KR20000027578A - Method for manufacturing lcd using diffraction exposure technique - Google Patents

Abstract

PURPOSE: A method for manufacturing LCD using diffraction exposure technique is provided to resolve a problem in which a thickness of a surface is heterogeneously formed after etching a gate insulating film by removing a residual photoresist during an etching process and then completing the etching process. CONSTITUTION: An aluminum or an aluminum alloy is deposited and patterned on a transparent glass substrate(101) and a gate wire(113) is formed for connecting a gate electrode(111) and a gate electrode(111). A gate pad(115) is formed to an end side of the gate wire(113). A gate insulating film(117), a semiconductor material(133a), and a metal are successively deposited on the transparent glass substrate(101). A metal layer is patterned, and then a source electrode(121), a drain electrode(131) and a source wire(123) are formed. An impurity semiconductor layer(135) contacted to the semiconductor material(133a) under the source electrode(121) and the drain electrode(131) is formed. A protecting film(137) is deposited on the transparent glass substrate(101).

Description

Method for manufacturing liquid crystal display device using diffraction exposure technique

The present invention relates to a method of manufacturing a liquid crystal display by etching using a diffraction exposure technique. More particularly, the present invention relates to a manufacturing method of manufacturing a liquid crystal display device in which a substrate on which an insulating film, a semiconductor layer, and an insulating film are laminated is diffracted by a single mask process using a diffraction exposure technique will be.

Of the screen display devices that display image information on the screen, a cathode ray tube (or cathode ray tube (CRT)) has been used most often so far, which is bulky and heavy compared to the display area. Therefore, even if the display area is large, the thickness thereof is thin, so that a thin film type flat panel display device which can be used easily at any place has been developed and gradually replacing the CRT display device. Particularly, a liquid crystal display (or LCD (liquid crystal display)) is superior to a flat panel display having a different display resolution, and when a moving image is implemented, the quality of the liquid crystal display to be.

The driving principle of the liquid crystal display device is based on the optical anisotropy and polarization properties of liquid crystal. Since the structure is thin and long, the direction of molecular alignment can be controlled by artificially applying an electromagnetic field to liquid crystal molecules having directionality and polarization in the molecular arrangement. Therefore, when the alignment direction is arbitrarily adjusted, the light can be transmitted or blocked according to the arrangement direction of the liquid crystal molecules due to the optical anisotropy of the liquid crystal, and thus the liquid crystal display device is applied to a screen display device. At present, active matrix liquid crystal display devices in which a thin film transistor (or a thin film transistor) and a pixel electrode connected thereto are arranged in a matrix manner are excellent and offer the image quality and natural color. The structure of a liquid crystal panel which is a basic component of a general liquid crystal display device will be described in detail as follows. FIG. 1 is a perspective view showing a general structure of a liquid crystal panel, and FIG. 2 is a sectional view of a liquid crystal panel cut along a cutting line II-II in FIG.

In the liquid crystal panel, two panels (3, 5), in which various elements are installed, are opposed to each other and a liquid crystal layer (10) is sandwiched therebetween. On one panel of the liquid crystal display device, elements for implementing color are constituted. This is commonly referred to as "color filter panel 3 ". In the color filter panel 3, color filters 7 of red (R), green (G), and blue (B) are sequentially arranged along the positions of pixels designed in a matrix arrangement manner on the first transparent substrate 1a have. A very thin net-shaped black matrix 9 is formed between these color filters 7. [ This prevents mixed colors from appearing between each color. A common electrode 8 covering the color filter 7 is formed. The common electrode 8 serves as one electrode forming an electric field to be applied to the liquid crystal 10. [

