JP2001166336A - Method of producing liquid crystal display device and method of forming wires in liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a TFT-LCD having a tapered cross section of a Mo alloy/Al alloy laminated line and having good coverage for an insulating film by using a wet etching method to process a laminated line of a molybdenum alloy upper layer and an aluminum alloy lower layer into a tapered cross section and then by using a shower type batch etching method to obtain good coverage for an insulating film. SOLUTION: A gate line is formed on a glass substrate, a resist pattern is formed by photolithography on the gate line, and wet etching is carried out by using a mixture as the etchant having a composition of phosphoric acid (H3PO4), nitric acid (NHO3), acetic acid (CH3COOH) and water (H2O) containing >=7 mol% and <=12 mol% of the nitric acid (HNO3) and at least one of ammonium fluoride (NH4F) and hydrogen fluoride (HF) in a minute amount as 0.01 to about 0.1 mol%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing an active matrix type liquid crystal display device driven by a thin film transistor (TFT).

[0002]

2. Description of the Related Art The market for thin-film transistor-driven liquid crystal display devices (TFT-LCDs) has been expanding as image display devices capable of achieving thinner, lighter weight and higher definition than conventional cathode ray tubes. The TFT-LCD includes a gate wiring, a drain wiring formed on a glass substrate, a thin film transistor formed near an intersection of the gate wiring and the drain wiring, a pixel electrode connected to the thin film transistor, a gate insulating film, a protective film, and a counter substrate. And a liquid crystal layer sandwiched between a glass substrate and a counter substrate. Recently, TFT-LC
As the screen of D increases in size and resolution, the required specifications for lowering the wiring and production yield are becoming stricter.

For the purpose of lowering the resistance of wiring, aluminum or aluminum alloy has been widely used. However, when aluminum or an aluminum alloy is applied to the wiring in a single layer, hillocks are generated on the surface, which causes poor coverage of the insulating film covering the wiring. Further, a TFT having a structure using indium tin oxide (ITO) for taking out a terminal from a wiring.
-In LCD, when ITO and aluminum or ITO and aluminum alloy are directly connected,
There is a problem that the contact deteriorates due to corrosion. Therefore,
For example, in a reverse stagger type TFT-LCD gate wiring,
A countermeasure is taken by a clad structure in which a wiring pattern of aluminum or an aluminum alloy is covered with a high melting point metal. Such an example is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-341299.
JP-A-7-64109, JP-A-9-127555, and JP-A-10-213809.

In order to form the above-mentioned clad structure, it is necessary to carry out photolithography once for aluminum or an aluminum alloy and once for high-melting-point metal, that is, twice, which makes the process complicated. turn into.

For the purpose of simplifying the process, for example, in the case of an inverted staggered TFT-LCD gate wiring, aluminum or an aluminum alloy and a high melting point metal are successively laminated and formed by one photolithography. A method of forming a pattern is employed. Such an example is disclosed in, for example, JP-A-11-74537 and JP-A-6-281954.
JP-A-4-240824, JP-A-4-20930, and JP-A-10-240150.

In JP-A-11-74537, molybdenum, molybdenum-tungsten alloy, molybdenum-tantalum alloy, and molybdenum-niobium alloy having compressive stress characteristics are employed as an upper layer of a gate laminated wiring, and aluminum, copper, and gold are employed as a lower layer. Is adopted. As an etching method, the upper layer is wet-etched with a solution of a mixture of phosphoric acid, nitric acid, and acetic acid, and the lower layer is dry-etched, or the upper and lower layers are collectively wet-etched with a solution of a mixture of phosphoric acid, nitric acid, and acetic acid. A single etching method is employed, and the processing is performed so that the width of the upper layer is smaller than the width of the lower layer.

In Japanese Unexamined Patent Publication No. Hei 6-281954, a molybdenum-tantalum alloy is adopted as an upper layer of a gate laminated wiring.
Aluminum is used as the lower layer. As an etching method, the upper layer is chemically dry-etched with a mixed gas of CF ₄ + O ₂ and the lower layer is subjected to reactive ion etching with a mixed gas of Cl ₂ + BCl ₃ + He. As a result, the lower layer has a tapered shape, and the width of the upper layer is processed to be smaller than the width of the lower layer.

