JPH05203990A - Thin film transistor panel - Google Patents

Abstract

PURPOSE:To reduce the cost of production of a TFT panel by efficiently forming a black mask and a transparent insulating film covering this black mask only by a single metal film forming process. CONSTITUTION:A metal film 10 is formed on a substrate 1, the part of the film 10 corresponding to a picture element electrode 2 is oxidized over the entire thickness and only an upper layer while other part at a lower layer is leaved as it is non-oxidized, part of the film 10 is oxidized. The lower unoxidized layer of the film 10 is used as a black mask 10a and the oxidized layer of the film 10 is used as a transparent insulating film 10b covering the black mask 10a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor panel used for an active matrix liquid crystal display device.

[0002]

2. Description of the Related Art As a thin film transistor panel (hereinafter referred to as a TFT panel) used for an active matrix liquid crystal display device, there is one in which a black mask is formed on a substrate.

FIG. 3 is a sectional view of a part of a conventional TFT panel. In this TFT panel, a plurality of transparent pixel electrodes 2 and a plurality of thin film transistors 3 that are active elements thereof are formed on a transparent substrate 1 made of glass or the like.
The pixel electrodes 2 are arranged vertically and horizontally, and the thin film transistors 3 are arranged on the sides corresponding to the respective pixel electrodes 2.

The thin film transistor 3 has an inverted staggered structure, and the thin film transistor 3 includes a gate electrode G, a gate insulating film 4 made of Si N (silicon nitride) formed on the gate electrode G, and a gate insulating film 4. An i-type semiconductor layer 5 made of a-Si (amorphous silicon) formed on the gate insulating film 4, and an n-type semiconductor layer made of a-Si doped with an n-type impurity on the i-type semiconductor layer 5. It is composed of a source electrode S and a drain electrode D which are formed through

The gate electrode G of this thin film transistor 3
Is integrally formed with a gate line (not shown) wired corresponding to the row of each pixel electrode 2, and the gate insulating film 4 is formed on almost the entire surface of the substrate 1 so as to cover the gate electrode G and the gate line. . The pixel electrode 2 is formed on the gate insulating film (transparent film) 4 and is connected to the source electrode S of the thin film transistor 3 at one end thereof. Although not shown, the gate insulating film 4
Data lines are provided on the upper side of the pixel electrodes 2 so as to correspond to the columns of the pixel electrodes 2, and the drain electrodes D of the thin film transistors 3 are connected to the data lines. The pixel electrode 2, the thin film transistor 3 and the data line are covered with a transparent protective insulating film 7 made of SiN or the like.

On the other hand, each pixel electrode 2 is formed on the substrate 1.
The grid-like black mask 8 is formed so as to correspond to the rows and columns. This black mask 8 is the substrate 1
A metal film of Cr (chromium) or the like is formed thereon by a sputtering device, and the metal film is patterned by a photography method. In addition, the black mask 8
Is covered with a transparent insulating film (hereinafter referred to as an interlayer insulating film) 9 made of Si 3 N 4 or the like formed by a plasma CVD apparatus, and the pixel electrode 2 and the thin film transistor 3 are formed on the interlayer insulating film 9. Has been formed.

[0007]

However, in the above-mentioned conventional TFT panel, in forming the black mask 8 and the interlayer insulating film 9 covering the black mask 8, a metal film to be the black mask 8 is formed. And two steps of forming the interlayer insulating film 9 made of Si 3 N 4 and the like are required. Moreover, the interlayer insulating film 9 is formed by a plasma CVD apparatus, but since the film forming efficiency of the plasma CVD apparatus is low, in order to form the interlayer insulating film 9 having a sufficient withstand voltage, It takes a considerable amount of time for film formation.

Therefore, the conventional TFT panel described above has a problem that it takes time to form the black mask 8 and the interlayer insulating film 9, which increases the manufacturing cost of the TFT panel.

An object of the present invention is to efficiently form a black mask and a transparent insulating film covering the black mask only once to form a metal film, and to reduce the manufacturing cost. It is to provide a TFT panel.

[0010]

In the TFT panel of the present invention, a portion corresponding to a pixel electrode is oxidized on a transparent substrate over its entire thickness, and the other portion is left with a non-oxidized layer as a lower layer. A metal film whose part is oxidized is provided, the non-oxidized layer of the metal film is used as a black mask, and the oxidized layer of the metal film is used as a transparent insulating film that covers the black mask.

