KR20060011414A - Method for fabricating liquid crystal display device of color-filter on transistor type - Google Patents

Abstract

The present invention relates to a method for manufacturing a COT type liquid crystal display device to reduce the number of processes by applying a lift-off method, comprising: forming a gate wiring and a gate electrode on a substrate and forming a gate insulating film thereon; Forming an active layer on the gate insulating film, forming a data line and a source / drain electrode perpendicular to the gate wiring, forming an interlayer insulating film on the data wiring, and forming an interlayer insulating film on the data wiring Forming a black matrix, applying a protective film and a photoresist on the black matrix, removing the gate insulating film, the interlayer insulating film or the protective film exposed between the photoresist, and patterning the photoresist; Depositing a first transparent conductive film on the entire surface including a resist, and the first transparent conductive film Forming a color filter layer on the substrate; And depositing a second transparent conductive film on the entire surface including the color filter layer, and selectively removing the first and second transparent conductive films by lifting off the photoresist to form a pixel electrode. It is done.

Diffraction Exposure, Low Mask, COT

Description

Method of manufacturing COT type liquid crystal display device {Method For Fabricating Liquid Crystal Display Device Of Color-filter On Transistor Type}

1A to 1C are process cross-sectional views of a liquid crystal display device according to the prior art.

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

3A to 3F are process cross-sectional views of a COT liquid crystal display device according to the present invention.

* Explanation of symbols on the main parts of the drawings

111 substrate 112a gate electrode

113: gate insulating film 114: active layer

114a: n + a-Si 115: data wiring

115a, 115b: source / drain electrodes 116: interlayer insulating film

117a and 117b: first and second pixel electrodes 118 protective film

132: storage lower electrode 135: storage upper electrode

191: black matrix 192: color filter layer

200: photoresist

The present invention relates to a COT type liquid crystal display device (COLT) of forming a color filter layer and a thin film transistor on a single substrate at the same time, in particular, to improve productivity by introducing diffraction exposure to simplify the process. The present invention relates to a method for manufacturing a COT type liquid crystal display device to be improved.

BACKGROUND ART Liquid crystal display devices, which have recently been spotlighted as flat panel display devices, have been actively researched due to their high contrast ratio, suitable for gradation display or moving picture display, and low power consumption.

In particular, it can be manufactured with a thin thickness so that it can be used as an ultra-thin display device such as a wall-mounted TV in the future, and is light in weight and consumes significantly less power than a CRT CRT. It is being used as a next generation display device.

In general, the liquid crystal display device includes a thin film transistor array substrate having a thin film transistor (TFT) and a pixel electrode formed in each pixel region defined by a gate wiring and a data wiring, and a color filter layer array substrate having a color filter layer. Arranged so as to face each other, a liquid crystal having dielectric anisotropy is formed therebetween, and a voltage is applied to the pixel by switching a thin film transistor added to hundreds of thousands of pixels through a pixel selection address wiring. It is driven in a way.

Hereinafter, a liquid crystal display device according to the related art will be described in detail with reference to the accompanying drawings.                         

1A to 1C are cross-sectional views of a liquid crystal display device according to the related art. Hereinafter, the thin film transistor array substrate will be mainly described.

First, as shown in FIG. 1A, after depositing a low resistance metal material on the glass substrate 11, a plurality of gate wiring layers, that is, gate wirings (not shown) and gate electrodes 12a using photolithography techniques are used. ) And the storage lower electrode 32.

Next, an inorganic material such as silicon nitride (SiNx) or silicon oxide (SiOx) is deposited at a high temperature on the entire surface including the gate wiring 12 to form a gate insulating layer 13.

Subsequently, an island shape semiconductor layer 14 is formed on the gate insulating layer 13 so as to overlap the gate electrode 12a.

In this case, the gate insulating layer 13 and the semiconductor layer 14 are typically deposited by plasma enhanced chemical vapor deposition (PECVD).

Subsequently, a low resistance metal material is deposited on the entire surface including the semiconductor layer 14 and patterned by photolithography to form a data wiring layer. The data wiring layer includes a data wiring 15 intersecting the gate wiring 12 to define a unit pixel region, and a source electrode 15a and a drain electrode 15b overlapping edges of the semiconductor layer 14. do.

The gate electrode 12a, the gate insulating layer 13, the semiconductor layer 14, and the source / drain electrodes 15a and 15b stacked as described above are thin film transistors that control on / off of a voltage applied to a unit pixel. The thin film transistor is formed at an intersection point of the gate line 12 and the data line 15.

Next, a protective film 16 is formed by depositing an inorganic material such as silicon nitride (SiNx) or silicon oxide (SiOx) at a high temperature on the entire surface including the data line 15.

