KR101015335B1 - Fabrication method of liquid crystal display device using 2 mask - Google Patents

Abstract

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a process of manufacturing a liquid crystal display device by applying two masks. Forming a transparent electrode, a first conductive layer, and a first semiconductor layer on the substrate by applying a first diffraction mask on the substrate; forming a first photoresist pattern on the high concentration impurity layer; Forming a source electrode, a drain electrode, and a pixel electrode by applying a photoresist pattern; forming a second semiconductor layer, an insulating layer, and a second conductive layer on the source electrode, the drain electrode, and the pixel electrode; Forming a second photoresist pattern on the layer, and forming an active layer and a gate electrode by applying the photoresist pattern, and manufacturing a liquid crystal display using a low mask to improve production, shorten a process, and the like. The effect can be obtained.

2 masks, slit exposure, amorphous silicon layer

Description

2. Manufacturing method of liquid crystal display device using mask {FABRICATION METHOD OF LIQUID CRYSTAL DISPLAY DEVICE USING 2 MASK}

1 is a plan view showing the structure of a conventional liquid crystal display device.

2 is a cross-sectional view taken along line II ′ of FIG. 1.

3A to 3I are views showing a conventional method for manufacturing a liquid crystal display device.

4 is a plan view showing a part of unit pixels of a liquid crystal display of the present invention;

5A to 5G are flowcharts illustrating a process of manufacturing a liquid crystal display device according to an embodiment of the present invention.

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

501: substrate 502 transparent electrode

503, 507: conductive layer 504, 505: semiconductor layer

503b: source electrode 503a: drain electrode

510a, 510b: mask 520,530: mask

507a: gate electrode

The present invention relates to a liquid crystal display device, and more particularly, to a method of manufacturing a liquid crystal display device using two masks.

In display devices, particularly flat panel displays such as liquid crystal display devices, each pixel includes an active device such as a thin film transistor to drive the display device. The driving method is often called 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 figure, each pixel of a thin film transistor liquid crystal display device in which N × M pixels are arranged horizontally and horizontally includes a gate line 3 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 intersection region of 5). The thin film transistor includes a gate electrode 11 connected to the gate line 3, a semiconductor layer 12 formed on the gate electrode 11 and activated when a scan signal is applied to the gate electrode 11, and the semiconductor. It consists of a source electrode 13 and a drain electrode 14 formed on the layer 12. As the semiconductor layer 12 is activated by being connected to the source electrode 13 and the drain electrode 14 in the display area of the pixel, an image signal is applied through the source electrode 13 and the drain electrode 14 so that the liquid crystal is applied. A pixel electrode 16 for operating (not shown) is formed.

FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1, and the structure of the liquid crystal display device will be described in more detail with reference to the drawing.

As shown in the figure, the thin film transistor 10 is formed on the first substrate 20 made of a transparent material such as glass. The thin film transistor 10 includes a gate electrode 11 formed on the first substrate 20, a gate insulating layer 22 stacked over the entire first substrate 20 on which the gate electrode 11 is formed, and A semiconductor layer 12 formed on the insulating layer 22, a source electrode 13 and a drain electrode 14 formed on the semiconductor layer 12, and a protective layer stacked over the entire first substrate 120 ( passivation layer; The passivation layer 24 includes a pixel electrode 16 connected to the drain electrode 14 of the thin film transistor 10 through a contact hole 26 formed in the passivation layer 24.

On the other hand, the second substrate 30 made of a transparent material such as glass is formed in the region where the thin film transistor 10 is formed or in an image non-display area such as between the pixel and the pixel to prevent light from passing through the image non-display area. A black matrix 32 and a color filter layer 34 formed of red, green, and blue to form actual colors are formed, and the first substrate 20 and the second substrate 30 are bonded to each other, and the liquid crystal is interposed therebetween. The layer 40 is formed to complete the liquid crystal display device.

The liquid crystal display device is mainly manufactured by a complicated process such as a photolithography process using a mask, and a method of manufacturing the liquid crystal display device is illustrated in FIG. 3.