In Japanese Patent Application Laid-Open No. 4-240824, tantalum, niobium, tungsten, molybdenum or an alloy thereof is used as an upper layer of a gate laminated wiring, and aluminum or aluminum-1 at% copper-0.5 is used as a lower layer.
at% Aluminum alloy such as silicon is used. As an etching method, the upper layer is chemically dry-etched with a mixed gas of CF ₄ + O ₂ , and the lower layer is wet-etched with a mixed solution of phosphoric acid, nitric acid and acetic acid.

In Japanese Patent Application Laid-Open No. 4-20930, a molybdenum alloy containing 0.5 to 10% by weight of chromium is used as an upper layer of a gate laminated wiring, and aluminum or an aluminum alloy is used as a lower layer. As an etching method, the upper layer and the lower layer are collectively wet-etched with a solution in which phosphoric acid, nitric acid, and acetic acid are mixed, and the taper angle of the cross section is 5 °.
It is processed to 0 °.

In Japanese Patent Application Laid-Open No. Hei 10-204150, 0.01-20 at% of tungsten is used as an upper layer of a gate laminated wiring.
A molybdenum-tungsten alloy is used, and aluminum or an aluminum alloy is used as a lower layer. As for the etching method, the upper and lower layers are phosphoric acid,
Batch wet etching is performed with a mixed solution of nitric acid and acetic acid, and the taper angle of the cross section is processed from 20 ° to 70 °.

It is described in US Pat. No. 2,650,157, for example, that aluminum or an aluminum alloy can be etched with a mixed solution of phosphoric acid, nitric acid and acetic acid.

The fact that molybdenum or a molybdenum alloy can be etched with a solution in which phosphoric acid, nitric acid and acetic acid are mixed is disclosed in, for example, IEEE Trans. Electron Devices ED-1.
8,931 (1971).

As an example of examining various wet etching methods, the cross-sectional shape of a multilayer wiring in which the upper layer is molybdenum and the lower layer is aluminum is collectively etched with a mixed solution of phosphoric acid and nitric acid.
pers of 1994 INTERNATIONALWORKSHOP ON ACTIVE-MATRI
X LIQUID-CRYSTAL DISPLAYS, November 30−December
1, 1994, KOGAKUIN UNIVERSITY, Shinjuku, Tokyo, Jap
an, p188.

According to this, in the case of the dip type wet etching, the wiring cross section is subjected to forward taper processing, but in the case of the shower type or spray type, the upper layer has a cross-sectional shape protruding like an eaves from the lower layer. It has been reported that

[0015]

Among the wet etching methods used for wiring patterning, the dipping method is not suitable for patterning large and high-definition wiring, and is not suitable for wet etching having a large area and high in-plane uniformity. A shower or spray system is essential. However, as described above, when a multilayer wiring having an upper layer of molybdenum and a lower layer of aluminum is collectively etched by a shower method or a spray method using a solution of a mixture of phosphoric acid and nitric acid, the upper layer has a wiring sectional shape protruding like an eaves. It will be processed. The same wiring cross-sectional shape was reproduced in an experiment in which the inventors attempted a batch etching by a shower method using a mixed solution of phosphoric acid, nitric acid and acetic acid on a laminated film of a molybdenum alloy as an upper layer and an aluminum alloy as a lower layer. . If an insulating film layer is formed on such a wiring shape, coverage failure may occur.

Accordingly, an object of the present invention is to use a shower type or spray type wet etching to process a cross section of a laminated wiring of an upper layer of a molybdenum alloy and a lower layer of an aluminum alloy into a tapered shape, thereby improving the coverage of the insulating film. It is an object of the present invention to provide a method for forming a wiring of a liquid crystal display device.

Further, a TFT-L having a structure using indium tin oxide (ITO) for taking out a terminal from a wiring.
In a CD, a contact hole is formed in an insulating film before forming an ITO film. At this time, if the molybdenum alloy in the upper layer is also etched by the dry etching and the upper layer is penetrated, aluminum or aluminum alloy and IT
Direct connection with O occurs, which causes contact deterioration due to corrosion.

