JPH11163354A - Manufacture of thin-film transistor array substrate and liquid crystal display containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable strict management of a distance between thin films which are different in kind by performing photolithographic process by using a mask, having two or more kinds of mask patterns and at least two masks having mask patterns for eliminating unnecessary patterns. SOLUTION: A first mask pattern 2 forms a first resist pattern on a film turning to a first thin film forming the first thin film on a transparent substrate. A second mask pattern 3 forms a second thin film and forms a second resist pattern on a film turning to the second thin film. A mask pattern 12 of the second mask 11 eliminates a first resist pattern, which has been formed at the same time as the second resist pattern on the film turning to the second thin film. In a first thin film forming process, a mask pattern 22 of a third mask 21 eliminates the second resist pattern, which has been formed at the same time as the first resist pattern on the film turning to the first thin film.

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 TFT array substrate in which thin film transistors (hereinafter, referred to as "TFTs") are provided in a matrix on a transparent substrate together with pixel electrodes, and an active matrix type including the TFT array substrate. The present invention relates to a liquid crystal display device.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device comprises a TFT array substrate, a counter substrate and a liquid crystal material. The TFT array substrate includes: a transparent substrate; a plurality of pixel electrodes provided on a matrix on the transparent substrate; a TFT connected to the pixel electrode;
And a plurality of wirings for supplying an electric signal to the wiring. The plurality of wirings are provided on the outer periphery of the pixel electrode. The liquid crystal material is sealed between the TFT array substrate and the opposing substrate after the TFT array substrate and the opposing substrate are bonded at a predetermined interval. Normally, a display area of a liquid crystal display device is divided into a matrix, and each of the divided areas is called a pixel. Each pixel includes at least one pixel electrode. Each pixel can be selectively operated by applying an electric signal to a pixel electrode via a TFT.
The ratio of the area of the display area of the liquid crystal display device through which light emitted from the back surface of the liquid crystal display apparatus can be transmitted is indicated by the aperture ratio.

Next, a mask used in a conventional method for manufacturing a TFT array substrate will be described. FIG.
It is a plane explanatory view showing an example of two kinds of thin films formed on an FT array substrate. In FIG. 6, 131a indicates a first thin film, and 141a indicates a second thin film. Furthermore, the distance represented by _{d 1} the first thin film 131a and the second thin film 14
The interval between 1a is shown. FIG. 7 is an explanatory cross-sectional view showing a process of forming the two types of thin films of FIG. 6 using a conventional TFT array substrate manufacturing method. 7, reference numeral 100 denotes a transparent substrate; 133, a pattern made of a resist provided to form the second thin film 141a of FIG. 6 (hereinafter, simply referred to as "second resist pattern"); 6
Is a film made of, for example, metal (hereinafter, simply referred to as “second metal film”) to be the second thin film 141a. Further, in FIG. 7, the same parts as those in FIG. 6 are denoted by the same reference numerals.

In general, the distance d ₁ in FIG. 6 and FIG. 7 as the aperture ratio of the liquid crystal display device advances is short. Variation of the distance d _1, i.e. variation is strictly managed so causes defective display of a liquid crystal display device. However, the variation in the distance d ₁ is caused by a variation in a manufacturing error of a mask used for forming a resist pattern in a photoengraving process to remove an unnecessary portion of the formed film by etching, a variation in exposure accuracy in a photoengraving process, And various factors such as variation in the progress of etching. Among these factors, the one that is difficult to manage in the TFT array substrate forming process is a mask manufacturing error. Since the dimensional variation of the mask pattern is an etching distribution at the time of manufacturing the mask, there is no large difference between the masks. However, the variation is X direction in the long dimension accuracy on the mask, differs between the Y direction and the rotation is entangled mask, significantly influence on the distance d ₁ which is determined by the length dimension accuracy of two masks, on the mask There are also differences between locations.

FIG. 8 is an explanatory view showing an example of two masks used in a conventional method for manufacturing a TFT array substrate. 8A, reference numeral 101 denotes a first mask, 10
2 is a mask pattern provided on the first mask 101, 111 is a second mask, 103 is a second mask 1
11 shows a mask pattern provided in 11. Note that the pattern formed on the metal film using the mask is made of a resist, and the resist pattern is decomposed when irradiated with predetermined light. Furthermore, mask pattern 1
02 and the mask pattern 103 can block light. FIG. 9 is a cross-sectional explanatory view showing two types of films formed using the first mask and the second mask of FIG. 9, the same parts as those in FIGS. 6 and 7 are denoted by the same reference numerals. The distance d ₁ ′ indicates the distance between the first thin film 131a and the second thin film 141a,
Distance is a different length to d _1.