As shown in FIG. 1B, an organic insulating material such as BCB or acrylic resin is coated on the protective layer 16 to form an overcoat layer 18 to planarize the surface. Subsequently, the photoresist 19 having photosensitive properties is applied thereon, and then the photoresist is exposed by selectively irradiating light with a mask having a specific pattern formed on the photoresist.

Next, the photoresist 19 is patterned by removing the photoresist of the lighted portion using a developer, and the drain electrode is sequentially removed by removing the overcoat layer 18 and the protective film 16 of the exposed portions between the patterned photoresist. A contact hole 20 is formed in which 15b is exposed.

As described above, after the contact hole 20 is formed by a photoetching technique using an exposure apparatus, the photoresist 19 is stripped using a stripper.

Subsequently, as shown in FIG. 1C, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is deposited on the entire surface including the overcoat layer 18 and patterned by using photoetch technology. The pixel electrode 17 is electrically connected to the drain electrode 15b through the contact hole 20.

In this case, the pixel electrode 17 is formed to overlap the storage lower electrode 32 to form a storage capacitor. The storage capacitor corresponds to a thin film to prevent deterioration of image quality due to parasitic capacitance. It maintains the voltage charged in the liquid crystal capacitor in the turn-off period of the transistor.

This completes the TFT array substrate.

Subsequently, although not shown, after forming a sealant that serves as an adhesive on the edge of the TFT array substrate, the liquid crystal display device is completed by opposing-bonding the color filter array substrate with the liquid crystal layer interposed therebetween.

The color filter array substrate includes a black matrix that shields light leakage, a color filter layer of R, G, and B formed between the black matrix to express color, and a common electric field facing the pixel electrode of the TFT array substrate. An electrode is formed.

The present invention relates to a COT type liquid crystal display device which simultaneously forms a thin film transistor and a color filter layer on one substrate, unlike a general liquid crystal display device as described above. The COT is to reduce the number of processes by applying a lift-off method. It is an object of the present invention to provide a method for manufacturing a liquid crystal display device.

A method of manufacturing a COT liquid crystal display device for achieving the object of the present invention comprises the steps of forming a gate wiring and a gate electrode on the substrate, forming a gate insulating film on the front surface including the gate wiring, Forming an active layer on a gate insulating film, forming a data line defining a pixel region perpendicular to the gate wiring, forming a source / drain electrode on the active layer, and forming the data wiring Forming an interlayer insulating film on the entire surface, including forming a black matrix on the interlayer insulating film, applying a protective film and a photoresist on the entire surface including the black matrix, patterning the photoresist, and then Selectively removing the gate insulating film, the interlayer insulating film, or the protective film exposed between the above, Depositing a first transparent conductive film on the entire surface including the photoresist, and forming a color filter layer on the first transparent conductive film. And depositing a second transparent conductive film on the entire surface including the color filter layer, and selectively removing the first and second transparent conductive films by lifting off the photoresist to form a pixel electrode. It is done.

As described above, the present invention is characterized in that in the COT type liquid crystal display device in which the thin film transistor and the color filter layer are formed on the same substrate, the number of times of applying the photolithography technique is reduced, thereby reducing the process cost and the process time. That is, except for the process of forming the black matrix and the color filter layer, the COT liquid crystal display device may be completed by applying the three photolithography techniques using the lift-off method.

The lift-off method laminates a dry film resist (DFR), exposes and develops it through a mask process, applies an electrode material to the entire surface, and dries the dry film resist (DFR). It is done in such a way.

Hereinafter, a manufacturing method of a COT type liquid crystal display device according to the present invention will be described with reference to the accompanying drawings.

2 is a plan view of a COT liquid crystal display device according to the present invention, and FIGS. 3A to 3F are process cross-sectional views of the COT liquid crystal display device according to the present invention.

As shown in FIG. 2, the liquid crystal display device according to the present invention relates to a COT type liquid crystal display device in which a color filter layer 192 and a thin film transistor (TFT) are simultaneously provided on one substrate 111. The gate wiring (not shown) and the data wiring 115 which vertically cross the substrate 111 to define a pixel region, and the gate electrode 112a, the gate insulating film 113, and the active layer 114, a thin film transistor TFT in which the ohmic contact layer 114a and the source / drain electrodes 115a.115b are sequentially stacked, a black matrix 191 formed at an edge of the pixel region to block light leakage, and the pixel. Color filter layers 192 of R, G, and B formed in the openings of the regions to express colors, and deposited on the bottom and top surfaces of the color filter layers 192 and formed in the openings of the pixel regions, respectively, and drain electrodes 115b. A first contacting the first electrode to form a pixel electrode And second transparent conductive films 117a and 117b.

