JP3105606B2 - Liquid crystal device manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

(Contents) ・ Industrial application fields ・ Prior art (FIGS. 8 to 10) ・ Problems to be solved by the invention ・ Means for solving the problems ・ Functions ・ Examples (FIGS. 1 to 7) ) ·The invention's effect

[0002]

The present invention relates to a method for manufacturing a liquid crystal device, and more particularly to a method for manufacturing a liquid crystal device (LCD) having a thin film transistor (TFT) as a control element.

[0003]

2. Description of the Related Art FIGS. 8A to 8C and FIGS.
(F) and FIGS. 10 (g) and (h) are cross-sectional views for explaining a method of manufacturing a conventional TFT active matrix LCD.

First, as shown in FIG. 8A, in a region on a transparent substrate 1 where a channel layer of a thin film transistor (TFT) is to be formed, backlight light for driving a liquid crystal device is applied to this channel layer. The light shielding film 2 is selectively formed so as not to hit. At this time, the width of the light shielding film 2 is formed to be larger than the width of the channel region layer formed in consideration of the alignment margin. Next, the insulating film 3 is formed by covering the light shielding film 2. Subsequently, a resist film 4 whose photosensitive reaction is reversed by heat treatment is formed on the insulating film 3. In this conventional example, a resist film 4 whose photosensitive reaction changes from a negative type to a positive type by heat treatment is used. Then
Using the exposure mask 5a, the resist film 4 in a region other than the region where the pixel electrode, the source electrode, and the drain electrode are to be formed.
Is selectively exposed (FIG. 8B).

Next, after performing a heat treatment to reverse the photosensitive reaction of the resist film 4 to a positive type (FIG. 8C), subsequently, using another exposure mask 5b, the upper part of the light shielding film 2 is removed.
The resist film 4 in the region other than the band-like region where the channel layer of the TFT is to be formed is selectively exposed (FIG. 9D).

Next, when the resist film 4 is developed, a resist pattern 4a is formed in a region other than a region where a pixel electrode, a source electrode and a drain electrode are to be formed, and in a region where a channel region layer is to be formed (FIG. 9). (E)). Subsequently, an ITO film 6 serving as a pixel electrode / amorphous silicon (n ⁺ a-Si) film 7 doped with phosphorus is formed on the entire surface (FIG. 9F).

Next, when the remaining resist pattern 4a is removed, the ITO film 6 / n ⁺ a-Si in the region other than the region where the pixel electrode, the source electrode and the drain electrode are to be formed and the region where the channel region layer is to be formed is formed. The film 7 is removed by lift-off together with the resist pattern 4a, and the ITO film 6a / n ⁺ is formed in a region where a pixel electrode and a source electrode are to be formed and a region where a drain electrode is to be formed, except for a region where a channel region layer is to be formed. a-Si film 7a and IT
The O film 6b / n ⁺ a-Si film 7b remains. continue,
A first insulating film to be a part of the semiconductor layer and the gate insulating film is formed over the entire surface.

Next, a first insulating film, a semiconductor layer and n ⁺
The a-Si films 7a and 7b are selectively etched to obtain an IT
A pixel electrode 10 made of an O film 6a, a source electrode 11 made of an ITO film 6a and an n ⁺ a-Si film 7c connected to the pixel electrode 10, and a source electrode sandwiching a strip-shaped region where a channel layer of a TFT is to be formed. 11 and a drain electrode 12 composed of an opposing ITO film 6b and an n ⁺ a-Si film 7d, and the semiconductor layer 8 and the first layer 11 are formed so as to bridge between the opposing source electrode 11 and the drain electrode 12.
The insulating film 14a remains. Thereby, the source electrode 11
One TFT in which the upper semiconductor layer becomes the source region layer 8a, the semiconductor layer on the drain electrode 12 becomes the drain region layer 8b, and the semiconductor layer between the source electrode 11 and the drain electrode 12 becomes the channel region layer 8c Is completed.

Next, after forming a drain bus line 13 for connecting the drain electrode 12 of one TFT and the drain electrode 12 of another TFT (not shown) to each other, a second insulating film 14b serving as a part of the gate insulating film is formed. To form continue,
After a conductive film 15 serving as a gate electrode is formed on the second insulating film 14b, a resist film 16 is formed on the conductive film 15.