Accordingly, another object of the present invention is to provide a method for forming a wiring of a liquid crystal display device, which can impart sufficient dry etching resistance to a molybdenum alloy on a wiring.

Further, when a laminated wiring of an upper layer made of a molybdenum alloy and a lower layer made of an aluminum alloy is subjected to collective etching, the side surfaces of the lower layer are exposed to the aluminum alloy, so that hillocks may be generated from this part.

It is another object of the present invention to provide a method for forming a wiring of a liquid crystal display device which suppresses hillocks on the side surface of an aluminum alloy.

[0021]

In order to solve the above-mentioned object, a method for forming a wiring of a liquid crystal display device according to the present invention comprises:
A resist pattern is formed on the gate wiring (laminated structure of Mo alloy in upper layer and Al alloy in lower layer), and phosphoric acid (H ₃ PO ₄ )
, Nitric acid (HNO ₃ ), acetic acid (CH ₃ COOH) and water (H ₂
O) and 7 mol% or more and 12 mol% or less of nitric acid (HNO ₃ ), and ammonium fluoride (NH ₄ F)
At least one of hydrogen fluoride and hydrogen fluoride (HF).
Shower type or spray type wet etching is performed using an etchant having a composition containing a trace amount of about 0.1 to 0.1 mol%.

In order to impart sufficient dry etching resistance to the molybdenum alloy in the upper layer of the wiring, it is necessary to make the upper layer of the wiring 1.0 a.
A molybdenum alloy containing at least t% chromium, at least 3.0 at% hafnium, or at least 5.0 at% zirconium.

In order to suppress the hillock on the side surface of the aluminum alloy in the lower layer, the wiring lower layer is made of an aluminum alloy containing 0.2 at% or more, preferably 2 at% or more of neodymium.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a liquid crystal display device according to the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing a first embodiment of the present invention, and shows a method of forming a laminated wiring in which a lower layer is made of an Al alloy and an upper layer is made of a Mo alloy by wet etching of a shower system.

First, an Al alloy 2 and M
The o-alloy 3 is continuously formed. In this embodiment, as the Al alloy 2, an Al alloy 240 containing 2.0 at% of Nd is used.
A Mo alloy 20 nm containing 3.0 at% Cr as the Mo alloy 3 was formed by sputtering. Thereafter, a resist pattern 4 is formed by photolithography, and wet etching is performed by a shower etching apparatus 5. In the present embodiment, phosphoric acid (H ₃ PO ₄ ), nitric acid (HNO ₃ ) and acetic acid (CH
₃ COOH) and employing a mixture comprising water (H ₂ O).
Here, the nitric acid concentration was 12 mol%, and 0.1 mol% of ammonium fluoride was additionally added.

As a result of such an etching process, a wiring pattern of the laminated film of the Al alloy 2 and the Mo alloy 3 was collectively formed by one etching. The cross-sectional shape of the wiring was processed into a forward tapered shape of about 25 ° to 30 °. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was sufficient.

FIG. 2 is an explanatory view showing a second embodiment of the present invention. A cross section of a wiring when a laminated wiring in which the lower layer is made of an Al alloy and the upper layer is made of a Mo alloy is formed by a shower-type wet etching. The shape is shown.

First, an Al alloy 2 and M
The o-alloy 3 is continuously formed. In this embodiment, as in the first embodiment, the Al alloy 2 contains 240 at% Nd containing 240 nm of Nd, and the Mo alloy 3 contains 3.0 nm.
A 20 nm Mo alloy containing at% Cr was deposited by sputtering. Thereafter, a resist pattern is formed by photolithography, and wet etching is performed by a shower etching apparatus. In this embodiment, the etchant is phosphoric acid (H) having a nitric acid concentration of 12 mol%.
₃ PO ₄ ), nitric acid (HNO ₃ ), acetic acid (CH ₃ COOH) and water (H ₂ O). FIG. 2A shows a case where ammonium fluoride or hydrogen fluoride is not added to the etchant, and FIG. 2B shows a wiring cross-sectional shape when 0.01 mol% of ammonium fluoride is added to the etchant.