Since the respective mask patterns for different thin films (the first thin film 131a and the second thin film 141a) are formed on different masks, the dimensional accuracy differs. Therefore, since the two types of pattern positions formed by performing the exposure processing on the transparent substrate on which the metal film and the resist film are formed are slightly different from each other, variations in the distance d ₁ and the distance d ₁ ′ are caused by the exposure accuracy. Is larger than the variation due to

As measures for reducing variations in the distances d ₁ and d ₁ ′, (1) strict control of variations in accuracy (for example, variations in exposure accuracy) in the TFT array substrate fabrication process; 2) Increasing the long dimension accuracy of the mask can be considered two points. However, there is a problem that the measure (1) already has a limit and has a large influence on the tact time. The measure (2) has a problem that the price of the mask increases.

The present invention solves such a problem and does not make the management of the manufacturing process of the TFT array substrate complicated and difficult, and does not make the cost of the mask unnecessarily expensive. An object of the present invention is to provide a method of manufacturing a TFT array substrate capable of strictly controlling a distance between the TFT arrays and a liquid crystal display device including the TFT.

[0009]

According to a method of manufacturing a TFT array substrate of the present invention, a plurality of pixel electrodes provided in a matrix on a transparent substrate are formed by repeating a film forming step, a photoengraving step, and an etching step a plurality of times. A method of manufacturing a thin film transistor array substrate including: a thin film transistor connected to the pixel electrode; and a plurality of wirings provided on an outer peripheral portion of the pixel electrode and supplying an electric signal to the thin film transistor. Using a mask having the above mask pattern and at least two masks having a mask pattern for removing an unnecessary pattern among two or more patterns formed using the two or more mask patterns A photolithography process is performed.

[0010] The material of the pattern is a resist.

Further, when removing the resist, the resist is decomposed by irradiating a predetermined light to a portion to be removed.

Further, the predetermined light is visible light.

A liquid crystal display device according to the present invention comprises a transparent substrate, a plurality of pixel electrodes provided in a matrix on the transparent substrate, a thin film transistor connected to the pixel electrode, and an outer peripheral portion of the pixel electrode. A thin film transistor array substrate comprising a plurality of wirings for supplying an electric signal to the thin film transistor, a counter substrate facing the thin film transistor array substrate, and the thin film transistor array substrate and the counter substrate being attached at a predetermined interval. A liquid crystal display device comprising a liquid crystal material sealed between the thin film transistor array substrate and the opposing substrate after being combined, wherein the thin film transistor array substrate is a thin film transistor array substrate formed by using the manufacturing method according to claim 1.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a method of manufacturing a TFT array substrate and a liquid crystal display device including the TFT according to the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory plan view showing an example of three masks used in Embodiment 1 of the method for manufacturing a TFT array substrate according to the present invention. In FIG. 1A, reference numeral 1 denotes a first mask, 2 denotes a first mask pattern formed on the first mask 1, and 3 denotes a second mask pattern formed on the first mask 1. In the present embodiment,
The pattern formed on the metal film using the first mask is made of a resist, and the resist pattern is decomposed when irradiated with predetermined light. Further, it is assumed that the mask pattern can block light. The first mask pattern 2 is formed for a first thin film forming step of forming a first thin film on a transparent substrate constituting a TFT array substrate, and is formed on a film to be the first thin film. The first resist pattern can be formed. The second mask pattern 3 is formed for a second thin film forming step of forming a second thin film on a transparent substrate constituting a TFT array substrate, and is used as a second thin film. A second resist pattern can be formed thereon. FIG.
3B, reference numeral 11 denotes a second mask, and reference numeral 12 denotes a mask pattern formed on the second mask 11. The mask pattern 12 of the second mask 11 is a mask pattern for removing the first resist pattern formed simultaneously with the second resist pattern on the film to be the second thin film in the second thin film forming step. is there. Further, FIG.
Denotes a third mask 21 and 22 denotes a mask pattern formed on the third mask 21. In the first thin film forming step, the mask pattern 22 of the third mask 21
This is a mask pattern for removing the second resist pattern formed simultaneously with the first resist pattern on the film to be the thin film of FIG.

