JPH05273582A - Active matrix driving liquid crystal display device and its manufacture - Google Patents

Abstract

PURPOSE:To provide an active matrix driving liquid crystal display device which does not spoil display characteristics and obtains TFTs with extremely small inter-electrode capacity even if a defect such as an open circuit occurs to a video signal line, etc., owing to an increase in the number of picture elements. CONSTITUTION:In the active matrix driving liquid crystal display device wherein a thin film transistor 1 is used as an active element and the source electrode 4, gate electrode 5, and drain electrode 6 of the thin film transistor l are coupled with the video signal line 3, a scanning signal line 2, and a pixel electrode 8, the source electrode 4 and drain electrode 6 of the thin film transistor 1 are composed of side-wall type electrodes consisting of an insulation part 13 and conduction parts 14 arranged on both its flanks, the video signal line 3 is composed of a side wall type signal line consisting of an insulation part 13 and conduction parts 14 arranged on both its flanks, and the conduction part 14 of the video signal line 3 and the conduction part 14 of the drain electrode 6 form a closed loop as a whole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix drive liquid crystal display device using a thin film transistor (hereinafter referred to as a TFT) as an active element and a method for manufacturing the same, and more particularly to a high density of each pixel including the TFT. The present invention relates to an active matrix drive liquid crystal display device that can be configured and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, as one of active matrix drive liquid crystal display devices, an active matrix drive liquid crystal display device using a TFT as an active element is known. In an active matrix drive liquid crystal display device using this TFT, for example, a large number of pixels including TFTs are formed in a matrix on a transparent insulator substrate made of glass or the like, and a liquid crystal is provided corresponding to each pixel. Respectively TF
This is a system in which a drive voltage is supplied via T to control the display of the liquid crystal, and a relatively clear image display can be obtained. Therefore, recently, it has been used for terminal devices of OA equipment, televisions and the like. However, in each of the above applications, a display screen size of 10 inches or more is required due to its nature. Further, in each of the above applications, in order to display characters (characters, figures, etc.) clearly (in a high contrast state), it is also required to reduce the size of one pixel to increase the definition of the displayed image.

FIG. 12 is an electrically equivalent circuit diagram of one pixel in the active matrix drive liquid crystal display device.

In FIG. 12, 100 is a TFT and 101
Is a scanning (horizontal) signal line, 102 is a video (vertical) signal line,
103 is a liquid crystal capacity, 104 is a complete storage capacity, and 105 is a T
This is the stray capacitance between the gate and source of the FT100.

The TFT 100 is provided with each scanning signal line 1
01 and each video signal line 102 are respectively arranged, the gate is connected to the scanning signal line 101, the drain is connected to the video signal line 102, and the source is the liquid crystal capacitor 10.
3 and the complete storage capacitor 104.

Now, when a scanning signal is supplied to the scanning signal line 101, the TFT 100 is turned on, and the potential state of the video signal line 102 at this time is a charge and the liquid crystal capacitance 10
3 and the complete storage capacitor 104 are written. After that, when the supply of the scanning signal of the scanning signal line 101 is stopped, the TFT
100 is turned off, and the charges accumulated in the liquid crystal capacitor 103 and the complete storage capacitor 104 are maintained as they are, and the liquid crystal display according to the state of the charges is performed in this pixel portion.

13A and 13B are structural views showing an example of the structure of one pixel in the active matrix drive liquid crystal display device. FIG. 13A is a plan view and FIG.
It is a sectional view of an A'line.

In FIG. 13, 106 is a source electrode and 1 is a source electrode.
07 is a gate electrode, 108 is a drain electrode, 109 is a transparent pixel electrode, 110 is a common electrode, 111 is a common electrode signal line, 112 is a transparent insulator substrate, 113 is an insulating film, 114
Is a silicon semiconductor layer, 115 is a high-impurity semiconductor layer, and the same components as those shown in FIG. 15 are denoted by the same reference numerals.

Then, one TFT 100, part of one video signal line 102, transparent pixel electrode 109, common electrode 1
A portion within a dotted line including 10 and the like is a constituent portion which becomes one pixel, and a large number of scanning signal lines 101 are arranged in parallel in a horizontal (row) direction, and a large number of video signal lines 102 are vertically (column). ) Parallel to the signal lines 101, 1
The pixels are arranged in each region surrounded by 02, and a large number of common electrode signal lines 111 are arranged between the scanning signal lines 101 so as to be parallel to the scanning signal lines 101, and active matrix driving is performed. Parts are made up.

