KR101021715B1 - Manufacturing method of liquid crystal display device with improved storage doping process - Google Patents

Abstract

The manufacturing method of the liquid crystal display device of the present invention is to dop the storage region without additional photolithography process by applying diffraction exposure to the storage region when the active pattern is formed, to form a polycrystalline silicon thin film divided into an active region and a storage region on the substrate Making; Applying a photoresist to the entire polycrystalline silicon thin film; Irradiating light onto the photoresist through a diffraction mask applying a slit pattern to the storage area; Developing the photoresist irradiated with light to form a first photoresist pattern having a first thickness in the active region, and forming a second photoresist pattern having a second thickness smaller than the first thickness in the storage region. ; Selectively removing the polycrystalline silicon thin film under the mask using the first photoresist pattern and the second photoresist pattern to form an active pattern and a storage pattern of the polycrystalline silicon thin film in the active region and the storage region, respectively; ; Implanting high concentration impurity ions using the first photoresist pattern and the second photoresist pattern as a mask, and doping the storage pattern to form a first storage electrode; Forming a first insulating film on an entire surface of the substrate on which the active pattern and the first storage electrode are formed; Forming a gate electrode and a gate line on the first insulating film; Forming a second insulating film on the substrate on which the gate electrode and the gate line are formed; Forming a data line on the second insulating layer to define a pixel region crossing the source electrode, the drain electrode, and the gate line; Forming a third insulating film on the substrate on which the source electrode, the drain electrode, and the data line are formed; And forming a pixel electrode on the third insulating film.

Polycrystalline Silicon, Diffraction Exposure, Active Pattern, Storage Electrode

Description

TECHNICAL MANUFACTURING METHOD OF ELECTRONIC DISPLAY DEVICE IMPROVING STORAGE DOPING PROCESS

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

2 is a plan view showing a liquid crystal display device according to an embodiment of the present invention.

3A to 3F are exemplary views sequentially illustrating a manufacturing process along the line II-II ′ of the liquid crystal display shown in FIG. 2.

4A to 4D are exemplary views illustrating an active pattern forming and storage doping process according to an exemplary embodiment of the present invention in FIG. 3B.

FIG. 5 is an exemplary view schematically illustrating a diffraction mask in which a slit pattern is applied to a storage area in FIG. 4A. FIG.

6 is a graph showing the characteristics of the thin film transistor manufactured according to the present invention.

DESCRIPTION OF REFERENCE NUMERALS

110: array substrate 124: polycrystalline silicon thin film

124A: active pattern 124B ': first storage electrode

160A: storage line 160B: second storage electrode

170, 170A, 170B: photoresist 180: diffraction mask

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 method for manufacturing a liquid crystal display device having an improved doping process for a storage region composed of a polycrystalline silicon thin film as an active pattern.

In today's information society, display is more important as a visual information transmission medium, and in order to gain a major position in the future, it is necessary to satisfy requirements such as low power consumption, thinness, light weight, and high definition. Liquid Crystal Display (LCD), the flagship product of Flat Panel Display (FPD), has not only the ability to satisfy these conditions of the display but also mass production. It has been established as a core component industry that can gradually replace the existing cathode ray tube (CRT).

In general, a liquid crystal display device displays a desired image by individually supplying data signals according to image information to liquid crystal cells arranged in a matrix form to adjust a light transmittance of the liquid crystal cells. to be.

The active matrix (AM) method, which is a driving method mainly used in the liquid crystal display device, is a method of driving the liquid crystal of the pixel portion by using an amorphous silicon thin film transistor (TFT) as a switching element. .                         

Amorphous silicon thin film transistor technology was established in 1979 by LeComber et al., UK, and commercialized as a 3 "liquid crystal portable television in 1986. Recently, a large area thin film transistor liquid crystal display device of 50" or more has been developed.

