JPH1027910A - Manufacture of tft substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce costs of manufacturing a thin film transistor (TFT) substrate by providing a good quality of TFT substrate. SOLUTION: A Cr film 28 of about 60nm thick and an Al-Si film 29 of about 300nm thick are continuously formed by a sputtering process to form a resist pattern thereon. The AL-Si film 29 is subjected to a wet etching process using an etching solution of phosphoric acid, nitric acid, acetic acid and water base with the resist pattern used as a mask; and then the Cr film 28 is subjected to a dry etching process using a CF4 +O2 gas to form a source electrode 31 connected with a pixel electrode 24 and a drain electrode 32 connected with a video signal line. Subsequently an N<+> type amorphous Si film is subjected to a dry etching process using a SF6 +HCl gas to form an N<+> type semiconductor layer 27.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a TFT (Thin Film Transis) for an active matrix type liquid crystal display device.
tor; a thin film transistor).

[0002]

2. Description of the Related Art A method of manufacturing a conventional inverted stagger type TFT substrate will be described with reference to FIG. First, as shown in FIG. 4A, an Al film is formed on a glass substrate 1, the Al film is patterned by a photo-etching process, and a gate electrode 2 connected to a scanning signal line (not shown) is formed. Form. Next, as shown in FIG. 4B, an anodic oxidation treatment is performed to form an anodic oxide film 3 made of Al ₂ O _{3 on} the surface of the gate electrode 2 and the like. Next, as shown in FIG.
An ITO (Indium-Tin-Oxide) film is formed, and the ITO film is patterned by a photo-etching process.
To form Next, as shown in FIG. 4D, an SiN film, an i-type amorphous Si (a-Si) film not doped with a conductivity type determining impurity, and a phosphorus (P) film by a plasma CVD method.
The the N ⁺ -type amorphous Si film are continuously formed doped, i-type amorphous Si film, and patterning the N ⁺ -type amorphous Si film by a photoetching process, to form the i-type semiconductor layer 6 After that, the SiN film is patterned by a photoetching process to form an insulating film 5 serving as a gate insulating film. Next, as shown in FIG. 4E and FIG.
1 film 9 is continuously formed by sputtering, a resist pattern (not shown) is formed thereon, the Al film 9 is processed by wet etching using the resist as a mask, and then the Cr film 8 is processed by wet etching. Then, a source electrode 11 connected to the pixel electrode 4 and a drain electrode 12 connected to a video signal line (not shown) are formed. Next, the N ⁺ -type amorphous Si film is processed by dry etching to form an N ⁺ -type semiconductor layer 7, and then the resist is peeled off, and the gate electrode 2, the i-type semiconductor layer 6, the source electrode 11, and the drain electrode A TFT 13 including 12 and the like is provided. Next, as shown in FIG. 4F, a SiN film is formed by a plasma CVD method, and the SiN film is patterned by a photoetching process to form a protective film 10.

[0003]

However, such T
In the method of manufacturing the FT substrate, when the Cr film 8 is wet-etched, although the resist is present but the Al film 9 substantially serves as a mask, as shown in FIG.
Since the film 9 has a structure protruding from the Cr film 8, the protection film 10 cannot go under the eaves of the Al film 9, so that the cavity 14 is formed, thereby deteriorating the quality of the TFT substrate. For example, the cavity 14 is easily contaminated with an etchant, a resist stripper, etc.
If there is at least one pinhole, an etching solution or the like at the time of forming the protective film 10 enters the cavity 14 through the pinhole, and the cavity 14 becomes a passage for the etching solution or the like. The Al film 9 is damaged. Further, when the cavity 14 is formed, a crack 15 may be generated in the protective film 10 as shown in FIG. Further, when the thickness of the protective film 10 is reduced to reduce the manufacturing cost, the protective film 10 may not be formed in the cavity 14 as shown in FIG. It is also necessary to make the protective film 10 thicker.

The present invention has been made to solve the above-mentioned problems, and has as its object to provide a method of manufacturing a TFT substrate in which the quality of the TFT substrate is good and the manufacturing cost of the TFT substrate is low.

[0005]

According to the present invention, there is provided a method of manufacturing a TFT substrate in which a source electrode and a drain electrode are formed from first and second metal films. After the second metal film is continuously formed, the second metal film is processed by wet etching, and the first metal film is processed by dry etching.