Switching elements and wirings for generating an electric field for driving the liquid crystal are formed on the other panel of the liquid crystal display device. This is commonly referred to as "active panel 5 ". The active panel 5 has pixel electrodes 41 formed on the second transparent substrate 1b along the positions of pixels designed in a matrix manner. The pixel electrode 41 faces the common electrode 8 formed on the color filter panel 3 and serves as the other electrode forming the electric field applied to the liquid crystal 10. [ The signal lines 13 are formed along the horizontal alignment direction of the pixel electrodes 41 and the data lines 23 are formed along the vertical alignment direction. Here, in the case of the active matrix liquid crystal display device, the thin film transistor 19, which is a switching element for applying an electric field signal to the pixel electrode 41, is formed at one corner of the pixel electrode 41. In the case of an active matrix liquid crystal display device, the gate electrode 11 of the thin film transistor 19 is connected to the signal line 13 (accordingly, the signal line is also referred to as a "gate line"), 21 are connected to the data line 23 (thus, the data line is also referred to as a "source line"). The drain electrode 31 of the thin film transistor 19 is connected to the pixel electrode 41. A semiconductor layer 33 is formed between the source electrode 21 and the drain electrode 31 in the thin film transistor 19 and the source electrode 21 and the semiconductor layer 33 and between the drain electrode 31 and the semiconductor layer 33, (33) are in ohmic contact with each other. A gate pad 15 and a source pad 25 are formed at the ends of the gate wiring 13 and the source wiring 23, which are termination terminals (or terminals) for receiving signals applied from the outside. A gate pad terminal 57 and a source pad terminal 67 are further formed on the gate pad 15 and the source pad 25, respectively.

When an external electrical signal applied to the gate pad 15 is applied to the gate electrode 11 along the gate wiring 13, image information applied to the source pad 25 is applied to the source electrode 21 And is conducted to the drain electrode 31. [ On the other hand, when no signal is applied to the gate wiring 13, the source electrode 21 and the drain electrode 31 are disconnected. Therefore, it is possible to determine whether or not the data signal is applied to the drain electrode 31 by adjusting the signal of the gate electrode 11. Therefore, the data signal can be artificially transmitted to the pixel electrode 41 connected to the drain electrode 31. [ That is, the thin film transistor 19 serves as a switch for driving the pixel electrode. A gate insulating film 17 is formed for electrical insulation between the layer on which the gate wiring 13 and the like are formed and the layer on which the source wiring 23 and the like are formed and on the layer on which the source wiring 23 is formed, (37) are formed.

The two panels (the color filter panel 3 and the active panel 5) made in this manner are opposed to each other at regular intervals (the intervals are called "cell gaps"), 10) is filled. In order to keep the cell gap between the two panels (3, 5) constant and prevent the liquid crystal material from leaking out, the edges of the two substrates are sealed with a seal (81) like epoxy. Thus, a liquid crystal panel which is a main part of the liquid crystal display device is completed.

An active panel having a TFT and a pixel electrode, which is a switching element that plays a key role in driving liquid crystal in such a liquid crystal panel, is most important. Therefore, depending on how the active panel is made or the performance of the active panel, it has a decisive influence on the overall quality of the liquid crystal panel. Therefore, almost all technologies related to liquid crystal displays are focused on how to make an active panel. The present invention also relates to a method of manufacturing an active substrate, in particular, a method of manufacturing by a 4-mask process using a diffractive exposure technique. The conventional method of manufacturing an active substrate using the diffraction exposure technique according to the present invention and its problems will be described below. For ease of understanding, a conventional method of manufacturing an active substrate will be described with reference to FIG. 4, which is a cross-sectional view taken along line IV-IV of FIG. 3 and FIG. 3, which is a plan view of an active panel.

Aluminum or an aluminum alloy is deposited on the transparent glass substrate 1 and patterned to form a gate wiring 13 connecting the gate electrode 11 and the gate electrode 11. [ A gate pad 15 is formed at an end of the gate wiring 13. The gate electrode 11 is disposed at one corner of a designed pixel and the gate wiring 13 is connected to a gate electrode (Figs. 3 and 4A).

A gate insulating film including an insulating material such as silicon oxide (SiO x) or silicon nitride (SiN x) is formed on the substrate 1 on which the gate material (gate electrode 11, gate wiring 13 and gate pad 15) 17, a semiconductor material 33a such as intrinsic amorphous silicon, an impurity semiconductor material such as amorphous silicon doped with impurities, and a metal such as chromium, molybdenum, and the like in succession. The metal layer is patterned to form a source electrode 21, a drain electrode 31, a source wiring 23, and a source pad 25. The impurity semiconductor material is also etched at the same time when forming the source-drain material (the source electrode 21, the drain electrode 31 and the source wiring 23), and the impurity semiconductor material is etched under the source electrode 21 and the drain electrode 31 An impurity semiconductor layer 35 which makes an ohmic contact with the semiconductor material 33a is formed. The source electrode 21 and the drain electrode 31 are formed on both sides of the gate electrode 11 (FIGS. 3 and 4B).