However, the amorphous silicon thin film transistor is a peripheral circuit such as a CMOS (Complementary Metal Oxide Semiconductor) that requires high-speed operation of 1 MHz or more with a field effect mobility (<1 cm ² / Vsec) of electrons as carriers. There is a limit to use.

Accordingly, studies are being actively conducted to simultaneously integrate the pixel portion and the driving circuit portion on a glass substrate using a polycrystalline silicon thin film transistor having a greater field effect mobility than the amorphous silicon thin film transistor.

Polycrystalline silicon thin film transistor technology has been applied to small modules such as camcorders since the development of liquid crystal color television in 1982. Since it can realize low photosensitivity and high field effect mobility compared to amorphous silicon thin film transistors, ) And the driving circuit can be manufactured directly on the same substrate.

This integration eliminates the need for an additional process of connecting a driver integrated circuit (driver IC) and a pixel array, which has been conventionally required, thereby greatly improving productivity and reliability. As described above, the excellent characteristics of the polycrystalline silicon thin film As a result, it is possible to fabricate smaller and superior thin film transistors.                         

That is, the increase in mobility may improve the operating frequency of the driving circuit unit that determines the number of driving pixels, thereby facilitating high definition of the display device, and also distorting the transmission signal by reducing the charging time of the signal voltage of the pixel unit. This decreases the image quality can be expected.

Hereinafter, the structure of the liquid crystal display will be described in detail with reference to FIG. 1.

1 is a plan view schematically illustrating a structure of a general liquid crystal display device, and illustrates a driving circuit-integrated liquid crystal display device in which a driving circuit unit is integrated on an array substrate.

As shown in the drawing, the driving circuit-integrated liquid crystal display device 10 is largely a liquid crystal layer formed between the array substrate 20 and the color filter substrate 30 and the array substrate 20 and the color filter substrate 30. Not shown).

The array substrate 20 includes a pixel portion 25, which is an image display area in which unit pixels are arranged in a matrix, and a gate driving circuit portion 24 and a data driving circuit portion 23 positioned outside the pixel portion 25. It consists of a driving circuit part.

In this case, the driving circuit parts 23 and 24 of the array substrate 20 are located in a protruding region compared to the color filter substrate 30, and the data driving circuit part 23 is formed at one long side of the array substrate 20. ) Is positioned, and the gate driving circuit unit 24 is positioned at one end side of the array substrate 20.

In this case, although not shown in the drawing, a plurality of gates and data lines are formed in the pixel portion 25 of the array substrate 20 vertically and horizontally arranged on the substrate 20 to define a plurality of pixel regions. have. In addition, a thin film transistor as a switching element is formed in an intersection region of the gate line and the data line, and a pixel electrode is formed in each pixel region.

On the other hand, in general, the data driver circuit 23 and the gate driver circuit 24 use a thin film transistor having a CMOS structure as an inverter to properly output the input signal.

In this case, since the CMOS circuit-type liquid crystal display device having an integrated driving circuit has to form an N-type thin film transistor and a P-type thin film transistor together on the same substrate, a manufacturing process is more complicated than an amorphous silicon thin film transistor liquid crystal display device forming only a single type of channel. The disadvantage is that it is more complicated.

Meanwhile, the pixel electrode of the array substrate forms a liquid crystal capacitor together with the common electrode of the color filter substrate. The voltage applied to the liquid crystal capacitor is not maintained until the next signal comes in and leaks away. Therefore, in order to maintain the applied voltage, the storage capacitor must be connected to the liquid crystal capacitor.

In this case, in general, a polycrystalline silicon thin film transistor liquid crystal display device uses a polycrystalline silicon thin film, which is an active pattern, as one storage electrode to form a storage capacitor.

In addition, since the storage capacitor is generally formed in the pixel portion, which is an image display area, the storage capacitor is doped to the storage area made of the polycrystalline silicon thin film to secure sufficient capacitance without reducing the aperture ratio. An additional photolithography process (hereinafter, referred to as a photo process) according to the progress of the process causes a problem of increasing the manufacturing cost of the liquid crystal display device.

