KR19990080208A - Manufacturing method of liquid crystal display device - Google Patents

Abstract

The present invention provides a method of manufacturing a liquid crystal display device in which the aperture ratio is greatly improved by increasing the light transmittance in the active layer of the storage capacitor.

The present invention provides a method of forming a polycrystalline silicon layer on a transparent insulating substrate and patterning the island into islands, implanting impurities into the polycrystalline silicon layer to define a lower electrode of a storage capacitance, and forming the polycrystalline silicon layer. Forming a first insulating layer on the entire surface of the substrate by thermal oxidation, forming a gate electrode on the first insulating layer, and ion-implanting the gate electrode with a mask to form source and drain regions; Forming a transparent metal material layer on an entire surface of the first insulating layer including a gate electrode and then patterning the upper electrode of the storage capacitor to form an upper electrode of the storage capacitor forming region, and a front surface of the first insulating layer including the upper electrode and the gate electrode Forming a first interlayer insulating film, and forming one of the first interlayer insulating film and the first insulating layer Forming a data line on the first interlayer insulating layer to expose the source region by removing the powder, and forming a data line on the first interlayer insulating layer, and forming a second interlayer insulating layer on the first interlayer insulating layer including the data line. After forming, a portion of the second interlayer insulating film, the first interlayer insulating film and the first insulating film are sequentially removed to expose the drain region and to form a pixel electrode in the pixel region on the second interlayer insulating film so as to be connected to the drain region. It characterized in that it comprises a step.

Description

Manufacturing method of liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device. In particular, the ion implantation process for forming the lower electrode of the storage capacitor is performed by increasing the ion concentration of the active layer on which the lower electrode is to be formed before forming the gate insulating layer, thereby increasing the lower portion by The present invention relates to a method of manufacturing a liquid crystal display device in which the thickness of an active layer on which an electrode is to be formed is made thin so that the light transmittance is further increased to greatly improve the aperture ratio.

In order to reduce the power consumption of the liquid crystal display device, the aperture ratio must be increased, and methods of increasing the aperture ratio include a method of reducing the area occupied by the storage capacitor or the area occupied by the thin film transistor while having the same storage capacity value. .

FIG. 1A is a plan view illustrating a liquid crystal display according to the related art, and FIG. 1B is an equivalent circuit diagram of FIG. 1A. As shown in FIGS. 1A and 1B, the liquid crystal display is a matrix electrode 10 having a matrix form. The gate electrode 5 line formed in one direction with the gap between and the data electrode 8 formed in a direction perpendicular to the gate electrode 5 line and contacting the semiconductor layer 2 to be used as a source electrode of the thin film transistor 8. ) And a common electrode (6) line formed in the same direction as the gate electrode (5) line and formed over the pixel region.

Referring to the conventional manufacturing method of the liquid crystal display device configured as described above is as follows.

First, as shown in FIG. 1A, a polycrystalline silicon layer 2 to be used as an active layer is formed on a transparent insulating substrate 1 such as glass or quartz, and then patterned into islands.

Subsequently, as illustrated in FIG. 1B, the gate insulating layer 3 is deposited by thermal oxidation on the entire surface of the transparent insulating substrate 1 including the island-like polycrystalline silicon layer 2.

Subsequently, as shown in FIG. 1C, a photosensitive film is coated and patterned to form a lower electrode of the storage capacitor, and the polycrystalline silicon layer 2 is made of impurities such as boron or phosphorus using the patterned photosensitive film 4 as a mask. Ion implantation defines the bottom electrode region of the storage capacitor.

After removing the photoresist film 4 as shown in FIG. 1 (d), polycrystalline silicon and silicide materials are sequentially deposited and patterned on the entire surface of the substrate to form the gate electrode 5 and the common electrode 6 used as the upper electrode of the storage capacitor. To form. At this time, the wet etchant used should use a solution having a very good selectivity between the gate electrode and the thermal oxide film. In the electrodes 5 and 6, 5a and 6a represent polycrystalline silicide material layers, and 5b and 6b represent polycrystalline silicon material layers. Subsequently, ions such as boron or phosphorus are implanted to form the source / drain electrodes using the gate electrode 5 as a mask.

Then, as illustrated in FIG. 1E, a first interlayer insulating film 7 is deposited on the entire surface of the substrate, and a heat treatment process is performed at a high temperature to activate implanted ions for forming a source / drain electrode.

