KR100621608B1 - Method of manufacturing a TFT LCD pannel - Google Patents

Abstract

In the manufacturing method of the TFT LCD panel of the present invention, the lower plate is a step of forming a TFT structure on a glass substrate, forming a color filter by sequentially forming three color layers instead of a protective film on the TFT structure, the source electrode of the TFT Forming a contact hole and forming a pixel electrode connected to the source electrode through the contact hole, wherein the three color patterns are formed at a plurality of portions necessary for forming the color filter. Overlapping to form a black portion and the thickness of each color pattern is formed so that the sum of the two color layer is the thickness of the liquid crystal layer required so that the black portion serves as a spacer in the LCD panel black matrix and panel assembly step and In the forming of the TFT structure, an active region is formed of an amorphous silicon layer. In the process, the gate pad is exposed and etched in two-stage tones so that the metal is completely exposed and the insulating film on the gate line remains. Since the black matrix pattern forming step can be omitted, the manufacturing process of the TFT LCD panel can be simplified and the uniformity of the cell gap can be improved.

2 tone exposure, black matrix, spacer

Description

TF LCD panel manufacturing method {Method of manufacturing a TFT LCD pannel}

1 is a schematic cross-sectional view of a pixel portion of a general TFT LCD panel.

2 is a view showing a state in which a gate and a gate line are formed on a glass substrate.

 3 is a view showing a state in which a gate insulating film, an amorphous silicon film, a silicon film containing an impurity, a metal film for forming a source drain, and a source drain electrode, a drain electrode, and a data line are sequentially formed in the state of FIG.

FIG. 4 is a view showing a state in which an amorphous silicon pattern and an oxide film pattern are formed in the state of FIG.

FIG. 5 is a cross-sectional view illustrating a cross section of a gate pad gate line and a TFT portion in a state where a photoresist is developed in the process of forming FIG.

FIG. 6 is a view showing a state in which a color filter layer is formed using a mask technique with three RGB color layers in the state of FIG. 4, and a contact is formed in a part of a source of each pixel TFT.

FIG. 7 shows a state in which pixel electrodes are formed in each pixel portion in the state of FIG.

8 is a view showing a cross section of a pixel portion of a COA structure TFT LCD panel formed according to the present invention.

FIG. 9 is a bottom view of an LCD panel on which a black matrix is formed. FIG. 9 is a plan view illustrating a state in which a black matrix pattern is formed around a display area in a peripheral non-display area of an entire panel in a process of forming a black matrix from color resin.

※ Explanation of code for main part of drawing

101,114,701,714: polarizers 102,113,702,713: glass substrates

92,103: Black matrix 59,69,104,703,704,711: Color filter layer

105,705: ITO 35,45,106,706: Drain

37,107,707: amorphous silicon 34,49,108,708: source

22, 32, 109, 709: gates 63, 110, 710: pixel electrodes

111: protective film 38,47,57,67,112,712: gate insulating film

21,31,41,51,61: gate pad 23,33: gate line

36, 46, 56, 66: data line 48: active region

54,64: Contact window 93: Black matrix line

91: liquid crystal injection hole 94: sealing portion

The present invention relates to a method for manufacturing a TFT LCD panel, and more particularly, to a method for manufacturing a TFT LCD panel, in which a color filter acts as a protective film by forming a color filter without forming a separate protective film on the TFT. .

A general TN type TFT LCD is a device that composes a screen by injecting a liquid crystal between a top plate and a bottom plate and applying an electric field between a common electrode and a pixel electrode formed on the plate for each pixel to change the arrangement of the liquid crystals to pass or block light. .