Next, a resist film 16 is formed using an exposure mask.
Is selectively exposed (FIG. 10 (g)), and then the resist film 1 is exposed.
6 is developed to form a resist pattern 16a above the channel region layer 8c in a region where a gate electrode is to be formed. At this time, the width of the resist pattern 16a is formed to be larger than the width of the channel region layer 8c formed in consideration of the alignment margin. Next, the conductive film 15 is selectively etched and removed using the resist pattern 16a as a mask to form a gate electrode 15a (FIG. 10).
(H)). Thereafter, when a liquid crystal film (not shown) is formed on the entire surface, the liquid crystal device is completed.

[0011]

According to the above-described manufacturing method, as shown in FIG. 10 (g), the resist film 16 is selectively exposed and developed using an exposure mask 5c to form a channel region. When forming a resist pattern 16a above the layer 8c and serving as a mask for forming the gate electrode 15a, the width of the resist pattern 16a is made larger than the width of the channel region layer 8c in consideration of an alignment margin in a photo process. It is formed large. For this reason, considerable overlap occurs between the formed gate electrode 15a and the source electrode 11 and the drain electrode 12 adjacent to the channel region layer 8c. As a result, the parasitic capacitance increases, and the speed of the liquid crystal device increases. There is a problem that hinders.

The present invention has been made in view of the above-mentioned problems of the prior art, and provides a method of manufacturing a liquid crystal device capable of reducing the parasitic capacitance and increasing the speed of the liquid crystal device. Aim.

[0013]

The first object of the present invention is to first form a light-shielding film on a transparent substrate and then form an insulating film, and a photolithography method using the light-shielding film as a mask. On the insulating film above the light shielding film,
A first pattern formation film is selectively formed in a region where a channel region layer is to be formed between the regions where the source electrode and the drain electrode are to be formed, and by a photolithography method using a first exposure mask, Selectively forming a second pattern forming film on a region other than the region where the pixel electrode, the source electrode, and the drain electrode are to be formed on the insulating film; and forming the first and second pattern forming films on the insulating film. Forming a first conductor film that transmits exposure light on the insulating film through the first and second layers; removing the first and second pattern formation films from the first conductor film by lift-off; Forming a pixel electrode, a source electrode, and a drain electrode, and selectively forming a semiconductor layer and a first gate insulating film so as to bridge the source electrode and the drain electrode. Forming a drain bus line connected to the drain electrode, sequentially forming a second gate insulating film and a second conductor film transmitting the exposure light on the first gate insulating film; A third pattern forming film is formed on the second conductive film above the light shielding film by photolithography using the light shielding film as a mask, and the gate bus is formed by photolithography using a second exposure mask. Forming a fourth pattern forming film on the second conductor film in a region where a line is to be formed; and forming the second pattern film using the third and fourth pattern forming films as a mask.
Etching and removing said conductive film to form a gate electrode made of said second conductive film and a gate bus line connected to said gate electrode on said second gate insulating film. Achieved by the manufacturing method, the second
In the step of forming the first and second pattern forming films, a step of forming, on the insulating film, a first photosensitive film in which a photosensitive reaction type is reversed between a negative type and a positive type by heat treatment And a region other than a region where a channel region layer between the source electrode and the drain electrode is to be formed above the pixel electrode, the source electrode, the drain electrode, and the light-shielding film from the surface side opposite to the transparent substrate. After selectively irradiating the first photosensitive film with exposure light, a heat treatment is performed to reverse the photosensitive reaction type of the first photosensitive film, and the light-shielding film is used as a mask from the transparent substrate side. After selectively irradiating the first photosensitive film with exposure light, the first photosensitive film is developed to form a region on the insulating film where a channel region layer above the light shielding film is to be formed. And the pixel electrode, the source electrode, and Forming a first and a second pattern forming film respectively in a region other than a region where a rain electrode is to be formed, and a method of manufacturing a liquid crystal device according to the first invention. Thirdly, in the step of forming the third and fourth pattern forming films, the second photosensitive film is reversely switched between a negative type and a positive type by a heat treatment on the second conductive film. Forming a photosensitive film, and selectively irradiating exposure light to the second photosensitive film in a region where the gate bus line is to be formed, and then subjecting the second photosensitive film to a heat treatment by heating treatment. And selectively irradiating exposure light to an area above the drain bus line, and selectively irradiating exposure light to the second photosensitive film from the transparent substrate side using the light shielding film as a mask. After the second A photosensitive film is developed, and third and fourth regions are formed on the second conductive film in a region where a gate electrode is to be formed above the light shielding film and in a region where the gate bus line is to be formed, respectively. Forming a pattern forming film according to (1).
Alternatively, the invention is attained by the method of manufacturing a liquid crystal device according to the second invention, and fourthly, the drain bus line is a light-shielding conductive film such as an Al film. Fifth, achieved by a method of manufacturing a liquid crystal device,
The first conductor film is a two-layer conductor film of ITO film / n ⁺ a-Si film, the second conductor film is an ITO film, and the first and second gate insulating films Is a silicon nitride film, which is achieved by the method for manufacturing a liquid crystal device according to any one of the first to fourth inventions.