In this case, the gate insulating layer 113 formed on the gate wiring layer, the interlayer insulating layer 116 formed on the thin film transistor to protect the channel layer, and the protective layer 118 formed on the black matrix 191. ) Is removed only in the opening of the pixel region, so that the transmittance of the device is improved.

The lower storage electrode 132 on the same layer as the gate electrode 112a and the upper storage electrode 133 on the same layer as the source / drain electrodes 115a and 115b may form the gate insulating layer 113. The storage capacitor is overlapped with each other to form a storage capacitor. The storage lower electrode 132 is formed in parallel with the gate wiring to receive a voltage at an outer portion of the active region, and the storage upper electrode 135 The first and second transparent conductive films 117a and 117b are contacted to receive a voltage.

Hereinafter, the COT liquid crystal display device will be described in detail through a manufacturing method.

First, as shown in FIG. 3A, copper (Cu), aluminum (Al), and aluminum alloy (AlNd: Aluminum Neodymium) having low specific resistance to prevent signal delay on the transparent and high dielectric breakdown voltage 111. , Low-resistance metal materials such as molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), and molybdenum-tungsten (MoW) are deposited by sputtering and patterned by photolithography using a first mask. A gate wiring (not shown), a gate electrode 112a, and a storage lower electrode 132 are formed. The storage lower electrode 132 receives a voltage from an outside of the active area in parallel to the gate line 112.

Next, a silicon oxide (SiOx) or silicon nitride (SiNx), which is an inorganic insulating material having good dielectric breakdown voltage, is deposited on the entire surface including the gate electrode 112a by a plasma chemical vapor deposition method to form a gate insulating film 113 having a thickness of 2000 Å. To form.

In addition, n + a-Si implanted with amorphous silicon (a-Si: H) and impurities by plasma chemical vapor deposition using SiH ₄ and H ₂ mixed gas on the gate insulating layer 113. Are deposited in order, and copper (Cu), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), Low-resistance metal materials such as molybdenum-tungsten (MoW) are deposited by sputtering.

Subsequently, the amorphous silicon, n + a-Si, and low resistance metal materials are selectively removed using a photoetching technique using a second mask (diffraction mask) to form an active layer 114, an ohmic contact layer 114a, and a data wiring ( 115 and the source / drain electrodes 115a and 115b and the storage upper electrode 135 are formed at the same time.

In this case, the diffraction mask may be a half-tone mask or a slit mask, which is divided into three regions: a transparent portion, a diffraction exposure portion, and a light shielding portion.

Here, a portion where the data line 115 and the source / drain electrodes 115a and 115b are formed is a portion corresponding to the light blocking portion of the diffraction mask, and the channel layer between the source electrode 115a and the drain electrode 115b is diffracted. The portion corresponding to the diffractive exposure portion of the mask is a portion other than the portion corresponding to the transparent portion of the diffraction mask. In this case, however, the photoresist used in the photoetching technique is a positive photoresist in which the exposed portion is removed.

A plurality of pixel regions are defined by the above-described gate wiring and data wiring, and a thin film stacked on the intersection of the gate wiring and the data wiring by the gate electrode 112a, the semiconductor layer 114, and the source / drain electrodes 115a and 115b. The transistor TFT is disposed, and a storage capacitor stacked with the storage lower electrode 132, the gate insulating layer 113, and the storage upper electrode 135 is disposed in each pixel.

Subsequently, as illustrated in FIG. 3B, an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx) is deposited on the entire surface including the data line 115 to form an interlayer insulating film 116. The interlayer insulating film 116 serves to protect the TFT channel layer.

Next, a black matrix 191 is formed by depositing or applying a film capable of blocking light on the entire surface including the interlayer insulating layer 116 and then patterning the same by photolithography using a third mask. Here, in the case of coating, it is advantageous to apply an organic material including carbon, titanium, or an organic material mixed with two or more organic materials having absorption properties even if they do not contain titanium.

Here, the black matrix 191 is formed to correspond to the region where the thin film transistor and the wiring are formed so as to shield light leakage in an area where the electric field is unstable.

Subsequently, an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx) is deposited on the entire surface including the black matrix 191 to form a protective film 118. The passivation layer 116 is formed to prevent the organic black matrix 191 from being directly exposed to the developer and the stripper.

Next, as shown in FIG. 3C, the photoresist 200 is coated on the entire surface including the passivation layer 118 and exposed using a fourth mask, and then the exposed portion is stripped. At this time, the photoresist 200 of the opening of the pixel region including the predetermined portion where the drain electrode 115b and the storage upper electrode 135 are formed is removed. That is, the portion where the photoresist 200 remains is a light blocking portion of the pixel region, and corresponds to a portion where the edge of the pixel region and the thin film transistor are formed on the gate wiring and the data wiring.

