JPH03153217A - TFT panel and its manufacturing method - Google Patents

Abstract

PURPOSE:To securely insulate a gate electrode and a semiconductor layer, and an electrode for capacity formation and a picture element electrode from each other by forming a gate insulating layer of an oxide insulating layer and a gate insulating film in two-layered structure and forming a charge storage capacitor of an oxide insulating film and a gate insulating film in two layered structure with an insulating layer interposed. CONSTITUTION:The gate insulating film between the gate electrode 13a of a thin film transistor (TFT) 12 and a semiconductor layer is formed in two-layered structure of the oxide insulating layer 21b, formed by oxidizing the upper layer part of a metallic film 21 forming the gate electrode 13a, and the gate insulating film 14 formed thereupon. Further, the charge storage capacitor Cs is also structured by interposing the insulating layer in two-layered structure of the oxide insulating film 21b and the gate insulating film 14 laminated thereupon between the charge storage capacitor Cs and electrode 19 for capacity formation. Consequently, even if a defect such as a pinhole in the gate insulating film 14 is present thereon, the gate electrode 13a and semiconductor layer, and the electrode 19 for capacity formation and picture element electrode 20 can securely be insulated by the gate insulating layer and oxide insulating film 21b respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a TFT panel used in a TFT active matrix liquid crystal display element and a method for manufacturing the same.

[Conventional technology]

A TFT panel used in a TFT active matrix type liquid crystal display element consists of a transparent bipolar electrode and a thin film transistor (TFT) that selectively drives the bipolar electrode on a transparent substrate.
The gate and drain electrodes of each thin film transistor are connected to the gate line and data line wired between the rows of both elemental electrodes, and the source electrode is connected to both elemental electrodes. There is.

By the way, recently, in order to improve the reliability of the thin film transistor and the display quality of the liquid crystal display element in the upper 2 TPT panel, the gate insulating layer of the thin film transistor has been made into a two-layer structure to prevent short circuits between the gate electrode and the source and drain electrodes. In addition to reliably preventing the occurrence of , a capacitance forming electrode is provided below the bipolar electrode and faces the bipolar electrode via an insulating film, and charge is accumulated between the capacitance forming electrode and the bipolar electrode. A display drive voltage is applied to the bipolar electrode from the charge storage capacitor even when the bipolar electrode is not selected (during one frame period until the selectively driven bipolar electrode is next selectively driven). A system has been proposed in which the voltage can be applied in advance.

FIG. 3 shows what has been conventionally considered as this type of TFT panel. In the figure, 1 is a transparent substrate made of glass, and 2 is a thin film transistor formed on this substrate 1. This thin film transistor 2 is of an inverted stagger type, and includes a gate electrode 3a formed on a substrate 1, and a gate insulator made of silicon nitride (SI N) or the like formed on the gate electrode 3a over almost the entire surface of the substrate 1. film 4 and i-type amorphous silicon (ia-S) formed on the gate insulating film 4 to face the gate electrode 3a.
n-type amorphous silicon (n''-a-3
The source electrode 7 and the drain electrode 8 are laminated with an n-type semiconductor layer 6 interposed therebetween. The gate electrode 3a of the thin film transistor 2 is formed of a metal film 3 made of tantalum (Ta) or the like, which is formed on the substrate 1 to be thicker than the gate electrode 3a. 3a, and the upper layer part of this metal film 3 except for the gate electrode 38 part is made of a metal oxide (the metal film 3 is formed by anodic oxidation of this part).
In the case of a, the oxide insulating layer 3b is made of tantalum oxide (Ta0x). Note that the gate line (not shown) to which the gate electrode 3a is connected is formed integrally with the gate electrode 3a by the metal film, and therefore the oxide insulating layer 3b is also formed on this gate line. .

On the other hand, reference numeral 9 denotes a capacitance forming electrode made of a transparent conductive film such as ITO, which is formed in the bipolar electrode forming region on the substrate 1, and this capacitance forming electrode 9 is covered with the gate insulating film 4 of the thin film transistor 2. The bipolar electrode 10 is formed on the gate insulating film 4 so as to face the capacitance forming electrode 9. This double electrode 10 is made of a transparent conductive film such as ITO, and is made of the source electrode 7 of the thin film transistor 2.
is connected to the bipolar electrode 10 by forming its end over the edge of the bipolar electrode 10.

