KR20070072277A - Method for fabricating liquid crystal dispaly device - Google Patents

Abstract

A manufacturing method of an LCD(Liquid Crystal Display) is provided to solve the wavy noise badness and to reduce the number of masks. A gate metal layer, a gate insulating layer(105) and an active layer are sequentially stacked on a substrate(101). The gate metal layer, the gate insulating layer and the active layer are patterned. The first passivation layer and a conduction layer are stacked on the entire of the substrate. The conduction layer is patterned so that source/drain electrodes are formed. The second passivation layer is formed on the entire of the substrate. A photo resist pattern is formed on the second passivation layer. The first and second passivation layers are etched by the photo resist pattern as a mask so that hole patterns(125a,125b) are formed and source/drain electrodes(113a,113b) and a portion of the active layer are exposed. A transparent conduction layer is formed on the entire of the substrate including the hole patterns. A photo resist pattern is formed on the transparent conduction layer. The photo resist pattern is selectively removed so that the upper portion of the transparent conduction layer is exposed. The exposed transparent conduction layer is removed and the remaining photo resist layer and pattern are removed so that pixel electrodes are formed within the hole patterns.

Description

Liquid crystal display device manufacturing method {METHOD FOR FABRICATING LIQUID CRYSTAL DISPALY DEVICE}

1 is a plan view showing a unit pixel structure of a general liquid crystal display device.

2 is a cross-sectional view of the unit pixel of FIG. 1.

3A to 3G are cross-sectional views illustrating a method of manufacturing a liquid crystal display device using a mask process according to the prior art.

4A to 4E are coplanar views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

5A to 5N are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

******** Description of the symbols for the main parts of the drawings ********

101 substrate 103 gate electrode

105: gate insulating film 107: active layer

109: first photosensitive film 111: etch stopper

113: ITO thin film 115: conductive layer

117: second photosensitive film 119: diffraction mask

121: protective layer 123: third photosensitive film pattern

125a, 125b: hole pattern 127; Transparent conductive layer

129: fourth photosensitive film 127a, 127b: pixel electrode

The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly, to a liquid crystal display device and a method for manufacturing the same that can reduce the number of mask process.

In display devices, particularly flat panel displays such as liquid crystal display devices, active devices such as thin film transistors are provided in each pixel to drive the display devices.

The driving method of the display device of this type is commonly referred to as an active matrix driving method. In the active matrix method, the active elements are arranged in each pixel arranged in a matrix to drive the pixel.

1 is a view showing an active matrix liquid crystal display device. The liquid crystal display device having the structure shown in the drawing is a thin film transistor liquid crystal display device using a thin film transistor 10 as an active device.

As shown in the drawing, each pixel of a thin film transistor liquid crystal display device having N × M pixels arranged vertically and horizontally includes a gate line 13 to which a scan signal is applied from an external driving circuit and a data line to which an image signal is applied ( And a thin film transistor 10 formed at the cross region of 19).

The thin film transistor 10 includes a gate electrode 13a connected to the gate line 13, a semiconductor layer 17 formed on the gate electrode 13a, and activated when a scan signal is applied to the gate electrode 13a. And a source electrode 19a and a drain electrode 19b formed on the semiconductor layer 17.

An image signal is applied to the display area of the pixel through the source electrode 19a and the drain electrode 19b as the semiconductor layer 17 is activated by being connected to the source electrode 19a and the drain electrode 19b. A pixel electrode 25 for operating (not shown) is formed.

FIG. 2 is a cross-sectional view taken along the line I-I of FIG. 1 and will be described below with reference to the drawings. FIG.

Referring to FIG. 2, the thin film transistor 10 is formed on the first substrate 11 made of a transparent material such as glass to form an array substrate. The thin film transistor 10 includes a gate electrode 13a formed on the first substrate 11, a gate insulating layer 15 stacked over the entire first substrate 11 on which the gate electrode 13a is formed, and A semiconductor layer 17 formed on the insulating layer 15, a source electrode 19a and a drain electrode 19b formed on the semiconductor layer 17, and a protective layer stacked over the entire first substrate 11 ( passivation layer; The pixel electrode 25 is formed on the passivation layer 23 to be connected to the drain electrode 19b of the thin film transistor through a contact hole (not shown) formed in the passivation layer 23.

