KR100269519B1 - Method of forming photoresist pattern on metal layer and method of fabricating liquid crystal display - Google Patents

Abstract

PURPOSE: A method for forming a photoresist pattern on a metal layer and a method for manufacturing a liquid crystal display thereby are provided to remove clearly the photoresist pattern after processing by forming a buffer film on the surface of the metal layer. CONSTITUTION: A gate line(21) is formed on a substrate(20), and the first insulating film(22) is formed on the gate line(21). An active layer(23) is formed on the first insulating film(22) and a metal layer(24) is formed on the active layer(23). A photoresist pattern is formed on the metal layer(24) and a buffer film(25') adhered to the photoresist pattern is formed between the metal layer(24) and the photoresist pattern. The buffer film(25') is made of an oxide film, an aluminum film and so on. The metal layer(24) is etched by using the photoresist pattern as a mask, so that a source/drain line is formed. A pixel electrode is formed to connect with the drain line electrically.

Description

METHODS OF FORMING PHOTORESIST PATTERN ON METAL LAYER AND METHOD OF FABRICATING LIQUID CRYSTAL DISPLAY}

The present invention relates to a method of forming a photoresist pattern on a metal layer and a method of manufacturing a liquid crystal display device using the same. After the photolithography process, the present invention relates to a method of forming a photoresist pattern on a metal layer to remove the photoresist pattern cleanly and a method of manufacturing a liquid crystal display using the same.

Photolithography is a technique commonly used to form photoresist patterns in semiconductor device manufacturing processes. The photoresist pattern formed through the photolithography process is used as a mask for the selective etching process or the selective ion doping process. Photolithography is performed by forming a photoresist layer on a predetermined substrate, selectively exposing the photoresist layer, and then removing or leaving portions selected by the development process. Form. The purpose of development is to remove the unselected portions of the photoresist layer on the substrate by the developer. The predetermined substrate is various, such as a metal layer, an insulating film layer, or a semiconductor layer. Depending on the surface properties of these substrates, the photoresist adheres strongly or weakly to the substrate. The photoresist is an organic chemical substance whose molecular structure changes when light is projected, and has good adhesion with a material having hydrophobicity due to the nature of the material structure.

1A to 1E show a manufacturing process diagram of a liquid crystal display device according to the prior art. For convenience, a description of the gate line and the data line will be omitted in the manufacturing process described later.

Referring to FIG. 1A, after the first conductive layer is formed on the insulating substrate 10, the first conductive layer is patterned by photolithography to form the gate electrode 11. Subsequently, the first insulating film 12, the amorphous silicon layer and the amorphous silicon layer doped with the high concentration impurity are sequentially formed on the exposed entire surface, and then dehydrogenation and laser annealing are performed to form the amorphous silicon layer and the high concentration impurity. The doped amorphous silicon layer is polycrystalline. Subsequently, the silicon layer doped with the high concentration impurity that has been crystallized is patterned by photolithography to form an ohmic contact layer 15, and the crystallized silicon layer at the bottom thereof is etched using the ohmic contact layer 15 as a mask. To form an active layer 14. In this case, the first insulating layer 12 is formed by depositing a conventional insulating material such as silicon oxide or silicon nitride.

Referring to FIG. 1B, after forming the second conductive layer 17L on the exposed substrate, a photoresist layer is continuously formed by applying photoresist on the entire surface of the substrate. Thereafter, the photoresist is selectively exposed and developed to form the photoresist pattern PR. In this case, it is common to remove the substrate by precipitating the developer in a developer capable of removing the photoresist in a development process in order to form a photoresist pattern.

Referring to FIG. 1C, a source electrode 17S and a drain electrode 17D are formed by etching the second conductive layer 17L at the bottom thereof using the photoresist pattern PR as a mask. Subsequently, the photoresist pattern PR used as a mask is removed by dipping a substrate in a developer. Next, the exposed portion of the ohmic contact layer 15 is etched and removed using the source electrode 17S and the drain electrode 17D as a mask.