Subsequently, as shown in FIG. 1F, a portion of the first interlayer insulating layer 7 and the gate insulating layer 3 positioned on the source region of the liquid crystal display device is removed to expose the source region, and then a metal layer is deposited and patterned. Line 8 is formed.

Then, as shown in Fig. 1 (g), a second interlayer insulating film 9 is deposited to insulate the data line 8.

Subsequently, as shown in FIG. 1H, portions of the first and second interlayer insulating films 7 and 9 and the gate insulating film 3 are removed to form a lower electrode contact hole and to deposit ITO, which is a transparent electrode material. Subsequently, the bottom plate is completed by patterning the pixel electrode 10.

In the above-described manufacturing method of the liquid crystal display, since the common electrode 6 used as the gate electrode 5 and the upper electrode of the storage capacitor is formed using polycrystalline silicon and silicide, the common electrode 6 is opaque. It is.

Accordingly, there is a problem that the aperture ratio of the pixel electrode 10 does not transmit as much as the portion corresponding to the common electrode 6, so that the aperture ratio is low.

In order to solve such a problem, the applicant of the present invention removes the opaque silicide material layer 6b, which is the upper layer of the common electrode 6, and invents the common electrode 6 to secure transparency. There was a patent application (Application No. 97-35159) on the date.

However, in the invention of the above-mentioned application, when the visible light passes through the polycrystalline silicon layer 2, a substantial portion is absorbed by the polycrystalline silicon layer 2, so that the transmittance is reduced to 50%. Therefore, the aperture ratio cannot be greatly improved. In order to solve this problem, the thickness of the polycrystalline silicon layer should be lowered to increase the light transmittance, but when the thickness of the active layer polycrystalline silicon layer 2 becomes thinner, the operating current (On-Current) of the transistor is reduced, and the metal contact hole or the ITO contact hole is reduced. When forming, the active layer is unbearable, so it can not be lowered below 500Å, which has a limit in increasing the opening ratio.

Accordingly, the present invention has been made in view of the above-described problems of the related art, and is to provide a method of manufacturing a liquid crystal display device in which the aperture ratio is greatly improved by increasing the light transmittance in the active layer of the storage capacitor.

1 (a) and (b) show a plan view of a conventional liquid crystal display and an equivalent circuit diagram thereof;

2 (a)-(h) are cross-sectional views of respective conventional manufacturing processes of a liquid crystal display device;

3A to 3I are cross-sectional views of respective liquid crystal display devices in the manufacturing process of the present invention.

Explanation of symbols for main parts of the drawings

1, 11: transparent insulating substrate 2, 12: polycrystalline silicon layer (active layer)

3, 14 insulating film 4, 13 photosensitive film

5, 15: gate electrode 6, 16: upper electrode (common electrode)

7, 17: interlayer insulation film 9, 19: interlayer insulation film

10, 20: pixel electrode

In order to achieve the object of the present invention, a method of manufacturing a liquid crystal display device includes forming a polycrystalline silicon layer on a transparent insulating substrate and patterning the island in a shape of islands, and deciding the impurities to define a lower electrode of the storage capacitance. Implanting an ion into a silicon layer, forming a first insulating layer on the entire surface of the substrate including the polycrystalline silicon layer by a thermal oxidation process, forming a gate electrode on the first insulating layer, and then using the gate electrode as a mask. Forming a source and drain region by ion implantation, forming a transparent metal material layer on the entire surface of the first insulating layer including the gate electrode, and then patterning the semiconductor layer to form an upper electrode of the storage capacitor on the storage capacitor formation region; A first interlayer insulating film is formed on the entire surface of the first insulating layer including the upper electrode and the gate electrode. Forming a data line so as to be connected to the exposed source region on the first interlayer insulating layer by exposing a source region by removing the first interlayer insulating layer and a portion of the first insulating layer; After the second interlayer insulating film is formed on the first interlayer insulating film including the data lines, a portion of the second interlayer insulating film, the first interlayer insulating film, and the first insulating film are sequentially removed to expose the drain region and to the drain region. And forming a pixel electrode in the pixel region on the second interlayer insulating layer so as to be connected.

An embodiment of the present invention will now be described with reference to FIGS. 3 (a) -3 (i).

First, as shown in FIG. 3A, a polycrystalline silicon layer 12 to be used as an active layer is formed on a transparent insulating substrate 11 such as glass or quartz, and then patterned into islands.

