JP3746924B2 - Method for manufacturing active panel of liquid crystal display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an active panel of a liquid crystal display device, and more particularly to a method of forming a gate wiring containing aluminum or an aluminum alloy of an active panel.
[0002]
[Prior art]
In recent years, active matrix liquid crystal display devices have been widely used for displays such as laptop computers and various portable devices because they are thin, lightweight, and can achieve high image quality and low power consumption. Yes. Thin film transistors (hereinafter referred to as TFTs) are mainly used as driving elements for such active matrix liquid crystal display devices, and active research and development have been carried out to improve performance, reduce costs, improve productivity, and manufacturing yield. It has been broken.
On the other hand, with respect to the active matrix liquid crystal display device, there is an increasing demand for a larger display screen, higher definition, and higher aperture ratio. In the TFT active matrix substrate, the gate wiring is made longer and more It is necessary to make it thinner. However, the extension and thinning of the gate wiring increases the resistance and time constant, thereby causing a delay in the gate line signal and making it impossible to drive a good liquid crystal. It is important to use.
[0003]
Aluminum (Al) and its alloys have been put to practical use as materials for gate electrodes and wiring of TFT active matrix substrates because of their low resistance and low cost. However, Al and its alloys are metal materials that are relatively difficult to handle. Even when the temperature is lower than the melting point of Al, the surface of the electrode becomes rough when heated to a certain temperature or more, and the diameter is several tens of nanometers to several micrometers. An infinite number of Al protrusions called Al hillocks having a crystal growth in a hemispherical shape, a conical shape, a dome shape or the like having a height of several nm to several μm are generated. This protrusion causes a defect that the gate insulating film becomes thin or the protrusion protrudes from the gate insulating film, and the gate electrode and the gate line are electrically short-circuited with the semiconductor layer and the source / drain electrode above the gate insulating film. There was a problem.
[0004]
As a method for solving this problem, there is a method of anodizing the surface of the Al wiring. However, since the process is complicated, a technique for coating the Al wiring with a refractory metal such as Cr is disclosed in JP-A-11-133455, No. 10-319431 and Japanese Patent Laid-Open No. 10-213809.
[0005]
FIG. 5 is a cross-sectional view of the main part of the panel for explaining the active panel manufacturing method including the wiring forming method disclosed in JP-A-10-213809 in the order of steps. As shown in FIG. 5A, Al or an Al alloy is vapor-deposited on a substrate 100 made of transparent glass and patterned to form a gate bus wiring 101, a gate electrode 103, and a gate pad 104.
[0006]
Next, a barrier metal film such as chromium, molybdenum, tantalum, or the like is deposited and patterned on the entire surface of the substrate on which the gate bus wiring 101, the gate electrode 103, and the gate pad 104 are formed, and then patterned. A two-gate electrode 103a and a second gate pad 104a are formed. The second gate bus line 101a, the second gate electrode 103a, and the second gate pad 104a are formed to remove hillocks on the Al metal surface.
[0007]
Next, as shown in FIG. 5B, an insulating material such as silicon oxide or silicon nitride is deposited on the entire surface of the substrate to form a gate insulating film 105. An intrinsic semiconductor material and a semiconductor material to which an impurity is added are continuously deposited on the surface of the gate insulating film 105 and patterned to form the semiconductor layer 106 and the impurity semiconductor layer 107.
[0008]
Next, as shown in FIG. 5C, chromium or a chromium alloy is deposited on the gate insulating film 105 including the impurity semiconductor layer 107 and patterned to hold the source electrode 108, the drain electrode 109, the source wiring 110, and the holding. A capacitor electrode 111 and a source pad 112 are formed. Thereafter, the exposed portion of the impurity semiconductor layer 107 between the source electrode 108 and the drain electrode 109 is removed.
[0009]
Next, an insulating material such as silicon nitride or silicon oxide is deposited on the entire surface of the substrate including the source electrode 108 and the drain electrode 109 to form the protective layer 113. A part of the protective layer 113 is patterned to form a drain contact hole 114 on the drain electrode 109 and a source contact hole 115 on the source pad 112. At the same time, a part of the protective layer 113 and the gate insulating film 105 covering the gate pad 104 is removed to form a gate contact hole 116. Similarly, the portion of the protective layer 113 where the storage capacitor electrode 111 is formed is removed to form a storage capacitor contact hole 117.
[0010]
Finally, as shown in FIG. 5D, ITO (Indium Tin Oxide) is vapor-deposited on the entire surface including the protective layer 113 and patterned to form the pixel electrode 118. The pixel electrode 118 is connected to the drain electrode 109 through the drain contact hole 114, and is connected to the storage capacitor electrode 111 through the storage capacitor contact hole 117. At the same time, the source pad connection terminal 119 formed of the ITO material is connected to the source pad 112 through the source contact hole 115. Similarly, the gate pad connection terminal 120 formed of the ITO material is connected to the gate pad 104 through the gate contact hole 116 to manufacture an active panel of a liquid crystal display device.