Meanwhile, the color filter substrate 220 facing the array substrate 11 may be formed on the second substrate 202 made of a transparent material such as glass, and formed on the second substrate 202 and forming the thin film transistor 110. Or a black matrix 205 formed in an image non-display area such as between pixels and pixels to prevent light from being transmitted to the image non-display area, and a color filter layer 206 consisting of red, green, and blue to realize actual colors. It is configured to include). When the color filter substrate 220 and the array substrate 210 are bonded together, the liquid crystal layer 240 is filled therebetween to complete the liquid crystal display device. Meanwhile, a common electrode 207 may be further formed on the color filter layer 206 to provide an electric field to the liquid crystal layer 240 together with the pixel electrode 120.

The liquid crystal display device is mainly manufactured by a complex process such as a photolithography process using a mask, and with reference to FIG. 3, a method of manufacturing a liquid crystal display device by a conventional four mask process using a diffraction mask will be described.

Referring to FIG. 3A, a metal layer is stacked on the entire surface of the first substrate 11, and then a photoresist is applied thereon, and a photolithography process is performed to connect the gate line and the gate line. The gate electrode 13a is formed.

Thereafter, referring to FIG. 3B, the gate insulating layer 15, the semiconductor layer 17, the ohmic contact layer (not shown), and the conductive layer are formed over the entire first substrate 11 on which the gate electrode 13a is formed. 19) are formed in sequence.

Subsequently, a photosensitive film pattern 21 is formed on the conductive layer 19 by diffraction exposure. At this time, the photoresist pattern 21 has a thin photoresist film thickness compared to other regions having an upper end of the channel region by diffraction exposure.

Next, referring to FIG. 3C, the conductive layer 19, the ohmic contact layer (not shown), and the semiconductor layer 17 are sequentially etched by applying the photoresist pattern 21 as an etch mask to form the active pattern 103. do.

Subsequently, the photosensitive film pattern 21 is ashed. At this time, in the ashing process, the photoresist pattern 230 of a relatively thin region, that is, a channel region, of the photoresist pattern is removed and the conductive layer 19 is exposed. In addition, the ashing process is a process of oxidizing and removing the photoresist film, which is an organic material, and a part of the photoresist pattern 21 is removed due to oxidation, thereby reducing the overall volume. At this time, the photoresist pattern 21 is removed from the photoresist pattern of the edge portion of the channel region and the active pattern.

3E, the source photoresist 104 and the drain electrode 105 are formed by removing the conductive layer and the ohmic contact layer of the channel region by applying the ashed photoresist pattern 21a as an etching mask.

In this case, as illustrated in FIG. 3E, the ace-sensitive photoresist pattern 21a also exposes an edge region of the active pattern 17, and thus an ohmic contact layer (not shown) and a conductive layer formed on the edge of the active pattern 17. The layer 19 is removed so that the active pattern 17 protrudes relative to the source and drain electrodes.

3F, the passivation layer 23 is formed on the substrate including the source and drain electrodes 19a and 19b after the ashed photoresist pattern 21a is removed.

Next, referring to FIG. 3G, a contact hole (not shown) for exposing the drain electrode 19b is formed in the passivation layer 23 by a photo process.

Next, the pixel electrode 25 connected to the drain electrode 19b and made of a transparent electrode material is formed.

The thin film transistor fabricated in the above-described process sequence may include a first mask when forming a gate electrode, a second mask when forming an active pattern and a source / drain electrode, and a third mask when forming a contact hole exposing a drain electrode and a pixel electrode when forming a pixel electrode. It is formed by a four mask process using four masks.

However, referring to FIG. 3E, since the second mask is an expensive diffraction mask, it may cause an increase in production cost.

In addition, when the source and drain electrodes are formed, the active pattern region 103b protruding from the source and drain electrodes diffracts backlight light, or the channel signal is shaken by the backlight light, thereby generating ripple noise on the screen. .

The noise is called wavy noise, which is a problem in the four mask process using a diffraction mask as a kind of screen defect.

Accordingly, an object of the present invention is to provide a method for manufacturing a liquid crystal display device that can solve the problems of the prior art, which can solve a wave noise defect and reduce the number of masks to improve device reliability. There is this.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: sequentially stacking a gate metal layer, a gate insulating film, and an active layer on a substrate; Patterning the gate metal layer, the gate insulating layer, and the active layer; Depositing a first protective layer and a conductive layer on the entire substrate; Patterning the conductive layer to form a source / drain electrode; Forming a second protective layer on the entire substrate; Forming a photoresist pattern on the second protective layer; Etching a second protective layer and a first protective layer using the photoresist pattern as a mask to form a hole pattern exposing a portion of the source / drain electrode and the active layer; Forming a transparent conductive layer on the entire substrate including the hole pattern; Forming a photoresist film on the transparent conductive layer; Selectively removing the photoresist to expose the upper portion of the transparent conductive layer; And forming a pixel electrode in the hole pattern by removing the exposed conductive layer and removing the remaining photoresist and the photoresist pattern.

