JP2003078145A - Active matrix substrate and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix substrate having good characteristics and to provide a simple method for manufacturing the same. SOLUTION: The active matrix substrate comprises a source wiring of a metal in a lowermost layer. Accordingly, the excellent active matrix substrate having small defect can be manufactured in simple manufacturing steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix substrate (hereinafter abbreviated as AM substrate) using a thin film transistor (hereinafter abbreviated as TFT) as a pixel switching element and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are views for explaining an AM substrate according to the prior art.

The AM substrate shown in FIG. 3 is a coplanar TFT.
Is used as a pixel switching element. Figure 3-a
Is a plan view thereof, and FIG. 3B is a sectional view taken along line BB ′. In this AM substrate, a semiconductor layer of a TFT including a channel region 301, a source region 302 and a drain region 303 is provided as the lowermost layer on an insulating substrate, and a gate insulating film 304 is provided so as to cover the semiconductor layer. Further, the gate electrode / line 305 rides thereon, and the interlayer insulating film 306 covers the gate electrode / line 305 and the gate insulating film 304. The pixel electrode 308 is electrically connected to the drain region 303 through the contact hole 307 opened through the gate insulating film 304 and the interlayer insulating film 306, and the data line 309.
Is electrically connected to the source region 302. Usually, the material of the pixel electrode 308 and the material of the data line 309 are different, so that in order to make an AM substrate of this structure, five photolithography process steps are required for at least six film formation steps, and for each pixel, There are two contact holes.

The AM substrate shown in FIG. 4 has a staggered structure TF.
T is used as a pixel switching element. Figure 4-
a is a plan view thereof, and FIG. 4-b is a sectional view taken along line CC ′. In this AM substrate, a channel region 401, a source region 402, and a drain region 403 are provided in the lowermost layer on an insulating substrate, and further, a source pad 404 and a drain pad 405 which are thicker than these semiconductor layers are similarly formed of a semiconductor material. Is provided in the bottom layer. A portion of the source region 402 covers a portion of the source pad 404 and a portion of the drain region 403 covers a drain pad 405.
Covers a part of. Usually, the source region 402 and the drain region 403 and the source pad 404 and the drain pad 405 are made of the same material, and the electrical property between them is the same. A gate insulating film 406 is provided so as to cover these semiconductor layers, and a gate electrode / line 407 is further formed thereon.
And the interlayer insulating film 408 covers the gate electrode / line 407 and the gate insulating film 406. Gate insulating film 406
The pixel electrode 410 is electrically connected to the drain pad 405 and the data line 411 is electrically connected to the source pad 404 through a contact hole 409 formed through the interlayer insulating film 408. There is. Generally, the material of the pixel electrode 410 and the material of the data line 411 are different, so that in order to make an AM substrate of this structure, at least seven film forming processes require six photolithography processing steps, and for each pixel, There are two contact holes.

8 and 9 also show another prior art A
It is a figure explaining M board and its manufacturing method.

In the AM substrate shown in FIGS. 8 and 9, a coplanar TFT is used as a pixel switching element, and a storage capacitor is formed by a polycrystalline silicon film containing impurities serving as a donor or an acceptor and a preceding gate line. There is. (Ja
pan Display '92 P.P. 451, Hir
FIG. 8-a is a plan view thereof, and FIG. 8-b is a cross-sectional view taken along line BB ′ of FIG.
The manufacturing process is depicted in FIG. In this AM substrate, a storage capacitor lower electrode 811 made of polycrystalline silicon containing an impurity serving as a donor or acceptor and a semiconductor layer of a TFT including a lowermost upper channel region 301, a source region 302, and a drain region 303 on an insulating substrate. There is.
There is a gate insulating film 304 so as to cover these. Further, a gate electrode / line 305 and a preceding gate line 813 which also serves as a storage capacitor upper electrode are laid on the gate electrode / line 305, and an interlayer insulating film 306 is provided to cover them. Contact hole 3 opened through the gate insulating film 304 and the interlayer insulating film 306
07, the pixel electrode 308 is electrically connected to the drain region 303, and the data line 309 is connected to the source region 30.
It is electrically connected to 2. In addition, another contact
The pixel electrode 308 is electrically connected to the storage capacitor lower electrode 811 through the hole 812.

A method of manufacturing an AM substrate having this structure will be described with reference to FIG. First, a polycrystalline silicon film is deposited on an insulating substrate, the silicon film is patterned by photolithography, and then the gate insulating film 304 is formed.
Are deposited (FIG. 9-a). Next, a photoresist 901 is formed so as to cover the region other than the region to be the lower electrode for the storage capacitor, and impurity ions 902 are implanted using this as a mask to form the lower electrode 811 for the storage capacitor ( Figure 9-b). Further, gate electrodes / lines 305 and 813
Is formed of a silicon film containing donor or acceptor impurities, and then impurity ion implantation is performed using the gate electrode as a mask to form a channel region 301, a source region 302, and a drain region 303 of the TFT (FIG. 9-
c). After that, an interlayer insulating film 306 is deposited by the APCVD method or the like, contact holes 307 and 812 are opened (FIG. 9-d), and finally the pixel electrodes 308 and A made of ITO or the like are formed.
The AM substrate is completed by forming the data line 309 composed of 1 or the like (FIG. 9-e). Usually, the material of the pixel electrode 308 and the material of the data line 309 are different, so that in order to make an AM substrate of this structure, at least 6 film formation steps require 6 photolithography processing steps, and for each pixel There are 3 contact holes. At the intersection of the data line and the gate line, the interlayer insulating film maintains a single layer of insulation, and the pixel electrode 308 and the data line 309 exist on the same layer.

[0008]

However, the following problems have been pointed out in the above-mentioned conventional methods.

Generally, the TFT characteristics are improved as the film thickness of the channel region is reduced. However, in the AM substrate structure shown in FIG. 3, when the film thickness of the channel region 301 is reduced, the film thickness of the source / drain region is automatically reduced. If the film thickness of the source / drain region is thin, contact failure occurs, and some of many TFTs have defects because electrical connection between the data line and the source region or between the pixel electrode and the drain region cannot be established. In addition, when the contact holes are opened, a large number of them peel off the source region or the drain region under the contact holes and are separated from the substrate, and again cannot function as a switch element. Therefore, in the substrate structure of FIG. 3, the channel region cannot be thinned, and the TFT having good characteristics
Cannot be used as a switching element.

On the other hand, in the AM substrate structure shown in FIG. 4, since the thick source pad and drain pad are present, the thin channel portion can be used, and the above-mentioned problem does not occur. However, in order to produce this AM substrate, 7 film forming steps and 6 photolithography steps are required, which is a complicated and redundant step, which causes a decrease in yield and a rise in product price. Further, in the case of the AM substrate shown in FIG. 3 or 4, there are two contact holes in each pixel,
There is also a problem in that fine pixels cannot be created.

Further, for the purpose of increasing the aperture ratio of the pixel area, the capacitance line is omitted, and the AM substrate having the structure of FIG. 8 in which the storage capacitance is formed by the gate line and the lower electrode of the preceding row is formed 6 times. The process and the photolithography process of 6 times are required, and there is a problem in that the process is complicated and redundant and the yield is decreased and the product price is increased. In the AM substrate of this structure, there are three contact holes in each pixel. The size of the contact hole is 4 μm, and the alignment margin on both sides is 3 μm
If the area is m, the area of the pad area for forming the contact hole is 10 μm for one contact hole.
× 10μm = 100μm ² and 3 contacts
An area of 300 μm ² is occupied by the holes.
In high-definition liquid crystal display devices, the pixel pitch tends to shrink, and its size is currently about 30 μm × 40 μm = 12.
Since it is about 00 μm ² , three contact holes occupy 25% of the whole. Further advancement of high definition, for example, pixel pitch of 20 μm × 30 μm = 600 μ
Even if an attempt is made to realize m ² , the area of 50% is lost due to the existence of the above-mentioned three contact holes, and there is a problem that it is impossible to achieve higher definition in practice. That is, reduction of the number of contact holes is strongly demanded. Further, in the conventional AM substrate shown in FIG. 3, FIG. 4, FIG. 8 and the like, since the wiring of the data line and the pixel electrode are in the same layer, there is a problem that the pixel electrode cannot be enlarged. In addition, when making a liquid crystal display device using these conventional AM substrates, it is necessary to provide black stripes on the substrates facing each other across the liquid crystal to prevent light leakage from adjacent pixels. The two substrates must be aligned so that they completely cover the edges of each pixel electrode. The distance between the two substrates is usually several μm, and the width of the black stripes must be widened in consideration of the alignment margin. As a result, the pixel aperture of the resulting liquid crystal display device is larger than the pixel electrode on the AM substrate. There is a problem that it becomes significantly smaller.