That is, in this TFT panel, the gate insulating layer between the gate electrode 3a of the thin film transistor 2 and the i-type semiconductor layer 5 is combined with the oxide insulating layer 3b obtained by oxidizing the upper layer portion of the metal film 3 forming the gate electrode 3a. It has a two-layer structure consisting of an insulating film 4, and a capacitance forming electrode 9 is provided below the bipolar electrode 10 and facing the bipolar electrode 10 with the gate insulating film 4 interposed therebetween. A charge storage capacitor C is formed between the electrode 10 and the electrode 10.

In this way, if the gate insulating layer of the thin film transistor 2 has a two-layer structure consisting of the oxide insulating layer 3b and the gate insulating film 4, even if the gate insulating film 4 has defects such as pinholes, the gate electrode 3a and the i-type soil conductor layer 5 can be reliably insulated by the oxide insulating layer 3b, so that the gate electrode 3a and the source and drain electrodes 7 can be reliably insulated.
8 will not be short-circuited through the i-type soil conductor layer 5 and the n-type soil conductor layer 6, so the reliability of the thin film transistor 2 can be improved. Further, as described above, if a capacitance forming electrode is provided under the bipolar electrode 10 and a charge storage capacitor RC is formed between the capacitance forming electrode 9 and the bipolar electrode 10, the thin film transistor 2 is turned on to selectively drive the bipolar electrode 10, charge is charged in the charge storage capacitor C, and even after the bipolar electrode 10 is in the non-selected state, the charge storage capacitor C is transferred to the bipolar electrode 10. Since the display driving voltage is applied, the liquid crystal is maintained in the electric field applied state even when both element electrodes are not selected, that is, during one frame period until the selectively driven pixel electrode 10 is selectively driven next. Therefore, the display quality of the liquid crystal display element can be improved.

[Problem to be solved by the invention]

However, in the conventional TFT panel, the charge storage capacitor C has a structure in which the capacitor forming electrode 9 and the bipolar electrode 10 are opposed to each other with only the gate insulating film 4 of the thin film transistor 2 interposed therebetween. There is a problem in that a short circuit occurs between the bipolar electrode 10 and the capacitor forming electrode 9, and the charge storage capacitor C loses its function.

This is because the gate insulating film 4 made of silicon nitride or the like is deposited by the plasma CVD method, and the film deposited by the plasma CVD method has defects such as pinholes. This is because the capacitance forming electrode 10 and the capacitor forming electrode 9 will be short-circuited. In addition,
The defects described above are scattered in the Ga insulating film 4 deposited over almost the entire surface of the substrate 1, but
Since a large number of amorphous electrodes 10 are arranged vertically and horizontally over almost the entire area of the substrate 1, a charge storage capacitor jIC which loses its charge storage function due to a short circuit between the amorphous electrode 10 and the capacitor forming electrode 9 is
This always occurs with a certain probability in one TFT panel.

When the charge storage capacitor C loses its function in this way, the bipolar electrode 10 corresponding to the charge storage capacitor C becomes unselected and at the same time the voltage application is cut off, and conversely, the liquid crystal layer Accumulated? ! ! Since the charge escapes from the bipolar electrode 10 to the capacitance forming electrode 9, it becomes impossible to maintain the liquid crystal in this area with an electric field applied, and point defects occur in the displayed image of the liquid crystal display element. It ends up.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to ensure a short circuit between the gate electrode and the source and drain electrodes by forming the gate insulating layer of a thin film transistor into a two-layer structure. In addition to preventing
The charge storage capacitor also does not cause short circuits between the bipolar electrode and the capacitor forming electrode (it has high J-axis properties, and can be easily manufactured using the same manufacturing process as conventional TFT panels). It is an object of the present invention to provide a TFT panel that can be used as a TFT panel, and also to provide a method for manufacturing the same.

[Means to solve the problem]

The TFT panel of the present invention includes a thin film transistor including a gate electrode made of a lower part of a metal film formed on a substrate, an oxide insulating layer formed by oxidizing the upper part of the metal film, and a gate formed on the oxide insulating layer. The gate insulating layer has a two-layer structure consisting of an insulating film, a semiconductor layer and source and drain electrodes formed on the gate insulating film, and a capacitance forming electrode is provided in the double electrode forming area on the substrate. and forming an oxide insulating film on the capacitance forming electrode by oxidizing a metal film made of the same metal as the metal film that will become the gate electrode and oxide insulating layer of the thin film transistor over its entire thickness; A gate insulating film of the thin film transistor is laminated on this oxide insulating film, and a double electrode facing the capacitance forming electrode is formed on this gate insulating film.