First, as shown in FIG. 3A, a metal layer 11a is formed by stacking metal on the first substrate 20, and then a photosensitive photoresist layer 60a is formed thereon. Although not shown in the figure, the laminated photoresist layer 60a is baked at a constant temperature. Subsequently, when the mask 70 is positioned on the photoresist layer 60a and irradiated with light such as ultraviolet light and a developer is applied, the photoresist pattern is formed on the metal layer 11a as shown in FIG. 3B. 60 is formed. In this case, the photoresist is a negative photoresist, and the region not irradiated with ultraviolet rays is removed by the developer.

Subsequently, when an etchant is applied to the metal layer 11a while a part of the metal layer 11a is blocked by the photoresist pattern 60, as shown in FIG. 3C, the gate electrode 11 is formed on the first substrate 20. ) Is formed.

Thereafter, as shown in FIG. 3D, the gate insulating layer 22 is formed over the entire first substrate 20, and then the semiconductor layer 12a is formed thereon. A photoresist layer 62 is formed on the semiconductor layer 12a by stacking a photoresist layer on the stacked semiconductor layer 12a, placing a mask, irradiating ultraviolet rays, and applying a developer. When the etching solution is applied while the part of the semiconductor layer 12a is blocked by the photoresist pattern 62, the semiconductor layer 12 is formed on the gate electrode 11, as shown in FIG. 3E.

Subsequently, as shown in FIG. 3F, a metal is stacked over the entire first substrate 20, and then a photoresist pattern is formed using a mask, and the metal is etched using the photoresist pattern to form the semiconductor layer 12. The thin film transistor is completed on the first substrate 20 by forming the source electrode 13 and the drain electrode 14.

Meanwhile, as shown in FIG. 3G, a protective layer 24 is stacked on the first substrate 20 on which the source electrode 13 and the drain electrode 14 are formed to protect the thin film transistor. Thereafter, the protective layer 24 on the drain electrode 14 of the thin film transistor is etched by the above photo process (ie, a photoresist process using a mask) to form a contact hole 26.

Subsequently, as shown in FIG. 3H, a transparent material such as indium tin oxide (ITO) is stacked on the protective layer 24 and then etched by a photo process to form the pixel electrode 16 on the protective layer 24. Form. In this case, the pixel electrode 16 is electrically connected to the drain electrode 14 of the thin film transistor through the contact hole 26 formed in the protective layer 24.

3I, after forming the black matrix 32 and the color filter layer 34 on the second substrate 30, the first substrate 20 and the second substrate 30 are bonded to each other. After that, the liquid crystal layer 40 is formed therebetween to complete the liquid crystal display device.

As described above, in the conventional method for manufacturing a liquid crystal display device, an electrode or a semiconductor layer is formed by a photo process using a photoresist. However, the photo process using the photoresist has the following disadvantages.

First, the manufacturing process becomes complicated. As described above, the photoresist pattern is formed through photoresist coating, baking, exposure and development. Therefore, the manufacturing process is complicated. Furthermore, the process becomes more complicated because baking the photoresist requires a soft baking process performed at a specific temperature and a hard baking process performed at a temperature higher than the soft baking temperature.

Second, manufacturing costs will rise. In general, in an electric device process including a plurality of patterns (or electrodes), such as a transistor, a photoresist process is performed to form one pattern, and another photoresist process must be performed to form another pattern. This means that an expensive photoresist process line is required between each pattern line in the manufacturing line. Therefore, the manufacturing cost increases during the manufacture of the electric device. For example, in manufacturing a thin film transistor of a liquid crystal display device, the cost of the photoresist process accounts for about 40 to 45% of the total cost.

Third, it pollutes the environment. In general, since the application of the photoresist is performed by spin coating, many photoresists are discarded during application. The disposal of the photoresist not only increases the manufacturing cost of the electric device but also causes the environment to be contaminated by the discarded photoresist.

