KR100254924B1 - Method of fabricating image display device - Google Patents

Abstract

PURPOSE: A method for manufacturing an image display device is provided to remove an ion implantation process upon formation of source/drain by forming a semiconductor layer into which impurities are doped after formation of a contact hole. CONSTITUTION: A method for manufacturing an image display device forms an active layer(2) on an insulating substrate(1). A gate insulating film(3) and a gate electrode(4) are formed on the active layer(2). After forming an interlayer dielectric(3') on the gate electrode(4), the interlayer dielectric(3') and the gate insulating film(3) are selectively etched to expose a portion of the active layer(2). Polysilicon(5) into which impurities are doped and a conductive metal(6) are sequentially deposited in the active layer(2). The polysilicon(5) into which impurities are doped and the conductive metal(6) are simultaneously etched to form a source/drain electrode and a data signal line.

Description

Manufacturing Method of Image Display Device

1 (a) to 1 (e) are sectional views showing the manufacturing process of a conventional image display apparatus.

2 (a) to 2 (e) are sectional views showing the manufacturing process of the image display device of the present invention.

3 is a cross-sectional view of an image display device according to another embodiment of the present invention.

4 is a liquid crystal display pixel plane view including the image display device of the present invention.

* Explanation of symbols for main parts of the drawings

1 Insulation substrate 2 Active layer

3: gate insulating film 3 ': interlayer insulating film

4 gate electrode 5 source / drain region

6: source / drain electrode 7: protective film

8: low concentration impurity doping layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an image display device for a liquid crystal display device. In particular, a sheet of an image display device is formed by forming a polysilicon layer doped with impurities except for an impurity implantation process by an ion implantation process when forming a source / drain region. The present invention relates to a method of manufacturing an image display device which reduces the resistance (Sheet Registance) and contact resistance (Contact Registance) to improve the characteristics of the device and is suitable for the simplification of the process excluding the ion implantation process.

1 (a) to 1 (e) are cross-sectional views illustrating a manufacturing process of a conventional image display apparatus, and the manufacturing process and problems of the conventional image display apparatus will be described with reference to the following.

After depositing amorphous silicon to a certain thickness by chemical vapor deposition (CVD) on an insulating substrate (1) of clean, well-dried quartz, glass, etc., through the substrate preparation process, polycrystalline silicon After etching, the active layer 2 of the pattern structure is formed by selective etching through photo etching to prepare the same as the first (a), and then exposed on the active layer 2 and the etching process. After the gate insulating film 3 is formed on the insulating substrate 1, polycrystalline silicon or metal silicide doped with impurities is deposited on the gate insulating film 3 by the same chemical vapor deposition method as described above. And patterned gate electrode 4 is formed by selective etching through a photolithography process using a mask and then an ion implantation process using the gate electrode 4 as a mask is performed. The source / drain region 5 is formed by doping an impurity in a portion of the active layer 2 to form the same structure as in FIG. 1 (b), and then an interlayer insulating film 3 'is stacked on the gate electrode 4. Afterwards, the interlayer insulating film 3 ′ and the gate insulating film 3 on the source / drain region 5 are etched by selective etching through a photolithography process to expose the source / drain region 5 to expose the first / c region. Manufactured in the same structure as tiles.

Thereafter, a metal such as aluminum (Al), chromium (Cr), tungsten (W), etc. is deposited on the exposed source / drain region 5 through the above process, and then the pattern is selectively etched through the same photolithography process as described above. The source / drain electrodes 6 are formed in the same manner as the first (d), and then the protective film 7 is formed on the front surface of the silicon oxide film (SiO ₂ ) or the silicon nitride (SiOx). In the same manner as in e), an active layer 2 having source / drain regions 5 formed on both sides of the insulating substrate 1 is formed, a gate insulating film 3 is formed on the active layer 2, and the gate insulating film 3 is formed. A gate electrode 4 and an interlayer insulating film 3 'are formed thereon, a source / drain electrode 6 is formed on the source / drain region 5, and the source / drain electrode 6 is formed on each of the exposed portions. It is manufactured in the structure provided with the protective film 7.

The conventional image display device manufactured through the above process injects impurities through the ion implantation process for source / drain region activation after the gate electrode pattern, so a separate implantation process is required, and the process is complicated and the amount of impurities is correct during the ion implantation process. Difficult to control and increase the contact resistance and the sheet resistance, thereby lowering the performance of the device, as well as the problem that the disconnection is likely to occur because the data signal line is a metal of a single layer structure.

