JP3168696B2 - Liquid crystal display panel manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display panel having a thin film transistor matrix as an active matrix driving method, and more particularly to an electrode wiring of a thin film transistor matrix.

The above-mentioned electrode wiring is formed on a liquid crystal display panel (LC).
In order to avoid signal delay due to the enlargement of D), a reduction in resistance is required, and a two-layer structure of a low-resistance metal and a protective metal for protecting the same is provided. Simplification and further reduction in resistance are desired.

[0003]

2. Description of the Related Art In a liquid crystal display panel having a thin film transistor matrix, electrode wiring of the thin film transistor matrix is made of aluminum, which is a low-resistance metal for lowering resistance, and a protective metal such as titanium, which supplements and protects its heat resistance and chemical resistance. And the titanium covers the exposed surface (upper surface and side surface) of aluminum. This structure is necessary especially for electrode wiring on a transparent insulating substrate (glass substrate).

Conventionally, this electrode wiring is formed by the following steps. First, an aluminum film is formed on a glass substrate and patterned by photolithography. Next, a titanium film is formed thereon and patterned by photolithography so as to be wider than the aluminum pattern, thereby completing the process.

The above-mentioned photolithography requires a process of applying a resist on an aluminum film or a titanium film, exposing and developing the resist film (forming a resist mask), and etching an aluminum film or a titanium film. Since a photomask for exposure must be prepared for each photolithography, many steps are required.

The reason why the pattern width of titanium is made wider than the pattern width of aluminum is that titanium covers the side surface of aluminum. The difference between the two pattern widths needs to be several μm or more in order to allow a margin for alignment with the aluminum pattern.

[0007]

Therefore, the conventional method of forming the above-mentioned electrode wiring has a problem that it requires an extremely large number of steps because photolithography is performed twice. When the number of steps increases, a problem such as adhesion of dust also occurs.

There is another problem that the line width of aluminum becomes narrower than the wiring width by several μm or more. If the thickness of the aluminum film is increased so as to compensate for the narrow line width of aluminum in order to reduce the resistance, the step coverage of the upper layer film is affected and the upper layer wiring is easily broken.

The present invention relates to an LCD having a thin film transistor matrix, and more particularly to an electrode wiring of the thin film transistor matrix, which simplifies the process of forming a two-layer structure in which the upper and side surfaces of a low-resistance metal are covered with a protective metal. An object of the present invention is to provide a method of manufacturing an LCD in which the line width of the low-resistance metal is widened within the wiring width of the electrode wiring.

[0010]

In order to achieve the above object, a method of manufacturing an LCD according to the present invention is to provide an LCD having a thin film transistor matrix formed on a transparent insulating substrate. A step of forming a two-layer film including a first film of a low-resistance metal and a second film of a protective metal thereon on the insulating substrate, and a step of patterning the two-layer film; Depositing a third film made of the protective metal on the patterned two-layer film and the insulating substrate outside the patterned two-layer film, and forming a side surface of the two-layer film by anisotropic etching on the third film. And removing it so as not to remain on the outside thereof.

In this case, it is preferable that the deposition thickness of the third film is equal to or greater than the thickness of the first film, the low-resistance metal is aluminum, and the protection metal is
The metal should be selected from titanium, molybdenum, tantalum, tungsten, nickel, and chromium.

[0012]

According to the above-described steps, after the anisotropic etching is completed, a desired electrode wiring is formed in which the upper and side surfaces of the low resistance metal are covered with the protective metal. The second film covers the upper surface, and the third film covers the side surfaces.

The photolithography required during that time is one time for patterning the two-layer film, which is one time less than the conventional two times. Instead the third
Deposition and anisotropic etching are added, but the process is much less than a single photolithographic process. Therefore, the process is simplified as compared with the related art.

Although the patterning of the third film by anisotropic etching corresponds to the conventional patterning of titanium (protective metal), it is self-aligned with the pattern of the two-layer film. Since it is performed, it is essentially the same as omitting the alignment margin previously required,
The line width of the low-resistance metal is increased within the wiring width of the electrode wiring to be formed.

The above conditions for the thickness of the third layer are such that, during the anisotropic etching, the thickness of the low resistance metal side surface due to an excessively small thickness cannot be caused. In addition, the above metals listed as protective metals, other than titanium, also have properties for protecting the electrode wiring in the same manner as titanium.