A protective film 37 including an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx) is deposited on the substrate 1 on which the source-drain material is formed. In the first portion where the source electrode 21 and the drain electrode 31 are formed by using the diffraction exposure technique, all materials below the protective film 37 remain as they are. In the second portion where the gate wiring 13 is formed, The semiconductor material 33a and the gate insulating film 17 are etched to leave only the gate insulating film 17 and the remaining third portions of the protective film 37, the semiconductor material 33a, (1) is exposed. The fourth portion, which is a part of the drain electrode 31, removes the protective film 37 to form a drain contact hole 71 exposing the drain electrode 31. The diffraction exposure technique is used to change the degree of etching according to the portions in a single mask process. The detailed technique is as follows. First, a photoresist 91 is applied to a thickness of about 2 탆 on the protective film 37. The photoresist 91 is covered with a mask 93 and then exposed to light rays such as ultraviolet rays. In one example, the first portion is fully open because the photoresist must remain completely, and the second portion has a lattice-like opening pattern 95 to leave only a small thickness of photoresist, and the third portion and fourth portion The part should be free of photoresist, so use a completely masked photoresist. The lattice-like open pattern 95 has a lattice spacing suitable for the diffractive exposure technique. That is, it has a lattice spacing that is narrower than the resolution of the light source used for photosensitive exposure. The photoresist 91 is removed by about 2 mu m in the first portion and the photoresist 91 is removed by using the diffraction exposure technique in the second portion so that the photoresist 91 has a thickness similar to that of the gate insulating film 17 2000 Å to 4000 Å. Then, the protective film is exposed as it is without the photoresist 91 in the third and fourth parts. At this time, there is no photoresist 91 on a part of the protective film 37 covering the drain electrode in order to expose a part of the drain electrode 31 (FIGS. 3 and 4C).

The photoresist 91, the protective film 37, the semiconductor material 33a, and the gate insulating film 17 are etched in the second portion while the protective film 37, the semiconductor material 33a, and the gate insulating film 17 are etched in the third portion, In the first portion, only the photoresist 91 is etched to leave only about 2000 Å to 5000 Å. On the other hand, the protective film 37 covering the fourth portion which is a part of the drain electrode 31 is removed. Since the drain electrode 31 is a metal after the protective film 37 is etched, the fourth part is not affected by the etchant etching the protective film 37, the semiconductor material 33a, and the gate insulating film 17 at all. As a result, the semiconductor layer 33 is formed in the gate electrode 11, the gate wiring 13 is insulated by the gate insulating film 17, and the drain contact hole 71 exposing the drain electrode 31 is formed. . A gate contact hole 51 exposing the gate pad 15 and a source contact hole 61 exposing the source pad 25 are formed (FIGS. 3 and 4D).

Then, ITO (Indium Tin Oxide), which is a transparent conductive material, is deposited and patterned to form a pixel electrode 41 which contacts the drain electrode 31 through the drain contact hole 71. The pixel electrode 41 is formed in contact with the glass substrate 1 directly. A gate pad terminal 57 which contacts the gate pad 15 through the gate contact hole 51 and a source pad terminal 67 which contacts the source pad 25 through the source contact hole 61 (Figs. 3 and 4E).

By using the diffraction exposure method, it is possible to reduce the number of mask processes by varying the degree of partial etching as required while continuously etching the protective film, the semiconductor material, and the gate insulating film. However, in the diffraction exposure technique, since the etch process is performed using the remaining photoresist, the uniformity of the remaining gate insulating film to protect the gate wiring depends on the uniformity of thickness of the remaining photoresist in the continuous etching process . Generally, the photoresist is applied by a method such as spin coating, and its thickness is not uniform while undergoing exposure and development. Therefore, if the thickness of the surface of the gate insulating film formed using the diffraction exposure is not uniform after etching, a problem may occur such that the gate wiring is short-circuited in the following step. These problems ultimately cause various deteriorations in the quality of the liquid crystal display device.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of making a surface of an insulating film remaining in a portion using diffraction exposure uniform in a method of manufacturing a liquid crystal display device.

1 is a perspective view showing the structure of a general liquid crystal display device.

2 is a cross-sectional view showing the structure of a general liquid crystal display device.

3 is a plan view showing a general liquid crystal display device.

4 is a cross-sectional view showing a conventional method of manufacturing a liquid crystal display device using a diffraction exposure technique.

5 is a plan view showing a liquid crystal display device according to the present invention.

6 is a cross-sectional view illustrating a method of manufacturing a liquid crystal display device using the diffraction exposure technique according to the present invention.