[0014]

In the method of manufacturing a liquid crystal device according to the present invention, a region where a channel region layer is to be formed between a region where a source electrode and a drain electrode are to be formed by photolithography using a light-shielding film on a transparent substrate as a mask. And a gate electrode is formed by photolithography using the same light-shielding film as a mask. Therefore, the source electrode and the drain electrode on both sides of the channel region layer and the gate electrode are self-aligned, so that the overlap therebetween can be reduced to the minimum necessary. Thereby, the stray capacitance between the electrodes can be reduced.

A photolithography method using a photosensitive film whose photosensitive reaction mode is reversed between a negative type and a positive type, and combining exposure from the front side and exposure from the rear side through a light shielding film from the transparent substrate side; and By the lift-off method, the source and drain electrodes and the pixel electrode facing each other with the channel region layer self-aligned with the gate electrode formed by only one formation of the photosensitive film, thereby simplifying the process. Can be achieved.

Further, using a photosensitive film whose photosensitive reaction mode is reversed between a negative type and a positive type, a photolithography method combining exposure from the front side and exposure from the back side through a light shielding film from the transparent substrate side, Since the gate electrode self-aligned with the channel region layer and the gate bus line connected to this gate electrode are formed only by forming the photosensitive film once, the process can be simplified as described above. Can be. In addition, even when a light-shielding conductive film such as a drain bus line is included and exposure from the back surface is obstructed, exposing this portion from the front surface in advance allows the photosensitive film to be formed only once. Thus, a gate electrode self-aligned with the channel region layer and a gate bus line connected to this gate electrode are formed.
The process can be simplified.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. FIGS. 1A to 7Q are diagrams illustrating a method of manufacturing a liquid crystal device (LCD) having a staggered thin film transistor (TFT) as a control element according to an embodiment of the present invention. 1 (a) and FIG.
(D), FIGS. 3 (f) to 4 (k), FIG. 6 (n), FIG.
(P) is a sectional view, FIGS. 2 (e), 5 (l), (m), 6 (o), and 7 (q) are top views, and AA in FIG. 2 (e).
FIG. 2D is a sectional view taken along the line, FIG. 6N is a sectional view taken along the line BB of FIG. 6O, and FIG. 7 is a sectional view taken along the line CC of FIG.
(P).

First, as shown in FIG. 1A, a transparent substrate 21 made of synthetic quartz is used so that backlight for driving the liquid crystal device does not shine on the channel region layer of the TFT.
A light-shielding film 22 made of a chromium (Cr) film having a thickness of about 600 ° is selectively formed in a region including a region where a channel region layer of a thin film transistor (TFT) is to be formed. At this time, the width of the light shielding film 22 is formed to be substantially the same as the width of the channel region layer to be formed. Subsequently, the insulating film 2 covering the light shielding film 22 and made of a SiO ₂ film having a thickness of about 5000 °
Form 3

Next, after a resist film (first photosensitive film) 24 whose photosensitive reaction type changes from negative type to positive type by heat treatment is formed on the insulating film 23, a pixel electrode, a source electrode, a drain electrode and a source electrode are formed. The resist film 24 in a region other than a region where a channel region layer is to be formed between the gate electrode and the drain electrode is selectively exposed using an exposure mask (first exposure mask) 25 (FIG. 1B).