The present invention has been made in view of the above circumstances, and its purpose is to provide a simple structure A in which a semiconductor layer can be thinned and a TFT having good characteristics is used as a switching element.
It is to provide an M substrate and an easy manufacturing method thereof.

Another object of the present invention is to provide an AM substrate which reduces the number of contact holes to promote fineness and improves the aperture ratio, and an easy manufacturing method thereof.

[0014]

The present invention provides an active matrix substrate using a thin film transistor formed on at least an insulating layer as a pixel switching element.
On the insulating layer, a data electrode made of a metal material, a pixel electrode extraction pad made of the same metal material, and a part of a semiconductor layer of a pixel thin film transistor are formed in the same layer. A part of the source region and a part of the drain region of the pixel thin film transistor are partially covered with the pixel electrode extraction pad, and the pixel electrode and the pixel electrode extraction pad are electrically connected. Characterize.

Further, the present invention is a method of manufacturing an active matrix substrate, wherein at least a thin film transistor formed on an insulating substrate is used as a pixel switching element. In the method, a metal film is deposited, and then data lines and pixels are formed by patterning. First step of forming an electrode lead-out pad, and after depositing a semiconductor film, both ends of the semiconductor layer of the pixel thin film transistor cover part of the data line and part of the pixel electrode lead-out pad And a second step of patterning the semiconductor film so as to form the semiconductor layer.

Further, according to the present invention, in an active matrix substrate in which a thin film transistor formed on at least an insulating layer is used as a pixel switching element, a data line made of an electrically conductive material and an active layer semiconductor film of the thin film transistor are first insulated. That the gate line made of an electrically conductive material and the gate electrode of the thin film transistor are formed on the second insulating layer, and the pixel electrode is formed on the third insulating layer. Characterize.

Further, according to the present invention, in a method of manufacturing an active matrix substrate in which a thin film transistor formed on at least an insulating substrate is used as a pixel switching element, a data line is formed by patterning after depositing an electrically conductive material. First step of forming and second step of depositing a semiconductor film and then patterning the semiconductor film so that one end of the thin film transistor covers a part of the data line to form an active layer of the thin film transistor A third step of depositing a gate insulating layer, a fourth step of depositing an electrically conductive material on the gate insulating layer and then forming a gate electrode and a gate line of the thin film transistor by patterning, and interlayer insulation A fifth step of depositing a layer and electrically conducting a portion of the drain region of the thin film transistor or the drain region. A sixth step of forming a contact hole in the gate insulating layer and the interlayer insulating layer so that a part of the region in the state is exposed, and a seventh step of forming a pixel electrode on the interlayer insulating layer. It is characterized by including a process.

Further, according to the present invention, in an active matrix substrate in which a thin film transistor formed on at least an insulating layer is used as a pixel switching element, a data line made of an electrically conductive material, an active layer semiconductor film of the thin film transistor, and the data line are provided. The storage capacitor lower electrode made of the same material is formed on the first insulating layer, and the gate line made of the electrically conductive material and the gate electrode of the thin film transistor are formed on the second insulating layer. The pixel electrode and the lower electrode for the storage capacitor, which also serves as the upper electrode for the storage capacitor of the pixel in the next row, are electrically connected.

The present invention also relates to a method of manufacturing an active matrix substrate in which a thin film transistor formed on at least an insulating substrate is used as a pixel switching element, and a data line is formed by patterning after depositing an electrically conductive material. First step of forming a storage capacitor lower electrode, and after depositing a semiconductor film, pattern the semiconductor film so that one end of the thin film transistor covers a part of the data line to form an active layer of the thin film transistor. The second step of processing, the third step of depositing a gate insulating layer, and the deposition of an electrically conductive material on the gate insulating layer, followed by patterning to hold the gate electrode of the thin film transistor and the pixel of the next row. It is characterized in that it includes a fourth step of forming a gate line so as to also serve as a capacitor upper electrode.

The present invention also relates to a method of manufacturing an active matrix substrate in which a thin film transistor formed on at least an insulating substrate is used as a pixel switching element, and a data line is formed by patterning after depositing an electrically conductive material. First step of forming a storage capacitor lower electrode, and after depositing a semiconductor film, pattern the semiconductor film so that one end of the thin film transistor covers a part of the data line to form an active layer of the thin film transistor. A second step of processing, a third step of depositing a gate insulating layer, and a gate electrode of the thin film transistor and a storage capacitance of a pixel in the next row by patterning after depositing an electrically conductive material on the gate insulating layer. A fourth step of forming a gate line so as to also serve as an upper electrode for a gate, a fifth step of depositing an interlayer insulating layer, and the thin film transistor. In the gate insulating layer and the interlayer insulating layer, a part of the drain region of the transistor or a part of the region electrically connected to the drain region and a part of the storage capacitor lower electrode are exposed. The method is characterized by including a sixth step of forming a contact hole and a seventh step of forming a pixel electrode on the interlayer insulating layer.

According to the present invention, in an active matrix substrate in which a thin film transistor formed on at least an insulating layer is used as a pixel switching element, a data line made of a metal material and a semiconductor layer of the thin film transistor are formed on the insulating layer. And a part of the source line of the thin film transistor covers a part of the data line,
That the data line is not covered by a part of the source region and is covered with an oxide of the metal material except for a part intended to establish electrical conduction with another Characterize.

Further, according to the present invention, in a method of manufacturing an active matrix substrate in which a thin film transistor formed on at least an insulating substrate is used as a pixel switching element, a metal film is deposited and then a data line is formed by patterning. After the first step of depositing the semiconductor film,
A second step of patterning the semiconductor film so that one end of the semiconductor layer of the thin film transistor covers a part of the data line to form the semiconductor layer of the thin film transistor; and a step of oxidizing the surface layer portion of the data line. It is characterized by including three steps.

[0023]

EXAMPLE 1 An example of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to the following example.

FIG. 1 is a view for explaining an example of an AM substrate according to the present invention, and FIGS. 2A to 2C are sectional views showing a manufacturing process of an AM substrate according to the present invention.

FIG. 1-a is a plan view and FIG. 1-b is a sectional view taken along line AA '. In the AM substrate according to the present invention, the channel region 101 and the source region 1 are formed in the lowermost layer on the insulating substrate.
02, a drain region 103, and a data line 1 made of a refractory metal such as molybdenum, tungsten, chromium, vanadium, niobium, or tantalum.
A pixel electrode extraction pad 105 made of the same metal as 04 is provided. Part of the source region 102 is the data line 1
04, and a part of the drain region 103 covers a part of the metal pixel electrode extraction pad 105. A gate insulating film 106 is provided so as to cover these semiconductor layer, metal data line, and metal pixel electrode extraction pad, and a gate electrode / line 108 is provided on the gate insulating film. A contact hole 107 is formed in the gate insulating film on the metal pad 105, and a pixel electrode 109 is formed on the gate insulating film through the contact hole. Example 1
In the above, the pixel electrode and the gate electrode are formed of the same material on the same layer, but these materials may be different or may be formed on different layers. For example, it is possible to remove the gate insulating film in the pixel electrode region at the same time when the contact hole is opened and provide the pixel electrode in the lowermost layer of the same layer as the semiconductor layer.