Description of the Related Art

1, 101: substrate 11, 111: gate electrode

13, 113: gate wiring 15, 115: gate pad

17, 117: gate insulating film 21, 121: source electrode

23, 123: source wiring 25, 125: source pad

31, 131: drain electrode 33, 133: semiconductor layer

35, 135: an impurity semiconductor layer 37, 137: a protective film

41, 141: pixel electrode 51, 151: gate contact hole

57, 157: gate pad terminal 61, 161: source contact hole

67, 167: source pad terminal 71, 171: drain contact hole

91, 191: photoresist 93, 193: mask

195: grid pattern

According to an aspect of the present invention, there is provided a method of manufacturing a semiconductor device, including: applying a photoresist to a substrate on which an insulating film, a semiconductor layer, and a protective film are stacked, and developing and developing the photoresist with a mask including a lattice- Forming a third portion of the photoresist, wherein the photoresist is less than half of the first portion, by applying the lattice-like pattern to the substrate; Etching until the third portion of the insulating film and the semiconductor layer are removed by an etching method; removing the photoresist until all the photoresist of the second portion is removed; The semiconductor layer of the second portion is completely removed so that the insulating film completely disappears, and the dry etching It provides a method for manufacturing a liquid crystal display device comprising the step of proceeding. Hereinafter, embodiments and a method of manufacturing a liquid crystal display device according to the present invention will be described in detail with reference to FIG. 5, which is a plan view, and FIG. 6, a cross-sectional view taken along a line VI-VI in FIG.

Aluminum or an aluminum alloy is deposited on the transparent glass substrate 101 and patterned to form a gate wiring 113 connecting the gate electrode 111 and the gate electrode 111. A gate pad 115 is formed at the end of the gate line 113. The gate electrode 111 is disposed at one corner of the designed pixel, and the gate wiring 113 connects the gate electrodes 111 arranged in the row direction (FIGS. 5 and 6A).

A gate insulating film (not shown) including an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx) is formed on a substrate 101 on which the gate materials (gate electrode 111, gate wiring 113 and gate pad 115) A semiconductor material 133a such as an amorphous silicon film 117, intrinsic amorphous silicon, an impurity semiconductor material such as amorphous silicon doped with impurities, and a metal such as chromium, molybdenum and the like. The metal layer is patterned to form the source electrode 121, the drain electrode 131, and the source wiring 123. The impurity semiconductor material is also etched at the same time when forming the source-drain material (the source electrode 121, the drain electrode 131, and the source wiring 123), and the impurity semiconductor material is etched under the source electrode 121 and the drain electrode 131 And an impurity semiconductor layer 135 in ohmic contact with the semiconductor material 133a is formed. The source electrode 121 and the drain electrode 131 are formed on both sides of the gate electrode 111 (FIGS. 5 and 6B).

A protective film 137 including an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx) is deposited on the substrate 101 on which the source-drain material is formed. In the first part where the source electrode 121 and the drain electrode 131 are formed, all the materials below the protective film 137 remain as they are. In the second part where the gate wiring 113 is formed, The semiconductor material 133a and the gate insulating film 117 are both etched so that the glass substrate 101 is exposed so that the protective film 137, the semiconductor material 133a and the gate insulating film 117 are both etched to leave only the gate insulating film 117, do. The fourth portion, which is a part of the drain electrode 131, removes the protective film 137 to form a drain contact hole 171 exposing the drain electrode 131. The diffraction exposure technique is used to change the degree of etching according to the portions in a single mask process. The detailed method is as follows. First, a photoresist 191 is applied to a thickness of about 2 탆 on the protective film 137. The photoresist 191 is covered with a mask 193 and then exposed to light rays such as ultraviolet rays. In one example, the first portion is fully open since the photoresist 191 must remain completely, and the second portion has a lattice-like open pattern 195 to leave only a small thickness of the photoresist 191, The third and fourth portions should be free of photoresist and thus sensitized using a fully shielded mask 193. The lattice-like open pattern 195 has a lattice spacing that is narrower than the resolution of the light source used for photo-sensitization so as to have an appropriate lattice spacing in the diffraction exposure technique. After the photoresist 191 is patterned, a photoresist 191 is left on the first portion of the photoresist 191 by about 2 탆 and a photoresist 191 is formed on the photoresist 191 by using a diffraction exposure technique, (4000 to 5000 Å) which is about ¼ of the thickness. Then, the protective film is directly exposed to the third and fourth portions without the photoresist 191. At this time, there is no photoresist 191 on a part of the protective film 137 covering the drain electrode 131 in order to expose a part of the drain electrode 131. In this state, the protective film 137 and the semiconductor material 133a are etched in the third portion, and the photoresist 191 is etched to some extent in the first portion and the second portion. The etching process is stopped with the second portion of the photoresist remaining (Figs. 5 and 6D).