Fourth, the failure of electrical appliances. In general, the photoresist layer is applied by spin coating, and it is difficult to control the thickness of the photoresist layer by the spin coating. Therefore, the photoresist layer is formed unevenly, so that non-stripped photoresist remains on the surface of the pattern when the pattern is formed, which causes a defect in the electric device.

Currently, a method for overcoming the above drawbacks by reducing the number of photo processes has been studied. However, there are limitations to substantially reducing the photo process, and in the case of decreasing process, the characteristics of the fabricated liquid crystal display device There was a problem of deterioration.

An object of the present invention is to reduce the mask process, which is the biggest problem of defects and increase in manufacturing cost in the manufacturing process of the conventional liquid crystal display device manufacturing a liquid crystal display device by applying a plurality of masks as described above. do. In particular, an object of the present invention is to manufacture a liquid crystal display device even when only two masks are applied.

In order to achieve the above object, the liquid crystal display device manufacturing process of the present invention comprises the steps of: continuously forming a pixel electrode, a first conductive layer, a first semiconductor layer on a substrate; Forming a first photoresist pattern on the high concentration impurity layer; Forming a source electrode, a drain electrode, and a pixel electrode by applying the first photoresist film; Forming a second semiconductor layer, an insulating layer, and a second conductive layer on the source electrode, the drain electrode, and the pixel electrode; Forming a second photosensitive film pattern on the second conductive layer; And forming an active layer and a gate electrode by applying the photoresist pattern.

In particular, the present invention is characterized by applying only two masks to form a thin film transistor.

Hereinafter, the structure of the liquid crystal display device of the present invention will be described with reference to FIG. 4 and the manufacturing process of the thin film transistor of the present invention will be described with reference to FIGS. 5A to 5G.

As shown in FIG. 4, the pixel unit 502 includes a pixel electrode 502 in a unit pixel area defined by a gate line 550 and a data line 560 perpendicular to the gate line. A thin film transistor is formed at the intersection of the gate line 550 and the data line 560.

The thin film transistor includes an active layer 505a formed of a semiconductor layer, and one side of the active layer 505a is connected to the source electrode 503b and the other side of the active layer is connected to the pixel electrode 502. .

In particular, the pixel electrode 502 is formed in direct contact with the substrate and is connected to the active layer 505a through a conductive layer (not shown) between the active layer 505a.

In addition, the source electrode 503b is formed under the active layer 505a and is connected to the active layer 505a via a conductive layer (not shown).

On the other hand, a gate electrode 507a is formed on the active layer 505a to apply a scan signal from the gate line to the thin film transistor.

Hereinafter, a process of forming the liquid crystal display of the present invention having the above structure by applying two masks will be described.

5A to 5G illustrate a process of manufacturing a liquid crystal display device according to the present invention with a cross sectional view of the line K-K ′ of FIG. 4 as a cutting line.

First, as shown in FIG. 5A, the transparent electrode 502, the first conductive layer, and the first semiconductor layer are successively formed on the transparent substrate 501.

The transparent electrode 502 is an electrode for forming a pixel electrode, and may be made of indium tin oxide (ITO), indium zinc oxide (IZO), or the like which is electrically conductive, and has a predetermined thickness on a substrate by a sputtering method. It can be formed as.

In addition, the first conductive layer 503 may be a metal layer or a silicon layer metalized by implanting a high concentration of impurities. The metal layer may be copper (Cu), aluminum (Al), molybdenum (Mo), or chromium (Cr). Metal films, such as these, can be used.

In addition, the first semiconductor layer 504 formed on the first conductive layer 503 is a semiconductor layer containing a high concentration of impurities such as n + type and is formed to improve ohmic contact characteristics of the source electrode and the active layer.

The high concentration impurity layer may be formed by a method such as PECVD in an atmosphere in which impurity ions are mixed.

Next, a photosensitive film is coated on the entire substrate on which the common electrode, the first conductive layer and the first semiconductor layer are formed.