[0011]
[Problems to be solved by the invention]
In the method for manufacturing the active panel of the conventional liquid crystal display device shown in FIG. 5, the surfaces of the gate bus wiring 102, the gate electrode 103, and the gate pad 104 formed by patterning by vapor deposition of Al or Al alloy are chromium or the like. Generation of Al hillocks can be prevented because it is covered with a barrier metal, but if dry etching is performed when forming a channel of a semiconductor layer, an etching gas such as fluorine permeates and Al becomes a fluorine radical (F *) To react with aluminum fluoride (AlF ₃ ). Thereafter, when the ITO film was deposited on the entire surface of the substrate and the ITO film was patterned by wet etching, the following problems occurred. That is, since the ITO film is deposited on the surface of the gate wiring (not shown) connected to the gate pad, it is necessary to etch the ITO film on the surface of the gate wiring when patterning the ITO film. In this case, the aluminum fluoride generated in the voids and pinholes in the barrier metal film such as chromium on the upper layer of the gate wiring dissolves in the etching solution of ITO, and erodes the underlying Al or Al alloy of the gate wiring material. May cause disconnection. This processing method can also be applied when the source electrode 108, the drain electrode 109, and the drain contact hole 114 have the same structure.
[0012]
An object of the present invention is to provide a method of manufacturing an active panel of a liquid crystal display device that solves the above-mentioned problems of the prior art.
[0013]
[Means for Solving the Problems]
The present invention includes a step of sequentially depositing a first barrier metal and an aluminum-based metal film on a substrate, and then patterning the aluminum-based metal film, and on the substrate including a surface and a side surface of the patterned aluminum-based metal film. And depositing a second barrier metal on the substrate, the lower surface of the patterned aluminum-based metal film with the first barrier metal, and the upper and side surfaces of the aluminum-based metal film with the second barrier metal, respectively. A gate pad and a gate electrode comprising a multilayer film of the first barrier metal, the aluminum-based metal film and the second barrier metal by patterning the first barrier metal and the second barrier metal so as to cover Forming a gate wiring, and depositing a gate insulating film on the substrate; In a method for manufacturing an active panel of a liquid crystal display device, comprising: forming a source electrode and a drain electrode on an insulating film; and forming a pixel electrode on the insulating film after depositing the insulating film on the substrate. After forming the gate pad, the gate electrode, and the gate wiring, before depositing the gate insulating film on the substrate, the surface of the gate pad, the gate electrode, and the gate wiring is heated to 30 ° C. to 50 ° C. An aluminum hydroxide film is formed on the defective portion of the second barrier metal by performing hot water treatment with warm water having a temperature and a pH value of 5 to 8 and having an acidity.
[0014]
In the present invention, the second barrier metal / aluminum or its alloy / first barrier metal multilayer wiring (referring to a gate pad, a gate electrode and a gate wiring) is patterned and then subjected to a hot water treatment to form the second barrier metal. Warm water permeates from the defective part such as voids generated in the substrate, thereby forming an Al hydroxide film (Al (OH) ₃ ) on the surface of the aluminum or aluminum alloy in the defective part such as voids, and plasma in the subsequent process Corrosion of aluminum due to etching gas or the like can be prevented and wiring defects can be reduced.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1A to FIG. 1D are cross-sectional views of the main part of the panel for explaining the steps of the method of manufacturing the active panel of the liquid crystal display device according to the embodiment of the present invention. FIG. 2D is a cross-sectional view of the main part of the explanation panel for explaining the process following FIG. First, as shown in FIG. 1A, an aluminum film (Al film) 3 having a thickness of 150 to 200 nm and a refractory metal such as chromium (Cr) are formed on a transparent glass substrate 1 by sputtering using argon gas. A first barrier metal 2 having a thickness of 50 to 100 nm is sequentially deposited. Subsequently, as shown in FIG. 1B, the Al film 3 is etched using a mixed acid aqueous solution of phosphoric acid + nitric acid + acetic acid using a novolak resin-based photoresist as a mask (not shown) to form Al in the gate pad portion. After the film 5 and the Al film 4 of the gate electrode portion are formed, the photoresist is peeled off. By this etching, the Al film (not shown) in the gate wiring portion is also patterned at the same time.
[0016]
Next, as shown in FIG. 1C, after depositing a second barrier metal 6 having a thickness of 100 to 150 nm made of a refractory metal such as chromium (Cr) by a sputtering method using argon gas, a novolac is deposited. A pattern of a resin-based photoresist 7 is formed.
