JPH0837310A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent corrosion and dissolution of transparent electrodes, suppress restrictions on the manufacturing process, and be excellent in mass productivity. [Configuration] Drain electrode 24 made of aluminum or the like
When the pattern is formed, the transparent electrode 18 made of ITO has a second (interlayer) insulating film 19 having a contact hole 22.
And the contact hole 22 is covered with the drain electrode 24. Therefore, the transparent electrode 18 does not dissolve in a normal developing solution (alkali aqueous solution) for a positive photoresist as a mask when etching the drain electrode 24, and the positive photoresist is easy to use and has high resolution. Can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in, for example, display driving of an active matrix type liquid crystal display device.
The present invention relates to a semiconductor device including a transparent electrode made of TO and a method for manufacturing the same.

[0002]

2. Description of the Related Art In the above active matrix type liquid crystal display device, a thin film transistor (TFT) is provided in each of pixels arranged in a matrix which constitutes a display portion. When the thin film transistor is turned on, display data is written in the electrostatic capacity portion (liquid crystal portion) of the pixel in the form of electric charge, and when the thin film transistor is turned off, the pixel is driven for a predetermined time by the written electric charge. There is.

FIG. 9 is a sectional view showing an example of a thin film transistor provided in such a liquid crystal display device. In this thin film transistor, a semiconductor thin film 2 is patterned on an insulating film substrate 1 made of glass or the like. The central portion of the semiconductor thin film 2 is a channel region 2a, and both sides thereof are contact regions 2b and 2c made of impurity regions. A gate insulating film 3 is formed over the entire surface of the semiconductor thin film 2 and the insulating substrate 1, and a gate electrode 4 and an anodic oxide film 5 are formed above the channel region 2a of the gate insulating film 3. An interlayer insulating film 6 is formed over the entire surface of the anodic oxide film 5 and the gate insulating film 3.

Contact holes 7 and 8 are formed in respective portions of the gate insulating film 3 and the interlayer insulating film 6 existing above the contact regions 2b and 2c.
On the upper surface of the interlayer insulating film 6 near the contact hole 7, a source electrode 9 made of aluminum or the like is formed by filling a part of the inside of the contact hole 7, and the source electrode 9 is formed in the contact region 2b. Connected with. ITO is provided at a predetermined position on the upper surface of the interlayer insulating film 6.
The transparent electrode 10 having a thin film thickness is formed by patterning. The transparent electrode 10 corresponds to a pixel electrode that contributes to display in a liquid crystal display device.

On the other hand, on the upper surface of the interlayer insulating film 6 near the contact hole 8, a drain electrode 11 made of aluminum or the like is formed by partially filling the inside of the contact hole 8, and this drain electrode is formed. 11 is connected to the contact region 2c.

[0006]

However, in the thin film transistor having such a structure, the transparent electrode 10 made of ITO is connected to the contact region 2c not directly but through the drain electrode 11 made of aluminum or the like. Therefore, there were the following problems. For example, when the drain electrode 11 made of aluminum or the like is in direct contact with at least a part of the upper surface of the transparent electrode 10 made of ITO, a positive photoresist used as a mask when patterning the drain electrode 11. There was a problem that the transparent electrode 10 made of ITO was dissolved in the developing solution (alkaline aqueous solution) through a pinhole or the like formed in the drain electrode 11.

Therefore, as a solution used for the patterning, there has been proposed a technique for preventing the corrosive dissolution of the transparent electrode made of ITO by using an alkaline aqueous solution in which a nitrate is added to a developing solution for the photoresist (Japanese Patent Laid-Open Publication No. Hei 5 (1999) -58). -226652).

However, in the case of this proposed technique, the durability and versatility of the developing solution are worse than at present, and there is a problem in view of mass productivity.

