JPH01214823A - Active matrix substrate and its manufacture - Google Patents

Abstract

PURPOSE:To equalize the size of a picture element electrode to that of an area surrounded with a data line, a scanning line, and a thin film transistor TR by forming the picture element electrode by self-matching. CONSTITUTION:An Mo wiring 103 on a glass plate 101 is coated with an SiO2 109, and a poly Si layer 104 is selectively provided to coat the SiO2 109. A resist 111 is provided and ions are injected to form source and drain electrodes 119 and 121. A picture element electrode 123 is formed by etching with a negative resist 125 as the mask. A positive resist is coated on the SiO2 film 109, and a mask having the same shape as the wiring is provided by using the wiring 103 as the mask to etch the SiO2 109. The mask is removed and a through hole is formed, and an Al film is accumulated, and a photomask is used to work the Al film, and a wiring 129 and a connection conductor 133 are formed. By this constitution, the size of the picture electrode is equalized to that of the area surrounded with the data line, by scanning line, and the thin film TR, and the aperture rate is raised.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is characterized in that the active element is a thin film transistor (TPT).
) and a method for manufacturing the same.

[Conventional technology].

In recent years, from the viewpoint of improving display quality, active matrix liquid crystal display devices, in which an active element such as a thin film transistor is provided for each pixel and the pixel electrode is driven by the active element, have attracted attention. It has a structure in which liquid crystal is sandwiched between an active matrix substrate and a counter substrate whose entire surface is supplied with a single potential. In an active matrix substrate, pixels consisting of active elements and pixel electrodes are arranged in a matrix on a transparent substrate, and scanning lines that control the operation of the active elements and data lines that supply data to the pixel electrodes are located between the pixels. They are arranged in a structure that intersects with each other.

FIG. 4 is a circuit diagram showing pixels, etc. of the active matrix substrate. In the figure, 201 is a data line, 203 is a scanning line provided to cross the data line 201 in a direction perpendicular to the data line 201, 213 is an intersection area between the data line 201 and the scanning line 203, 2o5 is a thin film transistor that is an active element, 2
09 is the source of the thin film transistor 205, 211 is the drain of the thin film transistor 205, and 207 is the drain 21.
This is a pixel electrode connected to 1.

Next, as shown in FIG. 5, a conventional matrix substrate manufacturing method (T.
00 pixel active matrix liquid crystal display device (A 6
40X400 Pixel Active-Matri
x LCD Usinga-5i TFT's) JI Triple E Transactions on Electron Devices (IEEE TRANSAC)
TIONS ON ELECTRON DEVICES
) ED-33, No. 8, 1986, 1218-12
(page 21) will be explained. First, as shown in FIG. 5(a), a protective film 303 is formed on a glass substrate 301, an ITO film is deposited, and the ITO film is processed using a first photomask to form a thin film transistor. A transparent electrode film 305 for use as source and drain lead lines, data lines, and pixel electrodes is formed. Next, the fifth
As shown in FIG. 5(b), an n-type amorphous silicon (n"a-8i) film 307 doped with phosphorus (P) is selectively deposited only on the transparent conductive film 305. Next, as shown in FIG. As shown in c), plasma vapor deposition (PCVD)
A semiconductor film 309 of a thin film transistor is formed by depositing amorphous silicon (a-8i) wA from 4 m thick and processing the amorphous silicon film using a second photomask. At this time, the n-type amorphous silicon film 307 in the region other than the semiconductor film 309 is removed at the same time as the amorphous silicon film. Next, Figure 5(d)
As shown in FIG. 3, a gate insulating film 311 is formed by depositing a silicon nitride (S i N, ) film. Next, the fifth
As shown in Figure (e), a scanning line 313 including the gate electrode of the thin film transistor is formed by depositing an aluminum (Al) film and processing the aluminum film using a third photomask.

The active matrix substrate thin film transistor manufactured by this active matrix substrate manufacturing method is called a top gate staggered structure because the gate electrode is located in the uppermost layer.

[Problem to be solved by the invention]

In the active matrix substrate manufactured by such an active matrix substrate manufacturing method, the pixel electrodes are formed by processing the ITO film using a photomask. Since it needs to be smaller than the area surrounded by , the aperture ratio, that is, the ratio of the area of the pixel electrode to the total area of the active matrix substrate becomes small.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an active matrix substrate with a large aperture ratio and a method for manufacturing the same.

[Means to solve the problem]

In order to achieve this object, in the present invention, pixels each consisting of four film transistors and a pixel electrode made of a transparent conductive film are arranged in a matrix on a transparent substrate, and scanning lines for controlling the operation of the thin film transistor and the pixels are arranged in a matrix on a transparent substrate. In an active matrix substrate in which data lines that supply data to electrodes are arranged intersecting each other between the pixels, a first wiring that becomes the gate electrode of the thin film transistor and the scanning line is provided, and the first wiring becomes the data line. A second wiring is provided, a semiconductor film is provided in a region overlapping with the second wiring except for a region that becomes an active layer of the thin film transistor and a region where the first wiring and the second wiring intersect, The pixel electrode is formed in a self-aligned manner in a region surrounded by the first wiring and the semiconductor film.