[0017]
Next, as shown in FIG. 1D, after patterning the first barrier metal 2 and the second barrier metal 6 by etching with a mixed aqueous solution of ceric ammonium nitrate and nitric acid using the photoresist 7 as a mask, The resist 7 is stripped, and the lower gate pad 8 and the first barrier metal 2, the Al film 4, and the second barrier metal 6 made of a multilayer film of the first barrier metal 2, the Al film 5, and the second barrier metal 6 are removed. A gate electrode 9 made of the multilayer film is formed. By this etching, a gate wiring (not shown) made of a multilayer film of the first barrier metal 2, Al film and second barrier metal 6 is also patterned.
[0018]
Then, it is immersed in warm water for 20 to 30 minutes and dried. In this warm water treatment, when a void 60 or the like exists in the second barrier metal 6 as shown in FIG. 4A, the surface of the Al film 3 exposed at the bottom of the void 60 as shown in FIG. 60 parts of voids are filled with an Al hydroxide film 70 formed by hydrating the surface of the Al film 3 by the intrusion of warm water. The Al hydroxide film 70 has a protective action against an etching gas in a post process of the void 60 part, and can prevent the etching of the Al film by the etching gas. Further, even if the hydration reaction of the Al film 3 at the void 60 part proceeds to the bottom of the Al film 3, the first barrier metal 2 exists in the base, so that the Al film 3 is prevented from being peeled off. In addition, since the melt | dissolution rate of Al film | membrane increases rapidly when temperature exceeds 50 degreeC, the preferable temperature of said warm water treatment is 30-50 degreeC. If the acidity (PH) of the hot water is less than 5 or exceeds 8, the dissolution rate of the Al film increases, so the pH of the hot water is controlled in the range of 5-8.
[0019]
After the above hot water treatment, as shown in FIG. 2A, after depositing a gate insulating film 10 having a thickness of 100 to 300 nm made of a silicon nitride film (SiN _x ) or a silicon oxide film (SiO ₂ ) on the entire surface of the substrate, A semiconductor film 11 having a thickness of 20 to 300 nm made of an amorphous silicon film and an impurity semiconductor film 12 having a thickness of 20 to 100 nm made of amorphous silicon doped with an impurity such as phosphorus are sequentially deposited, and a conductive film such as an Al film or Cr is further deposited. 13 is deposited.
[0020]
Next, as shown in FIG. 2B, the conductive film 13 and the impurity semiconductor film 12 are etched and patterned by photolithography to form the source electrode 14 and the drain electrode 15. Thereafter, a channel is formed in the semiconductor layer by plasma etching using fluorine gas. In this step, although the gate wiring 50 is exposed as shown in FIG. 3, even if there is a defect such as a void in the second barrier metal 6 of the gate wiring, the defective portion is Al hydroxylated by the above hot water treatment. Since it is protected by the film, the inner Al film is prevented from being eroded by the plasma gas. This processing method can also be applied when the source electrode, the drain electrode, and the drain contact hole have the same structure.
[0021]
Next, as shown in FIG. 2C, after an insulating film 16 made of a silicon nitride film (SiN _x ) having a thickness of 100 to 300 nm is deposited on the entire surface of the substrate, the insulating film 16, the semiconductor film 11, Three layers of the gate insulating film 10 are etched and patterned. In this step, a contact hole 20 reaching the gate pad 8, a contact hole 21 reaching the drain electrode, and a contact hole 22 reaching the source electrode 14 are also formed. FIG. 3 shows a plan view of the main part of the panel corresponding to the cross-sectional view of FIG. In FIG. 3, it can be seen that the gate wiring 50 is exposed. It can also be seen that the source wiring 30 is covered with the patterned insulating film 16.
[0022]
Next, as shown in FIG. 2D, an ITO film having a thickness of 30 to 200 nm is deposited on the entire surface by sputtering, and then the ITO film is patterned by plasma etching using fluorine gas to obtain a gate pad terminal 17 and a source pad. The active panel is manufactured by forming the terminal 18 and the pixel electrode 19. In this plasma etching process, the gate wiring 50 is exposed as shown in FIG. 3, but even if there is a defect such as a void in the second barrier metal 6 of the gate wiring, the defective portion is made of Al by the above hot water treatment. Since it is protected by the hydroxide film, the inner Al film is prevented from being eroded by the plasma gas.
[0023]
In the above embodiment, an Al film is used as the low resistance material of the wiring. However, a material in which Cu, Si, Mo, and Nd are added to Al can be used. In addition to Cr, Ti or Ti can be used as the barrier metal. Ta high melting point metal can also be used.