The first mask 510a is applied to the photosensitive film, and an exposure process and a development process are performed to form a constant mask pattern.

The first mask 510a may be a slit mask, and the photoresist may be divided into a non-exposed portion, a slit exposed portion, and a fully exposed portion by a mask. As shown in FIG. 5B, the source and drain regions may be unexposed. The pixel region is slit exposed and the channel region is fully exposed.

As a result of the exposure and development process, as shown in Fig. 5B, the channel region is opened and the remaining region is covered by the mask.

The first semiconductor layer 504, the first conductive layer 503, and the transparent electrode 502 formed in the channel region are removed by applying the first photoresist pattern 520 as a mask.

The first semiconductor layer 504 may be effectively removed by a dry etching method, and the first conductive layer 503 and the transparent electrode 502 formed of a metal layer or the like may be removed by wet etching. However, dry etching and wet etching may be selected according to the type and material of the thin film to be formed.

After applying the first photoresist pattern 520 as a mask and opening the channel region, the first photoresist pattern 520 is ashed.

The ashing process is a process of oxidizing and removing a portion of the first photoresist by spraying a plasma gas containing an oxidative active species to the first photoresist. As a result of the ashing, the first photoresist pattern is reduced in volume and part of the photoresist. Is removed. The first photoresist pattern 520 is formed by slit exposure, and the photoresist on the source region and the drain region is thicker than the other regions. Therefore, as a result of the ashing, even if some of the photoresist film is oxidized and removed, the photoresist film on the relatively thick source and drain regions remains as a pattern, and the photoresist pattern on the pixel region is removed to expose the transparent electrode of the pixel electrode formation portion.

The result can be confirmed through FIG. 5C.

Next, as shown in FIG. 5C, the first semiconductor layer 504 and the first conductive layer 503 formed on the pixel area are etched and removed by applying the ashed photoresist pattern 520a as a mask. Expose 502.

Thereafter, the photoresist pattern remaining on the source and drain regions is removed through a strip process, and the conductive layers of the source and drain regions are exposed.

Next, as shown in FIG. 5E, the second semiconductor layer 505, the insulating layer 506, and the second conductive layer 507 are successively formed in the resultant product.

The second semiconductor layer 505 may be formed of an amorphous silicon layer and is patterned, and then deposited by PECVD to form an active layer. In particular, the second semiconductor layer 505 is deposited in a channel region to act as a channel.

On the other hand, the insulating layer 506 formed on the second semiconductor layer 505 is an insulating layer for interlayer insulation, consisting of a silicon oxide film (SiO 2) or a silicon nitride film (SiNx) or a stack of silicon oxide films or silicon nitride films. Can be.

Next, the second conductive layer 507 formed on the insulating layer 506 may use a conductive material such as metal, and after patterning, constitutes a gate line and a gate electrode.

Next, a photosensitive film is coated on the second conductive layer 507 by a spin coating method or the like, and then a second slit mask 510b is applied to perform an exposure process.

As a result of exposing with the second slit mask, the photoresist coated on the substrate has a channel region unexposed, a source and a drain region slit exposed, and the remaining region is completely exposed. When the exposed photoresist is patterned by applying a developer, a second photoresist pattern 530 is formed in a stepped shape on the source and drain regions and the channel region, as shown in FIG. 5E.

By applying the second photoresist layer 530 as a mask, the second conductive layer 507, the insulating layer 506, and the second semiconductor layer 505 in the region where the photoresist layer is not formed are etched and removed, respectively. When the second conductive layer 507 is made of metal, the second conductive layer 507 may be efficiently etched by wet etching, and the insulating layer 506 and the second semiconductor layer 505 may be effectively removed by dry etching.

In particular, the first semiconductor layer 503a formed on the source and drain regions is further etched using the second photoresist pattern to expose the first conductive layer 503a. Although not shown in the drawing, the data pad part may be exposed.