In addition, the liquid crystal display device manufacturing method according to the present invention comprises the steps of providing a first substrate and a second substrate; Sequentially depositing a gate metal layer, a gate insulating layer, and an active layer on the first substrate; Patterning the gate metal layer, the gate insulating layer, and the active layer; Stacking a first protective layer and a conductive layer on the entire first substrate; Patterning the conductive layer to form a source / drain electrode; Forming a second protective layer on the entire first substrate; Forming a photoresist pattern on the second protective layer; Etching a second protective layer and a first protective layer using the photoresist pattern as a mask to form a hole pattern exposing a portion of the source / drain electrode and the active layer; Forming a transparent conductive layer on the entire substrate including the hole pattern; Forming a photoresist film on the transparent conductive layer; Selectively removing the photoresist to expose the upper portion of the transparent conductive layer; Forming a pixel electrode in the hole pattern by removing the exposed transparent conductive layer and removing the remaining photoresist and the photoresist pattern; Forming a black matrix and a color filter layer on the second substrate; Bonding the second substrate and the first substrate to each other; And forming a liquid crystal layer between the second substrate and the first substrate.

Hereinafter, a method of manufacturing a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

4A to 4E are coplanar views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

5A to 5N are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention.

Referring to FIG. 5A, a conductive layer 103 such as aluminum, an aluminum alloy, and molybdenum, a gate insulating film 105, and an active layer 107 are sequentially stacked on a transparent substrate 101 such as glass, and then placed thereon. 1 Photosensitive film 109 is applied.

Next, referring to FIG. 5B, the first photoresist layer 109 is diffracted and then developed using a diffraction exposure mask (not shown) to form a first photoresist layer pattern 109a having a different thickness.

Subsequently, the active layer 107, the gate insulating layer 105, and the conductive layer 103 are sequentially etched using the diffractive exposed first photoresist pattern 109a as a mask. At this time, an etching process is also performed on the pad part to define the pad area.

Next, referring to FIG. 5C, an ashing process may be performed to expose both sides of the active layer 107. In this case, the first photoresist pattern 109b of the pad part is also removed by an ashing process to expose the active layer 107.

5D, the active layer 107 is selectively etched using the ashed first photoresist pattern 109a as a mask to form an active layer pattern 107a. At this time, the active layer in the pad portion is also etched.

Next, referring to FIG. 5E, the first photoresist film pattern 109a is removed and the etch stopper 111, the ITO thin film 113, and the conductive layer 115 are sequentially stacked on the entire substrate.

Subsequently, referring to FIG. 5F, after the second photoresist layer 117 is coated on the conductive layer 115, ultraviolet rays are irradiated onto the second photoresist layer 117 using a diffraction exposure mask 119, and then developed. The second photosensitive film pattern 117 is formed.

Next, the conductive layer 113 is selectively etched using the second photoresist pattern 117 as a mask to define a source / drain electrode region.

Next, referring to FIGS. 4A and 5G, the second photoresist pattern 117a is exposed by performing an ashing process to remove the thin portion of the second photoresist pattern 117 so that a portion of the conductive layer 113 is exposed. The exposed portion of the conductive layer 113 and the ITO thin film 113 under the mask are removed to form source / drain electrodes 113a and 113b.

4B and 5H, the protective film 121 is deposited on the entire substrate after removing the second photoresist pattern 117a.

Subsequently, referring to FIG. 5I, after applying the third photoresist film on the passivation layer 121, the third photoresist film is irradiated with ultraviolet rays using a third mask, and then the third photoresist pattern 123 is subjected to a developing process. Form.

4C and 5J, hole patterns 125a and 125b are formed by selectively etching the passivation layer 121 and the etch stopper 111 using the third photoresist pattern 123 as a mask.

4D and 5K, phosphorous plasma treatment is performed on the surface of the active layer pattern 107 exposed under the hole pattern 125a.

Next, referring to FIG. 5L, after depositing a conductive layer 127 made of a transparent material such as ITO or IZO on the entire substrate including the hole patterns 125a and 125b, a fourth photosensitive film 129 is coated thereon. .

Subsequently, referring to FIG. 5M, an ashing process may be performed to remove the fourth photoresist layer 129 by a predetermined thickness so that the upper portion of the conductive layer 127 is exposed.