[0024]
【The invention's effect】
As described above, in the method for manufacturing an active panel of a liquid crystal display device according to the present invention, the second barrier metal / aluminum or aluminum alloy / first barrier metal multilayer wiring is patterned and then subjected to hot water treatment to perform the second barrier. Hot water permeates through the voids and other defective parts generated in the metal, thereby forming an Al hydroxide film (Al (OH) ₃ film) on the surface of the aluminum or aluminum alloy in the defective parts such as voids. It is possible to prevent disconnection of the gate wiring due to the plasma etching gas or the like and to improve the manufacturing quality of the active panel.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a panel for explaining a process of a method for manufacturing an active panel of a liquid crystal display device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the main part of the explanation panel for explaining the process following FIG.
FIG. 3 is a plan view of a main part of the panel corresponding to the cross-sectional view of FIG.
4 is a cross-sectional view of the main part of the panel for explaining the action of hot water treatment in the step of FIG. 1 (d), (a) is a cross-sectional view before the hot water treatment, and (b) is after the hot water treatment. FIG.
FIG. 5 is a cross-sectional view of a main part of the panel for explaining a manufacturing process of an active panel of a conventional liquid crystal display device.
[Explanation of symbols]
1,100 Substrate 2 First barrier metal 3, 4, 5 Al film 6 Second barrier metal 7 Photoresist 8 Lower gate pad 9 Gate electrodes 10, 105 Gate insulating films 11, 106 Semiconductor films 12, 107 Impurity semiconductor films 13 Conductive film 14, 108 Source electrode 15, 109 Drain electrode 16 Insulating film 17 Gate pad terminal 18 Source pad terminal 19, 118 Pixel electrode 20, 21, 22 Contact hole 30, 110 Source wiring 50 Gate wiring 60 Void 70 Al hydroxylation Film 101 Gate bus wiring 101a Second gate bus wiring 103 Gate electrode 103a Second gate electrode 104 Gate pad 104a Second gate pad 111 Retention capacitance electrode 112 Source pad 113 Protective layer 114 Drain contact hole 115 Source contact hole 116 Gate contact hole 117 Storage capacitor contact hole 119 Source pad connection terminal 120 Gate pad connection terminal

Claims (4)

After sequentially depositing a first barrier metal and an aluminum-based metal film on the substrate, patterning the aluminum-based metal film, and a second on the substrate including the surface and side surfaces of the patterned aluminum-based metal film A step of depositing a barrier metal, and covering the lower surface of the patterned aluminum-based metal film with the first barrier metal and the upper surface and side surfaces of the aluminum-based metal film with the second barrier metal. The first barrier metal and the second barrier metal are patterned to form a gate pad, a gate electrode, and a gate wiring composed of a multilayer film of the first barrier metal, the aluminum metal film, and the second barrier metal. Forming the gate insulating film on the substrate and then forming the gate insulating film on the gate insulating film; In a method for manufacturing an active panel of a liquid crystal display device, the method comprising: forming a source electrode and a drain electrode; and depositing an insulating film on the substrate and then forming a pixel electrode on the insulating film. After forming the gate electrode and the gate wiring, and before depositing the gate insulating film on the substrate, the surface of the gate pad, the gate electrode and the gate wiring is at a temperature of 30 ° C. to 50 ° C., And an aluminum hydroxide film is formed on the defective portion of the second barrier metal by hot water treatment with hot water having an acidity of 5 to 8 in pH value. Method. After sequentially depositing a first barrier metal and an aluminum-based metal film on the substrate, patterning the aluminum-based metal film, and a second on the substrate including the surface and side surfaces of the patterned aluminum-based metal film A step of depositing a barrier metal, and covering the lower surface of the patterned aluminum-based metal film with the first barrier metal and the upper surface and side surfaces of the aluminum-based metal film with the second barrier metal. The first barrier metal and the second barrier metal are patterned to form a gate electrode, a gate wiring, or a source electrode composed of a multilayer film of the first barrier metal, the aluminum-based metal film, and the second barrier metal. And a method of manufacturing an active panel of a liquid crystal display device including a step of forming a drain electrode Then, after forming the electrode or the wiring, the surface of the electrode or the wiring is warm water treated with warm water having a temperature of 30 ° C. to 50 ° C. and an acidity of PH value of 5 to 8, An active liquid crystal display device comprising a step of forming an aluminum hydroxide film on the surface of the aluminum-based metal film exposed to the defective portion by impregnating hot water into the defective portion of the second barrier metal. Panel manufacturing method. 3. The active panel of the liquid crystal display device according to claim 1, wherein one selected from Cr, Ti, and Ta is used as the first barrier metal or the second barrier metal. Production method. 3. The method for manufacturing an active panel of a liquid crystal display device according to claim 1, wherein the aluminum-based metal film is aluminum or an alloy obtained by adding silicon, copper, molybdenum, or neodymium to aluminum.

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