In view of the above-mentioned problems, the present invention forms a semiconductor layer doped with impurities after the formation of contact holes and removes source / drain metals to form ion resistance and contact resistance in order to remove ion implantation processes during source / drain formation. By reducing the characteristics of the device and improving the data signal line to form a two-layer structure of polycrystalline silicon and conductive metal doped with impurities, it is possible to prevent the disconnection of the data signal line, and to simplify the process by removing the ion implantation process.

2 (a) to 2 (e) are cross-sectional views showing the manufacturing process of the thin film transistor of the present invention, with reference to FIG. 5 which is a plan view of the pixel of the liquid crystal display device including the image display device of the present invention. Referring to the manufacturing process and the effect of the operation in detail as follows.

After depositing polysilicon (Poly-Si) on a well-dried glass, quartz, etc. insulating substrate (1) by chemical vapor deposition (CVD) and recrystallization, After manufacturing the active layer 2 of the pattern in the same manner as in the second (a) using a photo etching process of projecting ultraviolet (UV) light through a mask coated with a photo resist The gate insulating film 3 is formed on a portion of the insulating substrate 1 exposed by the active layer 2 and the selective etching process, and polycrystalline silicon, metal silicide, etc. doped with impurities on the gate insulating film 3 are subjected to the same chemistry as described above. After vapor deposition, a gate electrode 4 having a pattern structure is formed by selective etching after deposition, thereby fabricating a structure having the same structure as that of FIG. 2 (b).

Thereafter, the interlayer insulating film 3 'is formed on the gate electrode 4 formed through the above process, and then the interlayer insulating film 3' and the gate insulating film 3 are selectively etched in the same manner as the photolithography process. (2) by etching to the boundary to expose the active layer (2) where the gate electrode (4) does not exist to form a contact hole (2) as shown in (c) and then doped with polysilicon doped with impurities The source / drain region 5 is formed by depositing on the active layer 2 exposed by the above process, and then heat-treated by heat treatment, followed by aluminum (Al), chromium (Cr), molybdenum (Mo), and tantan (Ta). And continuously depositing a metal such as tungsten (W), and selectively etching through a photolithography process to form a source / drain electrode 6 as shown in FIG.

Afterwards, an insulating film such as silicon oxide (SiO ₂ ) or silicon nitride (SiNx) may be formed on the portions exposed to the source / drain electrode 6 and the surface to protect the image display device formed by the process. Similarly, the protective film 7 is formed to complete the manufacture of the image display device and used in the liquid crystal display device to have the same liquid crystal display device pixel plan view as in FIG.

In another embodiment of the present invention, as shown in FIG. 3, a gate electrode 4 is formed on the gate insulating film 3, and then a portion of the active layer 2 is exposed using the gate electrode 4 as a mask. After ion implantation into a portion of the active layer 2 to form a low concentration impurity doping layer 8 with an impurity of 5x10 ¹³ atoms / cm 2 or less, and then on the impurity doping layer 8 The source / drain region 5 is formed by depositing polysilicon doped with a high concentration impurity, and then a conductive metal is deposited on the source / drain region 5 to form the source / drain electrode 6, and then the pattern is selectively formed. After the formation, a protective film 7 is formed on the entire surface by deposition of silicon oxide (SiO ₂ ), silicon nitride (SiNx), or the like to complete the manufacture of the image display apparatus.

As described in detail above, the ion implantation process for source / drain formation is eliminated to reduce sheet resistivity of the source / drain regions, and to reduce contact resistance with the source / drain electrodes and to disconnect the data signal. It is possible to prevent the improvement of the characteristics of the device and the effect of simplifying the process by removing the ion implantation process.

Claims (5)

Forming an active layer 2 on the insulating substrate 1, forming a gate insulating film 3 and a gate electrode 4 on the active layer 2, and forming an interlayer insulating film on the gate electrode 4. 3 ') and then exposing a portion of the active layer 2 by selectively etching the interlayer insulating film 3' and the gate insulating film 3, and the polysilicon 5 doped with impurities in the active layer 2 And continuous deposition of the conductive metal (6), followed by etching the conductive metal (6) and the doped polysilicon (5) together to form a source / drain electrode and a data signal line. Manufacturing method. 2. A method according to claim 1, wherein the active layer (2) comprises a lightly doped impurity doping layer (8) in part. 3. A method according to claim 2, wherein said low concentration impurity doping layer (8) manufactures impurities at 5x10 < ¹³ > The method of claim 1, wherein the source / drain electrodes (6) are Al. W. Ta. Cr. A manufacturing method of an image display apparatus manufactured by one of Mo. 2. A method according to claim 1, wherein the source / drain regions (5) are made by heat treatment after doping the polysilicon layer.