As a result, as shown in FIG. 5F, an active layer 505a is formed, and a conductive layer pattern including an insulating layer 506 is formed on the active layer 505a. A second photoresist pattern is formed on the conductive layer pattern, and the photoresist pattern is ashed in a plasma gas atmosphere containing oxygen active species to remove a portion of the second photoresist pattern 503. As a result, the second photoresist layer pattern 530 remains only on the channel region while exposing the second conductive layer 507 on the source and drain regions.

After the ashing, the second conductive layer 507 is etched by using the photoresist pattern 507a formed on the channel region as a mask to form the gate electrode 507a. Although not shown in the drawing, the gate electrode is connected to the gate line and supplies a gaze signal to the thin film transistor through the gate line.

As a result, a pixel electrode and a source / drain electrode are formed through the first mask, and an active layer and a gate electrode are formed through the second mask to form a thin film transistor as a driving element of the liquid crystal display device through only two mask processes. Can be.

As described above, by manufacturing the liquid crystal display device according to the present invention, the process of manufacturing the liquid crystal display device can be drastically reduced, thereby increasing the production amount. In addition, it is possible to fundamentally block the occurrence of defects by reducing the mask process that causes a lot of defects, it is possible to reduce the use of the chemical solution used for the mask process it is possible to implement an environmentally friendly liquid crystal display device manufacturing process.

Claims (10)

Providing a substrate on which a source region, a channel region, a drain region and a pixel region are defined; Continuously forming a transparent electrode, a first conductive layer, and a first semiconductor layer on the substrate; Forming a first photoresist film on the first semiconductor layer; Patterning the first photoresist layer using a first slit mask to form a first photoresist pattern on the first semiconductor layer corresponding to the source region, the drain region, and the pixel region; Sequentially patterning the first semiconductor layer, the first conductive layer, and the transparent electrode using the first photoresist pattern as a mask to form a source electrode, a drain electrode, and a pixel electrode; Removing the first photoresist pattern; Continuously forming a second semiconductor layer, an insulating layer, and a second conductive layer on the front surface of the substrate including the source electrode, the drain electrode, and the pixel electrode; Forming a second photosensitive film on the second conductive layer; Patterning the second photoresist layer using a second slit mask to form a second photoresist pattern on the second conductive layer corresponding to the source region, the channel region, and the drain region; Sequentially patterning the second conductive layer, the insulating layer, and the second semiconductor layer using the second photoresist pattern as a mask to form a second conductive layer pattern, a gate insulating layer, and an active layer; And And forming a gate electrode on the gate insulating layer corresponding to the channel region by patterning the second conductive layer pattern. The method of claim 1, wherein the forming of the first photoresist pattern Wherein the source and drain regions are unexposed, the channel region is completely exposed, and the pixel region is slit exposed by applying the first slit mask. The method of claim 1, wherein forming the source electrode, the drain electrode, and the pixel electrode by applying the first photoresist pattern Removing the first semiconductor layer, the first conductive layer, and the transparent electrode on the channel region by applying the first photoresist pattern; Exposing the first photoresist pattern so that only the first semiconductor layer corresponding to the source and drain regions remains, thereby exposing a first semiconductor layer corresponding to the pixel region; And forming the pixel electrode by removing the exposed first semiconductor layer and the first conductive layer under the first photosensitive film pattern as a mask. delete The method of claim 1, wherein the first semiconductor layer is implanted with high concentration impurity ions. The method of claim 1, wherein the second semiconductor layer is amorphous silicon. The method of claim 1, wherein the forming of the second photoresist layer pattern Applying a second slit mask to expose the channel region and slit the source and drain regions; And developing the photosensitive film.  The method of claim 1, wherein forming the gate electrode Ashing the second photoresist pattern so that only the second conductive layer corresponding to the channel region remains; And patterning the second conductive layer by applying the ashed second photoresist pattern as a mask. The method of claim 1, wherein forming the active layer And etching the second conductive layer, the insulating layer, and the second semiconductor layer by applying the second photoresist pattern as a mask. delete

Images