In each pixel, a gate electrode 107 integrated with the scanning signal line 101 is provided on a transparent insulator substrate 112, and an insulating film 113 is provided thereon. A silicon semiconductor layer 114 is formed on the insulating film 113 corresponding to the gate electrode 107, and the transparent pixel electrode 10 is formed on the insulating film 113 adjacent to the silicon semiconductor layer 114.
9 is formed. The source electrode 1 is formed on the silicon semiconductor layer 114 via the high impurity semiconductor layer 115.
06 and the drain electrode 108 are arranged, and the source electrode 10
6 is conductively connected to the transparent pixel electrode 109, and the drain electrode 108 is integrally formed with a conductive connection portion branched from the video signal line 102. Further, a common electrode 110 integrally formed with the common electrode signal line 111 is arranged so as to face the transparent pixel electrode 109, and a complete storage capacitor 104 is formed between the two electrodes 109, 110. The complete storage capacitance 104 is based on the ratio (W / L) of the channel width W and the channel length L of the TFT 100, the gate-source stray capacitance 105, the dielectric constant of the insulating film 113, and the like (or the capacitance value (or The size of the common electrode 110) is determined.

By the way, in the active matrix drive liquid crystal display device as shown in FIG. 13, when the size of the display screen is increased, it is necessary to increase the number of pixels corresponding to the size of the display screen. ,
It is already known that improving the aperture ratio of each pixel is an effective means for increasing the contrast of a display image.

[0012]

However, if the number of pixels is increased as the size of the display screen is increased, the lengths of the signal lines 101, 102 and 111 are increased and the signal lines 101 are also increased. , 102, 111 also increase the arrangement density of the signal lines 101, 102, 11
1. Defects such as disconnection and breakage in 1, especially video signal line 10
The rate of generation of defective products having defects such as disconnection and breakage rapidly increases, which causes a problem that the yield of the active matrix drive liquid crystal display device is reduced and the cost is increased.

Further, the aperture ratio of each pixel is improved in order to increase the contrast of a display image.
When it is attempted to shift the TFT 100 to a finer direction, the pattern resolution is limited in the photolithography that is usually used when forming the TFT. However, there is a problem that it is difficult to set the channel length L of the TFT 100 to a fixed value or less determined by the pattern resolution with stable and good yield.

Further, as the miniaturization of the TFT 100 progresses,
The gate-source stray capacitance 105 due to the overlap of the source electrode 106 and the gate electrode 107 of the TFT 100 cannot be ignored, and the charge accumulated in the gate-source stray capacitance 105 becomes a jump voltage during the transient operation of the TFT 100, and the drain electrode 108. Etc., which adversely affects the display characteristics.

The present invention eliminates these problems. A first object of the present invention is to improve the display characteristics even if defects such as disconnection or breakage occur in the video signal line due to the increase in the number of pixels. It does not damage the interelectrode capacitance, especially the gate
An object of the present invention is to provide an active matrix drive liquid crystal display device which obtains a TFT having a floating capacitance between sources as small as possible.

A second object thereof is an active matrix drive liquid crystal capable of obtaining TFTs having a fine channel length in a stable and good yield with a resolution higher than that of a pattern resolution by photolithography which is usually used. It is to provide a manufacturing method of a display device.

[0017]

In order to achieve the first object, the present invention uses a thin film transistor as an active element, and a source electrode, a gate electrode and a drain electrode of the thin film transistor are a video signal line and a scanning signal, respectively. In an active matrix driving liquid crystal display device coupled to a line and a pixel electrode, the source electrode and the drain electrode of the thin film transistor are composed of a sidewall type electrode composed of an insulating part and conductive parts arranged on both side surfaces thereof. The video signal line is composed of a side wall type signal line composed of an insulating part and conductive parts arranged on both side surfaces thereof, and the conductive part of the video signal line and the conductive part of the drain electrode are formed as a whole. A first means coupled to form a closed loop.

In order to achieve the second object, the present invention is a method for manufacturing an active matrix drive liquid crystal display device using a thin film transistor as an active element in each pixel, which includes the following steps (1). Forming a gate electrode and a scanning signal line connected to the gate electrode on a transparent insulator substrate; (2) forming a gate insulating film on at least the gate electrode; and (3) forming a thin film transistor on the gate insulating film. A step of forming a silicon semiconductor layer on the formation portion,
(4). A step of forming a pixel electrode on the gate insulating film,
(5). A step of forming a high-concentration impurity layer on the silicon semiconductor layer, (6). A step of forming insulating layers on the source electrode and drain electrode forming portions and the video signal line forming portions of the thin film transistor, (7). A step of forming a conductive film on the insulating layer formation portion and its peripheral portion, (8). Forming the source electrode and drain electrode and the video signal line on the side surface of each insulating layer in a self-aligned manner. The second means for manufacturing each pixel is sequentially provided.