In addition, a general storage doping process requires an additional photoresist pattern formation and an ashing process, which is a removal process of the photoresist film, in order to doping only the storage region. As a result of the process, an active pattern which is a channel layer of a liquid crystal display device There is a problem that the surface of is damaged and deterioration of device characteristics appears.

An object of the present invention is to provide a method of manufacturing a liquid crystal display device having an improved storage doping process so that the storage region can be doped without an additional photo process.

Another object of the present invention is to provide a method of manufacturing a liquid crystal display device which reduces surface damage of an active pattern, which is a channel layer, during a doping process of a storage area.

Other objects and features of the present invention will be described in the configuration and claims of the invention described below.

In order to achieve the above object, the manufacturing method of the liquid crystal display device of the present invention in the manufacturing method of the liquid crystal display device consisting of an active layer and a gate electrode, a source electrode and a drain electrode, divided into an active region and a storage region on a substrate Forming a polycrystalline silicon thin film to be formed; Applying a photoresist to the entire polycrystalline silicon thin film; Irradiating light onto the photoresist through a diffraction mask applying a slit pattern to the storage area; Developing the photoresist irradiated with light to form a first photoresist pattern having a first thickness in the active region, and forming a second photoresist pattern having a second thickness smaller than the first thickness in the storage region. ; Selectively removing the polycrystalline silicon thin film under the mask using the first photoresist pattern and the second photoresist pattern to form an active pattern and a storage pattern of the polycrystalline silicon thin film in the active region and the storage region, respectively; ; Implanting high concentration impurity ions using the first photoresist pattern and the second photoresist pattern as a mask, and doping the storage pattern to form a first storage electrode; Forming a first insulating film on an entire surface of the substrate on which the active pattern and the first storage electrode are formed; Forming a gate electrode and a gate line on the first insulating film; Forming a second insulating film on the substrate on which the gate electrode and the gate line are formed; Forming a data line on the second insulating layer to define a pixel region crossing the source electrode, the drain electrode, and the gate line; Forming a third insulating film on the substrate on which the source electrode, the drain electrode, and the data line are formed; And forming a pixel electrode on the third insulating film.

In this case, the silicon layer may be formed of polycrystalline silicon.

Meanwhile, the forming of the first photoresist layer pattern and the second photoresist layer pattern may include applying a photoresist layer on the silicon layer, a first transmission region that transmits all light, a second transmission region that transmits only a part of the light, and blocking light. Irradiating light to the photoresist film through a mask provided with a blocking region and developing a photoresist film irradiated with light through the mask to form a photoresist pattern on the silicon layer, the first photoresist having a first thickness in an active region. A pattern may be formed and a second photoresist pattern having a second thickness may be formed in the storage area.

In this case, when the positive type photosensitive film is used, the blocking region of the diffraction mask may be applied to the active area of the silicon layer, and the second transmission area may be applied to the storage area, or when the negative type photosensitive film is used. The first transmission region of the diffraction mask may be applied to the active region of the silicon layer and the second transmission region may be applied to the storage region.                     

The diffraction mask may have a diffraction pattern formed in a second transmissive region that transmits only a portion of light, thereby forming a second photoresist pattern having a second thickness thinner than the first thickness on the storage region.

In addition, the second photoresist layer pattern having the second thickness may be thinly formed to have a thickness of about 100 μs to 1500 μs at which the lower storage pattern is doped through the photoresist pattern during impurity ion implantation.

On the other hand, another method of manufacturing a liquid crystal display device of the present invention is to form a silicon layer divided into an active region and a storage region on a substrate, a diffraction mask is applied to the silicon layer to form an active pattern in the active region and the storage Forming a first storage electrode in an area, depositing a first insulating film over the substrate, forming a gate electrode on the active pattern, and forming a second storage electrode on the first storage electrode; Implanting impurities into a predetermined region of the active pattern using an electrode as a mask to form a source region and a drain region, and forming a second insulating layer having a first contact hole exposing a portion of the source / drain region on the substrate And electrically connecting the source region on the second insulating layer. Forming a drain electrode electrically connected to a source electrode and the drain region, forming a third insulating film having a second contact hole exposing a portion of the drain electrode on the substrate, and forming the drain electrode on the third insulating film And forming a pixel electrode electrically connected to the pixel electrode.