A method of manufacturing an AM substrate according to the present invention is illustrated.
2 is used for the explanation. First, an insulating substrate such as a glass substrate
Deposit metal film on top by evaporation method or sputtering method
It In Example 1, the substrate temperature was 150 ° C. depending on the sputtering method.
Chrome was deposited at 2000 liters. In addition to this, molybde
Refractory metals such as tungsten and tungsten are also possible. At this time
The sheet resistance of chrome was 1.12Ω / □. next
By processing this metal film by photolithography process
Data line 104 and pixel electrode extraction pad 105 are formed
To do. (FIG. 2-a) Then, the semiconductor film is formed by the LPCVD method or the like.
Form. In the first embodiment, the polycrystalline crystal is formed by the LPCVD method.
A recon film was deposited. The substrate temperature is 555 ℃ and
The monosilane partial pressure during deposition of the con-film was 0.94 mtorr.
There was The thickness of the polycrystalline silicon film is 280Å and the deposition time is
Was 1 hour, 5 minutes and 50 seconds. Then Photo Lithography
The semiconductor film is processed by the fi process, and then ECR-PE
The gate insulating film 106 is formed by the CVD method or the like. Example
In 1, the substrate temperature is 100 ° C and the SiO is 1200 Å.₂ Stack the membrane
Piled up. (Fig.2-b) Next, in the photolithography process
Therefore, contact hole 1 on the pixel electrode extraction pad
Hole 07 is opened to form a transparent electrically conductive film. Example
In No. 1, indium tin oxide (IT
O) was deposited 2500 Å. The sheet resistance at this time is 28
It was Ω / □. After that, the photolithography process
The gate electrode / line 108 and the pixel electrode 109 are formed.
Next, a non-mass-separation type ion implanter is used to make a donor or actuation.
Semiconducting impurities that become scepters using the gate electrode as a mask
Implanted in body membrane, channel region 101 and source region 1
02 and the drain region 103 are formed. In Example 1
Aims to create an n-type field effect transistor, diluting hydrogen
Phosphine (PH ₃) At an acceleration voltage of 90 kv
5 x 10¹⁵1 / cm² I typed it in. Then under nitrogen atmosphere
The implanted ions are activated by heat treatment at 350 ° C. for 2 hours.
The M board is completed (Fig. 2-c).

AM substrate TFT manufactured in this manner
Is an on-current (Vds = 4v, Vgs = 10v L / W =
10 μm / 10 μm Ids) is 1.2 μA, off current (Vds = 4 v, Vgs = 0 v L / W = 10 μm / 1
The Ids of 0 μm was 0.067 pA, which showed a good switching characteristic, and was a good AM substrate. This is because the film thickness of the channel portion can be made sufficiently thin in the AM substrate structure of the present invention. In addition, problems such as contact failure could not occur. Further, according to the present invention, the number of contact holes for each pixel is halved, the aperture ratio of the pixel area is improved accordingly, and the defects caused by the contact holes can be halved.
In addition, the present invention comprises a simple manufacturing method including four film forming steps and four photolithography steps.

(Embodiment 2) FIG. 5 is a view for explaining an example of an AM substrate according to the present invention. FIG. 5-a is a plan view and FIG. 5-b is a sectional view taken along line AA '. AM according to the second embodiment
In the substrate, an active layer semiconductor film including a channel region 101, a source region 102 and a drain region 103 is provided on an insulating substrate which is a first insulating layer, and molybdenum, tungsten, chromium, vanadium, niobium, tantalum, etc. are provided on the same layer. A pixel electrode extraction pad 105 made of the same metal as the data line 104 made of a high melting point metal is provided. A part of the source region 102 covers a part of the data line 104, and a part of the drain region 103 is a metal pixel electrode extraction pad 1.
Part of 05 is covered. There is a gate insulating film 106 which is a second insulating layer so as to cover these semiconductor layer, metal data line, and metal pixel electrode extraction pad, and a gate electrode / line 108 is provided on this second insulating layer. Further, there is an interlayer insulating film 110 which is a third insulating layer on these. A contact hole 107 is formed in the gate insulating film and the interlayer insulating film on the metal pad 105, and the pixel electrode 10 is formed on the interlayer insulating film, which is the third insulating layer, through the contact hole.
9 is formed. In the second embodiment, the pixel electrode lead-out pad 105 is provided on the first insulating layer. However, if the active layer semiconductor film has a sufficient thickness so as not to cause problems such as contact failure, the pixel electrode lead-out pad 105 may be taken out. Omit the pad,
The contact hole 107 may be opened directly on the drain region 103. As a result, the pixel aperture ratio is improved as much as the pixel electrode extraction pad is eliminated. As the gate electrode / line 108, aluminum, copper, nickel, iron,
Various metals such as chromium, molybdenum, tungsten and tantalum are possible. The pixel electrode 109 may be a transparent conductive material such as indium tin oxide (ITO) or a metal material when the present invention is used in a reflective liquid crystal display device. In the second embodiment, since the data line, the gate line, and the pixel electrode are formed on different layers, the pixel electrode can be made as large as possible. The edge of the pixel electrode 109 overlaps with the gate line via the interlayer insulating film, and overlaps with the data line via the interlayer insulating film and the gate insulating film. In the second embodiment, the data line and the gate line are made of metal, and both are made of an electrically conductive light-shielding material. Therefore, these lines are black stripes because they overlap the edge portion of the pixel electrode. That is, when the AM substrate of Example 2 is used, it is not necessary to form a thick black stripe on the counter substrate side, and the substantial aperture ratio of the completed liquid crystal display device is greatly improved.

Next, a method for manufacturing an AM substrate according to the present invention will be described. First, a metal film is deposited on an insulating substrate such as a glass substrate by a vapor deposition method or a sputtering method. As the metal, the above-mentioned refractory metal is preferable, but non-metal such as metal silicide can be used as long as it is an electrically conductive light-shielding substance. Next, the metal film is processed by a photolithography process to process the data line 104 and the pixel electrode extraction pad 10.
5 is formed. Then, a semiconductor film is formed. As described in the first embodiment, the semiconductor film is formed by the LPCVD method 55.
There are various methods other than the method of directly depositing a polycrystalline silicon film at a temperature of about 5 ° C. or less. For example, monosilane (Si
H ₄ ) or disilane (Si ₂ H ₆ ) as a raw material, and after depositing an amorphous semiconductor film at a temperature of about 550 ° C. or lower, 600 ° C.
A method of performing crystallization by performing heat treatment in a furnace at a temperature below a certain level, a method of irradiating laser light or arc lamp light for a short time to perform crystallization, and the like are also effective. Also, the semiconductor film is not limited to silicon, and various semiconductor films such as a silicon-germanium film are also possible. In each of these steps, the temperature is about 600 ° C. or lower, which is a relatively low temperature as compared with the melting point of the metal material such as the data line, so that the data line and the like will not be thermally deteriorated. Subsequently, the semiconductor film is processed by a photolithography process, and then the gate insulating film 106 is formed by the ECR-PECVD method or the like.

When the ECR-PECVD method is used, the gate insulating film can be formed at a temperature of about 100 ° C. Besides this, A
3 by PCVD method or CVD method using ozone (O ₃ ).
The gate insulating film may be formed at a temperature of 50 ° C. or lower. Subsequently, a metal film is deposited on the gate insulating film by a sputtering method or the like, and a gate electrode / line is formed by a photo and lithography process. When depositing the metal film by the sputter method, the substrate temperature is preferably 300 ° C. or lower. Then, an impurity serving as a donor or an acceptor is implanted into the semiconductor film by a mass non-separation type ion implantation apparatus using the gate electrode as a mask to form a channel region 101, a source region 102, and a drain region 103. When a hydride of an impurity element is ion-implanted by using a mass non-separation type ion implanter, 350
Impurity ions can be activated by a low temperature heat treatment at about ℃ or less. Subsequently, the interlayer insulating film 110 is formed by various CVD methods at about 350 ° C. or lower. Thereafter, heat treatment is performed in a nitrogen atmosphere at a temperature of about 350 ° C. or less for 1 hour to 2 hours for the purpose of both hardening the interlayer insulating film and activating the implanted ions. Finally, a contact hole 107 is opened, a conductive material such as ITO is deposited on the interlayer insulating film by a sputtering method, etc., and a pixel electrode 109 is formed by a photolithography process.
The M board is completed. When the conductive material is deposited by the sputter method, the substrate temperature can be suppressed to about 300 ° C or lower.
According to the second embodiment, the maximum process temperature after forming the gate insulating film is as low as about 350 ° C., and the time is about several hours. Therefore, there is no thermal deterioration of the electrically conductive light-shielding substance such as the data line, the gate electrode and the line. In the second embodiment, A
Until the completion of the M substrate, 6 film formation processes and 5 photolithography process steps are required, which is the same as the number of film formation processes and photolithography processes of the prior art shown in FIG.
However, in the present invention, the conventional data line wiring and the pixel electrode can be provided in the same layer, but the present invention can be provided in a different layer, and thus the area of the pixel electrode can be increased. Besides, in the present invention, the pixel electrode and the data line and the gate line can be overlapped, and the black stripe of the counter substrate can be omitted. Further, conventionally, there were two contact holes in each pixel, but in the present invention, the number of contact holes can be reduced to one, so that a high-definition liquid crystal display device having fine pixels can be realized.