[0019]

According to the first means, the probability of occurrence of defects such as breakage or disconnection of the video signal lines and the scanning signal lines is increased with the increase in the number of pixels due to the higher definition of the screen display content. At least, the video signal line is at least a side wall type signal line, and the drain electrode of the TFT conductively coupled to the video signal line is also a side wall type electrode, and ,
Since the side wall type signal line and the conductive part of the side wall type electrode form a closed loop as a whole and a so-called redundant conductive part, for example, a part of the closed loop is Even if the defect as described above occurs due to the reason, since the active state of the closed loop is maintained through the conductive portion on the non-defective side, an active matrix drive liquid crystal display device that does not impair display characteristics can be obtained. ..

Further, as described above, not only the drain electrode of the TFT but also the source electrode is composed of the side wall type electrode, and the overlapping portion between the gate electrode of the TFT and other electrodes is excluded. The capacitance between the gate electrode and the other electrode, especially the capacitance between the gate and the source can be minimized, and the adverse effect on the screen display due to the capacitance between the gate and the source can be eliminated.

Further, according to the second means, conventionally,
In place of the photolithography means which has been conventionally used when forming a conductive channel or the like of a TFT, a drain electrode and a source electrode of the TFT and at least a video signal line are formed in self-alignment with the insulating layer and its side surface. Since it is configured by the side wall type electrode and the side wall type signal line including the conductive portion, the portion substantially related to the resolution when the conductive channel of the TFT is formed is the insulation of the drain electrode and the source electrode. It is a space between layers, and since the conductive portion is formed on the side surface of the insulating layer between the spaces in a highly self-aligned manner with high accuracy, the limit of resolution in the conventional means is limited. A conductive channel having a length that is reduced beyond that can be secured, and further miniaturization of the TFT can be achieved, and It is possible to improve the aperture ratio of the pixel.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are configuration diagrams showing a first configuration example of one pixel of an active matrix drive liquid crystal display device according to the present invention. FIG. 1 is a plan view thereof and FIG.
2A is a cross-sectional view taken along the line AA ′ of FIG. 1, FIG.
Is a sectional view taken along the line BB ′.

In FIGS. 1 and 2, 1 is a TFT, 2 is a scanning signal line, 3 is a video signal line, 4 is a source electrode, 5 is a gate electrode, 6 is a drain electrode, 7 is an amorphous silicon semiconductor, and 8 is. Is a transparent pixel electrode, 9 is a common signal electrode line, 10 is a common electrode, 11 is a glass substrate, 12 is a gate insulating film, 13
Is an insulating layer, 14 is a conductor, and 15 is a high impurity semiconductor layer.

The TFT formed in each pixel
Reference numeral 1 mainly comprises a portion composed of a source electrode 4, a gate electrode 5, a drain electrode 6, and an amorphous silicon semiconductor 7. A scanning signal line 2 crosses a portion where the TFT 1 is arranged. A video signal line 3 is formed and arranged so as to be orthogonal to 2, and a common signal electrode line 9 is formed and arranged in parallel with the scanning signal line 2.

In each pixel, first, the gate electrode 5 and the scanning signal line 2 which are integrally formed are formed and arranged on the glass substrate 11, and the gate insulation is performed in a wide range including the above portion. The membrane 12 is formed and arranged. Next, on the gate insulating film 12, the amorphous silicon semiconductor 7 is provided in a portion where the gate electrode 5 is arranged, the transparent pixel electrode 8 is provided in a portion adjacent to the gate electrode 5, and the transparent pixel electrode 8 is provided.
Video signal lines 3 are formed and arranged adjacent to each other, and a source electrode 4 and a drain electrode 6 are further formed and arranged on the silicon semiconductor 7 with a high impurity semiconductor layer 15 interposed therebetween. The transparent pixel electrode 8 is conductively connected to the drain electrode 6 at an end portion thereof, and is arranged to face the common electrode 10 of the common signal electrode line 9 at the center portion thereof via a liquid crystal (not shown). In this case, the source electrode 4 and the drain electrode 6 together constitute a sidewall type electrode in which the conductor 14 is arranged on the peripheral surface of the insulating layer 13, and the video signal line 3 also includes the peripheral surface of the insulating layer 13. A side wall type signal line is formed by arranging the conductor 14 in the.

Further, the conductor 14 forming the drain electrode 6 is conductively connected to the conductor 14 forming the video signal line 3, and the conductor 14 of one video signal line 3 corresponds to the drain electrode 6. The other video signal line 3 via the conductor 14
The conductors 14 are formed and arranged so that each conductor 14 forms a closed loop.