[0011]

That is, according to the present invention, the black mask and the transparent insulating film covering the black mask are formed of the same metal film, and are transparent when oxidized (metal oxide film).
If a metal film to be formed is formed on the substrate and the portion corresponding to the pixel electrode of this metal film is oxidized over its entire thickness, and the other portion is left as a non-oxidized layer and the upper portion is oxidized. The non-oxidized layer of the metal film serves as a black mask, and the oxidized layer of the metal film serves as a transparent insulating film that covers the black mask.

Therefore, according to the present invention, the black mask and the transparent insulating film can be formed only by forming the metal film once, and the metal film can be formed in a short time by a sputtering apparatus. A film can be formed, and the oxidation treatment of this metal film can be performed in a short time by anodic oxidation that causes a chemical conversion reaction in the metal film. Therefore, the black mask and the transparent insulating film can be efficiently formed, and the manufacturing cost of the TFT panel Can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a part of the TFT panel, and FIG. 2 is a manufacturing process diagram of the TFT panel. 1 and 2, parts having the same configurations as those of the conventional TFT panel shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

In the TFT panel of this embodiment, as shown in FIG. 1, a portion corresponding to each pixel electrode 2 is oxidized on the transparent substrate 1 made of glass or the like over its entire thickness, and other portions (each In the portions corresponding to the rows and columns of the pixel electrodes 2), a metal film 10 in which a non-oxidized layer is left underneath and the upper portion is oxidized is provided, and the non-oxidized layer of the metal film 10 is used as a black mask 10a The oxide layer of the metal film 10 is an interlayer insulating film 10b covering the black mask (non-oxidized layer) 10a.

For the metal film 10, a metal that becomes a transparent insulating film (metal oxide film) when oxidized, such as Al (aluminum), Al-based alloy, Ta (tantalum), etc., is used. An interlayer insulating film (oxide layer) 10b obtained by oxidizing 10 is a transparent film.

The thin film transistor 3 is formed on the interlayer insulating film 10b so as to correspond to the black mask 10a. In addition, this thin film transistor 3
Of the gate insulating film 4 is formed on the interlayer insulating film 10b over substantially the entire surface thereof, and the pixel electrode 2 is formed on the gate insulating film 4 by the black masks 10a, 10b.
It is formed corresponding to the region between a.

The above TFT panel is manufactured as follows.

[Step 1] First, as shown in FIG. 2A, a metal film 10 made of Al, Al alloy, Ta or the like is formed on a substrate 1 by a sputtering apparatus. The metal film 10 is formed thicker than the black mask 10a.

[Step 2] Next, as shown in FIG. 2B, a resist mask 11 is formed on the metal film 10 except the portion corresponding to the pixel electrode 2, and in this state, the metal film is formed. The portion corresponding to 10 pixel electrodes is oxidized over its entire thickness.

The metal film 10 is oxidized by, for example, anodic oxidation using an electrolytic solution.
The metal film 10 on the substrate 1 is formed by immersing the substrate 1 in an electrolytic solution.
Facing the counter electrode (platinum electrode) in the electrolyte,
The metal film 10 is used as an anode and the counter electrode is used as a cathode, and a voltage is applied between both electrodes. Thus, when a voltage is applied between the metal film 10 and the counter electrode in the electrolytic solution, a portion of the metal film 10 as an anode which is not covered with the resist mask 11 (a portion in contact with the electrolytic solution) causes a chemical conversion reaction. Are anodized. In this case, the metal film 10 is oxidized from the surface side thereof, but the depth of oxidation is mainly determined by the applied voltage. Therefore, if the applied voltage is set according to the film thickness of the metal film 10, the metal film 10 is formed. It can be oxidized over its entire thickness. Since the volume of metal is increased when it is oxidized, the thickness of the oxidized portion of the metal film 10 becomes thicker than that before oxidation.

When such an oxidation treatment is performed, the insulating film 10b in which the entire thickness of the metal film 10 corresponding to the pixel electrode is transparent.
Therefore, the non-oxidized portion of the metal film 10 becomes the pixel electrode 2
The black mask 10a has a shape corresponding to the space between the rows and the space between the columns.