Incidentally, the anisotropic etching is performed in the third step.
In order to remove this film on the side surface of the above-mentioned two-layer film so as not to leave the film outside the film, the thickness of the third film is slightly over-etched. This cleans the surface of the protective metal because the surface of the second film in the two-layer film is slightly dripped to remove surface residual impurities such as resist. This cleaning is useful for preventing LCD defects.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the side views in the order of steps shown in FIG. This embodiment is an example in which aluminum and titanium are used for a gate electrode wiring by a sputtering method.

In FIG. 1, first, referring to (a), a first film 2 is formed on a glass substrate 1 which is a transparent insulating substrate.
Then, aluminum as a low-resistance metal is deposited to a thickness of 500 °, and titanium as a second metal 3 is deposited as a second film 3 to a thickness of 1000 ° to form a two-layer film 4. The deposition of aluminum for the first film 2 and the deposition of titanium for the second film 3 are performed using a DC sputtering apparatus in an Ar atmosphere at a pressure of about 0.005 Torr.
After that, a resist mask 5 having a pattern corresponding to the electrode wiring to be formed (strictly reduced by about 0.1 μm inward from the outline) is formed on the two-layer film 4.

Next, referring to (b), RIE (reactive ion etching) which is anisotropic etching
Thus, the second film 3 and the first film 2 of the two-layer film 4 are etched into the same pattern using the resist mask 5 as a mask. After that, the resist mask 5 is removed.

Next, referring to (c), the same protective metal (titanium) as the second film 3 is formed as the third film 6 by 1000.
Deposited to a thickness of This deposition is performed under the same conditions as the deposition of the second film 3. The third film 6 covers the upper surface and the side surfaces of the two-layer film 4, and the surface on the glass substrate 1 is higher than the surface on the two-layer film 4 by two.
It becomes lower by the step difference of the layer film 4.

Next, referring to (d), the third film 6 is removed by RTE as anisotropic etching so that the third film 6 remains on the side surface of the two-layer film 4 but does not remain outside. For this purpose, the thickness of the third film 6 is slightly over-etched. As a result, the thickness of titanium, which is the second film 3 of the two-layer film 4, becomes about 800 °, and at the same time, the remaining titanium, which is the third film 6, is the first film 2 of the two-layer film 4. The side surfaces of aluminum are covered with a thickness of about 800 °, and the upper surface and the side surfaces of aluminum, which is a low-resistance metal, are covered with titanium, which is a protective metal.

As apparent from the above description, the difference between the wiring width and the line width of the low-resistance metal inside the electrode wiring is only about 0.16 μm, and the difference is several μm or more. As compared with the conventional method, the line width of the low-resistance metal is increased and the resistance is reduced.

The protective metal used for the second film 3 and the third film 6 can be appropriately selected from titanium, molybdenum, tantalum, tungsten, nickel, and chromium. The dimensions described in the embodiments are merely examples, and
Can vary depending on the design of

[0024]

As described above, according to the present invention, the present invention relates to an LCD having a thin film transistor matrix, and more particularly to an electrode wiring of the thin film transistor matrix, which has a two-layer structure in which the upper and side surfaces of a low-resistance metal are covered with a protective metal. A manufacturing method is provided in which the forming process is simplified, the line width of the low-resistance metal is widened within the wiring width of the electrode wiring, and the surface of the protective metal is cleaned. And contribute to the improvement of performance.

[Brief description of the drawings]

FIG. 1 is a side view in the order of steps of an embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Glass substrate (transparent insulating substrate) 2 First film made of low-resistance metal (aluminum) 3 Second film made of protective metal (such as titanium) 4 Two-layer film made of first film and second film 5 resist mask 6 third film made of the same protective metal as the second film

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-120068 (JP, A) JP-A-61-117521 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1362 G02F 1/1343 H01L 29/78

Claims (3)

(57) [Claims] When forming an electrode wiring of a thin film transistor matrix in a liquid crystal display panel having a thin film transistor matrix formed on a transparent insulating substrate, a first film made of a low-resistance metal is formed on the insulating substrate. Forming a two-layer film made of a second film made of a protective metal thereon; patterning the two-layer film; forming the two-layer film on the patterned two-layer film and the insulating substrate outside the patterned two-layer film. Depositing a third film of a protective metal, and removing the third film by anisotropic etching so as to remain on the side surface of the two-layer film but not to the outside thereof. Characteristic liquid crystal display panel manufacturing method. 2. The method for manufacturing a liquid crystal display panel according to claim 1, wherein the deposition thickness of said third film is equal to or greater than the thickness of said first film. 3. The low resistance metal is aluminum,
3. The method according to claim 1, wherein the protective metal is a metal selected from the group consisting of titanium, molybdenum, tantalum, tungsten, nickel, and chromium.