JP2000243964A - Manufacture of thin film transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To offer a manufacturing method of thin film transistors, which will improve productivity and avoid residual resist. SOLUTION: A shading metal film is formed on an insulating substrate 1. After forming a first interlayer dielectric 3, islands region made of thin silicon film, a gate insulating film 5, a gate electrode 6 are formed in order, and then a source region 8 and a drain region 9 are formed on the islands region 4. After forming a second interlayer dielectric 10, resist patterns are selectively formed on the islands region 4 and on the shading metal film 2 at the same time, and a first contact hole and a hole above the shading metal film 2 are formed. The above-mentioned process is followed by a process in which a second contact hole is formed through the first interlayer dielectric 3 in the region where the hole was formed, a process in which a metal wiring 14 is formed on the first contact hole, and a metal wiring 15 is formed on the hole and the second contact hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film transistor used for a liquid crystal image display device or the like.

[0002]

2. Description of the Related Art In recent years, a technique of forming a thin film transistor on a large-sized insulating substrate using an amorphous silicon thin film or a polycrystalline silicon thin film has been developed, and an active matrix type liquid crystal display in which a pixel electrode is selected by using the thin film transistor as a switching element. Used in equipment.

Further, a liquid crystal display device of a thin film transistor array with a built-in peripheral circuit for forming a driving circuit with a thin film transistor using a polycrystalline silicon thin film and forming a switching element with the thin film transistor to select a pixel electrode has been put into practical use. I have.

Recently, such a liquid crystal display device has been applied to video projection, and a device using an intense light source has been increasing in order to improve luminance of a screen. For this reason, when the gate voltage is turned off, a light leak current flows through the thin film transistor due to the light source or the irregularly reflected light from the light source, which adversely affects image quality such as a decrease in contrast and generation of flicker.

As a countermeasure, a process has been developed in which a light-shielding film is provided below an active region of a thin film transistor. Here, when the light-shielding film is made of metal, the metal light-shielding film is dropped to the ground in order to exert a gate effect on the thin film transistor.

A conventional method of manufacturing a thin film transistor will be described with reference to FIGS.

First, as shown in FIG. 8, a metal light-shielding film 2 made of tungsten silicide or the like is selectively formed on an insulating substrate 1 as a light-shielding film for light of a light source (not shown).

Next, as shown in FIG. 9, a first interlayer insulating film 3 is formed on the entire surface. Next, after an amorphous silicon thin film, a polycrystalline silicon thin film, or a single crystal silicon thin film (hereinafter, referred to as a silicon thin film) is formed, an island region 4 for forming a transistor is formed using a resist pattern.

Next, as shown in FIG. 10, a gate insulating film 5 is formed on the surface of the island region 4, and a gate electrode 6 is selectively formed thereon.

Next, as shown in FIG.
Is used as a mask to implant impurity ions 7, and a source region 8 and a drain region 9 are formed in the island-shaped region 4 by self-alignment.

Next, as shown in FIG. 12, after a second interlayer insulating film 10 is formed on the entire surface, the second interlayer insulating film 10 and the gate insulating film 5 are penetrated, and the source region 8 and the drain region 9 are formed. Are formed respectively to reach the first contact holes 11.

Next, as shown in FIG. 13, the metal light-shielding film 2 penetrates through the second interlayer insulating film 10 and the first interlayer insulating film 3.
Is formed.

Next, as shown in FIG. 14, after depositing a metal film such as aluminum containing silicon on the entire surface, a pattern is formed by photolithography to form a metal wiring layer connected to the source region and the drain region. 14 and a metal wiring layer 15 connected to the metal light shielding film 2 are formed.

[0014]

SUMMARY OF THE INVENTION In the conventional manufacturing method,
When forming the second contact hole 13, it is necessary to penetrate two films of the first interlayer insulating film 3 and the second interlayer insulating film 10. As a result, there is a disadvantage that productivity is reduced due to a longer etching time.

[0015] Further, there is a disadvantage that the resist surface is burned at the time of etching due to the long etching time, and the resist remains.

[0016]

According to a first aspect of the present invention, there is provided a method of manufacturing a thin film transistor, comprising the steps of: forming a metal light-shielding film in a predetermined region on an insulating substrate; Forming a first interlayer insulating film on an insulating substrate having a light-shielding film; forming an island-shaped region made of a silicon thin film in a predetermined region on the first interlayer insulating film; Forming a gate insulating film and a gate electrode sequentially on the transistor, forming a source region and a drain region in the island region, forming a transistor, and forming a second interlayer insulating film on the transistor And the second interlayer insulating film and the gate insulating film on the island region so as to communicate with the second interlayer insulating film above the metal light shielding film and the source region and the drain region, respectively. Forming a contact hole and a first contact hole, and forming a second contact hole in the first interlayer insulating film in a region where the hole is formed, the second contact hole being connected to the metal light shielding film. .

Thus, when the second contact hole is formed, the second interlayer insulating film and the gate insulating film on the metal light-shielding film have already been etched at the time of forming the first contact hole. The etching time can be shortened, and generation of resist burn can be prevented.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 are process sectional views of a method for manufacturing a thin film transistor according to an embodiment of the present invention.