Hereinafter, the manufacturing method of the liquid crystal display device of the present invention configured as described above will be described in detail through a preferred embodiment.

First, FIG. 2 is a plan view showing a liquid crystal display device according to an exemplary embodiment of the present invention, in particular one pixel including a thin film transistor.

That is, in an actual liquid crystal display device, N gate lines and M data lines cross each other, and there are NxM pixels. However, only one pixel is shown in the figure for simplicity.

In this embodiment, the polycrystalline silicon thin film transistor using the polycrystalline silicon thin film as the channel layer is taken as an example. In particular, the N type thin film transistor of the pixel portion is described as an example, but the present invention is not limited thereto.

As shown in the figure, a gate line 116 and a data line 117 are formed on the array substrate 110 of the liquid crystal display device to cross each other to define a pixel area. In this case, the thin film transistor 120 and the pixel electrode connected to the thin film transistor 120 for switching the liquid crystal cell (not shown) by receiving a scan signal and image information from an external driving circuit unit (not shown) in the cross region. 118 is formed.

In this case, the thin film transistor 120 includes a gate electrode 121 connected to the gate line 116, a source electrode 122 connected to the data line 117, and a drain electrode 123 connected to the pixel electrode 118b. have. In addition, the thin film transistor 120 includes a first insulating film (not shown), a second insulating film (not shown), and the gate electrode 121 for insulating the gate electrode 121 and the source / drain electrodes 122 and 123. The active pattern 124A forms a conductive channel between the source electrode 122 and the drain electrode 123 by the gate voltage supplied to the source electrode 122.

On the other hand, a portion of the active pattern 124A made of a polycrystalline silicon thin film extends into the pixel region to form the first storage electrode 124B ', and is arranged in parallel with the gate line 116 at a predetermined interval. A portion of the line 160A extends to a predetermined area in the pixel area to form the second storage electrode 160B.

A part of the first storage electrode 124B ′ and the second storage electrode 160B configured as described above overlap each other to form a first storage capacitor with a first insulating layer interposed therebetween, and the second storage electrode 160B includes a pixel. The second storage capacitor is formed to overlap the electrode 118 with the second insulating layer and the third insulating layer (not shown) interposed therebetween.

At this time, the first storage electrode 124B 'is subjected to storage doping using diffraction exposure (ie, without an additional photolithography process) when the active pattern 124A is formed. Explain in detail.

3A to 3F are exemplary views sequentially illustrating a manufacturing process along the line II-II ′ of the liquid crystal display shown in FIG. 2.

First, as shown in FIG. 3A, a polycrystalline silicon thin film 124 is formed on a substrate 110 made of a transparent insulating material such as glass.

In this case, after forming a buffer layer (not shown) consisting of a silicon oxide film (SiO ₂ ) on the substrate 110, the polycrystalline silicon thin film 124 may be formed on the buffer film. In this case, the buffer layer serves to block impurities such as sodium (natrium) from the glass substrate 110 from penetrating into the upper layer during the process.

Meanwhile, the polycrystalline silicon thin film 124 may be formed by depositing an amorphous silicon thin film on the substrate 110 by using various crystallization methods, which will be described below.

First, an amorphous silicon thin film may be deposited by various methods, and representative methods of depositing the amorphous silicon thin film include a low pressure chemical vapor deposition (LPCVD) method and a plasma enhanced chemical vapor deposition (Plasma Enhanced Chemical Vapor) method. Deposition (PECVD) method.