Then, the photoresist remaining in the second portion is removed by ashing with oxygen plasma. At the same time, the photoresist of the first portion is also removed to the same thickness. As a result, about 1 mu m of the photoresist remains in the first portion and the photoresist disappears in the remaining portions (the second and third portions). In this state, the etching process is restarted to completely remove the gate insulating film 117 from the third portion, and the protective film 137 and the semiconductor material 133a are removed from the second portion, and in the first portion, Only the photoresist 191 is etched to leave only about 3000 Å to 5000 Å. On the other hand, the protective film 137 covering the fourth portion, which is a part of the drain electrode 131, is removed. Since the drain electrode 131 is a metal after the protective film 137 is etched, the fourth part is not affected at all during the etching of the protective film 137, the semiconductor material 133a, and the gate insulating film 117. As a result, the semiconductor layer 133 is formed in the gate electrode 111, the gate wiring 113 is insulated by the gate insulating film 117, and the drain contact hole 171 exposing the drain electrode 131 is formed. . A gate contact hole 151 exposing the gate pad 115 and a source contact hole 161 exposing the source pad 125 are formed (FIGS. 5 and 6E).

Then, ITO (Indium Tin Oxide), which is a transparent conductive material, is deposited and patterned to form a pixel electrode 141 which contacts the drain electrode 131 through the drain contact hole 171. The pixel electrode 141 is formed in direct contact with the glass substrate 101. A gate pad terminal 157 which contacts the gate pad 115 through the gate contact hole 151 and a source pad terminal 167 which contacts the source pad 125 through the source contact hole 161 (Figs. 5 and 6F).

The present invention relates to a method for preventing unevenness in the thickness of a gate insulating film to which diffraction exposure is applied due to a non-uniform thickness of a photoresist in a method of manufacturing a liquid crystal display device using diffraction exposure. In the diffraction exposure technique, since the etch process is performed using the remaining photoresist, the uniformity of the thickness of the remaining gate insulating film to protect the gate wiring is determined according to the uniformity of thickness of the remaining photoresist in the continuous etching process In the present invention, since the remaining photoresist is removed during the etching and the etching process is completed, the surface of the gate insulating film has a uniform flat surface. Therefore, in the present invention, the problems that occur due to the non-uniform thickness of the surface of the gate insulating film after etching using the diffraction exposure do not occur.

Claims (4)

Forming a gate material on the substrate with a first metal; Continuously depositing a first insulating material, a semiconductor material, and a second metal on the gate material, and patterning the second metal to form a source-drain material; Forming a passivation layer over the source-drain material; Applying a photoresist on the protective film and forming a first portion in which the photoresist is completely left using diffraction exposure and a second portion in which the photoresist is about 1/4 to 1/2 remaining, Forming a removed third portion; The etch process is stopped, the remaining photoresist of the second portion is completely removed, and the etch process is resumed again, so that the first portion may be etched away to remove any remaining material And the third portion is formed by removing all of the protective film, the semiconductor layer and the gate insulating film to complete the thin film transistor. A method of manufacturing a liquid crystal display device. The method according to claim 1, And forming a pixel electrode connected to the drain electrode of the thin film transistor with a conductive material on the completed substrate. Applying a photoresist over a substrate on which a gate material, a gate insulating film, a semiconductor material, a source-drain material, and a protective film are stacked; Forming a first portion in which the photoresist is completely left using a diffraction exposure, a second portion in which the photoresist is left in 1/4 to 1/2 of the area, and a third portion in which the photoresist is completely removed Wow; The etch process is stopped, the remaining photoresist of the second portion is completely removed, and the etch process is resumed again, so that the first portion may be etched away to remove any remaining material And the third portion is formed by removing all of the protective film, the semiconductor layer and the gate insulating film to complete the thin film transistor. A method of manufacturing a liquid crystal display device. The method of claim 3, And forming a pixel electrode connected to the drain electrode of the thin film transistor with a conductive material on the completed substrate.