JP2694912B2 - Active matrix substrate 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 for manufacturing an active matrix substrate used in a liquid crystal display device or the like.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional example of a method of manufacturing an active matrix substrate of this type. As shown in FIG. 3A, a gate electrode 2 is first formed on a glass substrate 1 and then a gate electrode 2 is formed. Then, the gate insulating film 3 is formed on the gate electrode 2, and then the semiconductor layer 4 is formed on the insulating film 3. Then, a channel protective film 5 is patterned on a portion of the semiconductor layer 4 above the gate electrode 2. Then, P ⁺ ions are implanted from above the channel protective film 5 to form the semiconductor layer 4
Contact layers 6a and 6b are formed on the surface side of the. Then, unnecessary portions of the contact layers 6a and 6b are removed by photolithography and etching to form the contact layers 6a and 6b shown in FIG. 3B by patterning.

Then, the source electrode 7 and the drain electrode 8 shown in FIG. 4 are patterned on the contact layers 6a and 6b patterned as described above to form a thin film transistor (hereinafter referred to as TFT: Thin Film Tr).
(this is called an anistor) is formed. Then, the interlayer insulating film 9 is formed on the entire surface of the substrate 1 so as to cover the TFT formed as described above, and the pixel electrode 10 is formed on the drain electrode 8 of the TFT through the contact hole 90 provided in the interlayer insulating film 9. Are electrically connected.

[0004]

By the way, according to the above method, since the contact layers 6a and 6b are patterned after ion implantation into the semiconductor layer 4, the contact layers 6a and 6b after the pattern formation are formed. A contact layer is not formed on the side surface of the. Therefore, after forming the pattern,
When the source electrode 7 and the drain electrode 8 are patterned on the contact layers 6a and 6b, respectively,
There is a drawback that current leakage occurs between a and 6b and the source electrode 7 and the drain electrode 8 and the TFT characteristics are deteriorated.

[0005] In addition, the channel protective film 5 is patterned on the semiconductor layer 4, when implanting P ⁺ ions from its upper, above since the conventional method has been implanted with P ⁺ ions as the channel protective film A slight amount of impurities is also implanted on the surface of the metal 5. Therefore, ion implantation is performed to form the contact layers 6a and 6b, and then the source electrode 7 and the drain electrode 8 are formed on the contact layers 6a and 6b, respectively. Contact layers 6a and 6b
A current leak occurs between the source electrode 7 and the drain electrode 8 and the TFT characteristics are deteriorated similarly to the above.

The present invention solves the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a method of manufacturing an active matrix substrate which can obtain good TFT characteristics by using ion implantation.

[0007]

A method of manufacturing an active matrix substrate according to the present invention is a thin film transistor switch.
In a method of manufacturing an active matrix substrate used for a switching element, a gate electrode is patterned on an insulating substrate.
And the insulating substrate so as to cover the gate electrode.
A gate insulating film, a semiconductor layer, and a channel protective film in this order
Next, a step of depositing and forming a resist on the channel protective film.
The semiconductor layer and the channel in the pattern of the semiconductor layer.
Patterning the protective film and masking the resist
Patterning the channel protection film as
And a state in which the resist remains on the channel protective film
Then, ion implantation is performed from above and the resist is removed.
Contact to the surface area of the semiconductor layer not covered by
A step of forming a layer, the contact layer and the channel protective layer.
The source electrode and the drain partly overlap with these on the protective film.
And a step of forming an in-electrode, which achieves the above object.

[0008]

[0009]

According to the above process, first of all, the surface of the semiconductor layer is formed.
Ion implantation for forming a contact layer in the surface region
It is performed with the resist left on the channel protective film.
Therefore, impurities are not implanted into the channel protection film.
Therefore, the source electrode and the drain electrode are formed on the channel protective film.
Even if a pattern is formed with the poles partially overlapping, the source
Current leakage may occur between the electrode and the drain electrode.
And not. Second, after patterning the semiconductor layer,
In the surface area of the semiconductor layer not covered by the resist
Since the contact layer is formed, it is impure on the side surface of the semiconductor layer.
Things will be doped. Therefore, ion implantation
Source and drain electrodes that will be patterned later
No current leakage between both sides of the contact layer
(Or, this current leak can be reduced significantly).

Moreover, since the contact layer is formed by ion-implanting the semiconductor layer after patterning it, impurities are also doped on the side surface of the semiconductor layer. Therefore, even if the source electrode and the drain electrode are patterned after the ion implantation, it is possible to reduce the current leak that occurs between the side surface of the contact layer where the ion implantation is performed and the source electrode and the drain electrode.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 shows a method of manufacturing an active matrix substrate according to the present invention, and the active matrix substrate shown in FIG. 2 is produced through the following steps.