Looking at the general method of forming a TFT formed on the lower plate, first, a gate layer is laminated on a glass substrate with aluminum or chromium, and then a generalized mask technique using a first mask, that is, photoresist coating and exposure using a pattern mask, development, pattern Gate and gate lines are formed through a chain process of etching and stripping. A gate insulating film, amorphous silicon, silicon with impurities, and a metal layer for forming a source drain electrode are stacked thereon, and a source drain electrode is formed through a general masking technique using a second mask. In this case, the metal layer and the silicon layer to which the impurities are added may be etched to form a pattern of the source drain electrode. Next, a mask technique using a third mask is used to form an active region with an amorphous silicon layer. In some cases, the above-described process may form a source drain electrode by laminating and patterning a metal layer thereon while forming an active region first after the formation of the gate and the gate line. Through the above process, a TFT portion including a gate, a source, a drain electrode, a gate insulating film, and a channel of an amorphous silicon layer is formed.

After laminating an insulating protective film thereon, the TFT layer is completed by exposing the contact window of the source portion and the pad portion of the gate line and the data line again using a mask. A pixel electrode connected through the source and the contact of the TFT is formed on the passivation layer, and an alignment layer is formed thereon. In the case of a reflective LCD, the pixel electrode may also serve as a reflector.

On the other hand, when the top plate is formed, the common electrode is formed on the glass substrate and the alignment layer is covered. In the case of color LCDs, color filters are usually formed on the top plate. The color filter is formed by layering films by mixing pigments with materials having photosensitivity for each RGB color and using a masking technique.In order to increase the contrast around the color layer of each pixel and prevent negative effects due to color overlap, the black matrix (Black Matrix) Will be formed first. The black matrix is formed by stacking a black matrix layer of photosensitive material and leaving a pattern connecting the periphery of each pixel by a mask technique.

Therefore, the LCD top plate in which the color filter is formed is formed by using four mask techniques and forming a transparent common electrode layer and an alignment layer on the formed color filter layer.

The inner surface of the upper plate and the lower plate is oriented, and then, in order to maintain the gap between the two plates, the spacers are scattered, a paste for sealing is formed around the glass, and the upper and lower plates are overlapped to assemble a hollow LCD panel. Inject. The upper plate or the lower plate is attached to the outside of the liquid crystal does not touch the pad and the pad formed on the glass is connected to the driving circuit. In addition, a retarder, diffuser, backlight, and the like are attached as necessary to complete the LCD. FIG. 1 schematically shows a cross section of a pixel portion of an LCD panel made through the above process.

In fact, for LCD manufacturing, processes that facilitate production and improve quality through many partial modifications in the above processes and methods are being developed. The general purpose of the development techniques is to increase aperture ratio, increase viewing angle, and consume power in the screen. It is focused on achieving reduction, large screen, high definition, and light weight.

In addition, in terms of production technology, while developing LCDs of the same quality, it is necessary to continuously develop technologies that reduce process steps and increase yields.

Good examples of recent developments include color filter on array (COA) LCDs and patterned vertical alignment (PVA) type LCDs.

The LCD of the COA structure uses a method of forming a film made of photosensitive RGB color resin on the TFT instead of a protective film. Therefore, a TFT is formed on the glass substrate, a color filter layer is formed on the glass substrate, a contact window is formed thereon, and a pixel electrode is formed thereon. In addition, since a transparent electrode is formed on the glass substrate and only the black matrix pattern except the color layer is formed thereon, the upper plate may naturally have an ultra-high opening ratio structure. The upper and lower plates are assembled to inject liquid crystal, connect the driving circuit, and attach a polarizing plate, a retardation plate, a backlight, and the like to complete the LCD.

In the case of the PVA type LCD, a VA type LCD is used in which the liquid crystals are arranged approximately perpendicular to the panel surface without using an alignment film alignment process on the inner surface of the substrate to which the liquid crystal is injected and contacted. The furnace area is formed in a divided pattern to make a section that affects the liquid crystal and use it to increase the viewing angle of the display panel.