However, when the source / drain is formed using a metal material such as chromium, titanium, or tungsten instead of aluminum, the photoresist may not be completely removed even after the development process. This is because the photoresist has a strong adhesion to metals such as chromium, titanium, or tungsten, and thus is not completely removed by the developer and remains on top of the source / drain. In the drawing, portions marked in bold on the top of the source electrode 17S and the drain electrode 17D represent residual photoresist.

Referring to FIG. 1D, after the protective film 18 is formed on the entire surface of the substrate, the protective film 18 is patterned by photolithography to form a contact hole C exposing a part of the drain electrode 17D. Thereafter, an oxygen ashing process using an oxygen plasma is performed to remove the photoresist remaining on the upper end of the drain electrode 17D to remove the photoresist remaining on the exposed drain electrode. The oxygen ashing process is performed to prevent contact failure between the drain electrode 17D and the pixel electrode in a subsequent process by removing the photoresist remaining on the upper end of the drain electrode 17D.

Referring to FIG. 1E, after the transparent conductive layer is formed over the exposed substrate, the transparent conductive layer is patterned by photolithography to form the pixel electrode 19 connected to the exposed drain electrode 17D.

As described above, in the prior art, an oxygen ashing process is performed to remove contact between the drain electrode and the pixel electrode, thereby removing the photoresist remaining on the upper end of the drain electrode. However, since this process proceeds after forming the protective film, the photoresist is exposed to heat or other contaminated environment and deteriorates in the protective film forming step. In this case, the photoresist becomes difficult to remove even by the oxygen ashing process.

As an alternative to this, even if the oxygen ashing process is performed before the protective film formation process, as shown in FIG. 1C, the oxygen ashing process must be performed while the upper end of the active layer is exposed, thereby causing contamination of the active layer, thereby improving device characteristics. Weakens.

In the present invention, when the metal layer is formed using a metal material having a high adhesion to the photoresist, the metal layer is surface-treated to form a buffer film having weak adhesion with the photoresist on the surface of the metal layer, thereby completing the photolithography process. You are trying to get rid of it cleanly.

The present invention provides a process for applying a photoresist on a metal layer, selectively exposing and developing the applied photoresist to form a photoresist pattern, and optionally applying the photoresist pattern as a mask to the metal layer. In the advanced technology, the metal layer is surface treated so as to weaken adhesion to the photoresist before the process of applying the photoresist. The surface treatment of the metal layer may be performed by oxygen plasma, a wetting technique using an oxidation promoter solution, an ion beam treatment, a sputtering treatment, or the like.

A first step of forming a gate wiring on a substrate, a second step of forming a first insulating film covering the gate wiring material, a third step of forming an active layer on the first insulating film, and forming a metal layer on the active layer A fourth step of forming a photoresist pattern on the metal layer, a sixth step of forming a source / drain wiring by etching the metal layer using the photoresist pattern as a mask, and the drain A method of manufacturing a liquid crystal display device comprising a seventh step of forming a pixel electrode to be connected, wherein a buffer film having weak adhesion to the photoresist is formed on a surface of the metal layer between the fourth step and the fifth step. It is characterized by. The buffer film may be an oxide film, an aluminum film, a hydrophilic film, or the like.

1A through 1E are manufacturing process diagrams of a liquid crystal display device according to the related art.

2A through 2F are manufacturing process diagrams of the liquid crystal display device according to the present invention.

2A to 2E show a manufacturing process of the liquid crystal display according to the present invention. For convenience, a description of the gate line and the data line will be omitted in the manufacturing process described later. In this embodiment, for example, the source electrode and the drain electrode are formed of a metal material having high adhesion to the photoresist such as chromium, titanium, or tungsten.