Subsequently, crystallization is performed after a dehydrogenation process for removing hydrogen atoms present in the amorphous silicon thin film. In this case, general heat treatment methods for crystallizing an amorphous silicon thin film include a solid phase crystallization (SPC) method and an excimer laser annealing (ELA) method.

On the other hand, as the laser crystallization, an excimer laser annealing method using a pulse-type laser is mainly used. In recent years, sequential horizontal crystallization (SLS), which greatly improves crystallization characteristics by growing grain in the horizontal direction, has been performed. The method has been proposed and widely studied.

The sequential horizontal crystallization takes advantage of the fact that grain grows perpendicular to the interface at the interface of liquid and solid phase silicon (Robert S. Sposilli, MA Crowder, and James S. Im). , Mat.Res.Soc.Symp.Proc.Vol.452,956-957,1997), by adjusting the size of the laser energy and the irradiation range of the laser beam appropriately and growing the grain by a predetermined length, the size of the silicon grain It is a crystallization method to improve the.

As illustrated in FIG. 3B, the polycrystalline silicon thin film 124 thus formed forms an active pattern 124A in the active region through a photo process and a storage doping process, and simultaneously forms a first storage electrode 124B 'in the storage region. To form.

In this case, the active pattern 124A and the first storage electrode 124B 'composed of the polycrystalline silicon thin film 124 use diffraction exposure (that is, a diffraction mask or a half-tone mask). By doing so, it can be formed through a single photo process, which will be described in detail below.

First, in the diffraction mask used in this embodiment, the light transmitting region has a slit structure, and the exposure amount irradiated through the slit region is smaller than the exposure amount irradiated on the complete transmission region that transmits all the light. When the same photoresist is applied, the photoresist is exposed to light using a mask in which a slit region and a completely transparent region are partially provided. . That is, in the case of a positive photoresist, the thickness of the photosensitive film irradiated with light through the slit region is formed thicker than that of the completely transmissive region, whereas in the case of a negative photoresist, the thickness of the photoresist remaining in the fully transmissive region is increased. It is formed thick.

Particularly, in the present invention, when the active pattern is formed, a diffraction pattern, that is, a slit region is applied to the storage region to form a storage pattern at the same time, and then the ion is only stored in the storage pattern through the photoresist pattern of the storage region formed relatively thin by applying the diffraction pattern. By injecting the doping into the storage area without an additional photo process, it will be described in more detail with reference to the drawings.

That is, FIGS. 4A to 4D are exemplary views illustrating an active pattern forming and storage doping process according to an exemplary embodiment of the present invention.

First, as shown in FIG. 4A, a photoresist such as photoresist 170 is coated on the entire polycrystalline silicon thin film 124.

Subsequently, light is irradiated to the photoresist 170 through the diffraction mask 180 of the present invention in which a slit region is applied to a storage region (A2 region to be described later).

In this case, the diffraction mask 180 is provided with a first transmission region A1 for transmitting all the light, a second transmission region A2 for transmitting only a part of the light, and a blocking region A3 for blocking all the irradiated light. Only light transmitted through the mask 180 is irradiated to the photoresist 170.

Subsequently, after the photoresist 170 exposed through the diffraction mask 180 is developed, as shown in FIG. 4B, all light is transmitted through the first and second transmission regions A1 and A2. Photoresist patterns 170A and 170B having a predetermined thickness remain in the area irradiated or partially irradiated with light, and photoresist is removed in a region A3 where the light is not irradiated.

In this case, the second photoresist pattern 170B formed through the second transmission region A2 is thinner than the first photoresist pattern 170A formed in the first transmission region A1, which uses a negative photoresist. The present invention is not limited thereto, and a positive photoresist may be used.

Next, using the first photoresist pattern 170A and the second photoresist pattern 170B formed as described above as a mask, the polycrystalline silicon thin film 124 formed thereon is selectively removed to form the active pattern 124A and The storage pattern 124B for the storage capacitor is formed.

