JPH0477719A - Manufacture of active matrix type liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve an etching selection ratio among an object to be etched, mask member and base material and to enable high-accuracy and high-yield etching by forming an ITO film on a high fusing point metal wiring layer, patterning the ITO film while masking photoresist and afterwards patterning the high fusing point metal wiring with the ITO film as a mask. CONSTITUTION:As source drain metal 7, Cr is filmed by a sputtering method, and an ITO film 10 is similarly filmed by the sputtering method. Next, wet etching is executed to the ITO film 10 with photoresist 11 as the mask. Afterwards, the source drain metal 7 is selectively etched by using chlorine dry etching gas with the ITO film 10 as the mask. Then, an ITO film 8 for display pixel electrode is stuck and the photoresist 11 is patterned. Finally, wet etching is selectively executed to the ITO film 8 for display pixel electrode with a photoresist 11 as the mask. Thus, since the etching selection ratio can be enlarged, pattern conversion can be reduced and the defect of Cr disconnection can be eliminated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an active matrix liquid crystal display device, and in particular to a method for patterning a high-melting point metal used for metal wiring with high precision and high yield. Regarding the method.

[Conventional technology]

Conventionally, the manufacturing method of the thin film transistor (TPT) array part of this type of liquid crystal display device is as shown in FIGS.
f).

That is, the gate metal 2 is provided on the glass substrate 1 (FIG. 3(a)). Next, gate insulating film 3. A semiconductor Si4 etching stopper 5 is provided (FIG. 3(b)). Then n
``A Si layer 6 is provided, and a semiconductor S layer is formed by a photoresist process.
Pattern i4 and n'' Si layer 6 (Fig. 3(c))
), then a source/drain metal 7 is provided, and the source/train metal is patterned by dry etching using a photoresist process (FIG. 3(d)). Next, an ITO film for display pixel electrodes is prepared and patterned (see Fig. 3).
e)). Finally, channel etching openings 9 were provided to complete the process. Here, the gate metal 2 and source/drain metal 7 shown in FIGS. 3(a) and 3(d) are usually made of Cr,
A high melting point metal such as Mo is used. Further, since the source train metal 7 forms metal silicide at the boundary with the underlying silicon, a dry etching technique has come to be used to remove this metal silicide at the same time as the source train metal 7.

[Problem to be solved by the invention]

The conventional manufacturing method described above has the drawback that the etching selectivity with respect to the photoresist film that serves as a mask during dry etching of Cr is poor, and side etching progresses, increasing pattern conversion and causing Cr disconnection defects. . For example, in the case of Cr, the etching rate of Cr using a 4+02 series etching gas is: the etching rate of the photoresist film -0.6:1.

[Means to solve the problem]

The manufacturing method of the present invention involves patterning a high melting point metal, followed by patterning an IT○ film using a photoresist film as a mask by forming an IrO2 film and a phosphorography process, and patterning the IT○ film. This consists of patterning f and :cr using the mask as a mask.In this way, the etching selection ratio between the object to be etched, the mask material, and the underlying material is increased during each etching process, making it possible to perform machining and sowing with high precision and high yield. There is.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the manufacturing process of the first embodiment of the present invention. This example shows a case where the present invention is applied to Cr drain-in. Up to Figure 1(a), the conventional method
Figures (a) to (c) are manufactured in exactly the same manner. Next, Cr was formed as a source/drain metal 7 by sputtering, and I
TOMIO is also formed into a film by the sputtering method. The photoresist layer 1 is patterned through coating, exposure and development steps of the photoresist film (FIG. 1(b)). Next, using the photoresist 11 as a mask, the IT◯ film 10 is selectively wet-etched with an aqueous solution of nitric acid and hydrochloric acid or ferric chloride and hydrochloric acid (FIG. 1(C)). Next, ITO film 1
Using 0 as a mask, the source/drain metal 7 is selectively etched using a chlorine-based dry etching gas (FIG. 1(d)). Next, an ITO film 8 for a display pixel electrode is deposited, and a photoresist 11 is patterned.

Next, using the photoresist 11 as a mask, the IT○ film 8 for the display pixel electrode is selectively wet-etched (FIG. 1(f)).
Same as e). However, the ITO film thickness on Cr is less than (I
thickness of TO film 10 + thickness of ITO film 8 for display pixel electrode)
Only the O8 film thickness is).

As described above, in this embodiment, since the TO is used as a mask for etching the Cr source/drain metal, the etching selection ratio can be increased, pattern conversion is small, and Cr disconnection defects can be eliminated.

FIG. 2 is a longitudinal sectional view showing the manufacturing process of a second embodiment of the present invention. Up to FIG. 2(d), FIG. 1(d) of the first embodiment is shown.
)' is exactly the same as before. Next, the entire surface of the ITO film 10 is etched using an aqueous solution of nitric acid and hydrochloric acid or ferric chloride and hydrochloric acid (FIG. 2(e)). Next, an ITO film 8 for display pixel electrodes is formed and patterned by a photolithography process (FIG. 2(f)).

In this embodiment, the ITO film thickness of the pixel portion is the same as that of the Cr film. Therefore, there is an advantage that there is no open failure due to step breakage during film formation and patterning of the pixel IT◯ at the stepped portion of the Cr pattern.

In the previous embodiments, chromium was used as the high melting point metal. However, beyond the scope of the present invention, other high melting point metals (M
Needless to say, it is also applicable to other materials (e.g., O, Pt, etc.).

〔Effect of the invention〕

As explained above, in the present invention, when selectively etching Cr, Cr and ITO are sequentially formed, ITO is selectively etched using a photoresist mask, and then Cr is selectively dry etched using an IT○ mask. do. In this way, it is possible to obtain a selectivity of 10 or more between the photoresist of the mask and the underlying Cr when etching ITO.

Similarly, when etching Cr, a selectivity ratio of 10 or more between the ITO mask and the underlying gate insulating film can be easily obtained. Therefore, pattern conversion is small and it is possible to eliminate Cr disconnection defects.

In addition, in the present invention, the display pixel electrode TO is made thin and made of Cr.
The upper ITO can be made thicker. Therefore, the light transmittance of the pixel portion can be kept high, and the Cr wiring can be made into a two-layer wiring of Cr and ITO to provide low resistance and redundancy.

Further, ITO films are very commonly used as transparent electrode materials in display pixel portions of active matrix liquid crystal display devices. Therefore, there is an advantage that there is no need to introduce new equipment for film formation and etching.

[Brief explanation of the drawing]

FIGS. 1(a) to (f) are cross-sectional views showing the manufacturing process of the first embodiment of the present invention, and FIGS. 2(a) to (f) are sectional views showing the manufacturing process of the second embodiment of the present invention. Cross-sectional view showing the process, Figure 3(a)~
(f) is a cross-sectional view at each manufacturing step of the conventional manufacturing method. DESCRIPTION OF SYMBOLS 1...Crowd substrate, 2...Gate metal, 3...Cool 1-insulating film, 4...Semiconductor Si, 5...Etching stopper, 6...n'' Si layer, 7... Source train metal, 8...ITO19 for display pixel electrodes.
・Channel etching opening, 10...ITO film, 1]
...Photoresist.

Claims (1)

[Claims] In the method for manufacturing an active matrix liquid crystal display device, when patterning the high melting point metal wiring, an indium and tin oxide film (ITO film), which is a transparent conductive film, is placed in contact with and on top of the high melting point metal wiring layer. 1. A method for manufacturing an active matrix liquid crystal display device, comprising forming an ITO film, patterning the ITO film using a photoresist as a mask, and then patterning a high melting point metal wiring using the ITO film as a mask.