KR100645036B1 - Method for Forming a Panel of a Liquid Crystal Display Device - Google Patents

Abstract

The present invention relates to a transistor side panel of a liquid crystal display device of the present invention and a method of forming the same.

In the panel of the present invention, in the top gate type polysilicon thin film transistor formed on the inner surface of the panel, the source drain electrode is formed of the polysilicon layer through the contact formed while the color filter layer is formed directly on the gate electrode of the transistor and passes through the color filter layer. Electrical connection with the drain region, a polysilicon layer active pattern is formed on the glass substrate, a gate insulating film is deposited over the active pattern, and a gate metal layer is laminated again, gate electrode patterning of the P-type transistor, and P-type ion In three steps, instead of the conventional simple insulating film, the photosensitive organic layer is formed on the thin film transistor electrode formed by implantation, gate auxiliary metal layer deposition, N-type transistor gate electrode undercut structure patterning, high concentration N-type ion implantation, and gate auxiliary metal layer removal. Made of insulating film After laminating the true color layer and forming a pattern on the pixel portion and the periphery except for the contact, the electrode layer was stacked and patterned again on the color layer to form an electrode, an organic insulating layer was formed on the electrode, and a via contact was formed on the drain electrode. A pattern forming of the next pixel electrode is sequentially performed.

Polysilicon, Color Filter

Description

Panel for thin film transistor of liquid crystal display device and method for forming the same {Method for Forming a Panel of a Liquid Crystal Display Device}

FIG. 1 shows a state in which a blocking layer is completely stacked on a glass substrate and a buffer pattern is formed.

FIG. 2 shows a state in which an active pattern is formed through photolithography and etching in a state where the amorphous silicon film is laminated on the front surface through LPCVD (low pressure chemical vapor deposition) in the state of FIG. 1 and formed of low temperature polysilicon through laser irradiation. .

FIG. 3 illustrates a state in which a gate insulating film is stacked on the entire surface over an active pattern in the state of FIG. 2 and a gate metal is stacked thereon.

FIG. 4 shows a state in which the gate pattern is formed in the driving circuit portion P-type transistor portion through photolithography and etching in the state of FIG. 3, the photoresist is removed, and then P-type impurities are implanted.

FIG. 5 shows a state in which a chromium layer is laminated on the entire surface in the state of FIG. 4 and an N-type transistor gate and a pixel portion capacitor electrode pattern are formed by using photolithography and etching.

FIG. 6 shows a state in which the photoresist is removed in the state of FIG. 5 and the N-type high concentration ion implantation is performed using a chromium pattern with an ion implantation mask.

FIG. 7 shows a state in which the chromium layer is removed in the state of FIG. 6 and N-type low concentration ion implantation is performed.

FIG. 8 shows a state in which three color layers are formed and patterned in the state of FIG.

FIG. 9 shows a state in which an electrode is patterned on a contact, and an organic insulating layer is thickly stacked on the contact to be flattened, and a via contact is patterned on the drain portion of the pixel portion, and then ITO is patterned on the pixel electrode. Indicates.

10A and 10B schematically show mask patterns suitable for the above operations.

※ Explanation of symbols for main parts of drawing

10: glass substrate 11: blocking layer

12: buffer 13: active pattern

15: gate insulating film 17: gate metal layer

171: gate pattern 172: gate

173: capacitor electrode 18: photoresist

19: chromium layer 20: drain region

30: source area 21, 31: contact hole

22: drain electrode 32: source electrode

40: channel 50: LDD

60: color layer 70: organic insulating film

80: pixel electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor side panel of a liquid crystal display device and a method of forming the same, and more particularly, to a thin film transistor side panel and a method of forming a liquid crystal display device using a color filter as an interlayer insulating film of a top gate polysilicon thin film transistor. 1

In recent years, the most actively developing field in relation to the display device is the LCD field, and the development of the active matrix type TFT LCD field is remarkable.

The LCD roughly injects liquid crystal between two substrates and applies voltage to two electrodes formed inside the substrate to adjust the arrangement of liquid crystals therebetween, thereby transmitting or blocking light in relation to the polarizing plate attached to the substrate. The principle is to use.