Further, in the method for manufacturing a TFT panel of the present invention, after forming a capacitance forming electrode in a bipolar electrode formation region on a substrate, a thin film transistor forming chain acid on the substrate and the bipolar electrode formation region are made of the same metal. a step of simultaneously forming a metal film formed in the thin film transistor formation region, and anodizing an upper layer portion of the metal film formed in the thin film transistor formation region to form a gate electrode consisting of a lower layer portion of the metal film and an oxide insulating layer consisting of an upper layer portion of the metal film. and forming an oxide insulating film by anodizing the metal film formed in the bipolar electrode formation region over its entire thickness; and forming an oxide insulating layer in the thin film transistor formation region and the bipolar electrode formation a step of depositing a gate insulating film on the oxide insulating film in the region; and forming on the gate insulating film a double electrode facing the capacitance forming electrode, and a semiconductor layer and source and drain electrodes of a thin film transistor. It is characterized by the following steps:

[Effect]

That is, in the TFT panel of the present invention, the gate insulating layer between the gate electrode of the thin film transistor and the semiconductor layer is formed by forming an oxide insulating layer in which the upper layer of the metal film forming the gate electrode is oxidized, and a gate formed thereon. In addition to the two-layer structure consisting of an insulating film, the charge storage capacity also has a two-layer structure consisting of an oxide insulating film and a gate insulating film layered on top of the oxide insulating film between the capacitor forming electrode and the bipolar electrode. As a structure in which an insulating layer is interposed, even if there is a defect such as a pinhole in the gate insulating film, the above-mentioned The oxide insulating layer and the oxide insulating film ensure reliable insulation. Therefore, the TFT panel of the present invention not only reliably prevents the gate electrode, source, and drain electrodes of the thin film transistor from being short-circuited through the semiconductor layer, thereby improving its reliability, but also improves the reliability of the thin film transistor by
: The storage capacitor can also be made highly reliable without causing a short circuit between the bipolar electrode and the capacitor forming electrode. Moreover, in the present invention, the oxide insulating film formed on the capacitance forming electrode is formed by oxidizing a metal film made of the same metal as the gate electrode and the oxide insulating layer of the thin film transistor over its entire thickness. Therefore, the metal film that will become the oxide insulating film can be formed simultaneously with the metal film that will become the gate electrode and the oxide insulating layer.
It can be easily manufactured using the same manufacturing process as manufacturing T panels.

Further, according to the method for manufacturing a TFT panel of the present invention, a metal film made of the same metal is simultaneously formed in a thin film transistor formation region and a bipolar electrode formation region on a substrate, and the metal film formed in the thin film transistor formation region is The upper layer portion is anodized to form a gate electrode consisting of the lower layer portion of this metal film and an oxide insulating layer consisting of the upper layer portion of the metal film, and the metal film formed in the bipolar electrode forming region is covered over its entire thickness. Since the oxide insulating film is formed by anodic oxidation, the oxide insulating film of the charge storage capacity can be formed using the process of forming the gate electrode and oxide insulating layer of the thin film transistor, and therefore the above TFT panel can be easily manufactured. can be manufactured.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a cross section of a part of the TFT panel of this embodiment. In the figure, 11 is a transparent substrate made of glass, and 12 is a thin film transistor formed on this substrate 11. In FIG.

This thin film transistor 12 is of an inverted stagger type, and includes a gate electrode 13a formed on a substrate 11, and a gate insulator made of silicon nitride (SiN) or the like formed on the gate electrode 13a over almost the entire surface of the substrate 11. film 14 and the gate electrode 1 on this gate insulating film 14.
I-type amorphous silicon (
An i-type semiconductor layer 15 made of i-a-31) and an n-type semiconductor layer 16 made of n-type amorphous silicon (n''-a-3t) are stacked on both sides of this i-type semiconductor layer 15. The formed source electrode 17 and drain electrode 18
It consists of Further, the gate electrode 13a of this thin film transistor 12 is formed of a metal film 13 formed on the substrate 11 to be sufficiently thicker than the thickness of the gate electrode 13a, and the upper layer portion of this metal film 13 serves as the gate electrode 13a, and The upper layer portion of the metal film 13 excluding the gate electrode 13a portion is an oxide insulating layer 13b made of a metal oxide formed by anodic oxidation of this portion. In addition,
In this embodiment, the metal film 13 is made of tantalum (Ta).
Therefore, the metal oxide of the oxide insulating layer 13b is tantalum oxide (TaOx).