Further, in the method for manufacturing an active matrix substrate according to claim 1, the first
a wiring formation step for forming wiring, a semiconductor film formation step for forming the semiconductor film by photoprocessing, and a semiconductor film formation step for depositing the transparent conductor film after the semiconductor film formation step, and depositing the transparent conductor film on the transparent conductor film. Apply a mold resist and apply the above first
irradiating light from the back surface of the transparent substrate using the wiring and the semiconductor film as a light shielding film to form a negative resist layer;
a pixel electrode forming step of forming the pixel electrode in a region surrounded by the first wiring and the semiconductor film by etching and removing the transparent conductor film using the negative resist layer as a mask; Let's do it.

[Effect]

In this active matrix substrate and the method for manufacturing an active matrix substrate, the pixel electrodes are formed in a self-aligned manner, so the size of the pixel electrodes can be adjusted depending on the size of the data line, scanning line, etc.
It can be made equal to the size of the area surrounded by the thin film transistor.

〔Example〕

FIG. 1 is a diagram showing a part of an active matrix substrate according to the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. In the figure, 101 is a glass substrate, 103 is a glass substrate 1
01, the wiring 103 becomes the gate electrode and scanning line of the thin film transistor, and the wiring 103 becomes the gate electrode and scanning line of the thin film transistor.
3 is made of molybdenum (Mo). 105 is wiring 103
A gate insulating film 105, which is a gate insulating film provided thereon, is made of silicon dioxide (SiO□). Reference numeral 129 is a second wiring that becomes a data line, and the wiring 129 is made of aluminum (A
Consists of l). Reference numeral 104 denotes a semiconductor film provided in a region that overlaps with the wiring 129 except for a region that becomes an active layer of a thin film transistor and an intersection region between the wiring 103 and the wiring 129. The semiconductor film 104 is made of polycrystalline silicon. 109 is an interlayer film made of silicon dioxide, and the interlayer film 109 prevents a back channel of the thin film transistor.

119 is the source electrode of the thin film transistor, 121 is the drain electrode of the thin film transistor, 123 is a pixel electrode formed in a self-aligned manner in a region surrounded by the wiring 103 and the semiconductor film 104, and 133 is the drain electrode 121 and the pixel electrode 1.
The connecting conductor 133 is made of aluminum.

Next, a method for manufacturing the active matrix substrate shown in FIGS. 1 and 2 will be explained with reference to FIG. first,
As shown in FIG. 3(a)-1 and FIG. 3(a)-2, a molybdenum film is deposited on a glass substrate 101, and the molybdenum film is processed using a first photomask.
Wiring 103 is formed. Next, as shown in FIG. 3(b)-1 and FIG. 3(b)-2, a gate insulating film 105 is formed by depositing a silicon dioxide film with a thickness of less than 100 mm by atmospheric pressure CVD. Then, after forming the semiconductor film 104 by depositing a polycrystalline silicon film with a thickness of 150 nm at a substrate temperature of 625° C. using a second photomask, a semiconductor film 104 is formed. An interlayer film 109 is formed by depositing a silicon dioxide film with a thickness of 1100 nm using a pressure CVD method. Next, as shown in FIG. 3(c), a positive type resist such as Microposite 1 manufactured by Shipley Co., Ltd. is applied on the first interlayer film 109.
A positive resist layer 111 having the same shape as the wiring 103 is formed on the glabellar membrane 109 by applying UV rays 400-27, using the wiring 103 as a light-shielding film, and irradiating ultraviolet rays from the back side of the glass substrate 101 and performing a development process. , using the positive resist layer 111 as a mask, impurities such as phosphorus ions 117 are applied to the semiconductor film 104 by 5X at an acceleration energy of 140 kV.
After implanting 1015■-2 and removing the positive resist layer 111, the impurity is activated by heat treatment and the source f
f1tl19 and the drain electrode 121 are formed. In this case, the interlayer film 109 serves as a protective film for ion implantation. Next, as shown in FIG. 3(d), after depositing a transparent conductive film by sputtering, a negative resist such as RD200ON manufactured by Hitachi Chemical Co., Ltd. is applied on the transparent conductive film.
Ultraviolet light 127 is irradiated from the back surface of the glass substrate 101 using the wiring 103 and the semiconductor film 104 as a light shielding film. Next, as shown in FIG. 3(e), a negative resist layer 125 is formed in a region other than the wiring 103 and the semiconductor film 104 by performing a development process. Next, in Figure 3 (f
)-1, as shown in FIG. 3(f)-2, the transparent conductive film is etched away using the negative resist layer 125 as a mask to form one pixel electrode 123, and then the negative resist M125 is removed. Next, Figure 3(g)-1, 3rd
As shown in FIG. (g)-2, a positive resist is applied on the interlayer film 109, and ultraviolet rays are irradiated from the back surface of the glass substrate 101 using the wiring 103 as a light-shielding film, and a development process is performed. A positive resist layer having the same shape as the wiring 103 is formed on top, and the interlayer film 1409 is removed using the positive resist layer as a mask to form a through hole, the positive resist layer is removed, and an aluminum film is deposited. Then, by processing the aluminum film using a third photomask, the wiring 129 and the connection conductor 13 are formed.
form 3.