At this time, the process conditions of the diffraction exposure are controlled so that the second photoresist pattern 170B has a predetermined thickness (about 100 GPa to 1500 GPa) for implanting ions into the storage region (ie, the storage pattern 124B). Can remain.

Meanwhile, a diffraction mask in which a slit pattern is applied to a storage area using a negative photoresist as in the present embodiment will be described with reference to the drawings.

FIG. 5 is an exemplary view schematically illustrating a diffraction mask in which a slit pattern is applied to a storage area in FIG. 4A.

In this case, the diffraction mask designed to be applied to the negative photoresist is shown as an example, but the present invention is not limited thereto, and when the mask pattern is reversely configured, the diffraction mask may be applied to the positive type photoresist.

As shown in the figure, the diffraction mask 180 is composed of a first transmission region A1 for forming the active pattern 124A and a second transmission region A2 for doping the storage region. In the regions other than the first transmission region A1 and the second transmission region A2, since the polysilicon thin film 124 is to be removed, a blocking region A3 for blocking the irradiated light is formed.

In this case, as described above, the second transmission region A2 is formed with a slit pattern in which slits are continuously arranged vertically to leave the photoresist pattern 170B having a predetermined thickness.

Meanwhile, in the present embodiment, for example, a diffraction mask including a diffraction pattern formed in the longitudinal direction is shown as an example, but the present invention is not limited thereto and may include various types of diffraction patterns.

After the active pattern 124A made of the polycrystalline silicon thin film and the storage pattern 124B are formed in this manner, as shown in FIG. 4C, the photoresist patterns 170A and 170B are used as masks to the storage pattern 124B. High concentration impurity ions are implanted. At this time, the first photoresist pattern 170A has a relatively thick thickness, which serves as a mask to prevent ions from being injected into the active pattern 124A, and the second photoresist pattern 170B to which a slit region is applied. The thickness thereof is controlled to be thin so that the implanted ions penetrate the photoresist pattern 170B and are doped into the storage pattern 124B to form the first storage electrode 124B '.

At this time, depending on the doping equipment and conditions, N-type impurities such as phosphorus (P) or arsenic (As) may be dosed at about 10 ¹³ to 10 ¹⁷ / cm ² with an acceleration energy of 10 k to 1 MeV. Ion may be implanted into the first storage electrode 124B '.

In the present embodiment, the thin film transistor of the pixel portion is described as an example. In general, since the thin film transistor of the pixel portion is formed of N type, N type impurity ions are implanted into the first storage electrode 124B '. However, the present invention is not limited thereto, and a P-type thin film transistor may be formed in the pixel portion, and a CMOS structure element may be formed in the driving circuit portion. P type impurity ions such as these may be implanted and doped.

Subsequently, as shown in FIG. 4D, a stripper is applied to remove photoresist patterns 170A and 170B remaining on the active pattern 124A and the first storage electrode 124B '.

After the active pattern 124A and the first storage electrode 124B 'are formed through one photo process as described above, as shown in FIG. 3C, the active pattern 124A and the first storage electrode 124B' are formed. The first insulating film 115A is deposited on the entire upper surface.

Thereafter, a conductive metal material made of molybdenum (Mo) or aluminum (Al) alloy is deposited on the first insulating film 115A, and then patterned the conductive metal material through a photo process to form an active region. The gate electrode 121 is formed on the active pattern 124A, and the second storage electrode 160B for the storage capacitor is formed on the first storage electrode 124B 'of the storage area.

In this case, a portion of the first storage electrode 124B ′ and the second storage electrode 160B overlapping the first insulating capacitor 115A may form a first storage capacitor.

Meanwhile, after the gate electrode 121 is formed, impurity ions are implanted into a predetermined region of the active pattern 124A to form a source region 124A 'and a drain region 124' ', which are ohmic contact layers. do. In this case, the gate electrode 121 serves as an ion stopper to prevent the dopant from penetrating into the channel region of the active pattern 124A.

