patterning the successively stacked first and second metals. The method of claim 8, wherein the forming of the metal layer comprises: depositing and patterning a first metal on the substrate; And depositing a second metal on the patterned first metal and patterning the same as the first metal.

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