When ammonium fluoride or hydrogen fluoride was not added to the etchant, a beard-like product 7 was observed on the side surface of the lower Al alloy 2. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was insufficient. On the other hand, ammonium fluoride is used as an etchant.
When 0.1 mol% is added, ammonium fluoride is added in an amount of 0.1 mol%.
As in the case of Example 1 in which 1 mol% was added, the cross-sectional shape of the wiring was processed into a forward tapered shape of approximately 25 ° to 30 °. Similarly, in the case of an etchant to which 0.01 mol% or 0.1 mol% of hydrogen fluoride is added as an alternative to ammonium fluoride, the cross-sectional shape of the wiring is approximately 25 ° to 30 °.
Was processed into a forward tapered shape. The coverage of the SiN film deposited by chemical vapor deposition on these wiring patterns was sufficient.

FIG. 3 is an explanatory view showing a third embodiment of the present invention, in which a cross section of a wiring when a lower layer is made of an Al alloy and an upper layer is made of a Mo alloy is formed by wet etching of a shower system. The shape is shown.

First, an Al alloy 2 and M
The o-alloy 3 is continuously formed. In this embodiment, as in the first embodiment, an Al alloy 2 containing 240 nm of Nd at 240 nm and an Mo alloy 3 having a thickness of 3.0 at%.
% Of a Mo alloy containing 20% Cr was formed by a sputtering method. Thereafter, a resist pattern is formed by photolithography, and wet etching is performed by a shower etching apparatus. In this embodiment, the etchant is phosphoric acid (H ₃ PO ₄ ) containing 0.1 mol% of ammonium fluoride, nitric acid (HNO ₃ ), and acetic acid (CH ₃ C).
OOH) and water (H ₂ O).

FIG. 3A shows a case where the nitric acid concentration of the etchant is 5.0 mol%, and the cross section of the wiring has a shape in which the upper Mo alloy 3 protrudes like an eave. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was insufficient. FIG. 3B shows that the nitric acid concentration of the etchant is 7.
0 mol%, and the cross-sectional shape of the wiring is approximately 45 ° to
It was processed into a forward tapered shape of 49 °. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was sufficient. FIG. 3C shows the case where the nitric acid concentration of the etchant is 9.5 mol%, and the cross-sectional shape of the wiring is approximately 35 ° to 40 °.
Was processed into a forward tapered shape. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was sufficient. FIG. 3D shows that the nitric acid concentration of the etchant is 12.0 mol%.
In this case, the cross-sectional shape of the wiring was processed into a forward tapered shape of approximately 25 ° to 30 °. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was sufficient. FIG.
(E) shows the case where the nitric acid concentration of the etchant is 14.5 mol%. In this case, the upper Mo alloy is largely retreated by etching. Insect-like defects were observed in some wiring patterns.

FIG. 4 is an explanatory view showing a fourth embodiment of the present invention. A cross section of a wiring when a laminated wiring in which the lower layer is made of an Al alloy and the upper layer is made of a Mo alloy is formed by wet etching of a shower system. The shape is shown.

First, an Al alloy 2 and M
The o-alloy 3 is continuously formed. In this embodiment, as the Al alloy 2, an Al alloy 240 containing 2.0 at% of Nd is used.
nm and Mo alloy 3 having various Cr contents 20
nm was formed by a sputtering method. Thereafter, a resist pattern was formed by photolithography, and wet etching was performed by a shower etching apparatus. In the present embodiment, as in the first embodiment, as the etchant 6,
The nitric acid concentration was 12 mol% and ammonium fluoride was
Phosphoric acid (H ₃ PO ₄ ) and nitric acid (HN
A mixture containing O ₃ ), acetic acid (CH ₃ COOH) and water (H ₂ O) was employed.