In this case, after the first metal film is processed by dry etching, the N ⁺ type amorphous Si film is processed by dry etching.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing an inverted staggered TFT substrate according to the present invention will be described with reference to FIG. First,
As shown in FIG. 1A, a 300 nm-thick Al—Ti—Ta film is formed on a glass substrate 21 by a sputtering method.
The Al-Ti-Ta film is patterned by a photo-etching process to form a gate electrode 22 connected to a scanning signal line (not shown). Next, as shown in FIG. 1B, an anodizing treatment is performed to form an anodized film 23 of Al ₂ O _{3 with} a thickness of 180 nm on the surface of the gate electrode 22 and the like. Next, as shown in FIG. 1C, an ITO film having a thickness of 140 nm is formed, and the ITO film is patterned by a photo-etching process to form a pixel electrode 24. Next, as shown in FIG.
240 nm thick SiN film by the method, 200 nm thick i-type amorphous Si not doped with conductivity-determining impurities
N ⁺ type amorphous Si 25 nm thick doped with film and phosphorus
Films are continuously formed, i-type amorphous Si film, N ⁺ type amorphous Si
The film is patterned by a photoetching process to obtain i
After forming the mold semiconductor layer 26, the SiN film is patterned by a photoetching process to form an insulating film 25 serving as a gate insulating film. Next, FIG. 1 (e) and FIG.
As shown in the figure, a Cr film 28 having a thickness of 60 nm and a thickness of 300
An Al-Si film 29 is continuously formed by sputtering, a resist pattern (not shown) is formed thereon, and the resist is used as a mask to convert the Al-Si film 29 into a phosphoric acid: nitric acid: acetic acid: water system. After processing by wet etching using an etching solution, the Cr film 28 is
Processed by dry etching using ₄ + O ₂ gas,
A source electrode 31 connected to the pixel electrode 24 and a drain electrode 32 connected to a video signal line (not shown) are formed. Next, the N ⁺ -type amorphous Si film is processed by dry etching using SF ₆ + HCl gas to form an N ⁺ -type semiconductor layer 27, and then the resist is peeled off, and the gate electrode 22 and the i-type semiconductor layer 26 are removed. And a TFT 33 including a source electrode 31, a drain electrode 32, and the like. Next, FIG.
As shown in (f), a SiN film is formed by a plasma CVD method, and the SiN film is patterned by a photo-etching process to form a protective film 30.

In this method of manufacturing a TFT substrate, C
Since the r film 28 is processed by dry etching, FIG.
As shown in (1), since the Al-Si film 29 does not have a structure protruding from the Cr film 28, no cavity is formed. For this reason, even if the protective film 30 has a pinhole, the Cr film 28 and the Al—Si film 29 in a wide range are not damaged, and the protective film 30 is not cracked, and the manufacturing cost is further reduced. Even if the thickness of the protective film 30 is reduced to reduce the thickness, the protective film 30 can be formed on the entire surface, so that the protective film 30 can be thinned and the manufacturing cost can be reduced.

Although the Cr film 28 is used as the first metal film in the above embodiment, a Cr-Mo film or the like may be used as the first metal film. In the above-described embodiment, the Al-Si film 29 is used as the second metal film, but a Mo film, a Ti film, or the like may be used as the second metal film. Further, in the above embodiment, the N ⁺ type amorphous Si film is processed by dry etching using SF ₆ + HCl gas to form the N ⁺ type semiconductor layer 27. However, the N ⁺ type amorphous Si film is formed. May be processed by dry etching using CF ₄ + O ₂ gas to form an N ⁺ type semiconductor layer 27.

[0010]

As described above, the TF according to the present invention
In the method of manufacturing the T substrate, the second metal film does not have a structure that protrudes from the first metal film, so that no cavity is formed, so that the quality of the TFT substrate is good. Further, since the protective film can be made thin, TF
The manufacturing cost of the T substrate is reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method for manufacturing a TFT substrate according to the present invention.

FIG. 2 is an explanatory diagram of a method for manufacturing a TFT substrate according to the present invention.

FIG. 3 is a cross-sectional view showing a part of the TFT substrate manufactured by the method for manufacturing a TFT substrate according to the present invention.

FIG. 4 is an explanatory view of a conventional method for manufacturing a TFT substrate.

FIG. 5 is an explanatory diagram of a conventional method for manufacturing a TFT substrate.

FIG. 6 shows a TFT manufactured by a conventional method for manufacturing a TFT substrate.
It is sectional drawing which shows a part of board | substrate.

FIG. 7 shows another TFT manufactured by a conventional method of manufacturing a TFT substrate.
It is sectional drawing which shows a part of FT board.

FIG. 8 shows another TFT manufactured by a conventional TFT substrate manufacturing method.
It is sectional drawing which shows a part of FT board.

[Explanation of symbols]

27 N ⁺ type semiconductor layer 28 Cr film 29 Al-Si film 31 Source electrode 32 Drain electrode

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location H01L 21/306 H01L 21/88 C 21/3213

Claims (2)

[Claims] 1. A method of manufacturing a TFT substrate in which a source electrode and a drain electrode are formed from first and second metal films, wherein the first and second metal films are continuously formed, and then the second and second metal films are formed. A method for manufacturing a TFT substrate, wherein the metal film is processed by wet etching, and the first metal film is processed by dry etching. 2. The method according to claim 1, wherein after the first metal film is processed by dry etching, the N ⁺ type amorphous Si film is processed by dry etching.
A method for manufacturing an FT substrate.