(Embodiment 3) FIG. 6 is a view for explaining an example of an AM substrate according to the present invention, and FIGS. 7A to 7D show A according to the present invention.
It is the figure which showed the manufacturing process of M board | substrate in the cross section. 6-a is a plan view and FIG. 6-b is a sectional view taken along line AA '.

The AM substrate shown in FIGS. 6 and 7 uses a coplanar TFT as a pixel switching element and has a storage capacitor. In the AM substrate of the present invention, an active layer semiconductor film including a channel region 101, a source region 102, and a drain region 103, and molybdenum, tungsten, chromium, vanadium, are formed on an insulating substrate which is a first insulating layer.
Data line 104 based on refractory metal such as niobium or tantalum
A pixel electrode extraction pad 105 made of the same metal and a storage capacitor lower electrode 611 made of the same metal are formed. There is a gate insulating film 106 so as to cover these. The gate insulating film is the second insulating layer, and the gate electrode line 1 is formed on the second insulating layer.
08, the pixel electrode 109, and the gate line 613 in the preceding row which also serves as the storage capacitor upper electrode are provided. The pixel electrode 109 is electrically connected to the pixel electrode lead-out pad 105 through a contact hole 107 formed in the gate insulating film, and is electrically connected to the storage capacitor lower electrode 611 through another contact hole 612. . With this structure, the film thickness of the active layer semiconductor film can be made as thin as several tens of tens, which is the limit at which the film can exist as a film. If the active layer semiconductor film is thick enough not to cause contact failure or the like, the pixel electrode lead pad may be omitted and the pixel region 109 may be directly contacted with the drain region 103.

A method of manufacturing an AM substrate having this structure will be described with reference to FIG. First, an electrically conductive substance such as a metal film is deposited on the insulating substrate which is the first insulating layer by a vapor deposition method or a sputtering method. As the metal, the above-mentioned refractory metal is preferable, but other electrically conductive substances such as metal materials and non-metal materials are also possible as long as they are stable to the thermal environment to be encountered in the subsequent semiconductor film formation process. . Next photo
By patterning this electrically conductive material by a lithography process, the pixel electrode extraction pad 105 and the data line 1 are formed.
04, a storage capacitor lower electrode 611 is formed (FIG. 7-
a). When the pixel electrode lead-out pad is not necessary, it is not necessary to leave the pixel electrode lead-out pad by this patterning. Then, a semiconductor film is deposited. Since the most severe thermal environment during the AM substrate manufacturing process of the present invention is this semiconductor film deposition process, if the temperature is lowered, the selection of electrically conductive materials such as data lines will spread, and the size of the insulating substrate will increase. It is easy to reduce the price. When a polycrystalline silicon film is used as the semiconductor film, monosilane is used as a source gas in the LPCVD method, the deposition temperature is 555 ° C. or less, and the monosilane partial pressure is 1 mtor.
There is a method of directly depositing a high quality film at r or less. Also, LP
There is a method in which disilane (Si ₂ H ₆ ) is used as a source gas by the CVD method and an amorphous silicon film is deposited at a deposition temperature of about 450 ° C. and a pressure of about 0.5 torr, and then crystallization proceeds. In order to promote crystallization of the amorphous film, a method of performing heat treatment at a temperature of about 600 ° C. for several hours, a method of heating at about 900 ° C. for several seconds by a rapid thermal treatment called so-called rapid thermal annealing (RTA), , Laser irradiation, etc. The laser irradiation is, for example, a method of irradiating a XeCl excimer laser at an intensity of 50 mJ / cm ² to 500 mJ / cm ² for a time of about 50 ns to instantaneously melt and crystallize the silicon film. With this method, since the heating time is short and short, the electrically conductive substance such as the insulating substrate and the data line is hardly deteriorated by heat. Further, when silicon germanium is used as the semiconductor film, a polycrystal can be obtained at a lower temperature. In addition, a method of advancing crystallization by each method described above after depositing an amorphous semiconductor film by a sputtering method is also effective. After the semiconductor film is formed in this manner, the semiconductor film is processed by a photolithography process (FIG. 7B). Then ECR-PECVD method, ozone TEO
Forming a gate insulating film 106 with _{S (Si- (CH 3 -CH 2} -O) 4) method or the like opening contact holes 107 and 612 by a photo-lithography method (Fig. 7
c). Next, an electrically conductive material is deposited, and a gate electrode / line 108 pixel electrode 109 is formed on the gate insulating film that is the second insulating layer by photolithography. This pixel electrode is electrically connected to the storage capacitor lower electrode 611 through the contact hole 612, and the storage capacitor is formed by the lower electrode 611 and the preceding gate line 613. Finally, ion implantation is performed using the gate electrode as a mask to form a channel region 101, a source region 102, and a drain region 103. Laser irradiation or light irradiation such as RTA is effective for activating the implanted ions. Gate electrode
When a transparent material is used for the lines and the pixel electrodes, most of the light is transmitted, and these temperature rises are not seen by light irradiation for a short time, and there is no heat deterioration. In addition, when a metal material is used for these, almost all the light is reflected, and the thermal degradation does not occur. The same applies to the data line and the pixel electrode extraction pad. Other Example 1
As described above, the ion implantation may be performed by the mass non-separation type ion implantation apparatus, and the implanted ions may be activated at a low temperature of 300 ° C to 350 ° C. In this way, the AM substrate is completed (FIG. 7-d).

Conventionally, 6 photolithography processing steps were required for 6 film forming steps in order to form an AM substrate having a holding capacity, but according to the present invention, 4 film forming steps are required. It became possible to simplify the photolithography four times. Further, in the past, three contact holes were present for each pixel, but in the present invention, this can be reduced to two. Further, since the data line and the part of the pixel electrode extraction pad are covered with part of the source / drain region, the film thickness of the active layer semiconductor film can be reduced to several tens of liters, and a high performance TFT can be obtained. In the third embodiment, since the pixel electrode lead-out pad and the storage capacitor lower electrode are formed separately, the pixel electrode is electrically connected through the two contact holes 107 and 612. If the storage capacitor lower electrode and the storage capacitor lower electrode are not separated but are formed by one connected island, only one contact hole is required. In this case, there is one contact hole for each pixel, which enables further miniaturization of the pixel.

(Embodiment 4) FIG. 10 is a view for explaining an example of an AM substrate according to the present invention, and FIGS. 11A to 11D are sectional views showing the steps for manufacturing an AM substrate according to the present invention. Figure 10
10A is a plan view and FIG. 10B is a sectional view taken along line AA ′.