On the other hand, the electrical characteristics of the active pattern 124A is changed according to the type of dopant to be implanted, and as described above, if the dopant to be implanted corresponds to a Group 3 element such as boron, a P-type thin film transistor such as phosphorus or arsenic If it is a Group 5 element, it operates as an N-type thin film transistor.

Thereafter, a process of activating the dopant implanted after the ion implantation process may be performed.

Next, as illustrated in FIG. 3D, a second insulating film 115B is deposited on the entire surface of the substrate 110 on which the gate electrode 121 and the second storage electrode 160B are formed, and then the photolithography process is performed. A portion of the first insulating layer 115A and the second insulating layer 115B is removed to form a first contact hole 140A exposing portions of the source / drain regions 124A 'and 124A' '.

Thereafter, as shown in FIG. 3E, a conductive metal material is deposited on the entire surface of the substrate 110, and then a source electrode connected to the source region 124A ′ through the first contact hole 140A using a photo process. 122 and a drain electrode 123 connected to the drain region 124A '' are formed.

Finally, as shown in FIG. 3F, an organic material such as benzocyclobutene (BCB) or photo acryl is formed on the entire surface of the substrate 110 including the source electrode 122 and the drain electrode 123. By applying the film, the third insulating film 115C is formed.

In this case, the third insulating film 115C may be formed of an inorganic insulating film such as a silicon oxide film or a silicon nitride film (SiN _x ), or may be formed of a double layer of an organic insulating film and an inorganic insulating film.

The third insulating layer 115C is patterned to form a second contact hole 140B exposing a part of the drain electrode 123.

Thereafter, a transparent conductive material having excellent transmittance, such as indium tin oxide (ITO) or indium zinc oxide (IZO), is deposited on the entire surface of the substrate 110 and then using a photo process. The pixel electrode 118 is formed in the entire image display area.                     

In this case, the second storage electrode 160B overlapping the pixel electrode 118 forms a second storage capacitor with the second insulating film 115B and the third insulating film 115C interposed therebetween to form the second storage capacitor 160 and the first storage capacitor described above. Together, they have sufficient capacitance, resulting in signal retention, flicker and afterimage reduction.

On the other hand, when the active pattern 124A and the first storage electrode 124B 'are formed at the same time in one photo process, the additional mask process for doping the existing storage area can be omitted. The manufacturing process and manufacturing time of the display element is reduced.

In addition, as described above, two conventional photoresist film thinning processes are reduced to one time, thereby reducing damage to the surface of the active pattern including the channel layer. As a result, deterioration of device characteristics is reduced. The detailed description is as follows.

FIG. 6 is a graph illustrating characteristics of a thin film transistor manufactured according to the present invention, and illustrates transfer characteristics of the thin film transistor before and after improving the storage doping process.

In this case, the graph shown as a rectangular figure represents the electrical characteristics of the thin film transistor fabricated by performing a photo process for a separate storage doping before improving the storage doping process, the graph shown as a circle is a storage doping in accordance with the present invention It shows the electrical characteristics of the thin film transistor fabricated without the additional photo process.                     

Further, the graphs shown by the unfilled rectangles and circles show the characteristics of the thin film transistors at the drain voltage of 0.1V, and the graphs shown by the filled rectangles and circles show the characteristics of the thin film transistors at the drain voltage of 10V.

As shown in the figure, the on-current at drain voltages of 0.1V and 10V is lower than after the improvement of the storage doping process, and leakage current (i.e., off current) improves the storage doping process. It turns out that the case before the following is high compared with the case where it improved.

That is, in the past, an additional photo process has to be performed for the doping of the storage area. At this time, the surface of the channel layer may be damaged when the photoresist is ashed according to the photo process. As a result, deterioration of device characteristics may occur. The possibilities are great. However, as described above, in the present invention, when the active pattern is formed, the storage region may be doped without applying an additional photo process (that is, a photoresist layer) by applying a diffraction pattern, thereby deteriorating device characteristics. .