Subsequently, as shown in FIG. 3B, a photosensitive film is coated to form a lower electrode of the storage capacitor, and then patterned to form impurities such as boron or phosphorus in the polycrystalline silicon layer 12 using the patterned photosensitive film 13 as a mask. Injecting to define the lower electrode region of the storage capacitor.

After removing the photosensitive film 13 as shown in FIG. 3C, the gate insulating layer 14 is deposited on the entire surface of the transparent insulating substrate 11 including the island-like polycrystalline silicon layer 12 by a thermal oxidation process.

Thereafter, as shown in FIG. 3 (d), polycrystalline silicon and silicide materials are sequentially deposited and patterned to form the gate electrode 15, and ion implantation such as boron or phosphorus is performed to form a source / drain electrode.

Reference numerals 15a and 15b denote silicide layers and polycrystalline silicon layers, respectively.

Next, as shown in FIG. 3E, the transparent metal ITO is deposited on the entire surface of the substrate, and then the transparent metal ITO is patterned by a photo process and a wet etching process to form the upper electrode 16 of the storage capacitor as a common electrode. At this time, the et etchant used is a solution having an excellent selectivity ratio between the gate electrode and the thermal oxide film.

Subsequently, as shown in FIG. 3F, a first interlayer insulating film 17 is deposited on the entire surface of the substrate, and a heat treatment process is performed at a high temperature to activate implanted ions to form a source / drain electrode.

3 (g), a portion of the first interlayer insulating layer 17 and the gate insulating layer 14 positioned on the source region of the liquid crystal display device is removed to deposit a metal layer to expose the source region, and then pattern the metal layer. The data line 18 is formed to be connected to the exposed source region.

Next, as shown in FIG. 3H, a second interlayer insulating film 19 is deposited to insulate the data line 18.

Subsequently, as shown in FIG. 3 (i), portions of the first and second interlayer insulating layers 17 and 19 and the gate insulating layer are removed to expose the drain region, and the pattern is formed by depositing and patterning ITO, which is a transparent electrode material. The pixel electrode 20 is formed to be connected to the drain region, thereby completing manufacturing of the bottom plate of the liquid crystal display.

As described above, according to the manufacturing method of the present invention, an ion implantation process for forming the lower electrode of the storage capacitor is performed by forming a semiconductor layer formed of polycrystalline silicon in a portion where the lower electrode of the storage capacitor is to be formed before the gate insulating layer 14 is formed. By increasing the ion concentration of 2) (the oxide film growth rate when the ion concentration is increased is known to be 1.5-2 times the oxide film growth rate at the high temperature of the polysilicon without ion implantation), and then using the thermal oxidation process of the silicon oxide film. When the phosphorus insulating layer is formed, the oxide growth rate is increased, and only the thickness of the active layer, which is the polycrystalline silicon layer of the storage capacitor portion, can be reduced to greatly reduce the absorption of light in the polycrystalline silicon layer, thereby increasing the transmittance of the light and greatly improving the aperture ratio. There is an effect.

Claims (2)

Forming a polycrystalline silicon layer on the transparent insulating substrate and patterning it into islands; Implanting impurities into the polysilicon layer to define a bottom electrode of the storage capacitor; Forming a first insulating layer on the entire surface of the substrate including the polycrystalline silicon layer by thermal oxidation; Forming a gate electrode on the polysilicon layer on the first insulating layer and ion implanting the gate electrode with a mask to form source and drain regions; Forming a transparent electrode layer on the entire surface of the first insulating layer including the gate electrode and then patterning the upper electrode of the storage capacitor on the storage capacitor formation region; Forming a first interlayer insulating film on an entire surface of the first insulating layer including the upper electrode and the gate electrode; Removing the first interlayer insulating layer and a portion of the first insulating layer to expose a source region, and then forming a data line on the first interlayer insulating layer to be connected to the exposed source region; After forming a second interlayer insulating film on the first interlayer insulating film including the data line, a portion of the second interlayer insulating film, the first interlayer insulating film and the first insulating film is sequentially removed to expose the drain region and the drain region. And forming a pixel electrode in the pixel region on the second interlayer insulating film so as to be connected to the second interlayer insulating film. The method of claim 1, And a top electrode and a pixel electrode of the storage capacitance are formed of ITO.