The AM substrate shown in FIGS. 10 and 11 uses a coplanar TFT as a pixel switching element, and each pixel has a storage capacitor. In the AM substrate of the present invention, the channel region 1 is formed on the insulating substrate which is the first insulating layer.
Active layer semiconductor film 03 and a data line 104 made of a refractory metal such as molybdenum, tungsten, chromium, vanadium, niobium, and tantalum, a pixel electrode extraction pad 105 made of the same metal, and a storage capacitor lower electrode 611 made of the same metal. Are formed. There is a gate insulating film 106 so as to cover these. The gate insulating film is the second insulating layer,
A gate electrode / line 108 and a preceding gate line 613 which also functions as a storage capacitor upper electrode are provided on the gate electrode / line 108. Further, there is an interlayer insulating film 110 which is a third insulating layer on these.
A pixel electrode 109 is provided on the interlayer insulating film. A contact hole 10 is formed in the interlayer insulating film and the gate insulating film.
7 and 612 are opened, and the pixel electrode is electrically connected to the pixel electrode extraction pad and the storage capacitor lower electrode through these holes. With the pixel electrode extraction pad, the active layer semiconductor film can be thinned to several tens of liters. On the contrary, if the active layer semiconductor film is sufficiently thick, the pixel electrode extraction pad may be omitted, and a contact hole may be directly formed in the drain region 103 to establish conduction with the pixel electrode. In addition, since the pixel electrode lead-out pad and the storage capacitor lower electrode are separately formed in the fourth embodiment, the pixel electrode is electrically connected to the pixel electrode lead-out pad and the storage capacitor lower electrode through the two contact holes. However, if the pixel electrode lead-out pad and the storage capacitor lower electrode are not separated and are formed by one island, the number of contact holes is reduced to one. In Example 4, the data line is formed on the first insulating layer, the gate line is formed on the second insulating layer, and the pixel electrode is formed on the third insulating layer in different layers. Can be made larger than before. As shown in FIG. 8, conventionally, since the data line and the pixel electrode were on the same layer, a separation region was always required between the pixel electrode and the data line. However, in the present invention, since the data line, the gate line, and the pixel electrode are formed on different layers, the isolation is performed by the gate insulating film or the interlayer insulating film, and the isolation region on the plane is unnecessary. Due to this, the pixel electrode is enlarged more than ever. Moreover, in the fourth embodiment, the edge portion of the pixel electrode overlaps the gate line and the data line. When the gate lines and data lines are made of a light-shielding material such as metal, these lines become black stripes. That is, when the AM substrate of Example 4 is used, thick black
This eliminates the need for forming stripes, facilitates the alignment of the AM substrate and the counter substrate, and significantly increases the substantial aperture ratio of the completed liquid crystal display device.

Next, a method for manufacturing an AM substrate according to the present invention will be described with reference to FIG. First, an electrically conductive substance such as a metal film is deposited on an insulating substrate such as a glass substrate. In addition to the above-mentioned refractory metal, a metal compound or non-metal is also effective for this as long as it is an electrically conductive substance that is stable with respect to the temperature of the semiconductor film forming process. Next, the electrically conductive material is processed by a photolithography process to form the data line 104, the pixel electrode extraction pad 105, and the lower electrode 611 for the storage capacitor (FIG. 11-a). Subsequently, a semiconductor film is deposited by the method described in detail in Example 3 and processed by a photolithography process (FIG. 11-b). After that, the gate insulating film 106 is PEC
VD method, ECR-PECVD method, APCVD method, CVD method using an organic silicon compound and ozone, etc. are deposited at a substrate temperature of about 350 ° C. or lower. Subsequently, an electrically conductive substance is deposited on the gate insulating film by a vapor deposition method, a sputtering method, or the like, and the gate electrode / line 10 is formed by a photolithography process.
8 and 613 are formed. Also in the case of depositing an electrically conductive substance, the substrate temperature is preferably about 350 ° C. or lower in order to prevent thermal change of the lower layer metal such as the data line and the semiconductor film or the gate insulating film. Next, an impurity serving as a donor or an acceptor is implanted by using a mass non-separation type ion implantation device using the gate electrode as a mask, and the channel region 101 and the source region 10
2 and the drain region 103 are formed (FIG. 11-c).
When the hydride of the impurity element is ion-implanted by the mass non-separation type ion implantation device, the impurity ions can be activated by the low temperature heat treatment at about 350 ° C. or less. Alternatively, after implanting the impurity ions with a usual mass separation type ion implanter, the implanted ions may be activated by laser irradiation. Next, the interlayer insulating film 110 is deposited at a substrate temperature of about 350 ° C. or lower by various CVD methods or PVD methods. When the source / drain region type ion implantation is performed by the mass non-separation type ion implantation apparatus, the heat treatment for about 30 minutes to 2 hours at a temperature of about 300 ° C. to 350 ° C. after the deposition of the interlayer insulating film activates the implanted ions. When the interlayer insulating film and the gate insulating film have different film qualities at the same time, they come close to each other or have the same film quality, and a contact hole in the next step is easily formed.
If there is a heating step at 350 ° C. or higher after the gate insulating film is deposited, hydrogenation treatment such as hydrogen plasma irradiation may be performed here. Subsequently, after forming the contact holes 107 and 612 by a photolithography process, a pixel electrode material is deposited by a sputtering method or the like, and further patterned by a photolithography process to complete the AM substrate (FIG. 11-d). ). As described above, according to the present invention, an AM substrate having a storage capacity is produced by performing the photolithography process five times in the film forming process six times. Conventionally, as shown in FIG. 9, six photolithography processing steps are required, so that the manufacturing process is simplified in addition to the above-described structural advantages.

(Embodiment 5) FIG. 12 is a view for explaining an example of an AM substrate according to the present invention, and FIGS. 13A to 13E are sectional views showing the steps for manufacturing an AM substrate according to the present invention. 12
12A is a plan view, FIG. 12B is a sectional view taken along line AA ′, and FIG. 12C is a sectional view taken along line BB ′.

The AM substrate shown in FIGS. 12 and 13 uses a coplanar TFT as a pixel switching element, each pixel has a storage capacitor, and the data line, gate line, and pixel electrode are formed on different layers. Has been done. This merely means that the fifth embodiment is described in comparison with the fourth embodiment shown in FIGS. 10 and 11, and the present invention is not limited to this. That is, FIG. 1 and FIG.
The present invention is also applicable to the AM substrate described in Example 2, the AM substrate described in Example 2 with reference to FIG. 5, and the AM substrate described in Example 3 with reference to FIGS. 6 and 7. Can be done.