In addition, a gate line (
(not shown) is formed integrally with the gate electrode 13a using the metal film, and therefore the oxide insulating layer 13b is also formed on this gate line.

On the other hand, reference numeral 19 denotes a capacitance forming electrode made of a transparent conductive film such as ITO formed in the bipolar electrode forming area on the substrate 11;
b is an oxide insulating film WA21b formed on the capacitor forming electrode 19, and the gate insulating film 14 of the thin film transistor 12 is laminated on the oxide insulating film 21b. The oxide insulating film 21b is the thin film transistor 1.
The metal film 21 made of the same metal (Ta) as the metal film 13 which becomes the gate electrode 13a and the oxide insulating layer 13b of No. 2 is anodized over its entire thickness, and this oxide insulating film 21b is also made of tantalum oxide (TaOx). It consists of Note that this oxide insulating film 21b and the gate insulating film 1
4 are all transparent films. Reference numeral 20 denotes a bipolar electrode made of a transparent conductive film such as ITO, and the bipolar electrode 20 is formed on the gate insulating film 14 to face the capacitance forming electrode 19. Note that this double electrode 20 is connected to the source electrode 17 by overlapping the end of the source electrode 17 of the thin film transistor 12 on the end thereof.

The portion where the bipolar electrode 20 and the capacitance forming electrode 19 are opposed to each other with the oxide insulating film 21b and the gate insulating film 14 in between is displayed on the bipolar electrode 20 when the bipolar electrode 20 is not selected. It serves as a charge storage capacitor C3 to which a driving voltage is applied.

FIG. 2 shows the method for manufacturing the TFT panel in the order of steps, and the TFT panel is manufactured as follows.

First, as shown in FIG. 2(a), a capacitance forming electrode 19 is formed by depositing a transparent conductive film on the bipolar electrode forming area on the substrate 11 and patterning it.
Tantalum (Ta) is deposited on the substrate 11 to a thickness of approximately 4000 nm by sputtering or the like, and this deposited film is patterned to deposit the same metal ( At the same time, a metal film 13.21 made of Ta) is formed. In this case, the metal film 13 formed in the thin film transistor forming region is formed to have a slightly larger area than the gate electrode 13a.

Next, as shown in FIG. 2(b), the upper layer of the metal N113 formed in the thin film transistor forming region is
The gate electrode 13a (approximately 1000 mm thick) is formed by anodizing the lower layer of the metal film 13, and the oxide insulating layer (TaOX) is formed by the upper layer of the metal film 13.
At the same time, the metal film 21 formed in the bipolar electrode formation region is anodized over its entire thickness, and this metal film 21 is formed into an oxide insulating film (TaOX film). 21b. Note that this metal film 13
．． The anodic oxidation of 21 may be performed in a separate process or at the same time. When both metal films 13.21 are anodized at the same time, the voltage applied to the metal film 13 in the thin film transistor forming region is applied to both electrodes. The voltage may be set lower than the voltage applied to the metal film 21 in the region to slow down the progress of oxidation of the metal film 13 in the thin film transistor forming region. Furthermore, since the oxidation of the metal film 13.21 proceeds not only from the upper surface side but also from the peripheral side, the periphery of the lower layer portion of the metal film 13 that will become the gate electrode 13a is also oxidized and becomes an insulating film. , this metal film 13 is connected to the gate electrode 1 as described above.
By forming the gate electrode 3a to be slightly larger in area, a sufficient area can be secured for the portion remaining as the gate electrode 13a.

After this, as shown in FIG. 2(c), silicon nitride (SiN) or the like is applied over almost the entire surface of the substrate 11 on the oxide insulating layer 13b in the thin film transistor formation region and the oxide insulating film 21b in the electrode formation region of the image 1g. A gate insulating film 14 consisting of
is deposited by a plasma CVD method, and then an n-type semiconductor layer 15 and an n-type semiconductor layer 16 of the thin film transistor 12 are formed on the gate insulating film 14 in the thin film transistor formation region. Note that the n-type semiconductor layer 15 and the n-type semiconductor layer 16 are formed by adding i-type amorphous silicon (ia-a-Si) and mouth-type amorphous silicon (n'-a-5t) to the soil of the gate insulating film 14. The deposited film is successively deposited, and the deposited film is buttered into the shape of a transistor element, and the n-type semiconductor layer 16 above the central portion (channel region) of the n-type semiconductor layer 15 is removed by etching.