Subsequently, the passivation layer 118, the interlayer insulating layer 116, and the gate insulating layer 113 exposed between the patterned photoresist 200 are etched. In this case, only the passivation layer 118 is removed in the portion where the drain electrode 115b and the storage upper electrode 135 are formed.

As shown in FIG. 3D, the first transparent conductive film 117a is deposited by depositing a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) on the entire surface including the patterned photoresist 200. Form.

Next, as shown in FIG. 3E, each pixel region is formed by applying a color resist having a photosensitive characteristic on the first transparent conductive layer 117a and irradiating light using a fifth mask, and then applying a developer to form a desired pattern. Color filter layers 192 of R, G, and B are formed on the substrate. In this case, the portion where the drain electrode 115b and the storage upper electrode 135 are formed removes the color filter layer 192 to expose the first transparent conductive film 117a.

Subsequently, as illustrated in FIG. 3F, a transparent conductive material such as ITO or IZO is deposited on the entire surface including the color filter layer 192 to form the second transparent conductive film 117b. At this time, the drain electrode 115b exposed to the outside and the first transparent conductive film 117a on the upper storage upper electrode 135 are in contact with the second transparent conductive film 117b.

Lastly, the photoresist 200 is lifted off to remove the first and second transparent conductive layers 117a and 117b deposited on the photoresist 200. 2 The transparent conductive films 117a and 117b remain. The first and second transparent conductive films 117a and 117b become pixel electrodes which form an electric field for controlling the alignment direction of liquid crystals.

As a result, the thin film transistor array substrate of the COT liquid crystal display device according to the present invention is completed. The thin film transistor array substrate is opposed to the opposite substrate with a liquid crystal layer interposed therebetween.

As described above, the present invention uses a first mask in forming a gate wiring, a second mask in forming the active layer and data wiring, and uses a third mask in forming the black matrix. In addition, a fourth mask is used in forming the color filter layer, and a fifth mask is used in patterning the photoresist.

That is, by applying the lift-off method, it is possible to complete the COT liquid crystal display device by applying only three photo-etching techniques in the remaining processes except for the patterning process of the black matrix and the color filter layer.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The manufacturing method of the COT type liquid crystal display device according to the present invention as described above has the following effects.

First, in the remaining processes except for the patterning process of the black matrix and the color filter layer, a total of three masks may be used to simplify the process to improve productivity.

Second, the light transmittance of the liquid crystal display can be increased by removing the gate insulating film, the interlayer insulating film, and the protective film in the opening of the pixel region.

Claims (10)

Forming a gate wiring and a gate electrode on the substrate; Forming a gate insulating film on the entire surface including the gate wiring; Forming an active layer on the gate insulating layer on the gate electrode; Forming a data line defining a pixel area perpendicular to the gate line and forming a source / drain electrode on the active layer; Forming an interlayer insulating film on the entire surface including the data line; Forming a black matrix on the interlayer insulating film; Applying a protective film and a photoresist on the entire surface including the black matrix; After patterning the photoresist, selectively removing a gate insulating film, an interlayer insulating film, or a protective film interposed therebetween; Depositing a first transparent conductive film on the entire surface including the photoresist; Forming a color filter layer on the first transparent conductive film; Depositing a second transparent conductive film on the entire surface including the color filter layer; And removing the first and second transparent conductive films to lift off the photoresist to form a pixel electrode to form a pixel electrode. The method of claim 1, In the step of forming the gate wiring using a first mask, In the step of forming the active layer and the data wiring using a second mask, Using a third mask in the step of forming the black matrix, In the step of forming the color filter layer using a fourth mask, And a fifth mask is used in the step of patterning the photoresist. The method of claim 1, Forming a storage lower electrode simultaneously with the gate wiring; And forming a storage upper electrode facing the storage lower electrode at the same time as the data line. The method of claim 1, And the active layer, the data line, and the source / drain electrodes are patterned at once using a diffraction mask. The method of claim 1, And the photoresist is formed above the gate wiring, the data wiring and the thin film transistor. The method of claim 5, And the thin film transistor is formed of a stacked film of the gate electrode, the gate insulating film, the active layer, and the source / drain electrode. The method of claim 1, The first transparent conductive film and the second transparent conductive film are contacted on the drain electrode and the storage upper electrode, the manufacturing method of the COT type liquid crystal display device. The method of claim 1, And removing the gate insulating film, the interlayer insulating film, and the protective film in the pixel opening portion. The method of claim 1, The gate insulating film, the interlayer insulating film, and the protective film are formed of an inorganic insulating material of silicon nitride (SiNx) and silicon oxide (SiOx). The method of claim 1, The first and second transparent conductive films are formed of indium tin oxide (ITO) or indium zinc oxide (IZO).

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