On the other hand, the following techniques have been proposed (Japanese Patent Publication No. 5-87811 and Japanese Patent Laid-Open No. 5-303116). This proposed technology is to form a transparent electrode made of ITO on an insulating substrate such as glass prior to the TFT, and then provide the transparent electrode at a position where the TFT and the transparent electrode overlap each other with an insulating film covering the transparent electrode sandwiched therebetween. The contact hole is partially filled to form an electrode made of aluminum. Subsequently, the TFT and the transparent electrode are electrically connected via this electrode so that the developing solution does not come into contact with the transparent electrode made of ITO to prevent corrosion and dissolution of the transparent electrode.

However, in the case of this proposed technique, since the transparent electrode made of ITO is formed first, the process of forming the TFT, particularly from amorphous silicon (a-Si) to the i-layer polysilicon (p-). There is a problem that the process for converting to Si) is greatly limited. This is due to the annealing or laser irradiation at about 600 ° C. performed in the process for converting to polysilicon.
This is because there is a possibility that the transparent electrode may have increased resistance, reduced transparency, or peeling.

The present invention has been made to solve the problems of the prior art as described above, and it is possible to prevent corrosion and dissolution of the transparent electrode, suppress restrictions on the manufacturing process, and have excellent mass productivity. And a method for manufacturing the same.

[0012]

According to the present invention, there is provided a semiconductor device comprising:
A gate electrode is formed on one side of the first insulating film, and a portion of the other side of the first insulating film facing the gate electrode is a channel region, and both sides of the channel region are contact regions. The formed semiconductor film and a second film formed on one side of the first insulating film so as to cover the gate electrode.
An insulating film, a source electrode connected to one contact region through a first contact hole penetrating the first insulating film and the second insulating film, and a penetrating the first insulating film and the second insulating film. A drain electrode connected to the other contact region via a second contact hole, and
And a transparent electrode formed between the insulating film and the second insulating film and connected to the drain electrode through a third contact hole penetrating the second insulating film. To be achieved.

In the semiconductor device of the present invention, the transparent electrode may be made of ITO.

In the semiconductor device of the present invention, the surface of the gate electrode may be anodized.

In the semiconductor device of the present invention, the source electrode and the drain electrode may be made of aluminum or a two-layer film or a multilayer film containing an aluminum film.

According to the method of manufacturing a semiconductor device of the present invention, a gate electrode formed on one side of the first insulating film and a portion of the other side of the first insulating film facing the gate electrode are used as a channel region. A semiconductor film formed on both sides of the channel region as contact regions, a second insulating film formed on one side of the first insulating film so as to cover the gate electrode, the first insulating film, and A source electrode connected to one of the contact regions via a first contact hole penetrating the second insulating film and another via a second contact hole penetrating the first insulating film and the second insulating film. Is formed between the drain electrode connected to the contact region and the first insulating film and the second insulating film, and is connected to the drain electrode through a third contact hole penetrating the second insulating film. Transparent electrode A method of manufacturing a semiconductor device comprising: a step of sequentially forming the semiconductor film, a first insulating film, and a gate electrode; a step of anodizing the gate electrode; A step of forming a transparent electrode,
A step of forming a second insulating film on the first insulating film so as to cover the gate electrode and the transparent electrode, a step of forming the first, second and third contact holes, and a step of forming the first contact hole Filling a part of the source electrode and forming a part of the second contact hole and the third contact hole to form the drain electrode, whereby the above object is achieved. It

[0017]

In the structure of the present invention, when the drain electrode made of aluminum or the like is patterned, the transparent electrode made of ITO is covered with the second insulating film having the contact hole, and the contact hole is formed. Is blocked by the drain electrode. Therefore, the transparent electrode does not dissolve in the normal developing solution (alkali aqueous solution) for the positive type photoresist as a mask when etching the drain electrode, and the positive type photoresist is easy to use and has high resolution. can do.

Further, according to the method of the present invention, when the transparent electrode made of ITO is patterned, the gate electrode is anodized even if the transparent electrode is formed in contact with the gate electrode made of aluminum or the like. , The gate electrode is not dissolved by the etchant of the transparent electrode. Therefore, the transparent electrode can be formed under the second insulating film.