 However, in the existing COA structure, the resin constituting the color filter instead of the protective film can be used to reduce the process and increase the aperture ratio.However, the combination of the color layers can form black and structurally as the color layers are used instead of the protective film. There was a point that I could not use enough that it could be used differently. Therefore, in the COA structure, as in the conventional technology, the upper black matrix pattern is still formed on the upper plate, and the spacer having the constant diameter is assembled before assembling the upper and lower plates to maintain the gap between the glass substrates. It had to be spread on a glass substrate.

In addition, if the ITO is patterned directly on the colored layer, the resin forming the colored layer may be damaged when the ITO is etched, which may cause partial removal, and a separate overcoat layer must be formed on the colored layer to prevent it. There is a case. In the additional process of depositing and patterning the overcoat film, the insulating film on the gate pad portion is usually etched as such. The overcoat film uses a photosensitive material, whereas the gate insulating film is a non-photosensitive material such as silicon nitride. There is a problem that the overcoat film may be damaged together.

In addition, even when a separate overcoat layer is not used on the color filter layer, a separate mask must be used to expose the gate pad part in the step of forming the TFT, thereby resulting in process inefficiency.

The present invention uses a variety of color layer characteristics in the process of forming the LCD panel of the COA structure to eliminate the process of forming a black matrix pattern on the top plate in the existing technology and the process of scattering the spacer on the front of the glass substrate before assembly It is also an object of the present invention to provide a TFT LCD panel manufacturing method that can reduce a number of process steps by eliminating the need to use a separate mask to expose only the pad metal in the TFT forming step.

In the manufacturing method of the TFT LCD panel of the present invention for achieving the above object, in the manufacturing of the panel of the TFT LCD, the lower plate is formed by forming a TFT structure on a glass substrate, patterning three color layers in turn instead of a protective film on the TFT structure And forming a color filter layer, forming a contact hole in the source electrode of the TFT, and forming a pixel electrode connected to the source electrode through the contact hole. The black color is formed by overlapping the three color patterns on a plurality of necessary parts in the forming step, and the black part serves as a black matrix of the LCD panel and a spacer in the panel assembly step.

In the present invention, the forming of the TFT structure may include forming a gate electrode, a gate line, and a gate pad on a substrate, a gate insulating layer, a semiconductor layer, and an ohmic contact on the gate electrode, the gate line, and the gate pad. Continuously forming a layer and a metal layer, forming a source drain electrode by etching the metal layer and the ohmic contact layer using a mask technique, and etching the semiconductor layer and the gate insulating layer using a mask technique, The data line is generally preserved, the gate insulating film cap of the gate line is left, and at least the gate insulating film of the gate pad portion is etched and opened.

At this time, in the step of patterning the gate insulating film and the semiconductor layer thereon using a mask technique, the gate line capping and the opening of the gate pad portion may be simultaneously achieved using a two-step exposure method. It is preferable to avoid the need for an opening process or to prevent structural damage of the LCD panel while opening the gate insulating film at the same time in another process.
The method for exposing with the two-stage tone is performed using a mask in which a mask pattern of a portion exposed in the intermediate tone is formed using a plurality of slits.

The black portion formed in the step of forming the color filter is formed in a portion where each TFT is formed and in a plurality of places on the gate line and the data line. In addition, the black portion is also formed in the panel peripheral portion in parallel with the sealing line.
In the present invention, after forming the color filter layer, forming an overcoat layer made of a transparent insulating material on the color filter layer may be prevented from damaging the color filter layer, and the contact formed on the source electrode may form a color filter layer. At the same time, the contact portion of the overcoat layer should be removed so that the source electrode is exposed. In this case, the pad portion is preferably exposed to the pad metal.

In the present invention, the color filter layer is generally composed of a combination of red, green, and blue parts to form a full-color screen, and the pixel electrode uses a transparent electrode so that light passing through the color filter layer can be transmitted well, and ITO is used. Is representative.

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

2 is a view showing a state in which a gate 22, a gate line 23, and a gate pad 21 are formed on a glass substrate. As the gate metal, aluminum, aluminum alloy, chromium, molybdenum, or the like may be used, and a stacked form thereof may also be used. The gate metal layer is stacked, the photoresist is applied, and the pattern is exposed through a general mask technique pattern forming process of forming and etching.