The TFT LCD controls the electrodes of the individual pixels forming the screen of the display device by using a transistor, which is a nonlinear element, in which the transistor is formed on a glass substrate using a semiconductor thin film. TFT LCD can be divided into amorphous silicon type and polysilicon type according to the material of semiconductor thin film used, and can be divided into top gate and bottom gate type according to the position of the gate. And can be distinguished.

Either way, efforts are being made to reduce the number of exposure steps in the process in order to reduce process costs and increase yields.Amorphous silicon can be formed using CVD at low temperatures, which is advantageous due to the characteristics of LCDs using glass substrates. There is a point. However, amorphous silicon is not suitable for forming a transistor element of a driving circuit requiring low operating characteristics due to low carrier mobility. Therefore, it is mainly used to form a switching transistor element in a pixel electrode on a glass substrate. This fact means that the IC for driving the LCD must be manufactured separately and attached to the LCD panel periphery. Therefore, the LCD manufacturing cost increases due to the increase of the process for the driving module.

On the other hand, polysilicon has a much higher mobility of carriers than amorphous silicon, and thus can be used to manufacture ICs for driving circuits. Therefore, when polysilicon is used as a semiconductor thin film for forming TFT of LCD, TFT device for pixel electrode and TFT device for driving circuit can be formed together on the same glass substrate through a series of processes. This has the effect of reducing the cost of the module process in LCD manufacturing, and at the same time has the advantage of lowering the power consumption of the LCD.

However, in order to use polysilicon, in order to form a polysilicon thin film on a glass substrate, an amorphous silicon thin film is first formed through a low temperature CVD process and an additional process for crystallization such as irradiating a laser beam is required, and carrier movement is required. When the gate voltage is turned OFF in the transistor formed by the high degree, the leakage current (OFF Current) is excessively flowed, thereby preventing a sufficient electric field from being maintained in the pixel portion. As a method of suppressing off current generation, an LDD region having low impurity concentration or an offset region without impurity ion implantation is provided as a barrier to OFF current at the junction between the source and drain regions of the thin film transistor and the channel. This is generally the way to do it. In the process of forming the N-channel TFT, the P-channel is sealed to prevent ion implantation, and the N-channel region must also be sealed with the protective layer during the formation of the P-channel TFT.

Considering the above method of manufacturing a polysilicon TFT LCD, in order to form a polysilicon TFT LCD having N-channel and P-channel TFT, several steps of exposure process, i.e., 8 to 9 mask operations, are performed compared to amorphous silicon type TFT LCD. This increase in the number of process steps leads to an increase in manufacturing costs. Therefore, there is an urgent need for the development of a method of reducing the process step rather than the polysilicon type.

Hereinafter, an example of a top gate polysilicon TFT forming method of a liquid crystal display device developed in recent years will be described. First, a silicon oxide film blocking layer is covered on the lower glass substrate, and a silicon layer containing impurities in the source drain and the capacitor region of the transistor is patterned to form a buffer layer (first mask), followed by amorphous silicon. Are laminated, irradiated with laser to polysilicon, and active patterning is performed leaving only the active region of the transistor (second mask). Next, a gate insulating film formed of a silicon oxide film or a nitride film is laminated on the active pattern, and then a gate metal of aluminum neodymium (AlNd) alloy is laminated.

Photolithography and etching are then used to pattern gate electrodes in the p-type transistor in the transistor region for the substrate peripheral drive circuit (third mask). This results in a top gate structure with a gate electrode over the active region. Next, the remaining photoresist is removed, and polysilicon in the source drain region of the p-type transistor is formed as a part of the electrode by using polysilicon doped with impurities through p-type ion implantation. Next, the entire surface is laminated with a chromium layer, and the gate and capacitor electrode patterning of the n-type transistor is performed again using photolithography and etching (fourth mask). At this time, the aluminum neodymium (AlNd) alloy layer under the chromium layer is wet-etched to form an undercut.