In the AM substrate of the present invention, the channel region 101, the source region 102 and the drain region 103 are formed on the insulating layer.
Active layer semiconductor film consisting of molybdenum and tungsten
The data line 104 made of a refractory metal such as chromium, vanadium, niobium, and tantalum, and the pixel electrode extraction pad 105 made of the same metal as the data line 104 and the storage capacitor lower electrode 6 made of the same metal.
11 is formed. All the portions of these metal surfaces that are not covered with the semiconductor film and have no contact holes are covered with the oxide of the same metal. The film thickness of the metal oxide 1201 is preferably about several tens of liters or less. If the active layer semiconductor film is thick enough, the pixel electrode extraction pad may be omitted and a contact hole may be directly formed on the drain region. When the storage capacitor is not needed, it is not necessary to make the lower electrode for the storage capacitor. A gate insulating film 106 is provided so as to cover these, and a gate electrode / line 108 and a preceding gate line 613 which also serves as a storage capacitor upper electrode are provided thereon. As shown in FIG. 12-c, in the cross section of the intersection of the gate line and the data line, the surface of the data line is completely covered with the oxide of the metal forming the data line, and the gate insulating film is provided thereon. Has been. Similarly, the surface of the lower electrode for the storage capacitor is completely covered with the metal oxide. Since the gate line is on the gate insulating film, two kinds of different insulating films are sandwiched between the gate line and the data line or between the gate line and the lower electrode for the storage capacitor. An interlayer insulating film 110 is provided on the gate electrode / line and the gate insulating film, and a pixel electrode 109 is further provided thereon.
The interlayer insulating film may be omitted and the pixel electrode may be provided on the gate insulating film. Alternatively, the gate electrode / line may be formed of a light-shielding material, and the pixel electrode may be formed of a transparent material on a different layer or on the same layer. Alternatively, both the gate electrode / line and the pixel electrode may be formed of a transparent material on the same layer. Alternatively, it may be formed on another layer. Contact holes 107 and 6 are formed in the interlayer insulating film and the gate insulating film.
12 is opened so that the pixel electrode is electrically connected to the pixel electrode extraction pad and the storage capacitor lower electrode. When the pixel electrode extraction pad and the storage capacitor lower electrode are formed on one island, or when the storage capacitor lower electrode is not provided, there is one contact hole for each pixel. In the fifth embodiment, since the data line, the gate line, and the pixel electrode are formed in different layers, the pixel electrode can be made larger than in the conventional case, and FIG.
Then, the edge part completely overlaps the gate line and the data line. If the gate line is made of a light-shielding material such as metal, the thick black stripes on the counter substrate can be omitted, and the substantial aperture ratio is further improved. In order to substitute the black stripe depending on the gate line and the data line in the conventional AM substrate shown in FIGS. 3 and 4, it is necessary to form the data line and the pixel electrode in different layers. It is necessary to deposit another interlayer insulating film on the insulating film 306 or 408 and form a pixel electrode thereon. In this case, a gate insulating film (the gate electrode is provided on the gate insulating film) on the substrate,
A first interlayer insulating film (there are data lines on it), a second interlayer insulating film (there are pixel electrodes on this), and at least three layers of insulating films are formed. When these are formed by SiO ₂ films, if the total film thickness of the three layers becomes large, these insulating films are cracked and cannot be used as an AM substrate. Therefore, the total thickness of the insulating film needs to be about 1.5 μm or less. Now the thickness of the gate insulating film is from 1000Å to 2
If the thickness is about 000Å, the thickness of each of the two interlayer insulating films is about 7,000Å, and the pixel electrode and the data line are 700
It will be overlapped with 0Å SiO ₂ film. In the meantime, various kinds of information are transmitted to the data line and the potential fluctuates while the pixel thin film transistor is off and the stored data is held when the pixel thin film transistor is on. If the pixel electrode and the data line overlap each other and the film thickness between them is thin, the value of the capacitance generated between the pixel electrode and the data line increases, and as a result, the pixel electrode potential that should be kept constant in the off state is the data line. Fluctuates under the influence of the information transmitted to the display, resulting in poor image quality such as crosstalk on the liquid crystal screen. Therefore, it is preferable that the overlap between the pixel electrode and the data line is small, and that the interlayer insulating film separating the pixel electrode and the data line is thick. This requirement becomes stronger as the pixel electrode becomes smaller or the storage capacitance becomes smaller. As described above, in the conventional AM substrate, the film thickness of the interlayer insulating film separating the pixel electrode and the data line is about 7,000 Å at the maximum. On the other hand, in the AM substrate of the present invention shown in FIGS. 5 and 10, the data line is on the insulating substrate, and the film thickness of the insulating film (that is, the gate insulating film and the interlayer insulating film) separating the pixel electrode and the data line is 1 It can be thickened to about 0.5 μm. Therefore, if the pixel pitch is the same as that of the conventional AM substrate and the overlapping area of the pixel electrode and the data line is the same, the AM substrate of the present invention has higher quality due to the thicker insulating film. This is because an image can be obtained. Alternatively, if the image quality is the same, the AM substrate of the present invention can increase the ratio of the overlapping area to the pixel area, and can produce a high-definition AM substrate having fine pixels. On the other hand, in the AM substrate of the present invention shown in FIG. 12 and described in the fifth embodiment, the surface of the data line is covered with the metal oxide film, and the gate insulating film and the interlayer insulating film are formed on the surface of the metal oxide film. The line coupling has an advantage that it is smaller than that of the AM substrate shown in FIGS. In addition,
As shown by 2-c, the surface of the data line is covered with an insulating film called a metal oxide, a gate insulating film is formed on the insulating film different from the metal oxide film, and the gate line is further formed thereon. Since it is provided, there is an advantage that the dielectric breakdown of the gate line and the source line and the leakage current are reduced. The type or cause of the current flowing through the insulating film generally differs depending on the insulating film type. For this reason, if the film thicknesses are the same, two types of different insulating films, although slightly thin, are more resistant to dielectric breakdown and leakage current than one type of thick insulating film. Based on this principle, in the AM substrate of the present invention shown in FIGS. 12 and 13, the defect rate such as a short circuit occurring at the intersection of the data line and the gate line is significantly reduced.

Next, a method of manufacturing an AM substrate according to the present invention will be described with reference to FIG. First, an electrically conductive substance such as a metal film is deposited on an insulating substrate such as a glass substrate. In addition to the refractory metal described above, any metal that is stable in the semiconductor film forming process is effective for this. Next, this electrically conductive material is processed by a photolithography process to form the data line 104, the pixel electrode lead-out pad 105, and the storage capacitor lower electrode 611 (FIG. 13A). Subsequently, a semiconductor film is formed by the method described in detail in Example 3 and processed by a photolithography process (FIG. 13-b). Then 600
The surface of the metal film such as the data line is oxidized in an oxidizing atmosphere at a temperature of not more than 0 ° C. (FIG. 13-c). The oxidation of the silicon film hardly progresses at a low temperature of 600 ° C. or lower, so that the metal oxide 1201 having a desired film thickness can be obtained by appropriately adjusting the atmosphere and temperature.
Thus, it becomes possible to use an extremely thin semiconductor film as an active layer at the same time. For example, if tantalum is used as the same metal, an oxide film of several tens of liters or more can be formed from a temperature of 300 ° C. under one atmosphere of oxygen, but under this condition, the oxidation of silicon does not proceed at all, so the film loss of the semiconductor film occurs Absent. Even if the semiconductor film is slightly oxidized, it does not cause any problem because it only forms a part of the gate insulating film. Here, the semiconductor film was formed by the method described in detail in Example 3, but other methods are possible. For example, after depositing and patterning an amorphous semiconductor film (FIG. 13-b), oxygen, laughing gas (N ₂ O), carbon dioxide (CO ₂ ), and water (H ₂ O) are contained in the range of several ppm to 1%. Heat treatment is performed for several hours to about 24 hours in a temperature environment of about 600 ° C. or less in a weakly oxidizing atmosphere. As a result, the amorphous film is crystallized, and at the same time, the metal oxide film 12 is formed.
01 is formed (FIG. 13-c). When heat treatment is performed in a weakly oxidizing atmosphere, oxygen replenishes intra-crystalline defects generated during amorphous crystallization, which has an advantage that a semiconductor film having a low threshold voltage and high mobility can be obtained. The kind and concentration of the oxide gas at the time of heat treatment are appropriately determined depending on the material of the metal used for the data line and the like and the film thickness of the required metal oxide. After that, the gate insulating film 10 is formed by the same method as described in detail in the fourth embodiment.
6, gate electrodes / lines 108 and 613 are formed, and the channel region 101 and the source region 10 are further formed by ion implantation.
2. Create the drain region 103 (FIG. 13-d). Subsequently, an interlayer insulating film 110 is deposited by the method described in detail in the fourth embodiment, and contact / contact is performed by a photolithography process.
Holes 107 and 612 are formed. This contact
Since holes must be formed in at least two types of insulating films, an interlayer insulating film, a gate insulating film, and a metal oxide,
Generally, two consecutive opening operations must be performed.
For example, when tantalum is used as the metal forming the pixel electrode extraction pad and the like, and the metal oxide is tantalum oxide and a silicon oxide film is used for the gate insulating film and the interlayer insulating film, silicon oxide is used in the first opening operation. A contact hole is made in the film, followed by an opening operation for tantalum oxide. However, if reactive ion etching (RIE) or chemical dry etching (CDE) is used, it is possible to form contact holes in two types of insulating films by a single opening operation. After forming the contact hole in this way, the pixel electrode material is deposited by the sputtering method or the like, and further patterned by the photolithography process.
The M substrate is completed (FIG. 13-e). As described above, according to the present invention, the above-described structural advantages can be obtained by the same six film forming steps and five photolithography processing steps as described in detail in the fourth embodiment.

In the fifth embodiment up to this point, the surface of the metal film such as the data line 104 has been oxidized in an oxidizing atmosphere of about 600 ° C. or lower. However, first, all the data lines are short-circuited and the anode is set. The metal oxide may be formed by an oxidation method. In this case, the pixel electrode lead-out pad 105 and the storage capacitor lower electrode 611 separated from the data line 104 are not oxidized, and the opening of the contact hole is facilitated. Even when an oxide film is formed on the data line by the anodic oxidation method, the intersection of the data line and the gate line has a two-layer structure of different kinds of insulating films, and dielectric breakdown and leakage current are also reduced. In addition, when the data line and the pixel electrode overlap, the coupling between them also decreases. Further, according to this method, since the metal oxide film is not formed on the surface of the storage capacitor lower electrode 611,
There is also an advantage that the storage capacity increases.

[0043]

As described above, according to the present invention, the following effects can be obtained.

(1) A thin film of a semiconductor film can be easily used and a TFT having excellent switching characteristics can be used as an element of an AM substrate.

(2) The number of photolithography processes can be reduced, and the manufacturing process can be simplified.

(3) The number of contact holes can be reduced, and a high-definition AM substrate having fine pixels can be manufactured.

