JP3079600B2 - Manufacturing method of matrix type display device - 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 a matrix type display device.

[0002]

2. Description of the Related Art A matrix type display device is generally constructed such that a display material such as liquid crystal is sandwiched between two opposing substrates, and a voltage is selectively applied to the display material. At least one of the substrates is provided with a pixel electrode made of a transparent conductive film arranged in a matrix, and a switching element such as a transistor for selectively applying a voltage to each of the pixel electrodes. Further, a charge storage capacitor is provided for each pixel in order to improve display characteristics. Conventionally, as this type of apparatus, there is one shown in FIGS. 3 and 4, which is disclosed in, for example, Japanese Patent Laid-Open Publication No. 1-140129. FIG. 3 is a plan view of a display portion of a conventional matrix type display device, and FIG. 4 is a cross-sectional view taken along a line AB in FIG.

In FIGS. 3 and 4, 1 is a transparent insulating substrate, 2 is a lower electrode of a charge storage capacitor connected on a gate electrode line, 3 is a gate electrode line, 5 is a gate insulating film, and 6 is a non-doped amorphous metal. A silicon layer, 7 is a phosphorus-doped amorphous silicon layer, 8 is a source electrode line, 9 is a drain electrode, 10 is a pixel electrode made of a transparent conductive film connected to the drain electrode, and 11 is a protective film.

In the conventional matrix type display device, the charge storage capacitor lower transparent electrode 2 and the gate electrode line 3 are connected as described above, so that the charge storage capacitor lower electrode 2 made of a transparent conductive film is firstly connected to the first electrode. After forming as a layer,
A gate electrode line material is formed, and a gate electrode line 3 is formed by photolithography and etching so that a part of the gate electrode line material is overlapped with the lower transparent electrode 2, and then a gate insulating film 4 and a semiconductor layer are formed. The electrode 10 is formed so as to partially overlap the lower transparent electrode 2 of the charge storage capacitor. At this time, the charge storage capacitor insulating film 4 is formed in the same layer as the gate insulating film 5. Finally, the protective film 11 is formed to complete the matrix display device.

[0005]

In a conventional method of manufacturing a matrix type liquid crystal display device, a gate electrode line is connected to a transparent lower electrode of a charge storage capacitor. It is necessary to form the gate electrode material on the transparent electrode material by using a wet etching method or a dry etching method. However, in the wet etching method, it is difficult to control the taper angle of the end face of the pattern, and therefore, there is a problem that the gate voltage leaks from the end face of the gate electrode line and reliability is reduced. Further, in the dry etching method, there is a problem that the transparent electrode is exposed to plasma, so that the material of the transparent electrode is damaged, and the production yield is reduced. Further, in the conventional matrix-type display device, the also serves as a charge storage capacitor insulating film in the gate insulating layer, increasing the thickness of the charge storage capacitor insulating film for short 絡防 stop charge charge storage capacitor Can not be performed , and furthermore, the film quality is reduced,
There was a problem that the yield was not improved for a reason .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and is intended to connect a lower electrode of a charge storage capacitor to a gate electrode line without lowering the yield, to short-circuit the charge storage capacitor, and to reduce the charge. It is an object of the present invention to realize a method of manufacturing a matrix type display device having a high aperture ratio and a high display quality, which can prevent a decrease in yield due to a deterioration in film quality of a storage capacitor insulating film .

[0007]

According to a method of manufacturing a matrix type display device according to the present invention, a gate electrode line having an end face of a pattern tapered is formed as a first layer and a second layer is formed as a first layer.
The charge capacity retention of the lower transparent electrode as a layer, formed to partly overlap with the preceding stage or the next stage of the gate electrode lines, the upper
Charge storage capacitor insulating film covering the lower transparent electrode of the charge storage capacitor
And remove the charge storage capacitor insulating film on the gate electrode.
After the removal, a part of the charge storage capacitor lower transparent electrode overlaps
The pixel electrode is formed on the charge storage capacitor insulating film so that
After forming the pixel electrode, a gate insulating film is formed.

[0008]

In the method of manufacturing a matrix type display device according to the present invention, the gate electrode lines are formed in the first layer. here,
If, for example, Cr is used as the gate electrode line material, the taper angle of the pattern can be controlled by the wet etching method. Therefore, the lower transparent electrode of the charge storage capacitor formed by the second layer is formed at the stepped portion of the gate electrode line. Thus, connection with the gate electrode line is possible without disconnection. In addition, there is no damage to the substrate because the dry etching method is not used,
In addition, since the gate electrode line is tapered, there is no leakage of the gate voltage at the end face.

Further, by forming the charge holding capacitor insulating film by a dedicated insulating film different from the gate insulating film and removing the charge holding capacitor insulating film on the gate electrode, the charge holding capacitor insulating film can be formed without changing the TFT characteristics. It is possible to set the insulating film thickness necessary for reducing the short circuit of the storage capacitor. In addition, the charge capacity
After forming the lower transparent electrode,
Formation, the quality of the charge storage capacitor insulating film may deteriorate.
And not.