In addition, it can be seen that due to the characteristics of the on current and the off current as described above, the threshold voltage is also improved in the case of the present invention in which storage doping is performed without further photo process.

Many details are set forth in the foregoing description but should be construed as illustrative of preferred embodiments rather than to limit the scope of the invention. Therefore, the invention should not be defined by the described embodiments, but should be defined by the claims and their equivalents.

As described above, in the method of manufacturing the liquid crystal display device according to the present invention, when the active pattern is formed, the storage area is applied to the diffraction pattern so that an additional photo process for storage doping is unnecessary, thereby reducing the overall manufacturing process and manufacturing time. To provide.

In addition, the present invention enables the storage region to be doped without the need for an additional photoresist film deposition process for the storage doping process, thereby providing an effect of significantly reducing deterioration of device characteristics.

Claims (11)

Forming a polycrystalline silicon thin film divided into an active region and a storage region on the substrate; Applying a photoresist to the entire polycrystalline silicon thin film; Irradiating light onto the photoresist through a diffraction mask applying a slit pattern to the storage area; Developing the photoresist irradiated with light to form a first photoresist pattern having a first thickness in the active region, and forming a second photoresist pattern having a second thickness smaller than the first thickness in the storage region. ; Selectively removing the polycrystalline silicon thin film under the mask using the first photoresist pattern and the second photoresist pattern to form an active pattern and a storage pattern of the polycrystalline silicon thin film in the active region and the storage region, respectively; ; Implanting high concentration impurity ions using the first photoresist pattern and the second photoresist pattern as a mask, and doping the storage pattern to form a first storage electrode; Forming a first insulating film on an entire surface of the substrate on which the active pattern and the first storage electrode are formed; Forming a gate electrode and a gate line on the first insulating film; Forming a second insulating film on the substrate on which the gate electrode and the gate line are formed; Forming a data line on the second insulating layer to define a pixel region crossing the source electrode, the drain electrode, and the gate line; Forming a third insulating film on the substrate on which the source electrode, the drain electrode, and the data line are formed; And And forming a pixel electrode on the third insulating film. The liquid crystal display of claim 1, wherein the diffraction mask includes a first transmission region for transmitting all of the light, a second transmission region for partially transmitting the light, and a blocking region for blocking all the irradiated light. Manufacturing method. The method of claim 2, wherein the second transmission region is formed with a slit pattern in which slits are continuously arranged vertically to leave a second photoresist pattern having a second thickness. . The method of claim 2, wherein in the case of using a positive type photoresist, the blocking region of the diffraction mask is applied to the active region of the polycrystalline silicon thin film and the second transmission region is applied to the storage region of the polycrystalline silicon thin film. A method of manufacturing a liquid crystal display device, characterized in that. 3. The method of claim 2, wherein in the case of using a negative type photoresist, the first transmission region of the diffraction mask is applied to the active region of the polycrystalline silicon thin film and the second transmission region is applied to the storage region of the polycrystalline silicon thin film. Method of manufacturing a liquid crystal display device, characterized in that applied. The second photoresist pattern of claim 1, wherein the first photoresist pattern is relatively thicker than the second photoresist pattern to prevent impurity ions from being injected into the active pattern, and to which the slit pattern is applied. Wherein the impurity ions are permeated to dope the storage pattern. The method of claim 6, wherein the second photoresist pattern having the second thickness is formed to have a thickness of about 100 μs to about 1500 μs at which the impurity ions are transmitted through the second photoresist pattern and the lower storage pattern is doped. A method of manufacturing a liquid crystal display device, characterized in that. The method of claim 1, wherein the impurity ion is a Group 5 element such as phosphorus. The method of claim 1, wherein the impurity ions are a Group 3 element such as boron. The second storage device of claim 1, further comprising a second storage capacitor formed on the first insulating layer, the second insulating capacitor being arranged in parallel with the gate line and partially extending in the pixel region to overlap the first storage electrode. Forming a storage electrode further comprising the step of manufacturing a liquid crystal display device. delete

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