(4) The data line, the gate electrode / line, and the pixel electrode can be formed on different layers, respectively, whereby the pixel electrode can be made larger. It is also possible to form the data line and the gate electrode / line with an electrically conductive light-shielding material, form the pixel electrode on another layer and overlap the edge portion thereof, and thereby the black stripe on the counter substrate side. Can be omitted, and the aperture ratio of the completed liquid crystal display device increases. Further, it is easy to align with the counter substrate, and the manufacturing efficiency is improved.

(5) Since the data line is formed in the lowermost layer and the pixel electrode is formed in the uppermost layer, even if the edge portion of the pixel electrode is overlapped with the data line, the occurrence of crosstalk or the like is significantly reduced.
High image quality can be obtained.

(6) By providing the metal oxide film on the surface of the data line, two different kinds of insulating films are formed between the data line and the gate line, and the number of short circuits between the data line and the gate line is greatly reduced. To do.

As described above, according to the present invention, there is a great effect that the high performance and the low price of the active matrix liquid crystal display are realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an active matrix substrate showing an embodiment of the present invention.

FIG. 2 is a sectional view of an element in each step of manufacturing an active matrix substrate showing an embodiment of the present invention.

FIG. 3 is a diagram showing an active matrix substrate according to the prior art.

FIG. 4 shows an active matrix substrate according to the prior art.

FIG. 5 is a diagram showing an active matrix substrate showing an embodiment of the present invention.

FIG. 6 is a view showing an active matrix substrate showing an embodiment of the present invention.

FIG. 7 is a sectional view of an element in each step of manufacturing an active matrix substrate showing an embodiment of the present invention.

FIG. 8 shows an active matrix substrate according to the prior art.

FIG. 9 is a sectional view of an element in each step of manufacturing an active matrix substrate according to a conventional technique.

FIG. 10 is a diagram showing an active matrix substrate showing an embodiment of the present invention.

FIG. 11 is a sectional view of an element in each step of manufacturing an active matrix substrate, showing an embodiment of the present invention.

FIG. 12 is a view showing an active matrix substrate showing an embodiment of the present invention.

FIG. 13 is a sectional view of an element in each step of manufacturing an active matrix substrate, showing an embodiment of the present invention.

[Explanation of symbols]

101 ... Channel area 102 ... Source area 103 ... Drain region 104 ... Data line 105 ... Pixel electrode extraction pad 106 ... Gate insulating film 107 ... Contact hole 108 ... Gate electrode / line 109 ... Pixel electrode 110 ... Interlayer insulating film 301 ... Channel area 302 ... Source area 303 ... Drain region 304 ... Gate insulating film 305 ... Gate electrode / line 306 ... Interlayer insulating film 307 ... Contact hole 308 ... Pixel electrode 309 ... Data line 401 ... Channel area 402 ... Source area 403 ... Drain region 404 ... Source pad 405 ... Drain pad 406 ... Gate insulating film 407 ... Gate electrode / line 408 ... Interlayer insulating film 409 ... Contact hole 410 ... Pixel electrode 411 ... Data line 611 ... Lower electrode for storage capacitor 612 ... Contact hole 613 ... Gate line of the previous row 811 ... Lower electrode for storage capacitor 812 ... Contact hole 813 ... Gate line in the previous row 901 ... Photo resist 902 ... Impurity ion implantation 1201 ... Metal oxide film

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[Procedure amendment]

[Submission date] July 24, 2002 (2002.7.2)
4)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: Active matrix substrate and manufacturing method thereof

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

[0014]

According to the present invention, in an active matrix substrate including a thin film transistor connected to a data line and a pixel electrode connected to the thin film transistor, the thin film transistor has a source region and a drain region. The pixel electrode is electrically connected to the pixel electrode lead-out pad, the pixel electrode lead-out pad and the data line are made of the same metal material, and part of the source region and A part of the drain region covers a part of the data line and a part of the pixel electrode extraction pad, respectively,
An impurity serving as a donor or an acceptor is implanted into the source region and the drain region.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

In the method of manufacturing a thin film transistor and an active matrix substrate, a step of forming a metal film on an insulating substrate, a step of patterning the metal film to form a pixel electrode extraction pad and a data line,
Forming a semiconductor layer so as to cover at least a part of each of the pixel electrode extraction pad and the data line; forming a gate insulating film on the semiconductor layer;
Forming an electrically conductive material on the gate insulating film,
Forming a gate electrode by patterning the electrically conductive material; and using the gate electrode as a mask, impurities serving as donors or acceptors are formed in portions of the semiconductor layer that cover the pixel electrode extraction pad and the data line. Forming a source region and a drain region.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Further, in an active matrix substrate including a thin film transistor connected to a data line and a pixel electrode connected to the thin film transistor, a first insulating layer and a data line formed on the first insulating layer. And a semiconductor layer, a second insulating layer formed on the data line and the semiconductor layer, a gate electrode formed on the second insulating layer, and a third insulating layer formed on the gate electrode. And a pixel electrode formed on the third insulating layer, the semiconductor layer having a source region into which a donor or an acceptor is implanted, and a part of the source region being the data line. It is characterized by covering a part of.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

In the method of manufacturing a thin film transistor and an active matrix substrate, at least a step of forming a metal film on an insulating substrate, a step of patterning the metal film to form a data line, and at least each of the data lines. Forming a semiconductor layer so as to cover a part thereof; forming a gate insulating film on the semiconductor layer; forming an electrically conductive material on the gate insulating film; and patterning the electrically conductive material. And forming a gate electrode, using the gate electrode as a mask, implanting an impurity serving as a donor or an acceptor into a portion of the semiconductor layer that covers the data line, and forming an interlayer insulating film on the gate electrode. And a step of forming a pixel electrode on the interlayer insulating film.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

In an active matrix substrate including a thin film transistor connected to a data line and a pixel electrode connected to the thin film transistor, a first insulating layer and a data line formed on the first insulating layer. ,
A semiconductor layer and a storage capacitor lower electrode, a second insulating layer formed on the data line, the semiconductor layer and the storage capacitor lower electrode, and a gate electrode and a gate line formed on the second insulating layer. A third insulating layer formed on the gate electrode and the gate line, and the pixel electrode formed on the third insulating layer, the source having a donor or acceptor implanted in the semiconductor layer. A region, a part of the source region covers a part of the data line, and the gate line also functions as a storage capacitor upper electrode of another pixel.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

In the method of manufacturing a thin film transistor and an active matrix substrate, a step of forming a metal film on an insulating substrate, a step of patterning the metal film to form a data line and a storage capacitor lower electrode, Forming a semiconductor layer so as to cover at least a part of each of the data lines, forming a gate insulating film on the semiconductor layer, and forming an electrically conductive material on the gate insulating film. Patterning the electrically conductive material to form a gate electrode, implanting an impurity serving as a donor or an acceptor in a portion of the semiconductor layer that covers the data line, using the gate electrode as a mask, and the gate electrode It is characterized by including a step of forming an interlayer insulating film on the interlayer insulating film and a step of forming a pixel electrode on the interlayer insulating film.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

In a method of manufacturing a thin film transistor and an active matrix substrate, a step of depositing an electrically conductive material, patterning the electrically conductive material,
Forming a data line and a storage capacitor lower electrode; depositing a semiconductor film; patterning at least a portion of the semiconductor film to cover the data line; and a gate insulating layer on the semiconductor film. And depositing a second electrically conductive material on the gate insulating layer,
Patterning the second electrically conductive material to form a gate electrode and an upper electrode for a storage capacitor of another pixel; and using the gate electrode as a mask, a donor or a part of the semiconductor film covering the data line is formed. The method is characterized by including a step of implanting impurities serving as an acceptor and a step of depositing an interlayer insulating layer on the second electrically conductive material.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

Further, in an active matrix substrate comprising a thin film transistor connected to a data line and a pixel electrode connected to the thin film transistor, the thin film transistor has a semiconductor layer having a source region and a drain region, A part of the source region covers a part of the data line, and the source region has
An impurity serving as a donor or an acceptor is implanted, and an oxide of the data line is included on a surface other than the part of the data line.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

Further, in the method of manufacturing a thin film transistor and an active matrix substrate, a step of forming a metal film on an insulating substrate, a step of patterning the metal film to form a data line, and at least each of the data lines. It is characterized by comprising a step of forming a semiconductor layer so as to cover a part thereof and a step of oxidizing the surface layer portion of the data line. Furthermore, in the method of manufacturing a thin film transistor and an active matrix substrate, a step of forming a metal film on an insulating substrate, a step of patterning the metal film to form a data line, and at least a part of each of the data lines. A step of forming a semiconductor layer made of an amorphous semiconductor so as to cover the semiconductor layer, a step of performing heat treatment in an oxidizing atmosphere to crystallize the semiconductor layer, a step of forming a gate insulating film, the gate insulating film A step of forming an electrically conductive material thereon, a step of patterning the electrically conductive material to form a gate electrode, and using the gate electrode as a mask,
Forming a source region and a drain region by implanting an impurity serving as a donor or an acceptor in a portion of the semiconductor layer that covers each of the pixel electrode extraction pad and the data line.