Next, as shown in FIG. 2(d), a bipolar electrode 20 is formed on the gate insulating film 14 in the bipolar electrode formation region so as to face the capacitance forming electrode 19, and a charge storage capacitor C5 Configure. This double electrode 20 is formed by depositing a transparent conductive film such as ITO on the gate insulator [14] and patterning this transparent conductive film.

Thereafter, a metal film such as chromium (Cr) is deposited thereon, and this metal film is patterned to form the source of the thin film transistor 12 on the n-type semiconductor layer 15 as shown in FIG. 2(C). , forming drain electrodes 17 and 18, and forming TF
Complete the T panel.

Note that in the above manufacturing process, after the 1-type semiconductor layer 15 and the n-type semiconductor layer 16 are formed on the gate insulator 11414, the double electrode 20 is formed, and then the source electrode 20 is formed.

Although the drain electrodes 17 and 18 are formed, the bipolar electrodes 20 may be formed after the n-type semiconductor layer 15, the n-type semiconductor layer 16, and the source and drain electrodes 17 and 18 are formed. In this case, the end portion of the bipolar electrode 20 may be formed to overlap the source electrode 17, and the bipolar electrode 20 and the source electrode 17 may be connected.

Therefore, in the TFT panel of the above embodiment, the gate insulating layer between the gate electrode 13a of the thin film transistor 12 and the n-type semiconductor layer 15 is oxidized by oxidizing the upper layer portion of the metal film 13 forming the gate electrode 13a. It has a two-layer structure consisting of an insulating layer 13b and a gate insulating film 14 formed thereon, and the charge storage capacitor C8 also has an oxide insulating film 21b and its Since it has a structure with a two-layer insulating layer consisting of the gate insulating film 14 laminated on top, plasma CVD is not possible.
Even if there is a defect such as a pinhole in the gate insulating film 14 deposited by the method, the gap between the gate electrode 13a and the n-type semiconductor layer 15 and between the capacitance forming electrode 19 and the dielectric electrode 20 will be maintained. , oxide insulating layer 13b and oxide insulating film 21
b ensures reliable insulation. therefore,
This TFT panel not only reliably prevents the gate electrode 13a of the thin film transistor 12 from being short-circuited to the source and drain electrodes 17 and 18 via the n-type semiconductor layer 15, but also improves its reliability. The charge storage capacitor C3 also does not cause a short circuit between the bipolar electrode 20 and the capacitor forming electrode 19 (j can be made to be highly obvious).

Moreover, in the TFT panel, the capacitance forming electrode 1
The oxide insulating layer 1fi21b formed on the gate electrode 13a of the thin film transistor 12 and the oxide insulating layer 13b formed on the thin film transistor 12
Since the metal film 21 made of the same metal as the metal film 13 is oxidized over its entire thickness, the metal 1121 that will become the oxide insulating film 21b is replaced by the metal film 1121 that will become the gate electrode 13a and the oxide insulating layer 13b. 13, and therefore, this TFT panel can be easily manufactured using a manufacturing process that is no different from manufacturing conventional TFT panels.

Further, according to the above TFT panel manufacturing method, the substrate 11
A metal film 13.21 made of the same metal is simultaneously formed in the upper thin film transistor formation region and the bipolar electrode formation region, and the upper layer portion of the metal film 13 formed in the thin film transistor formation region is anodized to remove the lower layer of this metal film 13. A gate electrode 13a consisting of a portion of the metal film 13 and an oxide insulating layer 13b consisting of an upper layer portion of the metal film 13 are formed, and the metal film 21 formed in both electrode formation regions is anodized over its entire thickness to form an oxide insulating film 21b. Therefore, the gate electrode 13a and the oxide insulating layer 13b of the thin film transistor 12
The oxide insulation M21b of the charge storage capacitor ffiCs can be formed using the process of forming the TFT panel, and therefore the TFT panel described above can be easily manufactured.

In the above embodiment, the thin film transistor 12 for selectively driving the bipolar electrodes 2U is of an inverted stagger type, but this thin film transistor may be of an inverted stagger type. In that case, the semiconductor layer of the thin film transistor is The source and drain electrodes 15, 16 and 17, 18 may be formed in the reverse order of the above embodiment.