Next, heat treatment is performed at a temperature of 120 ° C. for a time of 10 minutes to change the photosensitive reaction type of the resist film 24 from a negative type to a positive type (FIG. 1C). Next, using the light-shielding film 22 as a mask, the resist film 24 in the band-shaped region where the channel region layer of the TFT is to be formed is selectively exposed from the side of the transparent substrate 21 above the light-shielding film 22. At this time, the width of the non-exposed portion 26c on the light-shielding film 22 is made smaller than the width of the light-shielding film 22 by slightly exposing slightly (FIGS. 2D and 2E).

Next, when the resist film 24 is developed, it becomes a negative type resist film in the region 26b irradiated with the exposure light.
Then, the resist film in the region 26c not irradiated with the exposure light remains as a positive type resist film. That is, a resist pattern (first pattern forming film) is formed in a region where a channel region layer between a source electrode and a drain electrode is to be formed and a region other than a region where a pixel electrode, a source electrode and a drain electrode are to be formed. 24a and a resist pattern (second pattern forming film) 24b are formed (FIG. 3).
(F)).

Next, an about 500-Å thick n-type a-Si film (n.sup. ⁺ -A-Si film) doped with phosphorus by about 300 .ANG.
28 are sequentially formed on the entire surface by a plasma CVD method. Note that the two-layer conductor film of the ITO film 27 and the n ⁺ a-Si film 28 constitutes a first conductor film 39 (FIG. 3G).

Next, the remaining resist patterns 24a, 24
When b is removed, the ITO film 27 / n ⁺ a-Si other than the region where the pixel electrode, the source electrode and the drain electrode are to be formed is formed.
The film 28 is removed by lift-off together with the resist patterns 24a and 24b, and the ITO film 27a / n ⁺ a-Si film 28a
The two-layer conductor film remains in the region where the pixel electrode and the source electrode are to be formed, and the ITO film 27b / n ⁺ a-Si
The two conductor films of the film 28b remain in the region where the drain electrode is to be formed (FIG. 3 (h)).

Next, a-Si film having a thickness of about 200
And an insulating film made of a SiN film having a thickness of about 500.degree. Which becomes a part of the gate insulating film is sequentially formed by a plasma CVD method. Subsequently, an insulating film, a semiconductor layer, and n
⁺ a-Si films 28a and 28b are selectively etched to
A pixel electrode 29 composed of a TO film 27a, a source electrode 30 composed of an ITO film 27a / n ⁺ a-Si film 28c connected to the pixel electrode 29, and a source having a band-shaped region where a channel region layer of a TFT is to be formed. ITO film 27 facing electrode 30
A drain electrode 31 made of a b / n ⁺ a-Si film 28d is formed, and the semiconductor layer 32 and the drain electrode 31 are bridged so as to bridge between the opposing source electrode 30 and drain electrode 31.
The first gate insulating film 33 remains. Thus, the semiconductor layer on the source electrode 30 becomes the source region layer 32a, the semiconductor layer on the drain electrode 31 becomes the drain region layer 32b, and the semiconductor layer between the source electrode 30 and the drain electrode 31 becomes the channel region layer 32c. One completed TFT is completed.

Next, after forming a drain bus line 34 for connecting the drain electrode 31 of one TFT and the drain electrode of another TFT not shown (FIG. 4 (i)), a part of the gate insulating film is formed. A second gate insulating film 35 made of a SiN film having a thickness of about 3000 ° is formed.

Next, on the second gate insulating film 35, an IT film having a film thickness of about 3000 な る serving as a gate electrode and a gate bus line is formed.
An O film (second conductor film) 36 was formed (FIG. 4 (j)).
Thereafter, a resist film (second photosensitive film) 37 whose photosensitive reaction type changes from negative type to positive type by heating is formed on the ITO film 36 (FIG. 4 (k)).

Next, the resist film 37 in the region where the gate bus line is to be formed is selectively exposed using an exposure mask (not shown) (second exposure mask) (FIG. 5 (l)). Subsequently, heat treatment is performed under the conditions of a temperature of 120 ° C. and a time of 10 minutes to change the negative type resist film 37 into a positive type resist film 37. Here, when the exposure light is normally irradiated from the transparent substrate 21 side in the next step, the exposure light is not cast on the resist film 37 above the drain bus line 34 because the shadow is formed on the drain bus line 34. 3
When the resist 7 is developed, the resist film 37 remains in this portion. Therefore, the resist film 37 above the drain bus line 34 is exposed in advance from the front side using an exposure mask (not shown) so that it can be removed by development (FIG. 5 (m)).