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Claims (17)

[Claims] 1. An active matrix substrate using, as a pixel switching element, a thin film transistor formed on at least an insulating layer, a data line made of a metal material and a pixel electrode extraction pad made of the same metal material on the insulating layer. A part of the semiconductor layer of the pixel thin film transistor is formed, and a part of the data line and a part of the pixel electrode extraction pad are formed in a part of a source region and a part of a drain region of the pixel thin film transistor, respectively. An active matrix substrate which is covered and has electrical continuity between a pixel electrode and the pixel electrode extraction pad. 2. The active matrix substrate according to claim 1, wherein the semiconductor layer of the thin film transistor for pixels is made of polycrystalline silicon. 3. The active matrix substrate according to claim 1, wherein the pixel electrode and the pixel electrode of the pixel thin film transistor are formed of the same material on the same layer. 4. The active matrix substrate according to claim 3, wherein the semiconductor layer of the thin film transistor for pixels is made of polycrystalline silicon. 5. A method of manufacturing an active matrix substrate, wherein at least a thin film transistor formed on an insulating substrate is used as a pixel switching element. In the method, a metal line is deposited and then a data line and a pixel electrode extraction pad are formed by patterning. The first step of forming a semiconductor film, and after depositing a semiconductor film, both ends of the semiconductor layer of the pixel thin film transistor cover a part of the data line and a part of the pixel electrode extraction pad, and the semiconductor layer of the pixel thin film transistor. A method of manufacturing an active matrix substrate, comprising a second step of patterning the semiconductor film so as to form a. 6. An active matrix substrate using a thin film transistor formed on at least an insulating layer as a pixel switching element, wherein a data line made of an electrically conductive material and an active layer semiconductor film of the thin film transistor are formed on a first insulating layer. A gate line formed of an electrically conductive material and a gate electrode of the thin film transistor are formed on a second insulating layer, and a pixel electrode is formed on a third insulating layer. Active matrix substrate. 7. An electrically conductive material forming a data line and an electrically conductive material forming a gate line are both light-shielding materials, and the edge portion of the pixel electrode is a second insulating layer and a third insulating layer or a third insulating layer. 7. The active matrix substrate according to claim 6, wherein the active matrix substrate overlaps with the data line or the gate line via the insulating layer. 8. A method of manufacturing an active matrix substrate, wherein at least a thin film transistor formed on an insulating substrate is used as a pixel switching element, wherein a data line is formed by patterning after depositing an electrically conductive material. A step of depositing a semiconductor film, and a second step of patterning the semiconductor film so that one end of the thin film transistor covers a part of the data line to form an active layer of the thin film transistor; A third step of depositing an insulating layer, a fourth step of depositing an electrically conductive material on the gate insulating layer and then forming a gate electrode and a gate line of the thin film transistor by patterning, and depositing an interlayer insulating layer And a part of the drain region of the thin film transistor or an electrically conductive state with the drain region. A sixth step of forming a contact hole in the gate insulating layer and the interlayer insulating layer so that a part of the existing region is exposed, and a seventh step of forming a pixel electrode on the interlayer insulating layer. A method for manufacturing an active matrix substrate, which comprises: 9. In an active matrix substrate using a thin film transistor formed on at least an insulating layer as a pixel switching element, a data line made of an electrically conductive material, an active layer semiconductor film of the thin film transistor, and the same material as the data line. A storage capacitor lower electrode is formed on the first insulating layer, and a gate line made of an electrically conductive material and a gate electrode of the thin film transistor are formed on the second insulating layer. An active matrix substrate, which also functions as an upper electrode for a storage capacitor of a pixel, and is electrically connected to the pixel electrode and the lower electrode for the storage capacitor. 10. The active matrix substrate according to claim 9, wherein the pixel electrode is formed on the third insulating layer. 11. An electric conductive material forming a data line and an electric conductive material forming a gate line are both light-shielding materials, and the edge portion of the pixel electrode is a second insulating layer and a third insulating layer or a third insulating layer. 11. The active matrix substrate according to claim 10, wherein the active matrix substrate overlaps with the data line or the gate line via the insulating layer. 12. A method of manufacturing an active matrix substrate, wherein at least a thin film transistor formed on an insulating substrate is used as a pixel switching element, in the method of depositing an electrically conductive material and then patterning the data line and storage capacitor. A first step of forming a lower electrode; and, after depositing a semiconductor film, patterning the semiconductor film so that one end of the thin film transistor covers a part of the data line to form an active layer of the thin film transistor. The second step, the third step of depositing the gate insulating layer, and the step of depositing an electrically conductive material on the gate insulating layer and then patterning the gate electrode of the thin film transistor and the upper portion of the storage capacitor of the pixel of the next row. Manufacture of an active matrix substrate characterized by including a fourth step of forming a gate line also as an electrode Law. 13. A method of manufacturing an active matrix substrate, wherein at least a thin film transistor formed on an insulating substrate is used as a pixel switching element, in a method for depositing an electrically conductive material and then patterning the data line and storage capacitor. A first step of forming a lower electrode; and, after depositing a semiconductor film, patterning the semiconductor film so that one end of the thin film transistor covers a part of the data line to form an active layer of the thin film transistor. The second step, the third step of depositing the gate insulating layer, and the gate electrode of the thin film transistor and the upper electrode for the storage capacitor of the pixel of the next row by patterning after depositing an electrically conductive material on the gate insulating layer. A fourth step of forming a gate line so as to also serve as a gate line, a fifth step of depositing an interlayer insulating layer, and the thin film transistor. Of the gate insulating layer and the interlayer insulating layer so that a part of the drain region of the capacitor or a part of the region electrically connected to the drain region and a part of the storage capacitor lower electrode are exposed. 7. A method of manufacturing an active matrix substrate, comprising: a sixth step of forming a contact hole, and a seventh step of forming a pixel electrode on the interlayer insulating layer. 14. In an active matrix substrate using a thin film transistor formed on at least an insulating layer as a pixel switching element, a data line made of a metal material and a part of a semiconductor layer of the thin film transistor are provided on the insulating layer. Is formed, a part of the source region of the thin film transistor covers a part of the data line, is not covered by a part of the source region of the data line, and is electrically connected to the other. An active matrix substrate, characterized in that a portion other than a portion intended to be removed is covered with an oxide of the metal material. 15. A method of manufacturing an active matrix substrate, wherein at least a thin film transistor formed on an insulating substrate is used as a pixel switching element, wherein a data line is formed by patterning after depositing a metal film. And a second step of depositing the semiconductor film and then patterning the semiconductor film so that one end of the semiconductor layer of the thin film transistor covers a part of the data line to form the semiconductor layer of the thin film transistor. A method for manufacturing an active matrix substrate, comprising a third step of oxidizing a surface layer portion of the data line. 16. A method of manufacturing an active matrix substrate, wherein at least a thin film transistor formed on an insulating substrate is used as a pixel switching element, in which a data line is formed by patterning after depositing a metal film. After depositing the amorphous semiconductor film, the amorphous semiconductor film is patterned so that one end of the semiconductor layer of the thin film transistor covers a part of the data line to form the semiconductor layer of the thin film transistor. A method of manufacturing an active matrix substrate, comprising: a second step; and a third step of heat-treating the substrate that has undergone the above steps in an oxidizing atmosphere. 17. The method for manufacturing an active matrix substrate according to claim 15, wherein the surface layer portion of the data line is oxidized by an anodic oxidation method.