In such active matrix substrates and active matrix substrate manufacturing methods, the pixel electrodes 123 are formed in a self-aligned manner, so the size of the pixel electrodes 123 is determined by adjusting the size of the area surrounded by the data lines, scanning lines, and thin film transistors. Since the size can be made equal to the size, the aperture ratio becomes large.

Further, when forming a semiconductor film after forming the transparent conductive film 305 as in the past, when a polycrystalline silicon film is provided as the semiconductor film, the polycrystalline silicon film is usually deposited by a low pressure CVD method. In the CVD method, the substrate temperature needs to be 600°C or higher, so the transparent conductive film 305 is heated to 600°C or higher.
While the light transmittance of the transparent conductive film 305 decreases and the resistivity increases, the transparent conductive film 305 loses its original role.
When a transparent conductive film to become one pixel electrode 123 is deposited after depositing a polycrystalline silicon film to become 04, the transparent conductive film is not heated, so the light transmittance of the transparent conductive film decreases. This is because there is no increase in resistivity.

The characteristics of the pixel electrode 123 do not deteriorate.

Note that in the above embodiment, the case where the semiconductor film 104 is made of polycrystalline silicon has been described, but the semiconductor film 1
The present invention can also be applied when 04 is made of amorphous silicon.

In the above-described embodiment, the source electrode 119. Although the drain electrode 121 is formed, the source electrode and the drain electrode may be formed by depositing a doped amorphous silicon film or a doped polycrystalline silicon film.

〔Effect of the invention〕

As explained above, in the active matrix substrate and the method for manufacturing an active matrix substrate according to the present invention, the size of the pixel electrode can be made equal to the size of the area surrounded by the data line, the scanning line, and the thin film transistor. Therefore, the aperture ratio increases. in this way,
The effects of this invention are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a part of the active matrix substrate according to the present invention, FIG. 2 is a sectional view taken along the line A-A in FIG. 1, and FIG. 3 is a diagram showing the active matrix substrate shown in FIGS. FIG. 4 is a circuit diagram showing pixels of an active matrix substrate, and FIG. 5 is an explanatory diagram of a conventional method of manufacturing a matrix substrate. 101-...Glass substrate 103...First wiring 104...Semiconductor film 123...Pixel electrode 125...Negative resist layer 129...Second wiring patent applicant Nippon Telegraph and Telephone Corporation Agent Patent Attorney Junnosuke Nakamura Figure 1 Figure 2 (C) Figure 3 (a)-1 Figure 3 (CI) I-2 (b) -2 -〇Uro

Claims (1)

[Claims] 1. Pixels each consisting of a thin film transistor and a pixel electrode made of a transparent conductive film are arranged in a matrix on a transparent substrate,
In an active matrix substrate, a scanning line for controlling the operation of the thin film transistor and a data line for supplying data to the pixel electrode are arranged to cross each other between the pixels, and serve as the gate electrode of the thin film transistor and the scanning line. A first wiring is provided, a second wiring serving as the data line is provided, and the second wiring is provided excluding a region serving as an active layer of the thin film transistor and an intersecting region between the first wiring and the second wiring. 1. An active matrix substrate, wherein a semiconductor film is provided in a region overlapping with a second wire, and the pixel electrode is formed in a self-aligned manner in a region surrounded by the first wire and the semiconductor film. 2. A method for manufacturing an active matrix substrate according to claim 1, comprising: a wiring forming step of forming the first wiring by a photo process; a semiconductor film forming step of forming the semiconductor film by a photo process; After the semiconductor film forming step, the transparent conductor film is deposited, a negative resist is applied on the transparent conductor film, and the first wiring and the semiconductor film are used as a light shielding film to block light from the back surface of the transparent substrate. is irradiated to form a negative resist layer, and the transparent conductor film is etched away using the negative resist layer as a mask, so that the pixel electrode is surrounded by the first wiring and the semiconductor film. 1. A method of manufacturing an active matrix substrate, the method comprising: forming a pixel electrode in a region where the pixel electrode is formed.