FIG. 4A shows the case where the Mo alloy 3 is pure Mo containing no Cr. In this case, the upper Mo alloy is largely retreated by etching. Insect-like defects were observed in some wiring patterns. FIG. 4B shows M
In this case, the Cr content of the o-alloy 3 was 1.0 at%, and the cross-sectional shape of the wiring was processed into a forward tapered shape of about 20 ° to 25 °. Similarly, when the Hf content of the Mo alloy 3 was 3.0 at% and the Zr content was 5.0 at%, the cross-sectional shape of the wiring was similarly processed into a forward tapered shape of about 20 ° to 25 °. The coverage of the SiN film deposited by chemical vapor deposition on these wiring patterns was sufficient. FIG. 4C shows the case where the Cr content of the Mo alloy 3 is 3.0 at%, and the cross-sectional shape of the wiring is processed into a forward tapered shape of approximately 25 ° to 30 °. M
Similarly, when the Hf content of the o-alloy 3 is 10 at% and the Zr content is 20 at%, the cross-sectional shape of the wiring is also approximately 25 °.
It was processed into a forward tapered shape of ３０30 °. The coverage of the SiN film deposited by chemical vapor deposition on these wiring patterns was sufficient. FIG. 4D shows a case where the Cr content of the Mo alloy 3 is 9.0 at%, and the cross-sectional shape of the wiring is approximately 35%.
It processed into the forward taper shape of ° -40 °. H of Mo alloy 3
Similarly, when the f content was 20 at% and the Zr content was 30 at%, the cross-sectional shape of the wiring was similarly processed into a forward tapered shape of about 35 ° to 40 °. The coverage of the SiN film deposited by chemical vapor deposition on these wiring patterns was sufficient. FIG. 4E shows a case where the Cr content of the Mo alloy 3 is 18 at%, and the cross section of the wiring has a shape in which the upper Mo alloy 3 protrudes like an eaves. Mo alloy 3 has an Hf content of 30 at%
And when the Zr content is 40 at%, the upper layer M
The o-alloy 3 has a shape protruding like an eaves. The coverage of the SiN film deposited by chemical vapor deposition on these wiring patterns was insufficient.

FIG. 5 is an explanatory view showing a fifth embodiment of the present invention. A cross section of a wiring when a laminated wiring in which the lower layer is made of an Al alloy and the upper layer is made of a Mo alloy is formed by wet etching of a shower system. The shape is shown.

First, an Al alloy 2 and M
The o-alloy 3 was formed continuously. In the present embodiment, the Al alloy 2 is 240 nm having various Nd contents, and the Mo alloy 3 is the Mo alloy 20 containing 3.0 at% Cr.
nm was formed by a sputtering method. Thereafter, a resist pattern was formed by photolithography, and wet etching was performed by a shower etching apparatus. In this embodiment, as in the first embodiment, as an etchant, the concentration of nitric acid is 12 mol%, and phosphoric acid (H ₃ PO ₄ ) containing 0.1 mol% of ammonium fluoride and nitric acid (HN) are added.
A mixture containing O ₃ ), acetic acid (CH ₃ COOH) and water (H ₂ O) was employed. After wet etching, 30
The wiring pattern was heat-treated at 0 ° C.

FIG. 5A shows the case where the Nd content of the Al alloy 2 is 2.0 at% and the cross-sectional shape of the wiring is approximately 25%.
The workpiece was processed into a forward taper of 30 ° to 30 °. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was sufficient. FIG. 5B shows a case in which the Nd content of the Al alloy 2 is 0.1 at%, and a protruding product which seems to be a hillock was formed on the side surface of the Al alloy layer of the wiring. The coverage of the SiN film deposited by chemical vapor deposition on this wiring pattern was insufficient. Nd content of Al alloy 2 is 0.2a
In the case of t%, similarly to FIG. 5A, the cross-sectional shape of the wiring was processed into a forward tapered shape of approximately 25 ° to 30 °. However, the heat treatment temperature in vacuum after wet etching is 3
When the temperature was set to 50 ° C., similar to FIG. 5B, a protruding product which appeared to be a hillock was formed on the side surface of the Al alloy layer.

FIG. 6 is an explanatory view showing a sixth embodiment of the present invention, in which a gate wiring whose lower layer is made of an Al alloy and whose upper layer is made of a Mo alloy is formed by wet etching of a shower method.
An example in which an active matrix is formed by a so-called inverted staggered thin film transistor is shown. FIG. 6A is a cross-sectional view of a thin film transistor portion, and FIG.
FIG. 4 is a sectional view of a gate terminal portion.