As shown in FIG. 1A, first, Ta is deposited on the glass substrate 1 to a thickness of 300 nm by a sputtering method. Then, from this state, the gate electrode 2 is patterned on the Ta layer using a photomask. After that, the gate insulating film 3 made of SiNx and having a thickness of 300 nm and the amorphous silicon having a thickness of 30 nm are formed on the entire surface of the glass substrate 1 so as to cover the gate electrode 2 by the plasma CVD method. Layer 4 and S
A 200 nm-thick channel protection film 5 made of iNx is sequentially deposited in this order. Next, a resist 11 is applied on the uppermost channel protection film 5, and photolithography is performed with a pattern of a-Si to form a-Si shown in FIG.
The layer 4 and the channel protection film 5 are patterned.

Next, photolithography is performed from this state to pattern-form the channel protection film 5 shown in FIG. In this state, the resist 11 remains on the patterned channel protection film 5.

Then, as shown in FIG. 1C, P ⁺ ions are implanted from above the channel protective film 5 in this state without peeling off the resist 11. As a result, FIG. 1 (d)
Contact layers 6a and 6b shown in are formed.

Next, 300n is formed by the sputtering method.
A metal layer of Ti or Mo having a thickness of m is formed on the entire surface of the glass substrate 1, and the metal layer is patterned using a photomask to form the source electrode 7 and the drain electrode 8 shown in FIG. . A transparent electrode made of indium tin oxide (ITO) is formed on the entire surface of the glass substrate 1 to a thickness of 80 nm.
And is patterned with a photomask from this state to form the pixel electrode 10. As a result, the active matrix substrate of the present invention is produced.

According to the active matrix substrate thus manufactured, there is no current leakage between the contact layers 6a and 6b and the source electrode 7 and the drain electrode 8 (or because of the reason described in the above-mentioned action). An active matrix substrate having excellent TFT characteristics can be obtained).

[0018]

According to the method of the present invention described above, firstly,
To form a contact layer on the surface area of the semiconductor layer
Ion implantation leaves the resist on the channel protective film.
Since it is performed in a state in which the impurities are left on the channel protective film,
Not driven. Therefore, the source electrode on the channel protective film is
Pattern shape with the electrode and drain electrode partially overlapping
Even if it is formed, there is a current leakage between the source electrode and the drain electrode.
It does not generate slush. Second, the semiconductor layer is patterned.
After formation, the semiconductor is not covered by resist
Since the contact layer is formed on the surface area of the body layer,
The side surface of the layer will also be doped with impurities. Obedience
The source electrode and the patterned electrode after ion implantation.
Current between the drain electrode and both sides of the contact layer.
Does not occur (or this current leakage is significantly reduced)
it can). As a result, according to the present invention, the source electrode and the drain electrode are
No current leakage between the rain electrodes and contact
The current between both sides of the layer and the source and drain electrodes
Since leakage does not occur, Ioff current can be reduced T
To obtain an active matrix substrate with good FT characteristics
It is possible to achieve the effect of being able to.

[Brief description of the drawings]

FIG. 1 is a process drawing showing a method for manufacturing an active matrix substrate of the present invention.

FIG. 2 is a sectional view showing an active matrix substrate manufactured by the method of the present invention.

FIG. 3 is a process drawing showing a conventional manufacturing method.

FIG. 4 is a cross-sectional view showing an active matrix substrate manufactured by a conventional method.

[Explanation of symbols]

 1 glass substrate 2 gate electrode 3 gate insulating film 4 semiconductor layer 5 channel protective film 6a, 6b contact layer 7 source electrode 8 drain electrode 9 interlayer insulating film 10 picture element electrode 11 resist

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasunori Shimada, 22-22 Nagaikecho, Abeno-ku, Osaka City, Sharp Corp. (72) Inventor, Hiroshi Morimoto, 22-22, Nagaikecho, Abeno-ku, Osaka City, Sharp Corporation (56) References JP-A-2-196222 (JP, A) JP-A-2-224254 (JP, A)

Claims (2)

(57) [Claims] 1. A thin film transistor as a switching element
In the method of manufacturing an active matrix substrate used, a step of patterning a gate electrode on an insulating substrate, and a gate on the insulating substrate so as to cover the gate electrode.
Insulating film, semiconductor layer, and channel protection film are sequentially deposited
Step, forming a resist on the channel protective film,
Patterning the semiconductor layer and the channel protective film in a pattern
And a step of further patterning the channel protective film using the resist as a mask.
In the step of performing the heating and the state in which the resist remains on the channel protective film,
Ion implantation is performed from above and the resist is used.
A contact layer is provided on the surface area of the uncovered semiconductor layer.
Part of this process on the contact layer and the channel protective film
To form the source and drain electrodes that overlap each other
A method of manufacturing an active matrix substrate including: 2. The method of manufacturing an active matrix substrate according to claim 1, wherein the contact layer is formed by performing ion implantation after patterning the semiconductor layer.