In the TFT 1 of this embodiment, the ratio (W / L) of the channel length L and the channel width W, that is, the value W / L that determines the mutual conductance gm is, for example, about 3. Is set. However, the value W / L is not limited to this, and can be appropriately changed depending on the frame frequency, the number of scanning signal lines 2, the mobility of the TFT 1, the liquid crystal capacitance value, the complete storage capacitance value, and the like. .. In addition, the above-mentioned perfect storage capacity is common electrode 1
Although it depends on the size of the overlapping portion between 0 and the pixel electrode 8, its value also depends on the dielectric constant of the gate insulating film 12 and the like.

The active matrix drive liquid crystal display device having the above structure operates as described below.

When a signal for selecting the TFT 1 is supplied to the scanning signal line 2 and a video signal is further supplied to the video signal line 3, a current corresponding to the magnitude of the video signal is supplied to the TFT 1. The voltage depending on the magnitude of the current flows through the channel portion between the source electrode 4 and the drain electrode 6 and is induced in the transparent pixel electrode 8 to be accumulated and retained in the complete retention capacitor or the like. The induced voltage is stably applied to both ends of a liquid crystal element (not shown) arranged between the electrode 8 and the common electrode 10, whereby the required liquid crystal display can be performed by the liquid crystal element.

Next, FIG. 3 is a plan view showing an example of a part of an active matrix panel in which a plurality of pixels shown in FIG. 1, eight in this example, are arranged.

In FIG. 3, the same components as those shown in FIGS. 1 and 2 are designated by the same reference numerals, and in this example, the conductor 14 of the video signal line 3 and the conductor 14 of the gate electrode 5 are used. Is represented by a single thick line.

In this example, each pixel is formed and arranged in a row direction and a column direction at a regular repeating pitch, and the conductor 14 of the video signal line 3 and the conductor 14 of the gate electrode 5 form a loop as a whole. Since it is configured as described above, for example, even if a disconnection occurs at the point A in FIG. 3, the supply of the video signal to the portion beyond that is not interrupted,
There is no inactivated part.

Next, FIG. 4 is a sectional view showing a part of the configuration of an embodiment of the liquid crystal display device according to the present invention.

In FIG. 4, 16 and 17 are lower and upper polarizing plates, 18 and 18 'are lower and upper alignment films, 19 is a liquid crystal element, 20 is a color filter, 21 is an upper transparent glass substrate, and 22 is an organic protective film. 1 and 2 in addition to the above.
The same components as those shown in are denoted by the same reference numerals.

A pixel having the TFT 1 and the pixel electrode 8 is formed on the surface (upper surface) of the lower glass substrate 11, and a color filter 20 is formed on the surface (lower surface) of the upper glass substrate 21. A liquid crystal element 19 is enclosed between the lower glass substrate 11 and the upper glass substrate 21 via a lower alignment film 18 and an upper alignment film 18 ′ for setting the orientation of liquid crystal molecules. The lower polarizing plate 16 and the upper polarizing plate 17 are arranged so as to sandwich the glass substrate 21. An organic protective film 22 made of silicon nitride (SiN) and a common electrode 10 or a common signal electrode line 9 to which a common voltage Vcom is applied are arranged between the color filter 20 and the upper alignment film 18.

Although not shown in FIG. 4, on the surface (upper surface) of the lower glass substrate 11, a large number of pixels and a large number of scanning signal lines 2 and video signal lines 3 arranged in a matrix are arranged. Formed and arranged, each signal line 2,
One end of 3 is connected to a liquid crystal drive circuit (not shown) around the liquid crystal display unit.

In each of the above structural requirements, first, the color filter 20 is constructed by coloring a dyeing base material made of a resin material such as acrylic resin with a dye, and is placed at a position facing the pixel. It is provided for each pixel and is dyed separately for each color. The color filter 20 is formed and arranged in a stripe shape between each pixel between a pair of adjacent video signal lines 2 and 2. When forming and arranging the color filter 20, first of all, the upper glass substrate 21 is formed. A dyeing base material is formed on the surface, and the dyeing base material other than the red filter forming area is removed by using photolithography technology. Then, the dyeing base material is dyed with a red dye and a fixing process is performed to form a red filter portion. .. After that, the green filter portion and the blue filter portion are sequentially formed in the same manner.

FIG. 5 is a plan view showing an example of a case where a color filter is provided in a part of an active matrix panel formed by arranging a plurality of pixels.

In FIG. 5, 23 is a light-shielding layer, 24 is a red filter layer, 25 is a green filter layer, 26 is a blue filter layer, and the same components as those shown in FIGS. 1 and 2 are the same. It is marked.