Next, a method of manufacturing a TFT array substrate using the three masks shown in FIG. 1 will be described. 2 and 3 are process explanatory views showing Embodiment 1 of the method for manufacturing a TFT array substrate according to the present invention. 4 and 5 are process cross-sectional views showing Embodiment 1 of the method for manufacturing a TFT array substrate of the present invention. 2 to 5, the same parts as those in FIG. 1 are denoted by the same reference numerals. Further, 31a is the first
A thin film 31 made of, for example, a metal to be the first thin film 31a (hereinafter, simply referred to as a “first metal film”);
2 is a first resist pattern, 33 is a second resist pattern, and 33a is a resist pattern removed by the mask pattern 22 of the third mask 21 (hereinafter, “1st resist pattern”).
41a is the second thin film, 41a
Is a film made of, for example, a metal to be the second thin film 41 a (hereinafter, simply referred to as “second metal film”), 42 is a third resist pattern, and 42 a is removed by the mask pattern 12 of the second mask 11. Resist pattern (hereinafter, referred to as “second removal pattern”), 43 indicates a fourth resist pattern, and 100 indicates a transparent substrate. Note that FIG.
(A), FIG. 2 (b), FIG. 3 (a) and FIG. 3 (b) each show only a resist pattern, and FIG. 3 (c) shows a first thin film and a second thin film. Only shown.

The first resist pattern 32 has a first
The first mask pattern 2 in the step of forming a thin film of
The second resist pattern 33 is a resist pattern formed by the second mask pattern 3 in the step of forming the first thin film. Further, the third resist pattern 4
Reference numeral 2 denotes a resist pattern formed by the first mask pattern 2 in the step of forming the second thin film, and fourth resist pattern 43 denotes a second mask pattern 3 in the step of forming the second thin film. This is a resist pattern formed by the above method. Further, the first thin film and the second thin film constitute a part of the TFT and a plurality of wirings for supplying an electric signal to the TFT.

To form the first thin film and the second thin film on the transparent substrate, first, a first metal film 31 is formed on the transparent substrate 100 as a first film forming step. Next, as a first photolithography process, a first photolithography process is performed using the first mask 1.
A first resist pattern 32 and a second resist pattern 33 are formed at desired locations on the surface of the metal film 31 (see FIGS. 2A and 4A). The first resist pattern 32 and the second resist pattern 33
Can be obtained by providing a resist film on the surface of the first metal film 31 and then exposing through a first mask 1 to decompose and remove unnecessary portions of the resist film.

Subsequently, as a second photolithography step, the second resist pattern 33 which is unnecessary when the first thin film is formed using the third mask 21 is removed (FIG. 2B). ) And FIG. 4 (b)). In the figure, a first removal pattern 33a indicated by a two-dot chain line indicates that the second resist pattern 33 has been removed. The third mask 21 has a first resist pattern 32
A mask pattern 22 is formed at a position located above. Therefore, by exposing through the third mask 21, the second resist pattern 33 is decomposed and removed. The mask pattern 22 of the third mask 21 is provided not only above the first resist pattern 32 but also around the first resist pattern 32 in consideration of an alignment error when disposing the third mask above the transparent substrate. Can be

After that, as a first etching step,
Etching is performed on the first metal film to remove the first resist pattern to obtain a first thin film.

Further, as a second film forming step, a second metal film 41 is formed on the transparent substrate 100 provided with the first thin film 31a at a predetermined location. Next, as a third photolithography step, the second metal film 41 is formed using the first mask 1.
A third resist pattern 42 and a fourth resist pattern 43 are formed at desired positions on the surface (see FIGS. 3A and 5A). The third resist pattern 4
The second and fourth resist patterns 43 correspond to the first resist pattern 32 and the second resist pattern in the first photolithography process.
Is provided in the same manner as the resist pattern 33 of FIG.

Subsequently, as a fourth photolithography step, the third resist pattern 42 which is unnecessary when forming the second thin film using the second mask 11 is removed (FIG. 3B). ) And FIG. 5 (b)). In the figure, a second removal pattern 42a indicated by using a two-dot chain line indicates that the third resist pattern 42 has been removed. The second mask 11 has a fourth resist pattern 43
The mask pattern 12 is formed at a position located above. Therefore, by exposing through the second mask 11, the first resist pattern 42a is decomposed and removed. The mask pattern 12 of the second mask 11 is provided not only above the fourth resist pattern 43 but also around the fourth resist pattern 43 in consideration of an alignment error when the second mask is arranged above the transparent substrate. Can be

Then, as a second etching step,
Etching is performed on the second metal film to remove the fourth resist pattern to obtain a second thin film 41a. Therefore, the first thin film 31a and the second thin film 41a can be formed on the transparent substrate 100 (see FIGS. 3C and 5C).