 FIG. 3 shows a gate insulating film mainly made of silicon nitride, an amorphous silicon film, an amorphous silicon film with an impurity added thereto by ohmic contact, and a metal film such as chromium or molybdenum for source drain formation in the state of FIG. Next, a diagram showing a state in which a source 35 drain 35 electrode and a data line 36 connected to the drain electrode are formed using a mask technique. While etching the metal film, the silicon film to which the lower impurities are added is also etched. As a result, a channel between the source and drain is formed in the TFT portion.

4 is a view showing a state in which an amorphous silicon pattern and a gate insulating film pattern are formed in the state of FIG. Amorphous silicon and an insulating film are removed except for the source 49 drain 45 electrode, the data line 46 and the amorphous silicon pattern. Accordingly, the active region 48 of the TFT forms a state capped with amorphous silicon. However, at this time, the gate line portion should be kept capped by the insulating film 47 for insulation, so that the insulating film is not removed by exposing it to an intermediate tone using a pixel pattern mask or the like. Eventually, in the step of FIG. 4, the gate pad is exposed to the second tone to expose the metal of the gate pad, the gate line maintains the insulating film capping, and the active maintains the amorphous silicon layer.

In order to expose two-stage tones, a mask pattern may be used as a slit type, and a diffraction phenomenon may be used, or a pattern of the mask itself may be used as an intermediate tone, or a double exposure may be performed using two masks. For example, the two-stage tone exposure in the case of using the slit type is the pattern of the mask when the exposure is performed, the opaque portion corresponding to the data line and the TFT portion, the region capping the gate line is the portion of the middle tone, That is, the part where many fine slits are formed and the remaining part becomes a transparent part.

FIG. 5 is a cross-sectional view illustrating a cross section of the gate pad, the gate line, and the TFT portion in the state where the photoresist is developed in the process of forming FIG.

When the photoresist is exposed using a pattern mask and developed, as shown in FIG. 5, the photoresist 39 remains at the thickest t ₂ , and the region capping the gate line has a thinner t ₁ thickness as shown in FIG. 5. The resist 39 'remains, and the remaining regions, especially the pad regions, are in a state where the photoresist is almost removed. When anisotropic etching is performed in this state, the amorphous silicon film 37 and the gate insulating film 38 are removed by etching in the gate pad 31, and the amorphous silicon 37 film is etched in the portion capping the gate line 33. And removed, leaving the active area unetched.

FIG. 6 is a view showing a state in which the color filter layer 59 is formed using the mask technique using three RGB color layers in the state of FIG. 4, and the contact window 54 is formed in a part of the source of each pixel TFT. In this case, three masks are required to form a pattern of each color, and contact windows are generally formed at the same time as each color layer is formed. The color resin forming the color filter layer 59 serves as a TFT protective film at the same time as in the general COA structure.

The black portion 50 is formed by overlapping three color layers on the TFT portion except for the contact forming portion of the source electrode. Since the black part serves to block external light, leakage current in the TFT element formed by the influence of external light can be suppressed. After the color filter layer is patterned, a protective film may be formed to cover the color filter layer with a transparent organic insulating layer. In this case, a separate mask process for exposing a contact portion and a gate pad is required.

In addition to the TFT portion, a portion appearing in black may be formed by partially overlapping the color layer along the gate line and the data line. Here, the black portion serves as a black matrix surrounding each pixel, and at the same time, the thickness of each color layer is formed to be approximately 1/2 of the thickness of the required liquid crystal layer so that the sum of the thicknesses of the two color layers becomes the thickness of the liquid crystal layer. However, since the thickness of the color filter layer has a problem of color reproducibility, the thickness of RGB may not be the same. As a result, the sum of the thicknesses of the color resins of the two layers is 4 to 4.5 μm so that a separate spacer is not required. It is preferable to use a resin having a color reproducibility level of 50% through the control of pigment concentration. The black part is not formed in the form of a continuous barrier, but is installed in the form of a column, so there is no effect when the liquid crystal is injected.