After removing the upper photoresist, the chromium layer is implanted with a high density n-type ion implantation mask, and the low density n-type ion implantation is performed again with the chromium layer removed to form an LDD structure in the n-type transistor. The laser is then annealed to activate the implanted region. In the thus formed transistor electrode structure, the insulating film is covered over and the contact is patterned (fifth mask), and then the electrode is patterned thereon (sixth mask). An organic insulating film is formed over the electrode and a via contact is formed (first mask). 7 mask) A pixel electrode is patterned and the electrode structure is closed (eighth mask).

The top glass corresponding thereto forms a color filter layer including a black matrix and each color fluorescent film (four mask process), and a common electrode is formed thereon.

On the other hand, there is a technique for forming a color filter layer on a transistor as a technique being developed in recent years. It is common to form a transistor electrode and then use a silicon oxide film as an insulating film, and in the case of a color liquid crystal display, to form a color filter on the inner surface of the upper plate opposite to the lower plate on which the transistor is formed, but a thick photosensitive organic film is advantageous for additive patterning and planarization. It was used as an insulating film on the transistor electrode. Since the color filter layer is often formed of a photosensitive organic film, in the technical idea of eliminating one layer and functioning by using commonality, a color filter layer is formed on the transistor instead of forming a color filter layer on the top plate. At the same time, the insulating film of the transistor is used.

When the color filter is used as an insulating film on the transistor, the lower plate usually needs to be more complicated and precise, but in the case of the upper plate, the process is greatly reduced. In addition, while forming the color filter on the lower transistor, the color filter layer may be formed with a process burden that is much less than the process burden that would have to be incurred when forming the color filter on the upper plate using the relationship with the peripheral film. In addition, various types of process technologies using a color filter layer as an insulating film on a transistor have been researched because the gap between the apertures and the surface planarity can be reduced.

In the present invention, a thin film transistor side panel and a method of forming the same in a form of forming a color filter on a transistor in a polysilicon transistor type liquid crystal display device manufacturing, in which the overall process step has to be reduced. It aims to reduce the overall process and improve image quality with structural advantages.

The thin film transistor side panel of the liquid crystal display device of the present invention for achieving the above object is a top gate type polysilicon thin film transistor formed on the inner surface of the panel is a contact formed by the color filter layer is formed directly on the gate electrode of the transistor and passes through the color filter layer. The source drain electrode may be electrically connected to a source drain region formed of a polysilicon layer, respectively.

In order to achieve the above object, a method of forming a liquid crystal display panel thin film transistor side panel of the present invention is to form a polysilicon layer active pattern on a glass substrate once, as in the method of forming a lower electrode structure of a polysilicon type LCD developed in recent years. Stacking a gate insulating film over the active pattern and then stacking a gate metal layer, gate electrode patterning of a P-type transistor, p-type ion implantation, gate-assisted metal layer deposition, an N-type transistor gate electrode undercut structure patterning, a high-concentration N-type Instead of the conventional simple insulating film, a color layer consisting of the photosensitive organic insulating film is laminated on the thin film transistor electrode formed through the ion implantation and the gate auxiliary metal layer removing step, and a pattern is formed on the pixel part and the peripheral part except the contact. The electrode layer is laminated and patterned on the colored layer as in the conventional method. Formed, to form an organic insulating layer over the electrode to form a pattern, and then a pixel electrode forming the via contact and ildanrak the electrode structure.

Therefore, the core of the present invention is to form a lower electrode structure of a polysilicon liquid crystal display by stacking and patterning a color layer instead of an insulating layer in the insulating film formation patterning step on a conventional transistor electrode. Various methods exist in the formation of the thin film transistor and the pixel electrode formation before and after the step of stacking and patterning the color layer, and the structure forms a polysilicon top gate structure as in the present invention and forms the electrode upward through the contact. To the extent taken, the method of the present invention may be applied.

In the case where the lower electrode is formed according to the present invention, a black matrix layer and a common electrode layer except for the color layer will be formed on the upper substrate. In some cases, a data line or a gate line may be formed between pixels in an electrode structure of a transistor to serve as a black matrix, and a separate black matrix may not be formed.

