JPH05283429A - Manufacture of thin film transistor device - Google Patents

Abstract

PURPOSE:To obtain a manufacturing method of a thin film transistor which can form the channel part of a thin film transistor with high reproducibility. CONSTITUTION:A gate Cr electrode 12 is patterned on a glass substrate 10, and continuously an SiN film 11 and an a-Si film 13 are formed (process A). Photo resist 15 is patterned on a channel forming part, and an N<+>-a-Si film 14 is formed by a lift-off method (process B). Photo resist is patterned on a conducting film forming part containing a channel forming part, and the a-Si film 13 and the N<+>-a-Si film 14 except on the conducting film forming part are etched and eliminated at the same time (process C). Photo resist 15 is peeled (process D). After photo resist 18 is again patterned on a channel part 16B, a drain Cr film 16 is formed (process E). The photo resist 18 is peeled and eliminated and the channel part of a thin film transistor is formed (process F).

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 thin film transistor device, and more particularly, to a method of manufacturing a channel portion in a conductive film, and more particularly to a method of manufacturing a thin film transistor device in which a channel portion of a thin film transistor is formed with good reproducibility.

[0002]

2. Description of the Related Art In a conventional thin film transistor device, as a method of forming a channel portion, a drain Cr electrode is formed on a conductive film, and then the conductive film in a channel generating portion is dry-etched to a predetermined area using the drain Cr film as a mask. Means for removing the film thickness is adopted.

A conventional method for forming a channel portion of a thin film transistor will be described below with reference to FIG. 3A to 3C are cross-sectional views showing, in the order of steps, formation of a channel portion by a conventional method of manufacturing a thin film transistor device.
As shown in step A, after the gate Cr electrode 12 made of a Cr film is patterned on the glass substrate 10, plasma CV is performed.
By D, SiN film 11 as an insulating film and a as a conductive film
The -Si film 13 and the n ⁺ -a-Si film 14 are sequentially deposited. Then, the mask of the photoresist 19 for etching the n ⁺ -a-Si film 14 and the a-Si film 13 is patterned.

Next, a pattern of the conductive portion is formed. That is, using the photoresist 19 as a mask in the state of FIG.
The n ⁺ -a-Si film 14 and the a-Si film 13 are dry-etched using a fluorine-based reactive gas. Figure 3 Process B
FIG. 6 is a diagram showing a state in which the photoresist 19 is peeled off after the portions of the n ⁺ -a-Si film 14 and the a-Si film 13 other than under the photoresist 19 are removed by dry etching.

Then, a pattern is formed on the drain electrode portion. That is, after the drain Cr film 16 is formed on the entire surface by the sputtering method in the step B of FIG. 3, the photoresist 20 is used as a mask as shown in the step C of FIG.
₂ is used to dry-etch the drain Cr film 16 of the channel portion 16B.

After removing the drain Cr film 16 of the channel portion 16B in this way, the same photoresist 20 is used as a mask in the state of step C of FIG. 3 to switch the reactive gas to a fluorine-based gas, and dry etching is performed to the channel portion. 16
The n ⁺ -a-Si film 14 of B is removed, and a
-Si film 13 is removed by a predetermined thickness. After the above steps, the photoresist 20 is peeled and removed to form the thin film transistor shown in step D of FIG.

[0007]

In the conventional method of forming a thin film transistor described above, a method of removing the a-Si film 13 by a predetermined film thickness is used in the formation of the channel portion 16B. Since it is necessary to stop the dry etching of the film 13 on the way, there is a problem that the uniformity of the dry etching rate within the substrate must be maintained with good reproducibility. In the conventional method of forming a thin film transistor, the a-Si film 1 of the channel portion 16B is used.
Since 3 is the etching surface as it is, it has a problem that it is susceptible to plasma damage due to dry etching.

Therefore, an object of the present invention is to provide a method of manufacturing a thin film transistor device that solves the above problems. In particular, it is an object of the present invention to provide a method of manufacturing a thin film transistor device in which the channel portion can be formed relatively easily and accurately and the channel portion is not subject to plasma damage. A further object of the present invention is to provide a method of manufacturing a thin film transistor device, which stabilizes the manufacturing process of the thin film transistor device and improves the product reliability of the thin film transistor device.

[0009]

According to the present invention, after patterning a resist on a channel generating portion, a second step is performed.
Conductive film (n ⁺ -a-Si film) and drain film (drain C)
It is characterized in that the dry etching technique is not used for forming the channel portion by adopting a means of forming an r film).

That is, according to the present invention, (1) a step of patterning a gate electrode on a substrate, and subsequently forming an insulating film and a first conductive film, (2) a step of forming a gate electrode on the gate electrode. After the photoresist is patterned on the channel generation portion, the second conductive film is formed. (3) The photoresist is patterned on the conductive film generation portion.
And simultaneously etching and removing the two layers of the first conductive film and the second conductive film other than the conductive film generating portion, (4) All the photoresist on the conductive film generating portion and the photoresist on the channel generating portion are removed. Manufacture of a thin film transistor device characterized by including a step of peeling, (5) a step of patterning a photoresist again on the channel portion to form a drain film, and (6) a step of peeling the photoresist on the channel portion. The method is the gist.