〔Effect of the invention〕

In the TFT panel of the present invention, the gate insulating layer between the gate electrode of the thin film transistor and the semiconductor layer is composed of an oxide insulating layer formed by oxidizing the upper part of the metal film forming the gate electrode, and a gate insulating film formed thereon. In addition, the charge storage capacitor has a two-layer structure consisting of an oxide insulating film and a gate insulating film in contact with it, between the capacitance forming electrode and the bipolar electrode. Since the structure is such that even if there is a defect such as a pinhole in the gate insulating film, there will be no damage between the gate electrode and the semiconductor layer and between the capacitance forming electrode and the bipolar electrode. can be reliably insulated by the oxide insulating layer and the oxide insulating film. Therefore, according to the TFT panel of the present invention, not only can the gate electrode of the thin film transistor and the source and drain electrodes be reliably prevented from being short-circuited via the semiconductor layer to improve the reliability thereof, but also the charge storage capacity can be improved. Also, it is possible to provide a highly reliable structure in which no short circuit occurs between the bipolar electrode and the capacitor forming electrode. Moreover, in the present invention, the oxide insulating film formed on the capacitance forming electrode is formed by oxidizing a metal film made of the same metal as the gate electrode and the oxide insulating layer of the thin film transistor over its entire thickness. Therefore, the metal film that will become the oxide insulating film can be formed at the same time as the gate electrode and the metal film that will become the oxide insulating layer. It can be manufactured into containers using the same manufacturing process.

Further, according to the method for manufacturing a TFT panel of the present invention, a metal film made of the same metal is simultaneously formed in a thin film transistor formation region and a bipolar electrode formation region on a substrate, and the metal film formed in the thin film transistor formation region is The upper layer portion is anodized to form a gate electrode consisting of the lower layer portion of this metal film and an oxide insulating layer consisting of the upper layer portion of the metal film, and the metal film formed in the bipolar electrode forming region is covered over its entire thickness. Since the oxide insulating film is formed by anodic oxidation, the oxide insulating film of the charge storage capacity can be formed using the process of forming the gate electrode and oxide insulating layer of the thin film transistor, and therefore the above TFT panel can be easily manufactured. can be manufactured.

[Brief explanation of the drawing]

! @Figure 1 and Figure 2 are TFTs showing one embodiment of the present invention.
FIG. 3 is a cross-sectional view of a portion of a conventional TFT panel. 11...Substrate, 12...Thin film transistor, 13.
... Metal film, 13a... Gate electrode, 13b... Oxide insulating layer, 14... Gate insulating film, 15... I-type semiconductor layer, 16... N-type semiconductor layer, 17... Source electrode, 18... Drain electrode, 19... Capacitance forming electrode, 20... Ampholytic electrode, 21... Metal film, 21b.
... Oxide insulating film, Cs... Charge storage capacity.

Claims (2)

[Claims] (1) A bipolar electrode and a thin film transistor for selectively driving the bipolar electrode are formed on a substrate, and a capacitance forming electrode is provided below the bipolar electrode to face the pixel electrode with an insulating film interposed therebetween. , in a TFT panel in which a charge storage capacitor is formed between the capacitance forming electrode and the pixel electrode, the thin film transistor is formed by a gate electrode consisting of a lower layer portion of a metal film formed on the substrate, and an upper layer of the metal film. A gate insulating layer with a two-layer structure consisting of an oxide insulating layer partially oxidized and a gate insulating film formed on the oxide insulating layer, a semiconductor layer formed on the gate insulating film, and source and drain electrodes. A capacitance forming electrode is formed in the pixel electrode forming region on the substrate, and a capacitance forming electrode made of the same metal as the metal film which becomes the gate electrode and oxide insulating layer of the thin film transistor is formed on the capacitance forming electrode. An oxide insulating film is formed by oxidizing a metal film over its entire thickness, and a gate insulating film of the thin film transistor is laminated on this oxide insulating film, and the capacitance forming electrode and the capacitor forming electrode are formed on the gate insulating film. A TFT panel characterized in that opposing pixel electrodes are formed. (2) After forming a capacitance forming electrode in both electrode forming regions on the substrate, simultaneously forming a metal film made of the same metal in the thin film transistor forming region and the pixel electrode forming region on the substrate; An upper layer portion of the metal film formed in the thin film transistor formation region is anodized to form a gate electrode consisting of a lower layer portion of the metal film and an oxide insulating layer consisting of an upper layer portion of the metal film, and the pixel electrode formation region forming an oxide insulating film by anodizing the metal film formed over its entire thickness; and depositing a gate insulating film on the oxide insulating layer in the thin film transistor formation region and the oxide insulating film in the pixel electrode formation region. and a step of forming, on the gate insulating film, a bipolar electrode facing the capacitance forming electrode, a semiconductor layer, and source and drain electrodes of a thin film transistor. manufacturing method.