On the other hand, in general, the color filter is formed only on the display surface in which the pixel portion exists. When the driving circuit is also formed in the polysilicon type as in the present invention, an insulating film for the transistor of the driving circuit portion must also be formed, and the color layer serves as the insulating film. In addition to the display surface, the color layer should be laminated. On the other hand, since all three color layers do not need to be overlapped on the glass periphery with the driving circuit, a pattern mask will be manufactured and used to leave the color layer on the glass periphery only when one of the three colors is formed.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 shows a state in which a silicon oxide film is entirely stacked on a glass substrate 10 with a blocking layer 11 and a buffer pattern 12 is formed of a silicon film to which n-type impurities are added. To form a pattern, first, a silicon film containing an impurity is laminated, a photoresist is applied, an exposure is performed using a pattern mask, a photoresist pattern is developed by developing, and an etching is performed using an etching mask. Residual photoresist is removed with a strip.

FIG. 2 is a photolithography and etching process in which the amorphous silicon film is laminated on the front surface by LPCVD (low pressure chemical vapor deposition) in the state of FIG. 1 and partially recrystallized by laser irradiation to form low temperature polysilicon. The state in which the active pattern 13 to be formed is formed is shown.

FIG. 3 illustrates a state in which the gate insulating layer 15 is stacked on the front surface of the active pattern 13 with the silicon oxide film in the state of FIG. 2, and the gate metal layer 17 is laminated with a metal layer such as aluminum neodymium alloy thereon. . And before going to the next step, the front side is protected with photoresist and the amorphous silicon deposited on the back side of the glass substrate is removed. The amorphous silicon on the back is stacked together when forming the amorphous silicon for the active pattern on the front. The photoresist is removed after the process.

FIG. 4 shows a state in which the gate pattern 171 is formed in the driving circuit portion, that is, the P-type transistor portion of the glass periphery part through photolithography and etching in the state of FIG. 3, the photoresist is removed, and then the P-type impurity is implanted. B ₂ H ₆ is used as the P-type impurity.

FIG. 5 shows a metal layer such as a chromium layer 19 having an etching selectivity with the metal layer on the front surface in the state of FIG. 4, and an N-type transistor gate 172 and a pixel portion capacitor electrode 173 using photolithography and etching. The state which formed the pattern is shown. In this case, the P-type transistor region is protected by using a photoresist, and etching is performed by isotropic wet etching, and the aluminum neodymium alloy under the chromium layer 19 forms an undercut.

FIG. 6 shows a state in which the photoresist is removed in the state of FIG. 5 and the N-type high concentration ion implantation is performed using the chromium layer 19 pattern as an ion implantation mask. 7 shows a state in which the chromium layer is removed in the state of FIG. 6 and N-type low concentration ion implantation is performed. Through these steps, the N-type transistor structures of the source drain regions 30 and 20 and the channel 40 are formed, and the LDD 50 structure is formed near the channel. After ion implantation, laser annealing is performed to eliminate the increase in electrical resistance due to damage to the crystal structure during ion implantation and to diffuse impurities.

FIG. 8 illustrates a state in which three color layers 60 are formed and patterned in the state of FIG. 7. On the display surface, three colors are formed in different pixel areas through mask operations, but the drawings are based on one pixel, and thus only one pixel part in which one color layer 60 is formed is shown. In other words, the R color is stacked and left only in the pixel portion and the driving circuit portion around the glass substrate through patterning, and then the G color is stacked on the front side, and then left only in the pixel portion through patterning, and the B color is stacked again, and then only in the corresponding pixel. While remaining to form the entire color filter layer, the color filter layer serves as an insulating film of the transistor. 10 (a) and 10 (b) schematically show a mask pattern suitable for the above operation, in particular, when the color layer is formed in a stripe type. (a) is a mask pattern for the R color formed up to the glass periphery, and (b) is a mask for the G and B color formed only on the screen portion.