First, 240 nm Al alloy containing 2.0 at% Nd and 20 nm Mo alloy containing 3.0 at% Cr were formed on a glass substrate 1 having a size of 650 mm × 830 mm by sputtering. . afterwards,
A resist pattern is formed by photolithography, and wet etching is performed by a shower etching device.
Gate wiring 9 was formed. In this case, as an etchant, the concentration of nitric acid is 12 mol%, and phosphoric acid (H ₃ PO ₄ ) containing 0.1 mol% of ammonium fluoride and nitric acid (HN) are added.
A mixture containing O ₃ ), acetic acid (CH ₃ COOH) and water (H ₂ O) was employed.

As a result of examining the distribution of the cross-sectional shape of the gate wiring 9 on the glass substrate 1 of 650 mm × 830 mm, the gate wiring 9 was processed into a forward tapered shape, and the taper angle was distributed between about 25 ° to 30 °, and was substantially In-plane uniform wiring processing was performed.

Next, the SiN film 3 is used as the gate insulating film 10.
50 nm, amorphous Si (intrinsic semiconductor layer 140 nm and n-type semiconductor layer 20 nm) was formed as the semiconductor layer 11 by plasma enhanced chemical vapor deposition. After the film formation, no protrusions such as hillocks were observed on the side surfaces of the Al alloy layer of the gate wiring 9, and the coverage of these chemical vapor deposition films was good. Thereafter, a resist pattern is formed by photolithography, and the semiconductor layer 1 is formed by dry etching.
1 was patterned.

Next, a 300 nm CrMo alloy was formed as a drain wiring 12 and a source wiring 13 by a sputtering method. Thereafter, a resist pattern was formed by photolithography, and wet etching was performed by a shower etching apparatus to form a wiring pattern. In this case, a solution containing ceric ammonium nitrate was employed as an etchant. By the way, the gate wiring 9
The Mo alloy used for the upper layer has the property of dissolving in a solution containing ceric ammonium nitrate. Therefore,
In this case, there is a concern that a solution containing ceric ammonium nitrate may penetrate into the gate wiring 9 via a defect of the gate insulating film 10 and the Mo alloy layer of the gate wiring 9 may be dissolved. However, since the coverage of the gate insulating film 10 was good, the dissolution of the Mo alloy layer of the gate wiring 9 was not observed at any part of the glass substrate 1 of 650 mm × 830 mm. Subsequently, the n-type semiconductor layer between the drain wiring 12 and the source wiring 13 was etched by dry etching.

Next, the protection film is set to 14 and the SiN film is set to 35
0 nm was formed by a plasma enhanced chemical vapor deposition method. Thereafter, a resist pattern was formed by photolithography, and a contact hole 15 was formed by dry etching.

Next, a film of indium tin oxide (ITO) was formed by a sputtering method. Thereafter, a resist pattern was formed by photolithography, and an ITO electrode 16 was formed by wet etching using an HBr solution. The Al alloy used for the lower layer of the gate wiring 9 is HB
It has the property of dissolving in r solution. Therefore, in this case, there is a concern that the HBr solution may seep into the gate wiring 9 via defects of the protective film 14 and the gate insulating film 10 and the Al alloy layer of the gate wiring 9 may be dissolved. However, since the coverage of the protective film 14 and the gate insulating film 10 was good, the dissolution of the Al alloy layer of the gate wiring 9 was not observed at any part of the glass substrate 1 of 650 mm × 830 mm.

Through the above process, an active matrix using a so-called inverted staggered thin film transistor was formed.

Next, a seventh embodiment will be described.

In this embodiment, the contact matrix between the gate wiring 9 and the ITO film 16 is changed by changing the alloy composition of the upper layer of the gate wiring 9 in the active matrix formed by the so-called inverted staggered thin film transistor formed in the sixth embodiment. It is an example evaluated. FIG. 7 shows the evaluation results of the contact characteristics of the ITO film 16 with respect to the Mo alloy composition in the upper layer of the gate wiring 9. As a result, the Cr content of the MoCr alloy is lower than 1.0 at%,
Poor contact characteristics occurred when the f content was lower than 3.0 at% and when the MoZr alloy had a Zr content lower than 5.0 at%. These Cr, Hf,
In the case of the alloy having a small amount of the added element of Zr, the Mo alloy disappeared in the contact portion, and the Al alloy and the ITO film 16 were in direct contact, and corrosion was recognized in that portion.
The cause of the disappearance of the Mo alloy is that the Mo alloy layer having a small amount of Cr, Hf, and Zr is also etched by dry etching when forming the contact hole 15 in the protective film 14. Conversely, Cr,
The Mo alloy containing a large amount of the added element of Hf and Zr had dry etching resistance and was capable of forming the contact hole 15.