Referring to FIG. 2A, after forming the first conductive layer on the insulating substrate 20, the first conductive layer is patterned by photolithography to form the gate electrode 21. The first conductive layer may be formed by depositing a conventional metal material such as chromium or molybdenum by a deposition technique by sputtering. Subsequently, the gate insulating film 22, the amorphous silicon layer, and the amorphous silicon layer doped with the high concentration impurity are sequentially formed on the exposed entire surface, and then doped with the amorphous silicon layer and the high concentration impurity by dehydrogenation and laser annealing. The amorphous silicon layer is polycrystalline. Subsequently, the silicon layer doped with the high concentration impurity that has been crystallized is patterned by photolithography to form an ohmic contact layer 24, and the crystallized silicon layer at the bottom thereof is etched using the ohmic contact layer 24 as a mask. To form an active layer 23. In this case, the gate insulating film 24 may be formed by depositing a conventional insulating material such as silicon oxide or silicon nitride by a deposition technique by PECVD (Plasma Enhanced Chemical Vapor Deposition).

Referring to FIG. 2B, a second conductive layer 25L is formed by depositing a metal material such as chromium, titanium, or tungsten on the exposed substrate by a sputtering deposition technique. Thereafter, the second conductive layer 25L is surface treated to weaken the adhesion between the second conductive layer 25L and the photoresist. This step is performed to apply a photoresist on the second conductive layer 25L, and then to remove the photoresist cleanly after the step of using the photoresist.

In order to weaken the adhesion with the photoresist, a buffer film having a weak adhesion with the photoresist, such as an oxide film or an aluminum film, may be formed in the metal layer. The oxide film or aluminum film is less adhered to the photoresist than other thin films. Therefore, the photoresist located on the metal layer whose surface is oxidized can be removed cleanly. The method of forming an oxide film on the metal layer includes a wetting technique for oxidizing the surface by subjecting the metal layer to an oxygen plasma (O ₂ plasma) treatment or precipitating the metal layer by oxidizing the surface of the metal layer. There is a sputtering technique using aluminum as a method of forming an aluminum film on the substrate. In addition, there is a method of rearranging the particle structure of the surface so that the surface of the metal layer itself has a weak adhesion with the photoresist. As mentioned, the photoresist has poor adhesion with a hydrophilic material due to its structural properties. Therefore, if the particles are rearranged to have hydrophilic properties on the surface of the metal layer, the adhesion of the metal layer and the photoresist may be weakened and the photoresist may be removed cleanly. This object can be achieved by ion beam treatment on the surface of the metal layer.

Unexplained reference numeral 25 'denotes a buffer film formed on the surface of the second conductive layer, and as described above, the buffer film means a film having a weak adhesion degree with a photoresist such as an oxide film, an aluminum film, or a hydrophilic film.

Referring to FIG. 2C, a photoresist is formed on top of the second conductive layer 25L to form a photoresist layer. Thereafter, the photoresist layer is selectively exposed and developed to form a photoresist pattern PR. In this case, in the development process that is performed to form the photoresist pattern PR, it is common to precipitate and remove the substrate in a developer capable of removing the photoresist. Next, the second conductive layer at the bottom thereof is etched using the photoresist pattern PR as a mask to form the source electrode 25S and the drain electrode 25D.

Referring to FIG. 2D, the substrate is immersed in a developer to remove the photoresist pattern PR used as a mask. At this time, the photoresist pattern PR is a source electrode (25S) and the drain electrode surface-treated (top of the buffer film 25 'weakly adhered to the photoresist) and the drain electrode in order to weaken the adhesion to the photoresist Since it is located at the top of the (25D), it is easily separated from the source electrode (25S) and drain electrode (25D) during the development process and removed cleanly. Next, the exposed portion of the ohmic contact layer 24 is etched and removed using the source electrode 25S and the drain electrode 25D as a mask.

Referring to FIG. 2E, after the protective film 26 is formed on the entire surface of the substrate, the protective film 26 is patterned by photolithography to form a contact hole C exposing a part of the drain electrode 25D. At this time, when the buffer film is an oxide film, the buffer film disposed on the upper portion of the drain electrode 25D is removed to form the contact hole C so that the second conductive layer constituting the drain electrode 25D can be exposed as it is. This is for good contact between the pixel electrode and the drain electrode formed thereafter.