The light-shielding layer 23 and the red filter layer 2
4, the green filter layer 25, and the blue filter layer 26 are all formed in a pattern on the surface (lower surface) of the upper glass substrate 21, and are arranged facing each other for each pixel. , 25 and 26 are arranged in the order of red, green, blue, red, green, ... In the row direction, but have a stripe structure in which they are arranged in a single color in the column direction.

Next, in the organic protective film 22 made of silicon nitride (SiN), the dyes of three kinds of colors used in the construction of the color filter 20 leak to the liquid crystal element 19 side, so that the liquid crystal element 19 is not protected. It is provided to prevent the desired coloring, and is made of, for example, a transparent resin material such as an acrylic resin or an epoxy resin.

In the construction of the liquid crystal display device, required films or layers are sequentially formed on the lower glass substrate 11 and the upper glass substrate 21, respectively, and then the two glass substrates 11 and 21 are superposed on each other, and between them. The liquid crystal element 19 may be enclosed.

During operation of the liquid crystal display device, a backlight is irradiated from the lower side of the lower glass substrate 11 (the side opposite to the liquid crystal element 19), and a voltage (effective value of AC voltage) is applied between the pixel electrode 8 and the common electrode 10. ) Is supplied, the voltage is applied between the liquid crystal elements 19, the alignment state of the liquid crystal elements 19 changes, and the change in light transmittance due to the backlight is displayed.

Next, a method of manufacturing one pixel of the active matrix drive liquid crystal display device according to the present invention will be described with reference to FIGS. 1 and 2 and FIGS. 6 to 9 showing the order of each manufacturing process. Here, FIG. 7 to FIG.
1A shows the sectional structure taken along the line AA 'in FIG. 1, and each (b) in FIGS. 7 to 9 shows the sectional structure taken along the line BB' in FIG.

First, the gate electrode 5 having a film thickness of about 100 nm is formed on the lower glass substrate 11 using aluminum (Al). The gate electrode 5 is formed to have a slightly larger shape than the amorphous silicon semiconductor layer 7 formed on the gate electrode 5 because the backlight irradiated from the lower side of the lower glass substrate 11 is the gate. This is because it is blocked by the electrode 5 so as not to reach the amorphous silicon semiconductor layer 7, and a photocurrent due to a backlight is not generated in the amorphous silicon semiconductor layer 7. Further, when forming the gate electrode 5, the wiring portion related to the gate electrode 5, that is, the scanning signal line 2 may be formed at the same time. As the material for forming the gate electrode 5 and the scanning signal line 2, in addition to aluminum (Al), aluminum (Al) containing silicon (Si) or aluminum (Al) containing lead (Pb) is used. Etc. are used. Next, using silicon nitride (SiN) on the gate electrode 5 and the scanning signal line 2,
A gate insulating film 12 having a film thickness of about 300 nm is formed by a plasma PVD apparatus. As the gate insulating film 12, an alumina gate insulating film is formed on the gate electrode 5 made of aluminum (Al) or the like and the scanning signal line 2 by using an aluminization means such as anodization, and the gate insulating film 12 is used as a gate. It can also be used as the insulating film 12. The gate insulating film 12 of this type also contributes to prevention of short circuit between the gate electrode 5 and the scanning signal line 2 and the metal film forming the drain electrode 6 and the source electrode 4 formed thereabove.

Subsequently, an amorphous silicon semiconductor film 7 having a film thickness of about 180 nm is formed on the gate insulating film 12 immediately above the gate electrode 5 by using amorphous silicon or polycrystalline silicon. This amorphous silicon semiconductor film 7 is formed by forming the gate insulating film 12 using a plasma PVD apparatus and then forming the amorphous glass semiconductor film 7 on the lower glass substrate 11 using the plasma PVD.
It is continuously performed only by exchanging the material without exposing it to the outside of the D device.

Then, the surface of the amorphous silicon semiconductor film 7 is doped with phosphorus (P) for ohmic contact to form a highly-impurity anticonductor layer 15 having a film thickness of about 40 nm. The formation of the high-impurity anticonductor layer 15 is also performed by the plasma P
Subsequent to the formation of the amorphous silicon semiconductor film 7 by the VD apparatus, the lower glass substrate 11 is continuously exposed without being exposed to the outside of the plasma PVD apparatus.

Then, the lower glass substrate 11 is plasma P
The amorphous silicon semiconductor film 7 is taken out of the VD apparatus, and the amorphous silicon semiconductor film 7 is patterned into an island shape by a photolithography technique.
To form.

The component obtained by the manufacturing process up to this point is the thick line portion shown in FIG. 6 (a).