First, as shown in FIG. 1, a metal light shielding film 2 made of tungsten silicide or the like is selectively formed on an insulating substrate 1 as a light shielding layer for shielding light from a light source (not shown).

Next, as shown in FIG. 2, a first interlayer insulating film 3 is formed on the entire surface. Next, after an amorphous silicon thin film, a polycrystalline silicon thin film, or a single crystal silicon thin film (hereinafter, referred to as a silicon thin film) is formed, an island region 4 for forming a transistor is formed using a resist pattern.

Next, as shown in FIG. 3, a gate insulating film 5 is formed on the surface of the island region 4, and a gate electrode 6 is selectively formed thereon.

Next, as shown in FIG. 4, impurity ions 7 are implanted using the gate electrode 6 as a mask, and a source region 8 and a drain region 9 are formed in the island-shaped region 4 by self-alignment.

Next, as shown in FIG. 5, after a second interlayer insulating film 10 is formed on the entire surface, the metal light-shielding film 2 and the island-shaped region 4 are formed.
A resist pattern on the second interlayer insulating film 1
0 and a first contact hole 11 penetrating through the gate insulating film 5 and reaching the source region 8 and the drain region 9 respectively.
At the same time, a hole 12 penetrating through the second interlayer insulating film 10 is formed above the metal light shielding film 2.

Next, as shown in FIG. 6, a resist pattern is formed on the hole 12, the second contact hole 1 penetrating through the first interlayer insulating film 3 and reaching the metal light shielding film 2.
Form 3

Next, as shown in FIG. 7, after depositing a metal film such as aluminum containing silicon on the entire surface, a pattern is formed by photolithography, and the source region 8 and the drain region 9 are electrically connected. Metal wiring 14 for connecting to
Metal wires 15 connected to the metal light-shielding film 2 are formed to drop to the ground.

[0027]

As described above, according to the method for manufacturing a thin film transistor of the present invention, the etching time for forming the second contact hole can be shortened as compared with the conventional method, thereby improving the productivity. In addition to the above, it is possible to prevent the resist from being burned, so that it is possible to prevent the remaining resist from being generated, and to improve the yield.

[Brief description of the drawings]

FIG. 1 is a process cross-sectional view of a method for manufacturing a thin film transistor according to an embodiment of the present invention.

FIG. 2 is a process sectional view of a method for manufacturing a thin film transistor according to an embodiment of the present invention.

FIG. 3 is a process sectional view of a method for manufacturing a thin film transistor according to an embodiment of the present invention.

FIG. 4 is a process sectional view of a method for manufacturing a thin film transistor according to an embodiment of the present invention.

FIG. 5 is a process sectional view of the method for manufacturing the thin film transistor according to the embodiment of the present invention.

FIG. 6 is a process sectional view of the method for manufacturing the thin film transistor in the embodiment of the present invention.

FIG. 7 is a process sectional view of a method for manufacturing a thin film transistor according to an embodiment of the present invention.

FIG. 8 is a process sectional view showing a conventional method for manufacturing a thin film transistor.

FIG. 9 is a process sectional view showing a conventional method for manufacturing a thin film transistor.

FIG. 10 is a process sectional view showing a conventional method for manufacturing a thin film transistor.

FIG. 11 is a process cross-sectional view showing a conventional method for manufacturing a thin film transistor.

FIG. 12 is a process sectional view showing a conventional method for manufacturing a thin film transistor.

FIG. 13 is a process sectional view showing a conventional method of manufacturing a thin film transistor.

FIG. 14 is a process sectional view showing a conventional method for manufacturing a thin film transistor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 insulating substrate 2 metal light shielding film 3 first interlayer insulating film 4 island region 5 gate insulating film 6 gate electrode 7 impurity ion 8 source region 9 drain region 10 second interlayer insulating film 11 first contact hole 12 hole 13 Second contact holes 14, 15 Metal wiring

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshihide Shinsada 1-1, Sakaicho, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. F-term (reference) 2H092 JA24 JA41 JA46 JB52 KA04 KA05 KB25 NA27 NA29 RA05 5F110 CC02 GG02 GG12 GG13 GG15 HJ13 HL03 NN03 NN45 QQ11

Claims (2)

[Claims] A step of forming a metal light-shielding film in a predetermined region on the insulating substrate; a step of forming a first interlayer insulating film on the insulating substrate having the metal light-shielding film; A step of forming an island-shaped region made of a silicon thin film in a predetermined region on the film; a step of sequentially forming a gate insulating film and a gate electrode on the island-shaped region in a selective manner; A step of forming a transistor including a step of forming a drain region; a step of forming a second interlayer insulating film on the transistor; and a step of forming the second interlayer insulating film and the source region on the metal light-shielding film. Forming a hole and a first contact hole in the second interlayer insulating film and the gate insulating film on the island region so as to communicate with the drain region, respectively; and forming the hole. Forming a second contact hole in the region of the first interlayer insulating film which communicates with the metal light-shielding film. 2. A metal wiring for electrically connecting to a first contact hole formed to communicate with the source region and the drain region, and a second contact hole formed to communicate with the metal light shielding film; 2. The method according to claim 1, further comprising a step of forming a metal wiring to be grounded in the first contact hole.