Next, the resist film 37 was selectively exposed from the transparent substrate 21 side using the light shielding film 22 as a mask (FIG. 6).
After (n) and (o)), when the resist film 24 is developed, a resist 38 in a region 38b irradiated with exposure light as a negative type resist film 37 and a region 38e not irradiated with exposure light as a positive type resist film 37 are formed. The film remains. That is, a resist pattern (third pattern forming film) 37a having substantially the same size as the width of the channel region layer 32c is formed in the region where the gate electrode is to be formed, above the channel region layer 32c, and the gate bus line is formed. A resist pattern (fourth pattern forming film) 37b is formed in the region where the pattern is to be formed.

Next, the ITO film 36 is selectively etched and removed using the resist patterns 37a and 37b as masks to form a gate electrode 36a and a gate bus line 36b made of the ITO film (FIGS. 7 (p) and (q)). ). afterwards,
When a liquid crystal film (not shown) is formed on the entire surface, a liquid crystal device is completed.

As described above, according to the embodiment of the present invention,
The gap where the channel region layer 32c is formed between the source electrode 30 and the drain electrode 31 is formed by photolithography using the same light shielding film 22 as a mask.
And a gate electrode 36a on 32c. Therefore, the width of the channel region layer 32c between the source electrode 30 and the drain electrode 31 and the width of the gate electrode 36a are substantially equal, and both can be formed so as to be aligned above the light shielding film 22. Therefore, the overlap between the source electrode 30 and the drain electrode 31 and the gate electrode 36a is extremely small, so that the parasitic capacitance of the TFT element can be reduced and the speed of the liquid crystal device can be increased.

Although the exposure light is selectively irradiated from the surface on the side opposite to the transparent substrate 21 using an exposure mask, the exposure light is selectively irradiated using a device capable of narrowing the exposure light without using the exposure mask. May be irradiated.

[0032]

As described above, according to the embodiment of the present invention, a channel region layer between a region where a source electrode and a drain electrode are to be formed by photolithography using a light-shielding film on a transparent substrate as a mask. Are formed, and a gate electrode is formed by photolithography using the same light-shielding film as a mask. Therefore, since the source electrode and the drain electrode on both sides of the channel region layer are self-aligned with the gate electrode, the overlap between the source electrode, the drain electrode, and the gate electrode can be extremely reduced. Thus, the stray capacitance between the electrodes can be reduced, so that the speed of the liquid crystal device can be increased.

[Brief description of the drawings]

FIG. 1 is a diagram (part 1) for explaining a method of manufacturing a TFT active matrix LCD according to an embodiment of the present invention.

FIG. 2 is a diagram (part 2) for explaining the method of manufacturing the TFT active matrix LCD according to the embodiment of the present invention.

FIG. 3 is a diagram (part 3) for explaining the method of manufacturing the TFT active matrix LCD according to the embodiment of the present invention.

FIG. 4 is a diagram (part 4) for explaining the method of manufacturing the TFT active matrix LCD according to the embodiment of the present invention.

FIG. 5 is a view (No. 5) for explaining the method of manufacturing the TFT active matrix LCD according to the embodiment of the present invention.

FIG. 6 is a view (No. 6) explaining the method for manufacturing the TFT active matrix LCD according to the embodiment of the present invention.

FIG. 7 is a view (No. 7) for explaining the method of manufacturing the TFT active matrix LCD according to the embodiment of the present invention.

FIG. 8 is a cross-sectional view (part 1) for explaining a method of manufacturing a conventional TFT active matrix LCD.

FIG. 9 is a sectional view (part 2) for explaining the method of manufacturing the conventional TFT active matrix LCD.

FIG. 10 shows a conventional TFT active matrix LCD.
It is sectional drawing (the 3) explaining the manufacturing method of.