In this embodiment, the removal pattern is exposed after the necessary pattern is exposed, but the reverse (the required pattern is exposed after the removal pattern is exposed) may be used.

In the present embodiment, a mask having two types of mask patterns (ie, a first mask)
And 2 formed using the two types of mask patterns.
Two types of thin films (ie, a second thin film) using two masks (ie, a second mask and a third mask) each having a mask pattern for removing an unnecessary resist pattern from among the types of resist patterns And a third thin film). However, the number of types of masks and thin films is not limited to this, and four or more types of thin films may be formed using four or more types of masks.

The light used at the time of exposure may be any light that can decompose the resist, and visible light is used depending on the type of the resist.

Further, a liquid crystal display device may be formed using a TFT array substrate obtained by the method of manufacturing a TFT array substrate in the present embodiment.

[0028]

According to the present invention, it is possible to control the manufacturing process of a TFT array substrate without making it complicated and difficult, and without unnecessarily increasing the cost of a mask. Distance can be strictly controlled. Further, by forming a liquid crystal display device using the TFT array substrate obtained by the method for manufacturing a TFT array substrate in this embodiment, a high aperture ratio of the liquid crystal display device can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view showing an example of three masks used in Embodiment 1 of a method for manufacturing a TFT array substrate of the present invention.

FIG. 2 is a process explanatory view showing Embodiment 1 of the method for manufacturing a TFT array substrate of the present invention.

FIG. 3 is a process explanatory view showing Embodiment 1 of the method for manufacturing a TFT array substrate of the present invention.

FIG. 4 is a process cross-sectional view showing Embodiment 1 of the method for manufacturing a TFT array substrate of the present invention.

FIG. 5 is an explanatory process sectional view showing Embodiment 1 of the method for manufacturing a TFT array substrate of the present invention.

FIG. 6 is an explanatory plan view showing an example of two types of thin films formed on a TFT array substrate.

FIG. 7 shows a conventional TFT array substrate manufacturing method using FIG.
FIG. 4 is an explanatory cross-sectional view showing a process of forming two types of thin films.

FIG. 8 is an explanatory diagram showing an example of two masks used in a conventional method for manufacturing a TFT array substrate.

9 is an explanatory cross-sectional view showing two types of films formed using the first mask and the second mask of FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st mask 2 1st mask pattern 3 2nd mask pattern 11 2nd mask 12, 22 mask pattern 21 3rd mask

Claims (5)

[Claims] 1. A plurality of pixel electrodes provided in a matrix on a transparent substrate, a thin film transistor connected to the pixel electrodes, and a plurality of pixels formed by repeating a film forming step, a photoengraving step, and an etching step a plurality of times. A method of manufacturing a thin film transistor array substrate provided on an outer peripheral portion of an electrode and including a plurality of wirings for supplying an electric signal to the thin film transistor, wherein a mask having two or more types of mask patterns; A method of manufacturing a thin film transistor array substrate, wherein a photolithography process is performed using at least two masks each having a mask pattern for removing an unnecessary pattern among two or more types of patterns formed using the mask pattern. 2. The method according to claim 1, wherein the material of the pattern is a resist. 3. The resist is decomposed by irradiating a predetermined light to a portion to be removed when the resist is removed.
A method for producing the thin film transistor array substrate according to the above. 4. The method according to claim 3, wherein the predetermined light is visible light. 5. A transparent substrate, a plurality of pixel electrodes provided in a matrix on the transparent substrate, a thin film transistor connected to the pixel electrode, and a thin film transistor provided on an outer peripheral portion of the pixel electrode. A thin film transistor array substrate comprising a plurality of wirings for supplying electric signals to the thin film transistor array, a counter substrate facing the thin film transistor array substrate, and the thin film transistor after the thin film transistor array substrate and the counter substrate are bonded at a predetermined interval. A liquid crystal display device comprising a liquid crystal material sealed between an array substrate and a counter substrate, wherein the thin film transistor array substrate is a thin film transistor array substrate formed by using the manufacturing method according to claim 1.