Further, in the present invention, since a general developing solution can be used, mass productivity is high, and the TFT forming process is not limited since the transparent electrode is not formed.

[0020]

EXAMPLES Examples of the present invention will be specifically described below.

FIG. 7 is a sectional view showing a thin film transistor to which the present invention is applied. In this thin film transistor, a semiconductor film 14 made of polysilicon obtained by crystallizing amorphous silicon is patterned on a part of the upper surface of an insulating substrate 12 made of glass or the like. A gate insulating film 15 made of silicon oxide is formed on the substrate 12 so as to cover the semiconductor film 14.

A gate electrode 16 made of aluminum or the like is provided on the gate insulating film 15 above the semiconductor film 14.
And an anodic oxide film 17 is formed on the outer surface of the gate electrode 16. In the semiconductor film 14, the lower part of the anodic oxide film 17 is a channel region 14a, and the both side parts of the channel region 14a are contact regions 14b and 14c.

IT is formed on the gate insulating film 15 outside the upper part of the semiconductor film 14 and in the vicinity thereof.
A transparent electrode 18 made of O is formed. An interlayer insulating film 19 made of silicon nitride is formed so as to cover the gate insulating film 15 and the transparent electrode 18.

A source contact hole 20 is formed in each portion of the interlayer insulating film 19 and the gate insulating film 15 located on the contact region 14b. Interlayer insulating film 1 located on the contact region 14c
A drain contact hole 21 is formed in each portion of the gate insulating film 9 and the gate insulating film 15. The transparent electrode 18
A relay contact hole 22 is formed in a portion of the interlayer insulating film 19 located above.

A source electrode 23 made of aluminum or the like is formed in a portion of the upper surface of the interlayer insulating film 19 near the source contact hole 20 by filling the source contact hole 20. On the upper surface portion of the interlayer insulating film 19 near the drain contact hole 21 and the relay contact hole 22, a drain electrode 24 made of aluminum or the like is partially filled in the drain contact hole 21 and the relay contact hole 22. Are formed.

Next, a method of manufacturing the thin film transistor thus configured will be described with reference to FIGS.

First, as shown in FIG. 1, an amorphous silicon film 13 is deposited to a thickness of about 50 nm on the entire upper surface of the insulating substrate 12 made of glass or the like by the LPCVD method.

Next, as shown in FIG. 2, by irradiating a XeCl excimer laser, the amorphous silicon film 13 is crystallized to form a semiconductor film 14 made of a polysilicon film.

Next, the semiconductor film 14 is patterned only in the thin film transistor formation region by photolithography.

Next, as shown in FIG. 3, a gate insulating film 15 made of silicon oxide is deposited to a thickness of about 100 nm by TEOS-CVD on the entire surface of the substrate in this state.

Next, as shown in FIG. 4, the channel region 1
A gate electrode 16 made of aluminum or the like is patterned to a thickness of about 500 nm on the upper surface of the gate insulating film 15 corresponding to 4a using a sputtering apparatus.

Next, anodic oxidation is performed to form an anodic oxide film 17 around the gate electrode 16 to a thickness of about 200 nm.

Next, although not shown, the gate electrode 16
Using the anodic oxide film 17 as a mask, impurities are implanted into the portion of the semiconductor film 14 where the contact regions 14b and 14c are to be formed by an ion implantation device.

Next, the XeCl excimer laser is irradiated to activate the impurities implanted in the contact regions 14b and 14c.

Next, as shown in FIG. 5, the gate insulating film 1
At a predetermined position on the upper surface of No. 5 by using a sputtering device.
The transparent electrode 18 made of TO is patterned to a thickness of about 100 nm. In this case, after the ITO is uniformly deposited on the entire surface, the transparent electrode 18 is patterned by etching and removing the unnecessary portion of the ITO. However, the gate electrode 16 made of aluminum or the like
Since it is covered with the anodic oxide film 17, it is possible to prevent the gate electrode 16 from being dissolved by an etchant when etching ITO.