Next, a transparent conductive film (ITO, that is, a NES film) formed by a sputtering method is used in a portion of the lower glass substrate 11 adjacent to the amorphous silicon semiconductor film 7.
The transparent pixel electrode 8 having a film thickness of about 120 to 200 nm is formed. After the transparent pixel electrode 8 is formed, the transparent pixel electrode 8 is patterned for each pixel by the photolithography technique to form the transparent pixel electrode 8 having a desired shape.

The components obtained by this manufacturing process are
It is a thick line portion shown in FIG. 6B, and the manufacturing process up to this point is almost the same as the conventional manufacturing process.

Subsequently, as shown in FIGS. 7A and 7B, the upper side of the high impurity anticonductor layer 15, the peripheral surface portion of the amorphous silicon semiconductor film 7, and the upper side of a part of the transparent pixel electrode 8. , Silicon nitride (SiN) is formed on each of the portions where the video signal lines 3 are formed.
The insulating layer 13 having a desired film thickness is formed by using a plasma PVD apparatus using silicon oxide (SiO ₂ ) or the like. After forming the insulating layer 13, a gas such as CF ₄ is used to
The insulating layer 13 having a desired shape is formed by patterning the insulating layer 13 by dry etching. In this case, if the materials of the gate insulating film 12 and the insulating layer 13 are different,
The patterning end point detection in the patterning becomes clear.

Next, as shown in FIGS. 8 (a) and 8 (b),
A chromium (Cr) film having a film thickness of about 50 to 100 nm and a film thickness of 3 are formed on the lower glass substrate 11 by a sputtering method.
A conductive film 14 'composed of a two-layer film of an aluminum (Al) film having a thickness of about 00 to 400 nm is formed. In this case, the reason for making the film thickness of the chrome (Cr) film relatively thin is that stress increases as the film thickness increases, so it is preferable to select a maximum thickness of about 200 nm. The chrome (Cr) film is used because it is in good contact with the high-impurity anticonductor layer 15, and the aluminum (Al) film prevents diffusion into the high-impurity anticonductor layer 15. To form a barrier layer. Instead of chrome (Cr), refractory metal materials such as molybdenum (Mo), titanium (Ti), tantalum (Ta), and tungsten (W), MoSi ₂ , TiSi ₂ , TaSi.
It is also possible to use a refractory metal silicide film _2, WSi _2, and the like. Further, since the aluminum (Al) film has a smaller stress than the chrome (Cr) film, it is possible to form a thicker film, and the thick film thickness allows the source electrode 4, the drain electrode 6, and the image to be formed. The resistance value of the signal line 3 can be decreased, and if the resistance value is decreased, the operation speed of the TFT 1 configured and the signal transmission speed of the video signal line 3 can be increased. , The writing characteristics of the pixel are improved. Also in this case, silicon (Si) or copper (Cu) can be used instead of aluminum (Al).

Then, as shown in FIGS. 9A and 9B, an anisotropic gas such as CCl ₂ or SiCl ₂ which is a mixed gas of chlorine (Cl) is applied to the conductive film 14 ′. Is used to perform anisotropic dry etching, or anisotropic dry etching by reactive ion etching. That is, the conductive film 14 ′ is etched back to form the so-called sidewall type source electrode 4, drain electrode 6, and video signal line 3 in which the conductive film 14 ′ remains only on the side surface of the insulating layer 13. It is formed in a self-aligned manner. At this time, the highly-impurity anticonductor layer 15 is removed at the portion between the source electrode 4 and the drain electrode 6 during this anisotropic dry etching. That is, the high-impurity anticonductor layer 15 remaining on the amorphous silicon semiconductor film 7 is removed by the thickness thereof in a self-aligning manner.

Subsequently, plasma PVD is formed on the entire surface of the lower glass substrate 11 by using silicon nitride (SiN) or the like.
A silicon nitride protective film (not shown) having a film thickness of about 1 μm is formed by the apparatus, and after forming the silicon nitride protective film, only the terminal portion of the lower glass substrate 11 is exposed by a photolithography technique to complete a pixel. ..

The pixels manufactured in this manner are, in fact, a large number of pixels formed on the lower glass substrate 11 at the same time, and the lower glass substrate 1 on which a large number of pixels are formed is formed.
Similarly, 1 is superposed on an upper glass substrate 21 on which a color filter 20, a light-shielding layer 23 and the like are separately formed on the surface, and at the time of superimposing, a liquid crystal element 19 is enclosed between them to form an active matrix liquid crystal display. The device is formed as described above.