Referring to FIG. 2F, after the transparent conductive layer is formed over the exposed substrate, the transparent conductive layer is patterned by photolithography to form the pixel electrode 27 connected to the exposed drain electrode 25D. The pixel electrode 27 is safely connected to the drain electrode 25D without interference of foreign matter.

In the present invention, the buffer film is formed by surface treatment only on the second conductive layer forming the drain electrode connected to the pixel electrode. However, the present invention can be applied to other conductive layers having the same principle. In addition, although the embodiment of the present invention has been described only for the manufacture of a liquid crystal display device, the present invention can be applied to a manufacturing process requiring a process of removing the photoresist pattern.

According to the present invention, the metal layer is surface-treated in advance before applying the photoresist, so that the photoresist pattern can be removed on the metal layer in a subsequent step. Therefore, the contact between the metal layer and the conductive layer to be electrically connected to the metal layer in the absence of the foreign matter is made, it is possible to reduce the contact failure compared to the prior art.

Claims (18)

A process of applying a photoresist on a metal layer, a process of selectively exposing and developing the applied photoresist to form a photoresist pattern, and a technique of performing an arbitrary process on the metal layer using the photoresist pattern as a mask To And forming a photoresist pattern on the metal layer, wherein the metal layer is surface treated so as to weaken adhesion than when the metal layer and the photoresist are in direct contact before the photoresist coating step. The method according to claim 1, The surface treatment of the metal layer is a method of forming a photoresist on a metal layer, characterized in that by the oxygen plasma. The method according to claim 1, The surface treatment of the metal layer is a method of forming a photoresist on the metal layer, characterized in that by the wetting technique with an oxidation promoter solution. The method according to claim 1, The surface treatment of the metal layer is a method of forming a photoresist on the metal layer, characterized in that by the ion beam treatment. The method according to claim 1, The surface treatment of the metal layer is a method of forming a photoresist on the metal layer, characterized in that by the sputtering using aluminum. The method according to claim 1, And surface treating the metal layer to form an oxide film on the metal layer. The method according to claim 1, And surface treating the metal layer to form an aluminum film on the metal layer. The method according to claim 1, Surface treatment of the metal layer to form a photoresist on the metal layer, characterized in that the surface of the metal layer has a hydrophilic property. A first step of forming a gate wiring on a substrate, a second step of forming a first insulating film covering the gate wiring material, a third step of forming an active layer on the first insulating film, and forming a metal layer on the active layer A fourth step of forming a photoresist pattern on the metal layer, a sixth step of forming a source / drain wiring by etching the metal layer using the photoresist pattern as a mask, and the drain A method of manufacturing a liquid crystal display device comprising the seventh step of forming a pixel electrode to be connected, And forming a buffer film on the surface of the metal layer between the fourth process and the fifth process, wherein the buffer film has a weaker adhesion than when the photoresist is in direct contact with the metal layer. The method according to claim 9, The buffer film is a manufacturing method of a liquid crystal display device, characterized in that the oxide film. The method according to claim 9, The buffer film is a method of manufacturing a liquid crystal display device, characterized in that the aluminum film. The method according to claim 9, And the buffer film is a hydrophilic film formed by rearranging particles on the surface of the metal layer. The method according to claim 9, And the buffer film is formed by an oxygen plasma treatment. The method according to claim 9, And the buffer layer is formed by a wetting technique using an oxidation promoter. The method according to claim 9, And the buffer film is formed by sputtering. The method according to claim 9, And the buffer film is formed by ion beam treating the surface of the metal layer. The method according to claim 9, And the metal layer is formed of a metal material that is difficult to separate from the photoresist, such as chromium, titanium, or tungsten. The method according to claim 9, After the sixth step, Forming an insulating film covering the source / drain wiring; And forming a contact hole exposing a part of the drain.

Images