Next, as shown in FIG. 6, an interlayer insulating film 19 made of silicon nitride is formed on the entire surface by plasma CVD.
Is deposited to a thickness of about 400 nm.

Next, in the interlayer insulating film 19 and the gate insulating film 15, the source contact hole 20, the drain contact hole 21 and the relay contact hole 22 are formed on the contact regions 14b and 14c and the transparent electrode 18, respectively. To form.

Next, as shown in FIG. 7, a source electrode 23 made of aluminum or the like is patterned to a thickness of about 500 nm on the upper surface of the interlayer insulating film 19 near the source contact hole 20 by using a sputtering device. Form. At the same time, a drain electrode 24 also made of aluminum or the like is patterned to the same thickness on the upper surface of the interlayer insulating film 19 in the vicinity of the drain contact hole 21 and the relay contact hole 22. In this case, the source electrode 23 and the drain electrode 24 are pattern-formed by uniformly depositing an aluminum film on the entire surface and then etching and removing an unnecessary portion of the aluminum film by a photolithography technique. However, since the ITO is covered with the interlayer insulating film 19 and contacts the aluminum film only through the relay contact hole 22, even if a positive photoresist is used as a mask when etching the aluminum film, this positive film is used. It is possible to prevent the transparent electrode 18 made of ITO from being dissolved in the developing solution (alkali aqueous solution) for the photoresist.

In the thin film transistor of this embodiment manufactured as described above, when the ITO film uniformly deposited is etched to form the transparent electrode 18 as a pattern, the gate electrode 16 made of aluminum or the like is replaced by the anodic oxide film 17 Since it is covered with, it does not dissolve in an etchant when etching the ITO film.

The uniformly deposited aluminum film is etched to form the source electrode 23 and the drain electrode 24.
Since the transparent electrode 18 made of ITO is in contact with the drain electrode 24 made of aluminum only through the contact hole 22 when the pattern is formed,
Since the transparent electrode 18 does not dissolve in a developer (alkali aqueous solution) for a positive photoresist as a mask when etching the drain electrode 24, it is possible to use a positive photoresist which is easy to use and has high resolution. it can.

Further, in the case of this embodiment, the order of forming the interlayer insulating film 19 and the transparent electrode 18 is merely changed from that in the conventional case, so that the number of manufacturing steps can be prevented from increasing.

Although aluminum is used for the source electrode and the drain electrode in the above-mentioned embodiment, the source electrode and the drain electrode may be a two-layer film or a multilayer film having an aluminum film as an upper layer. As an example of the two-layer film, as shown in FIG.
A film composed of the titanium nitride film 25 and the aluminum film 26 is applicable.

[0043]

As described above, according to the present invention, when the drain electrode made of aluminum or the like is patterned, the transparent electrode made of ITO is used as the second (interlayer) electrode.
Since it is covered with an insulating film and has a structure that contacts with the drain electrode only through the third (relay) contact hole, a positive type photo mask as a mask when the drain electrode made of aluminum or the like is etched. Since the transparent electrode made of ITO does not dissolve in the developing solution (alkali aqueous solution) for the resist, it is possible to use a positive photoresist which is easy to use and has high resolution. Further, when patterning the transparent electrode made of ITO, even if the transparent electrode comes into contact with the gate electrode made of aluminum or the like, since the gate electrode is anodized, the gate electrode may be dissolved by the etchant of the transparent electrode. Without
A transparent electrode can be formed under the second (interlayer) insulating film.

Further, in the present invention, since a general developing solution can be used, mass productivity is high, and the TFT forming process is not limited because the transparent electrode is not formed.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a thin film transistor in the present embodiment, which is a cross-sectional view showing a state in which an amorphous silicon film is formed on the entire upper surface of an insulating substrate.