Next, referring to FIGS. 4E and 5N, the exposed conductive layer 127 is removed and the remaining portion of the fourth photoresist layer 129 is completely removed to remove the remaining portion of the fourth photoresist layer 129. ) 127b. In this case, the pixel electrode 127a portion is connected to the data line 113a.

On the other hand, although not shown in the figure, after depositing the matrix and the color filter layer on the second substrate in sequence to form a common electrode on the color filter layer according to the overcoat layer or alignment mode.

Then, after the second substrate and the first substrate are bonded together, a liquid crystal layer is formed between the second substrate and the first substrate to complete the manufacture of the liquid crystal display device.

As described above, the liquid crystal display device manufacturing method according to the present invention has the following effects.

According to the method of manufacturing a liquid crystal display device according to the present invention, the active layer and the gate are simultaneously formed using diffraction exposure, the source / drain and the finger are simultaneously formed, and finally, a contact hole filling (CHF) process is performed. By using this method, an element in a three mask IPS mode can be manufactured.

In addition, according to the method for manufacturing a liquid crystal display device according to the present invention, since the etch stopper is included, device reliability can be improved.

Therefore, the number of masks can be reduced, and the device reliability can be improved, thereby improving the cost competitiveness of the product.

Claims (14)

Sequentially depositing a gate metal layer, a gate insulating film, and an active layer on the substrate; Patterning the gate metal layer, the gate insulating layer, and the active layer; Depositing a first protective layer and a conductive layer on the entire substrate; Patterning the conductive layer to form a source / drain electrode; Forming a second protective layer on the entire substrate; Forming a photoresist pattern on the second protective layer; Etching a second protective layer and a first protective layer using the photoresist pattern as a mask to form a hole pattern exposing a portion of the source / drain electrode and the active layer; Forming a transparent conductive layer on the entire substrate including the hole pattern; Forming a photoresist film on the transparent conductive layer; Selectively removing the photoresist to expose the upper portion of the transparent conductive layer; And And removing the remaining photoconductive layer and the photoresist pattern to form a pixel electrode in the hole pattern after removing the exposed portion of the transparent conductive layer. The method of claim 1, wherein the first protective layer is an etch stopper and the second protective layer is a nitride. The method of claim 1, wherein the patterning of the gate metal layer, the gate insulating layer, and the active layer is performed by diffraction exposure using a diffraction mask. 4. The method of claim 3, wherein the diffraction exposure is followed by an ashing process. The method of claim 1, further comprising forming an ITO thin film between the first protective layer and the transparent conductive layer. The method of claim 1, wherein the forming of the source / drain electrodes by patterning the conductive layer is performed through a diffraction exposure process using a diffraction exposure mask. The method of claim 1, further comprising: performing a plasma treatment on the surface of the active layer exposed after forming the hole pattern. Providing a first substrate and a second substrate; Sequentially depositing a gate metal layer, a gate insulating layer, and an active layer on the first substrate; Patterning the gate metal layer, the gate insulating layer, and the active layer; Stacking a first protective layer and a conductive layer on the entire first substrate; Patterning the conductive layer to form a source / drain electrode; Forming a second protective layer on the entire first substrate; Forming a photoresist pattern on the second protective layer; Etching a second protective layer and a first protective layer using the photoresist pattern as a mask to form a hole pattern exposing a portion of the source / drain electrode and the active layer; Forming a transparent conductive layer on the entire substrate including the hole pattern; Forming a photoresist film on the transparent conductive layer; Selectively removing the photoresist to expose the upper portion of the transparent conductive layer; Removing the exposed portion of the transparent conductive layer to form a pixel electrode in the hole pattern by removing the remaining photoresist layer and the photoresist pattern; Forming a black matrix and a color filter layer on the second substrate; Bonding the second substrate and the first substrate to each other; And And forming a liquid crystal layer between the second substrate and the first substrate. The method of claim 8, wherein the first protective layer is an etch stopper and the second protective layer is nitride. The method of claim 8, wherein the patterning of the gate metal layer, the gate insulating layer, and the active layer is performed by diffraction exposure using a diffraction mask. The method of claim 10, wherein the diffraction exposure is followed by an ashing process. 10. The method of claim 8, further comprising forming an ITO thin film between the first protective layer and the transparent conductive layer. The method of claim 8, wherein the forming of the source / drain electrodes by patterning the conductive layer is performed through a diffraction exposure process using a diffraction exposure mask. The method of claim 8, further comprising: performing a plasma treatment on the surface of the active layer exposed after forming the hole pattern.

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