[Explanation of symbols]

 Reference Signs List 21 transparent substrate, 22 light shielding film, 23 insulating film, 24 resist film (first photosensitive film), 24 a resist pattern (first pattern forming film), 24 b resist pattern (second pattern forming film), 25 exposure Mask (first exposure mask), 26a, 26c, 38a, 38c, 38e Non-exposed part, 26b, 26d, 38b, 38d Exposure part, 27, 27a, 27b ITO film, 28, 28a, 28b, 28c, 28d a -Si film, 29 pixel electrode, 30 source electrode, 31 drain electrode, 32 semiconductor layer, 32a source region layer, 32b drain region layer, 32c channel region layer, 33 first gate insulating film, 34 drain bus line, 35th 2, a gate insulating film, an ITO film (second conductive film), a resist film (second photosensitive film), a resist pattern (third pattern forming film), a resist Pattern (fourth pattern forming film), 39 first conductor film.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-47981 (JP, A) JP-A-1-151271 (JP, A) JP-A-4-282267 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 29/786 G02F 1/1368 H01L 21/336 H01L 27/12

Claims (5)

(57) [Claims] A step of forming an insulating film after selectively forming a light shielding film on a transparent substrate; and a step of forming an insulating film on the insulating film above the light shielding film by photolithography using the light shielding film as a mask. Forming a first pattern formation film selectively in a region where a channel region layer is to be formed between the regions where the source electrode and the drain electrode are to be formed, and a photolithography method using a first exposure mask. A step of selectively forming a second pattern forming film on a region other than a region where a pixel electrode, a source electrode, and a drain electrode are to be formed on the insulating film; and the first and second patterns Forming a first conductor film that transmits exposure light on the insulating film via a formation film; removing the first and second pattern formation films and lifting off the first conductor film; From the membrane Forming a pixel electrode, a source electrode, and a drain electrode, and selectively forming a semiconductor layer and a first gate insulating film so as to bridge the source electrode and the drain electrode, and a drain connected to the drain electrode. A step of forming a bus line; a step of sequentially forming a second gate insulating film and a second conductor film that transmits exposure light on the first gate insulating film; and using the light shielding film as a mask Forming a third pattern forming film on the second conductive film above the light shielding film by photolithography, and forming a gate bus line by photolithography using a second exposure mask; Forming a fourth pattern forming film on the second conductive film, and etching the second conductive film using the third and fourth pattern forming films as a mask. Forming a gate electrode made of the second conductive film on the second gate insulating film and a gate bus line connected to the gate electrode on the second gate insulating film. 2. The method according to claim 1, wherein the step of forming the first and second pattern forming films includes, on the insulating film, a first photosensitive film in which the type of photosensitive reaction is reversed between a negative type and a positive type by heat treatment. A step of forming, from a surface side opposite to the transparent substrate, a region above a pixel electrode, a source electrode, a drain electrode, and a light-shielding film other than a region where a channel region layer between the source electrode and the drain electrode is to be formed; Selectively irradiating the first photosensitive film in the region with exposure light, and performing heat treatment to reverse the photosensitive reaction mode of the first photosensitive film; and forming the transparent substrate using the light-shielding film as a mask. The first from the side
After selectively irradiating the photosensitive film with exposure light, the first photosensitive film is developed, and a region on the insulating film on which a channel region layer above the light shielding film is to be formed, Forming a first and a second pattern forming film in a region other than a region where the pixel electrode, the source electrode, and the drain electrode are to be formed, respectively. Method. 3. The step of forming the third and fourth pattern forming films, wherein a second type of photosensitive reaction is reversed between a negative type and a positive type by heat treatment on the second conductive film. Forming a photosensitive film; and selectively irradiating exposure light to the second photosensitive film in a region where the gate bus line is to be formed, followed by heat treatment to perform a photosensitive reaction of the second photosensitive film. A step of inverting the format, and selectively irradiating the region above the drain bus line with exposure light, and selectively exposing the second photosensitive film from the transparent substrate side to the second photosensitive film using the light shielding film as a mask. After the irradiation, the second photosensitive film is developed to form a region on the second conductor film where a gate electrode is to be formed above the light-shielding film and the gate bus line is to be formed. Third and fourth patterns in the area respectively 3. A method for manufacturing a liquid crystal device according to claim 1, further comprising the step of: 4. The method according to claim 3, wherein the drain bus line is a light-shielding conductive film such as an Al film. 5. The first conductive film is an ITO film / n ⁺ a
2. The semiconductor device according to claim 1, wherein the second conductive film is an ITO film, and the first and second gate insulating films are silicon nitride films. 5. The method for manufacturing a liquid crystal device according to claim 2, wherein