Each pixel manufactured in this way has TF
The source electrode 4 and the drain electrode 6 of T1 are connected to the insulating portion 13
And a conductor 14 disposed on both side surfaces of the insulation layer 13 and the conductor 14 disposed on both sides thereof. Since it is composed of lines, the occurrence of disconnection of the video signal line 3 can be reduced by about 10% as compared with the conventional one, and each of the video signal line 3, the source electrode 4, and the drain electrode 6 is The occurrence of a short circuit between the scanning signal line 2 and the gate electrode 2 arranged via the gate insulating film 12 can be reduced by about 5% as compared with the conventional one. Furthermore, the parasitic capacitance Cgs between the source electrode 4 and the gate electrode 5 can be reduced by about 50%.

Further, in the case of manufacturing a pixel, especially the TFT1
Even when the source electrode 4, the drain electrode 6 and the video signal line 3 are manufactured, they can be configured with good accuracy in a self-aligning manner.

Next, FIG. 10 is a constitutional view showing a second constitutional example of one pixel of the active matrix drive liquid crystal display device according to the present invention. In this example, the signal scanning line and the sidewall type signal line are also shown. It is composed of.

In FIG. 10, the same components as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

The scanning signal line 2 is similar to the video signal line 3 in the insulator 13 and the conductors 14 arranged on both side surfaces thereof.
It is composed of a sidewall type signal line consisting of
The gate electrode 5 is integrally configured by being partially in contact with the conductor 14 forming the scanning signal line 2. The conductor 14 is configured so that the entire scanning signal line 2 has a closed loop shape.

The method of manufacturing the scanning signal line 2 composed of such sidewall signal lines is the same as the case of manufacturing the video signal line 3 described above. First, the gate electrode 5 is formed and then, The insulator 13 is formed, and the conductive film 14 'is further formed.
And then, the conductor 14 is formed on the side surface of the insulator 13 in a self-aligned manner by etch back. The manufacturing method for the remaining points is the same as the manufacturing method for forming the pixel of the first configuration example described above, and therefore further description is omitted.

The pixel thus obtained has the effect of the pixel of the first configuration example and can reduce the occurrence of disconnection in the scanning signal line 2, so that the yield is better. An active matrix drive liquid crystal display device can be obtained.

Next, FIG. 11 is a circuit configuration diagram showing the overall configuration of the display section of the active matrix drive liquid crystal display device according to the present invention.

In FIG. 11, 30 is a display unit,
31 is a liquid crystal display panel, 32 is a backlight light source, 33 is a light source adjusting circuit, 34 is a control circuit, 34A is an image data generating circuit, 34B is a timing signal generating circuit,
35 is a contrast adjusting circuit, 36 is a storage capacitor driving voltage generating circuit, 37 is a common electrode driving voltage generating circuit, 38 is a signal circuit, 39 is a scanning circuit, 40 is a liquid crystal panel, 41 is an external storage device, and others. The same components as those shown in FIG. 1 are designated by the same reference numerals.

The liquid crystal panel 40 has a video signal line 3 for supplying a signal voltage, a scanning signal line 2 for supplying a scanning signal, and a TFT arranged at each intersection of the signal lines 2 and 3.
Have one.

The operation of the display section having the above-mentioned structure is as follows.
Since it is the same as the commonly known display unit,
The detailed operation description for this example is omitted.

[0069]

As described above, according to the present invention,
At least the video signal line 3 is composed of a sidewall type signal line composed of the insulating portion 13 and the conductors 14 arranged on both side surfaces thereof, and the source electrode 4 and the drain of the TFT 1 connected to the video signal line 3 are formed. The electrode 6 is composed of a sidewall type electrode composed of an insulating portion 13 and conductors 14 arranged on both side surfaces thereof, and the conductor 14 of the sidewall type signal line is formed together with the conductor 14 of the drain electrode 6. Or, since it is independently configured in a loop, it is possible to provide at least the wiring including the video signal line 3 with redundancy, and even if the wiring is densified,
There is an effect that the occurrence of substantial disconnection of the wiring can be minimized.

Further, according to the present invention, by forming the drain electrode 6 and the source electrode 4 in a self-aligned manner, the channel length between the drain electrode 6 and the source electrode 4 can be obtained by a commonly used photolithography technique. Since the liquid crystal display device can be configured with an accuracy exceeding the resolution, the liquid crystal driving capability at the time of liquid crystal display is improved, and a highly uniform display can be performed.

Further, according to the present invention, the source electrode 4 and the drain electrode 6 of the TFT are constituted by the conductor 14 formed along the insulating layer 13 in a self-aligned manner,
Since the overlapping portion between the electrodes 4 and 6 and the gate electrode 5 is reduced and the parasitic capacitance between them is drastically reduced, there is also an effect that the display characteristics are remarkably improved when used for liquid crystal display.