In the manufacturing method of the liquid crystal display device of the present invention, the cross section of the laminated wiring having the Al alloy as the lower layer and the Mo alloy as the upper layer can be tapered by using shower etching, and the insulating film formed on the wiring can be tapered. The coverage insulating film is also improved.

[0051] Shower etching is an essential means for uniform in-plane etching in a production line using a large substrate. Therefore, according to the present invention which avoids the problem of shower etching, it is possible to manufacture a liquid crystal display device employing a multilayer wiring in which an Al alloy is a lower layer and a Mo alloy is an upper layer with a high yield on a production line using a large-area substrate. Will be possible. As a result, there is an effect that a high-definition liquid crystal display device having a large screen can be provided at low cost.

[0052]

According to the present invention, a liquid crystal display device capable of improving the coverage of an insulating film by processing a cross section of a laminated wiring of a molybdenum alloy as an upper layer and an aluminum alloy as a lower layer by using wet etching. Can be provided.

[Brief description of the drawings]

FIG. 1 shows a method of forming a laminated wiring in which a lower layer is made of an Al alloy and an upper layer is made of a Mo alloy by wet etching of a shower method.

FIG. 2 is a cross-sectional view of a wiring when a laminated wiring in which a lower layer is made of an Al alloy and an upper layer is made of a Mo alloy is formed by wet etching of a shower method (with or without addition of ammonium fluoride or hydrogen fluoride to an etchant); Impact).

FIG. 3 is a cross-sectional shape of a wiring when a laminated wiring in which the lower layer is an Al alloy and the upper layer is a Mo alloy is formed by wet etching of a shower system (effect of nitric acid concentration in an etchant).

FIG. 4 is a cross-sectional shape of a wiring when a laminated wiring in which a lower layer is an Al alloy and an upper layer is a Mo alloy is formed by wet etching of a shower method (influence of the contents of Cr, Hf, and Zr in the Mo alloy).

FIG. 5 is a cross-sectional view of the wiring when a laminated wiring in which the lower layer is made of an Al alloy and the upper layer is made of a Mo alloy is formed by shower-type wet etching (the effect of the content of Nd in the Al alloy).

FIG. 6 illustrates an example in which a stacked wiring in which a lower layer formed of an Al alloy and an upper layer is formed of a Mo alloy formed by shower-type wet etching is used as a gate wiring to form an active matrix of a so-called inverted staggered thin film transistor.

FIG. 7 shows ITO with respect to the Mo alloy composition of the upper layer of the gate wiring
Evaluation result of contact characteristics of film.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... Al alloy, 3 ... Mo alloy, 4 ... Resist pattern, 5 ... Shower etching apparatus, 6 ... Etchant, 7 ... Beard product, 8 ... Projection product, 9 ... Gate wiring, 10 ... gate insulating film, 11 ... semiconductor layer, 12
... drain wiring, 13 ... source wiring, 14 ... protective film, 1
5 contact hole, 16 ITO electrode.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kenichi Onizawa 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Toshiki Kaneko 3300 Hayano, Mobara-shi, Chiba Shares Hitachi, Ltd. Display Group (72) Inventor Takahiro Ochiai 3300 Hayano, Mobara-shi, Chiba Prefecture Hitachi, Ltd. Display Group (72) Ken-ichi Chabara 7-1-1, Omika-cho, Hitachi City, Ibaraki, Ltd. Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Masanori Terakado 3300 Hayano, Mobara-shi, Chiba Hitachi, Ltd. Display Group (72) Inventor Yuichi Harano 7-1-1, Omika-cho, Hitachi, Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Hideaki Yamamoto Hayano, Mobara City, Chiba Prefecture 3300 F-term in the Display Group, Hitachi, Ltd. F-term (reference) 2H092 GA25 HA06 JA40 JA44 JB24 JB33 KB04 MA18 NA15 NA16 4K057 WA11 WB05 WB08 WB11 WB15 WE02 WE04 WE07 WE12 WG03 WN01 5C094 AA21 AA42 BA04 EB04 EB04 AA27 BB15 BB16 DD23 EE07 FF03 GG02 5G435 AA16 AA17 BB12 EE33 EE41 HH12 KK05 KK09