FIG. 7 illustrates a state in which a pixel electrode 63 is formed in each pixel part in the state of FIG. 6. A pixel electrode is formed by depositing a transparent electrode such as indium tin oxide (ITO) by sputtering or the like and patterning the same according to a pixel pattern. And is formed between the gate line and the data line 66. At this time, the contact window 64 is also filled to complete the contact between the source electrode and the pixel electrode. The pixel electrode should not be formed in the black portion. In this case, it is also preferable to prevent the corrosion of the metal by laminating the metal layer exposed to the gate pad part with the transparent electrode and remaining during the pattern etching.

8 is a view showing a cross section of a pixel portion of a COA structure TFT LCD panel formed according to the present invention. The upper plate is used as it is without forming a black matrix pattern separately in a state where a common electrode is formed on the glass substrate 702 by the ITO 703.

In addition, a black matrix layer and a transparent electrode layer may be formed as in the related art, which is generally used to realize low resistance of the pixel electrode in a PVA or the like.

FIG. 9 illustrates a step of forming a black matrix using three layers of color resin on a lower plate, and is a plan view showing a state in which a black matrix pattern is formed around a display area in a peripheral non-display area of an entire panel.

 In the liquid crystal injection hole 91, a black matrix is not formed for liquid crystal injection, and a black matrix 92 is formed on each line and an opaque portion such as a TFT to serve as a spacer in the display area inside the dotted line. By forming the black matrix line 93 in parallel with the sealing portion 94 at the periphery of the entire screen made of glass, external light is incident on the side surface to prevent deterioration of the screen quality.

After that, the panel is completed by continuously forming a polyimide layer, a sealing material printing, assembling, pressing, liquid crystal injection, and finishing sealing, which are common liquid crystal processes.

In the present invention, since the exposure using two-stage tone, eliminating spacer scattering, and eliminating a separate black matrix pattern forming step can be simplified, the process of manufacturing a TFT LCD panel can be shortened, and a spacer column is constantly formed of color resin. The uniformity of the cell gap can also be improved.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (5)

In the production of the panel of the TFT LCD, Forming a TFT structure on the glass substrate; Forming a color filter by sequentially patterning three color layers on the TFT structure instead of a protective film, and simultaneously forming contact holes in the source electrode of the TFT; And Forming a pixel electrode connected to the source electrode through the contact hole; The black color is formed by overlapping the pattern of the three colors on a plurality of portions necessary in the forming of the color filter, so that the black portion serves as a black matrix of the LCD panel and a spacer in the panel assembly step. TFT LCD panel manufacturing method. The method of claim 1, Forming the TFT structure, Forming a gate electrode, a gate line, and a gate pad on the substrate; Continuously forming a gate insulating film, a semiconductor layer, an ohmic contact layer, and a metal layer on the gate electrode, the gate line, and the gate pad; Forming a source drain electrode by etching the metal layer and the ohmic contact layer using a mask technique; And The semiconductor layer and the gate insulating film are etched by using a masking technique, and are exposed in two-stage tones, simultaneously preserving the TFT portion and the data line, leaving the gate insulating film cap of the gate line, and at least the gate insulating film of the gate pad part being etched open. Process of doing; TFT LCD panel manufacturing method characterized in that it comprises a. The method according to claim 1 or 2, And the black portion is formed at a portion where each TFT is formed and at a plurality of positions on the gate line and the data line. The method of claim 3, wherein And forming the black portion at the periphery of the panel in parallel with the sealing line. The method of claim 2, The mask used in the two-step tone exposure is a TFT LCD panel manufacturing method, characterized in that the mask pattern of the portion exposed to the intermediate tone is formed using a plurality of slits.

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