[Brief description of drawings]

FIG. 1 is a plan view showing a first configuration example of one pixel of an active matrix drive liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view showing a partial cross-sectional configuration in the configuration example of FIG.

FIG. 3 is a plan view showing a partial configuration example of an active matrix panel configured by arranging a plurality of pixels of FIG.

FIG. 4 is a sectional view showing a part of the configuration of an embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a plan view showing an example of a configuration in the case where a color filter is provided in a part of the active matrix panel.

FIG. 6 is a plan view showing the configuration of one process in the process of manufacturing the pixel of FIG.

FIG. 7 is a cross-sectional view showing a configuration of a next step in the process of manufacturing the pixel of FIG.

FIG. 8 is a cross-sectional view showing the configuration of a further next step in the process of manufacturing the pixel of FIG.

9 is a cross-sectional view showing the configuration of a further next step in the process of manufacturing the pixel of FIG.

FIG. 10 is a plan view showing a second configuration example of one pixel of the active matrix drive liquid crystal display device according to the present invention.

FIG. 11 is a circuit configuration diagram showing an overall configuration of a display section of an active matrix driving liquid crystal display device according to the present invention.

FIG. 12 is an electrical equivalent circuit diagram of one pixel in an active matrix drive liquid crystal display device.

FIG. 13 is a configuration diagram showing an example of a structure of one pixel in a conventional active matrix drive liquid crystal display device.

[Explanation of symbols]

 1 thin film transistor (TFT) 2 scanning signal line 3 video signal line 4 source electrode 5 gate electrode 6 drain electrode 7 amorphous silicon semiconductor layer 8 transparent pixel electrode 9 common signal electrode line 10 common electrode 11 transparent glass substrate (lower transparent glass substrate ) 12 gate insulating film 13 insulating layer 14 conductor 14 'conductive film 15 high impurity semiconductor layer 16 lower polarizing plate 17 upper polarizing plate 18 lower alignment film 18' upper alignment film 19 liquid crystal element 20 color filter 21 upper transparent glass substrate 22 organic Protective film (silicon nitride protective film) 23 Light-shielding layer 24 Red filter layer 25 Green filter layer 26 Blue filter layer

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[Procedure amendment]

[Submission date] November 26, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 12]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

[Figure 9]

[Figure 10]

FIG. 11

[Fig. 13]

Claims (4)

[Claims] 1. A thin film transistor is used as an active element, and a source electrode, a gate electrode, and a drain electrode of the thin film transistor are a video signal line, a scanning signal line, and
In an active matrix driving liquid crystal display device coupled to a pixel electrode, the source electrode and the drain electrode of the thin film transistor are composed of a sidewall type electrode composed of an insulating part and conductive parts arranged on both side surfaces of the insulating part. The video signal line is composed of a sidewall type signal line including an insulating part and conductive parts arranged on both side surfaces thereof, and the conductive part of the video signal line and the conductive part of the drain electrode are totally closed loop. And an active matrix driving liquid crystal display device. 2. The scanning signal line is formed of a sidewall type signal line including an insulating portion and conductive portions arranged on both side surfaces thereof, and the conductive portion of the scanning signal line forms a closed loop as a whole. 2. The active matrix drive liquid crystal display device according to claim 1, wherein the active matrix drive liquid crystal display device is connected as described above. 3. A method of manufacturing an active matrix drive liquid crystal display device using a thin film transistor as an active element in each pixel, comprising the following steps: (1). A gate electrode and a gate electrode connected to it on a transparent insulator substrate. Forming a scanning signal line; (2); forming a gate insulating film on at least the gate electrode; (3) forming a silicon semiconductor layer on a thin film transistor forming portion on the gate insulating film; ). Forming a pixel electrode on the gate insulating film, (5). Forming a high concentration impurity layer on the silicon semiconductor layer, (6). Forming parts of a source electrode and a drain electrode of the thin film transistor, and A step of forming an insulating layer on each of the video signal line forming portions, (7) a step of forming a conductive film on the insulating layer forming portion and its peripheral portion, (8). Method for manufacturing an active matrix driving liquid crystal display device characterized by the production of each pixel by undergoing the step of forming the case to the source electrode and the drain electrode and the video signal lines, sequentially. 4. The step (1). Includes the following steps, (1-1). Forming an insulating layer on a gate electrode forming portion and a scanning signal line forming portion on a transparent insulator substrate. (1-2). A step of forming a conductive film on the insulating layer forming portion and its peripheral portion, (1-3). The gate electrode and the scanning signal line in a self-aligned manner on the side surface of each insulating layer. 4. The method for manufacturing an active matrix drive liquid crystal display device according to claim 3, further comprising the step of forming.