[0010]

[Embodiment 1] An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a plan view of a display portion of a matrix type display device prepared by a method according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along a line AB in FIG. First, the transparent insulating substrate 1
A Cr film is formed thereon by a sputtering method or the like. Next, a pattern of the gate electrode line 3 is formed by photolithography. At this time, etching is performed by taper etching using a wet etching method. As an etching solution, a mixed solution of nitric acid and cerium ammonium nitrate is used. Thereafter, a transparent electrode material such as ITO (indium tin oxide) is formed as a second layer, and a part of the transparent electrode material overlaps with the gate electrode line to form a charge storage capacitor lower transparent electrode 2.
To form As a result, the lower transparent electrode is connected to the preceding or next gate electrode line without disconnection.
Then, silicon nitride (S
i ₃ N ₄ ) is formed by a plasma CVD method or the like, and Si ₃ N ₄ on the gate electrode is removed. Then, a transparent electrode material such as ITO is formed into a film, and the pixel electrode 10 is formed so as to partially overlap the transparent electrode under the charge storage capacitor. further,
Silicon nitride as a gate insulating film 5 (Si ₃ N ₄₎ and non-doped amorphous silicon as an active layer (i-a
-Si) 6 and phosphorus-doped amorphous silicon (n ⁺
-A-Si) 7 is continuously formed by a plasma CVD method (PCVD) or the like. Then, first, the amorphous silicon layer is patterned into an island shape using photolithography or the like, and Cr and Al for forming the source electrode line 8 and the drain electrode 9 are formed by sputtering or the like, and are patterned. Using the source electrode line and the drain electrode as a mask, unnecessary phosphorus-doped amorphous silicon layers on the channel are removed by dry etching or the like. Finally, a protective film such as silicon nitride (Si ₃ N ₄ ) is formed.
The TFT array substrate is completed.

In this embodiment, a gate electrode line is formed of Cr as the first layer, and at this time, the end of the pattern is processed into a tapered shape by using a wet etching method. Next, a charge storage capacitor transparent lower electrode is formed as a second layer so as to partially overlap the gate electrode line. then,
The step of the gate electrode line has a tapered shape,
Even a transparent electrode having a relatively small thickness of about 0 nm can be connected without disconnection at the end of the gate electrode line. In addition, leakage of a gate signal due to poor coverage of the insulating film on the gate electrode line can be reduced. Next, a charge storage capacitor insulating film is formed using a dedicated insulating film, and the gate electrode of the thin film transistor (TFT) is removed. further,
By forming the pixel electrode so as to partially overlap the charge storage capacitor insulating film, a charge storage capacitor is formed.
Therefore, the film thickness of the charge storage capacitor insulating film required for reducing the short-circuit failure of the charge storage capacitor can be set without affecting the characteristics of the TFT. Thereafter, a matrix-type display device is manufactured in the same manner as in the related art.

[0012]

As described above, according to the present invention, a gate electrode line having an end face of a pattern tapered is formed as a first layer, and a lower electrode of a charge storage capacitor is formed by a second layer.
The charge storage layer is formed so as to partially overlap the previous or next gate electrode line, and covers the lower transparent electrode of the charge storage capacitor.
Forming a capacitance insulating film, and holding the charge on the gate electrode
After removing the insulating film, the charge storage capacitor lower transparent electrode
The pixel electrode is charged with the above-mentioned charge holding capacity so that
Formed on insulating film, gate insulating after forming pixel electrode
Since forming the film, the electrodeposition with connecting the charge storage capacitor lower transparent electrode and the gate electrode lines without reducing the yield, and to prevent a reduction in yield due to a short circuit of the charge storage capacitor
There is an effect that a matrix type display device with a high aperture ratio and high display quality, which can maintain the quality of the load holding capacitance insulating film, can be obtained. In addition, on the gate insulating film and the charge storage capacitor insulating film
Is formed separately, it is possible to set the insulating film thickness necessary for reducing the short-circuit failure of the electrode holding capacitor without changing the TFT characteristics, and it is possible to improve the yield of the charge holding capacitor .

[Brief description of the drawings]

FIG. 1 is a plan view of a pixel portion of a matrix type display device manufactured according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AB of a pixel portion in the matrix type display device of FIG.

3 is a plan view of a pixel portion of a conventional matrix-type display device.

4 is a cross-sectional view taken along line AB of a pixel portion in the matrix type display device of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Transparent insulating substrate 2 Transparent electrode below charge storage capacitor
DESCRIPTION OF SYMBOLS 3 Gate electrode line 4 Charge retention capacity insulating film 5 Gate insulating film 6 Non-doped amorphous silicon layer 7
Phosphorus-doped amorphous silicon layer 8 Source electrode line 9 Drain electrode 10 Pixel electrode

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-1-140129 (JP, A) JP-A-2-104328 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1368 H01L 27/12 H01L 29/786

Claims (1)

(57) [Claims] A plurality of gate electrode lines arranged in parallel on a transparent insulating substrate; a plurality of source electrode lines intersecting the gate electrode; a thin film transistor provided at an intersection of the two electrode lines; A pixel electrode made of a transparent conductive film connected to a drain electrode of the thin film transistor; at least a part of the pixel electrode overlaps with the charge storage capacitor lower transparent electrode via an insulating film; In a matrix display device in which electrodes are connected to the next or previous gate electrode lines, a gate electrode line having a tapered end surface of a pattern is formed as a first layer,
As the second layer , the charge storage capacitor lower transparent electrode is formed so as to partially overlap the preceding or next gate electrode line, and the charge storage capacitor lower transparent electrode is covered.
Forming a capacitor insulating film, and a charge holding capacitor on the gate electrode;
After removing the insulating film, the charge storage capacitor lower transparent electrode and
The pixel electrode has the above-mentioned charge storage capacity
After forming the pixel electrode on the edge film, the gate insulating film
Method of manufacturing a matrix type display device, and forming a.