The color layer is made of a photosensitive organic insulating layer and is patterned on the pixel portion through exposure and development without etching. In addition, the contact holes 31 and 21 on the source drain regions 30 and 20 are also formed by further etching the color layer pattern with the etching mask using the gate insulating layer exposed at the bottom of the hole formed in the color layer 60 through the color layer patterning process. do.

FIG. 9 is a pattern of source drain electrodes 32 and 22 formed in a contact in the state of FIG. Again, ITO is patterned on the pixel electrode 80 thereon. It is preferable that the organic insulating film used here also be able to form the contact hole of the via contact only by development without a separate etching process using a photosensitive material like the color layer.

The contact electrode consists of a multilayer of molybdenum tungsten alloy and aluminum neodymium alloy. Therefore, the data line also consists of this multilayered alloy.

Although the bottom plate formation of the LCD panel has been described above, the effect of the present invention can be obtained from the top plate. In other words, it is not necessary to perform four mask processes in order to form a color filter layer on the top plate, but only one mask process, that is, a black matrix is formed, and a black matrix is formed even when a data line or a gate line is formed between pixels. You can't. Therefore, in the case of applying the present invention, the insulating film is separately laminated in the process of forming the lower plate, and the contact formation is omitted through photolithography and etching, and when not forming a black matrix, one mask process can be further saved. Since the upper glass substrate has no curvature on the substrate surface due to the pattern formation, the upper glass substrate is convenient for work and has additional convenience in case of entering the pattern in rubbing or formation of the common electrode.

According to the present invention, since the color layer acts as an insulating film on the transistor electrode, photolithography and etching processes according to separate insulating film formation and patterning can be reduced, and the aperture ratio can be improved according to the structure thereof, and it is advantageous for the planarization of the cell so that the cell gap is uniform. This can lead to an improvement in image quality.

Claims (7)

Forming an active pattern made of polysilicon on the glass substrate; Sequentially forming a gate insulating film and a gate metal layer on the active pattern; Patterning the gate metal layer to leave the gate metal layer in a pixel region in which an image is displayed, and forming a P-type gate electrode in a driving region surrounding the pixel region; Forming a gate auxiliary metal layer on the glass substrate on which the P-type gate electrode is formed; Forming an N-type gate electrode in the driving region by patterning the gate auxiliary metal layer and the gate metal layer of the pixel region and then undercutting the gate metal layer; Removing the gate auxiliary metal layer after performing a high concentration of N-type ion implantation; Forming a color filter layer made of a photosensitive organic insulating material; Partially removing the color filter layer and the gate insulating layer to form a first contact hole; Forming a source electrode and a drain electrode electrically connected to the active pattern through the first contact hole on the color filter layer; Forming an organic insulating layer on the color filter layer in which the source electrode and the drain electrode are formed; Partially removing the organic insulating layer to form a second contact hole; And And forming a pixel electrode on the organic insulating layer, the pixel electrode electrically connected to the drain electrode through the second contact hole. delete The method of claim 1, And the color filter layer is formed in the pixel region and the driving region, and is formed of RGB color pixels. The method of claim 3, wherein At least one of the RGB color pixels is formed in the pixel region and the driving region, and the remaining color pixels are formed in the pixel region. The method of claim 1, Forming a buffer layer corresponding to the source electrode and the drain electrode before forming the active pattern; And And performing low concentration N-type ion implantation after removing the gate auxiliary metal layer. Glass substrates; A source pattern formed on the glass substrate and formed of polysilicon, a gate insulating film formed on the active pattern, a gate electrode formed on the gate insulating film, and a source formed on the gate insulating film and electrically connected to the active pattern, respectively. A thin film transistor having an electrode and a drain electrode; And And a color filter layer formed on the glass substrate on which the gate electrode is formed, and having a first contact hole that partially exposes the active pattern to electrically connect the active pattern to the source electrode and the drain electrode. A thin film transistor side panel of a liquid crystal display device. The method of claim 6, An insulating layer formed on the color filter layer and having a second contact hole partially removed to partially expose the drain electrode; And And a pixel electrode formed on the insulating layer and electrically connected to the drain electrode through the second contact hole.

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