The present invention will be described in detail below. Specifically, as a means for forming a channel portion according to the present invention, specifically, a gate electrode made of a Cr film is patterned on a glass substrate.
Then, a SiN film is formed as an insulating film and an a-Si film is formed as a first conductive film. After that, a photoresist is patterned on the channel generation portion on the gate electrode, and then an n ⁺ -a-Si film (second conductive film) is formed by a lift-off method.

Next, a photoresist is patterned on the conductive film forming portion including the channel forming portion, and the a-Si film and the n ⁺ -a-Si film other than the conductive film forming portion are simultaneously removed by etching. Strip the photoresist. Then, after patterning a photoresist again on the channel portion, a drain Cr film is formed, and then the photoresist is peeled off to form a channel portion of the thin film transistor.

According to the present invention, since dry etching is not performed for forming the channel portion as described above, the channel portion is formed by a stable process in manufacturing, and there is no fear of plasma damage of the channel portion. This has a great effect on improving reliability.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2 are views for explaining one embodiment of the present invention, in which FIG. 1 shows the formation state of a channel portion according to a method of manufacturing a thin film transistor device in a process order (process A to process C). It is a process order sectional view shown,
2A to 2C are cross-sectional views in order of the processes, which include processes D to F following FIG. 1.

First, as shown in FIG. 1A, a gate Cr electrode 12 made of a Cr film is patterned on a glass substrate 10 and then SiN as an insulating film is formed by plasma CVD.
The film 11 and the a-Si film 13 as the first conductive film are sequentially deposited. Next, the n ⁺ -a-Si film 14 is patterned as a second conductive film by using the lift-off method. That is, as shown in step B of FIG. 1, after patterning the mask of the photoresist 15 on the channel formation portion, n ^{+ is formed} as the second conductive film.
The -a-Si film 14 is deposited by plasma CVD.

Subsequently, in this state, as shown in step C of FIG. 1, a photoresist 17 is applied so as to cover the mask of the photoresist 15 formed by the lift-off method and the n ⁺ -a-Si film 14 to form a conductive film. After the portions are formed by photolithography, dry etching is performed on the n ⁺ -a-Si film 14 and the a-Si film 13 other than the conductive film forming portion using a fluorine-based reactive gas. After the above steps, photoresists 15 and 17
Peel off.

Here, as described above, n ⁺ -a-Si
Since the film 14 is formed by lift-off, the n ⁺ -a-Si film 14a on the photoresist 15 is removed together with the photoresist 15 by the stripping solution. Then, as shown in FIG. 2D, the channel portion 16B is formed with high precision by passing through the photoresist 15 and 17 peeling step.

Next, as shown in step E of FIG. 2, the drain electrode is formed again by the lift-off method. That is, FIG.
In the state of step D, a photoresist 18 is patterned on the channel portion 16B by photolithography, and then a drain Cr film 16 is deposited by plasma CVD. Then, the photoresist 18 is peeled and removed to form the thin film transistor shown in step F of FIG.

In the embodiment of the present invention, since the channel portion 16B is formed by the lift-off method, the a-Si film 13 in the channel forming portion is removed by a predetermined thickness by dry etching as in the prior art. This method does not have to be used and does not require the adoption of this method. Therefore, the manufacturing process is stable and the channel part
16B can be formed. Further, in the embodiment of the present invention, since the dry etching process is not performed in the formation of the channel portion 16B, a-
The Si film 13 does not suffer plasma damage and has the advantage of improving the reliability of the product.

[0020]

As described in detail above, according to the present invention, after the resist is patterned in the channel forming portion, the second conductive film (n ⁺ -a-Si film) and the drain film (drain Cr) are formed.
Since the method of forming the film is used, the channel portion can be formed relatively easily and accurately, and as a result, the manufacturing process of the thin film transistor is stabilized. Further, since the dry etching technique is not used for forming the channel portion, there is no fear that the channel portion will be damaged by plasma, and a great effect is brought about in improving the product reliability of the thin film transistor device.

[Brief description of drawings]

FIG. 1 is a diagram for explaining one embodiment of the present invention, which is a process order cross-sectional view showing a formation state of a channel portion in process order (process A to process C).

2A to 2C are cross-sectional views in order of the processes, including process D to process F following FIG.

FIG. 3 is a diagram for explaining a conventional method, which is a process order cross-sectional view showing the formation state of a channel portion in process order (process A to process D).

[Explanation of symbols]

10 glass substrate 11 SiN film 12 gate Cr electrode 13 a-Si film 14 n ⁺ -a-Si film 14a n ⁺ -a-Si film on photoresist 15 photoresist 16 drain Cr film 16B channel part 17-20 photoresist

Claims (2)

[Claims] 1. A step of (1) patterning a gate electrode on a substrate, and subsequently forming an insulating film and a first conductive film, (2) a channel generation portion on the gate electrode. After patterning the photoresist, a step of forming a second conductive film, (3) patterning the photoresist on the conductive film generation portion,
A step of simultaneously etching and removing the two-layer film of the first conductive film and the second conductive film other than the conductive film generating portion, (4) a step of removing all the photoresist on the conductive film generating portion and the photoresist on the channel generating portion And (5) a step of patterning a photoresist again on the channel portion to form a drain film, and (6) a step of peeling off the photoresist on the channel portion. 2. The thin film transistor device according to claim 1, wherein a SiN film is used as the insulating film, and an a-Si film and an n ⁺ -a-Si film are used as the first conductive film and the second conductive film. Production method.