[Step 3] Next, as shown in FIG. 2C, the resist mask 11 is removed, and the metal film 10 is anodized again. The anodic oxidation at this time is performed by applying a voltage between the metal film 10 and the counter electrode to oxidize the non-oxidized portion of the metal film 10 except for the underlying region.

When this oxidation treatment is performed, the metal film 10 is formed.
The non-oxidized portion of the black mask 10a is oxidized except for the lower layer region thereof, and the non-oxidized layer remaining in the lower layer of this portion becomes the black mask 10a, and the oxide layer formed thereon is the black mask 10a.
It becomes a transparent interlayer insulating film 10b covering a.

[Step 4] After that, the thin film transistor 3 is formed by a known method on the interlayer insulating film 10b formed in the above [Step 2] and [Step 3], and the gate insulating film 4 of this thin film transistor 3 is formed. A pixel electrode 2 is formed on top of this, and a protective insulating film 7 is formed thereon to complete a TFT panel.

That is, in the above embodiment, the black mask 10a and the transparent interlayer insulating film 10b covering the black mask 10a are formed of the same metal film 10.
Metal film 1 that becomes a transparent insulating film (metal oxide film) when oxidized
When 0 is formed on the substrate 1 and the metal film 10 is oxidized as described above, the non-oxidized layer of the metal film 10 becomes the black mask 10a and the oxidized layer of the metal film 10 becomes the black mask. Transparent interlayer insulating film 10b covering 10a
Therefore, the black mask 10a and the interlayer insulating film 10b
And the same metal film 10 can be formed.

Therefore, according to the above-described embodiment, the black mask 10a and the transparent interlayer insulating film 10b are formed into one layer.
The metal film 10 can be formed only by forming the metal film 10 once, and the metal film 10 can be formed by a sputtering apparatus in a short time.
Since it can be performed in a short time by anodic oxidation that causes a chemical conversion reaction, it is possible to efficiently form the black mask 10a and the transparent insulating film 10b and reduce the manufacturing cost of the TFT panel.

In the above embodiment, the anodic oxidation of the metal film 10 is performed by a method of causing a chemical conversion reaction in an electrolytic solution, but the anodic oxidation of the metal film 10 is performed by a chemical conversion reaction in a gas atmosphere. It may also be carried out by plasma oxidation.

[0028]

According to the present invention, the portion corresponding to the pixel electrode of the metal film formed on the substrate is oxidized over its entire thickness, and the other portion is left as the lower layer and the non-oxidized layer is left as the upper portion. By oxidizing the non-oxidized layer of the metal film as a black mask and the oxidized layer of the metal film as a transparent insulating film covering the black mask, the black mask and the transparent insulating film are formed once. The metal film can be formed simply by depositing the metal film, and the metal film can be deposited in a short time by a sputtering apparatus. Furthermore, the oxidation treatment of this metal film is also performed by anodic oxidation which causes a chemical conversion reaction in the metal film. Since it can be performed in a short time, the black mask and the transparent insulating film can be efficiently formed, and the manufacturing cost of the TFT panel can be reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a part of a TFT panel showing an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the TFT panel.

FIG. 3 is a plan view of a part of a conventional TFT panel.

[Explanation of symbols]

1 ... Substrate, 2 ... Pixel electrode, 3 ... Thin film transistor, G ...
Gate electrode, 4 ... Gate insulating film, 5 ... i-type semiconductor layer, 6
... n-type semiconductor layer, S ... source electrode, D ... drain electrode,
7 ... Protective insulating layer, 10 ... Metal film, 10a ... Black mask (non-oxidized layer), 10b ... Interlayer insulating film (oxidized layer), 11
... resist mask.

Claims (1)

[Claims] 1. A black mask is formed on a transparent substrate,
In a thin film transistor panel in which a pixel electrode and a thin film transistor that is an active element thereof are formed on a transparent insulating film that covers the black mask, a portion corresponding to the pixel electrode is oxidized on the substrate over its entire thickness. A metal film is formed by oxidizing the upper part of the metal film while leaving a non-oxidized layer in the lower part, the non-oxidized layer of the metal film is used as the black mask, and the oxide layer of the metal film is used as the insulating film. A thin film transistor panel characterized by the above.