FIG. 2 is a manufacturing process diagram of the thin film transistor in the present embodiment, which is a cross-sectional view showing a state in which an amorphous silicon film is crystallized and an unnecessary portion of the semiconductor film is etched and removed.

FIG. 3 is a manufacturing process diagram of the thin film transistor according to the present embodiment, which is a cross-sectional view showing a state in which a gate insulating film is formed.

FIG. 4 is a manufacturing process diagram of the thin film transistor in the present embodiment, which is a cross-sectional view showing a state in which a gate electrode and an anodic oxide film are formed, impurities are implanted into the amorphous silicon film, and then the implanted impurities are activated.

FIG. 5 is a manufacturing process diagram of the thin film transistor in the present embodiment, which is a cross-sectional view showing a state in which a transparent electrode is formed.

FIG. 6 is a manufacturing process diagram of the thin-film transistor according to the present embodiment, which is a cross-sectional view showing a state in which a contact hole is formed after forming an interlayer insulating film.

FIG. 7 is a manufacturing process diagram of the thin-film transistor according to the present embodiment, which is a cross-sectional view showing a state where a source electrode and a drain electrode are formed.

FIG. 8 is a sectional view showing a thin film transistor according to another embodiment of the present invention.

FIG. 9 is a cross-sectional view showing an example of a conventional thin film semiconductor device.

[Explanation of symbols]

12 insulating substrate 14 semiconductor film 14a channel region 14b, 14c contact region 15 gate insulating film (first insulating film) 16 gate electrode 17 anodic oxide film 18 transparent electrode 19 interlayer insulating film (second insulating film) 20 source contact hole ( 1st contact hole) 21 Drain contact hole (2nd contact hole) 22 Relay contact hole (3rd contact hole) 23 Source electrode 24 Drain electrode

Claims (5)

[Claims] 1. A gate electrode formed on one side of a first insulating film, and a portion of the other side of the first insulating film facing the gate electrode is a channel region, and both sides of the channel region are formed. A semiconductor film formed as a contact region, a second insulating film formed on one side of the first insulating film so as to cover the gate electrode, and penetrate the first insulating film and the second insulating film. A source electrode connected to one contact region via a first contact hole, and a drain connected to the other contact region via a second contact hole penetrating the first insulating film and the second insulating film An electrode and between the first insulating film and the second insulating film;
A semiconductor device comprising: a transparent electrode connected to the drain electrode through a third contact hole penetrating the insulating film. 2. The transparent electrode is made of ITO.
The semiconductor device according to. 3. The semiconductor device according to claim 1, wherein the surface of the gate electrode is anodized. 4. The semiconductor device according to claim 1, wherein the source electrode and the drain electrode are made of aluminum or a two-layer film or a multilayer film containing an aluminum film. 5. A gate electrode formed on one side of the first insulating film and a part of the other side of the first insulating film facing the gate electrode, which is a channel region, and both sides of the channel region. Penetrating the semiconductor film formed as each contact region, the second insulating film formed on one side of the first insulating film to cover the gate electrode, the first insulating film and the second insulating film. A source electrode connected to one contact region via a first contact hole, and a drain connected to the other contact region via a second contact hole penetrating the first insulating film and the second insulating film A semiconductor comprising an electrode and a transparent electrode formed between the first insulating film and the second insulating film and connected to the drain electrode through a third contact hole penetrating the second insulating film. Device manufacturing method A step of sequentially forming the semiconductor film, the first insulating film, and a gate electrode, a step of anodizing the gate electrode, and a step of forming the transparent electrode on the first insulating film. A step of forming a second insulating film on the first insulating film so as to cover the gate electrode and the transparent electrode, a step of forming the first, second and third contact holes, and a step of forming the first contact hole The source electrode is formed by filling a part of the second contact hole and the third contact hole.
Filling a part of the contact hole to form the drain electrode.