Claims (10)

[Claims] 1. A step of forming a metal thin film on a glass substrate, a step of forming a resist pattern on the metal thin film by photolithography, and etching the etchant with phosphoric acid (H ₃ PO ₄ ) and nitric acid (HNO ₃ ).
A mixture containing acetic acid (CH ₃ COOH) and water (H ₂ O), containing 7 mol% to 12 mol% of nitric acid (HNO ₃ ), ammonium fluoride (NH ₄ F) and hydrogen fluoride (H ₂ O).
F) at least one of which is from about 0.01 to about 0.1.
Performing wet etching with a composition containing mol%. 2. The method according to claim 1, wherein the metal thin film comprises Al or an Al alloy and M
2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the method is configured by continuously forming an o-alloy. 3. The method according to claim 1, wherein said Al alloy is at least 0.2 at%.
3. The method for manufacturing a liquid crystal display device according to claim 2, wherein said aluminum alloy contains 2 at% or more of neodymium. 4. The Mo alloy according to claim 1, wherein said Mo alloy is 1.0 at% or more and 9.0 at% or more.
at% or less of chromium or about 3.0 at% or more and about 20a
tf or less of hafnium or 5.0at% or more and 30at
3. The method for manufacturing a liquid crystal display device according to claim 2, wherein the molybdenum alloy contains zirconium in an amount of not more than%. 5. The method according to claim 1, wherein said Al alloy is at least 0.2 at%.
More preferably, it is an aluminum alloy containing 2 at% or more of neodymium, and the Mo alloy is 1.0 at% or more and 9.0 at% or less of chromium or 3.0 at% or more and 20 at% or less.
hafnium of at% or less or 5.0 at% or more and 30a
3. The method according to claim 2, wherein the molybdenum alloy contains t% or less of zirconium. 6. A step of forming a metal thin film on a glass substrate, a step of forming a resist pattern on the metal thin film by photolithography, and using an etchant of phosphoric acid (H ₃ PO ₄ ) and nitric acid (HNO ₃ ).
A mixture containing acetic acid (CH ₃ COOH) and water (H ₂ O), containing 7 mol% to 12 mol% of nitric acid (HNO ₃ ), ammonium fluoride (NH ₄ F) and hydrogen fluoride (H ₂ O).
F) at least one of which is from about 0.01 to about 0.1.
Carrying out wet etching with a composition containing mol%. 7. The method according to claim 1, wherein the metal thin film comprises Al or an Al alloy, M
7. The wiring forming method for a liquid crystal display device according to claim 6, wherein the wiring is formed by continuously forming an o-alloy. 8. The method according to claim 1, wherein said Al alloy is at least 0.2 at%.
8. The method according to claim 7, wherein the aluminum alloy contains at least 2 at% of neodymium. 9. The Mo alloy according to claim 1, wherein said Mo alloy is 1.0 at% or more and 9.0 at% or more.
at% or less of chromium or about 3.0 at% or more and about 20a
tf or less of hafnium or 5.0at% or more and 30at
8. The method according to claim 7, wherein the wiring is a molybdenum alloy containing zirconium at a ratio of not more than 10%. 10. The method according to claim 1, wherein said Al alloy is at least 0.2 at.
% Or more, desirably an aluminum alloy containing 2 at% or more of neodymium, and the Mo alloy is 1.0 at% or more and 9.0 at% or less of chromium or 3.0 at% or more and 2 at% or less.
0 at% or less of hafnium or 5.0 at% or more and 30
8. The method for forming a wiring in a liquid crystal display device according to claim 7, wherein the wiring is a molybdenum alloy containing zirconium of not more than at%.