JP6295543B2 - Liquid crystal display device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a liquid crystal display device and a method for manufacturing the same.

  In recent years, liquid crystal display devices are required to have excellent display characteristics such as high contrast and very wide viewing angle characteristics, and a fringe field switching (FFS) mode has been proposed as a liquid crystal display mode that satisfies them.

  A normal liquid crystal display device has a structure in which a liquid crystal material is sandwiched between two transparent electrode substrates, and a voltage is applied between the two substrates to cause the liquid crystal material to respond and display. On the other hand, in an FFS mode liquid crystal display device, two layers of electrodes are formed on the same substrate with an insulating film interposed between the lower electrode of the insulating film and the upper electrode of the insulating film between the slit-shaped electrodes. A voltage is applied to the liquid crystal material, and the liquid crystal material is caused to respond by a horizontal electric field concentrated on the peripheral portion of the slit-shaped electrode to perform display.

  An example of the configuration of the transparent substrate used in the FFS mode liquid crystal display device will be described. A plurality of gate lines are formed on the transparent substrate surface, and a plurality of signal lines orthogonal to the gate lines are formed via the first insulating film. Next, a thin film transistor is formed as a switching element near the intersection of the gate wiring and the signal wiring. This thin film transistor is obtained by etching a semiconductor film made of silicon to form a channel region for controlling the flow of electrons.

  After that, an interlayer insulating film is formed on the entire surface, and a second through hole is formed at a position corresponding to the connection region between the first through hole and the drain electrode at a position corresponding to the channel region of the thin film transistor. Each through hole is common in that the through hole is formed in the interlayer insulating film, but the first through hole does not maintain electrical connection with the lower layer, and is protected in the channel region located in the lower layer The second through hole is used to electrically connect the drain electrode in the lower layer of the interlayer insulating film and the pixel in the upper layer.

  A pixel electrode electrically connected to the drain electrode of the thin film transistor is formed on the interlayer insulating film through the second through-hole, and a second insulating film is formed on the pixel electrode. This second insulating film covers the pixel electrode and functions not only as an insulating film between the uppermost common electrode but also on the channel region of the thin film transistor exposed from the first through hole of the interlayer insulating film. And used as a protective film of a thin film transistor. Finally, a common electrode is formed on the uppermost layer. An FFS mode liquid crystal display device using such a thin film transistor substrate has been proposed (for example, Patent Document 1).

JP 2009-162981 A

  In the thin film transistor substrate used in the liquid crystal display device disclosed in Patent Document 1, a step of forming a channel region in a semiconductor film by etching and a step of forming a through hole at a position corresponding to the channel region of the interlayer insulating film are different steps. It is. Therefore, when the second insulating film is formed as a protective film in the channel region via the first through-hole formed in the interlayer insulating film, it is difficult to align the first through-hole and the channel region, and the position shift In consideration of this, the through hole is formed larger than the channel region. In other words, it is necessary to make the through hole larger than necessary. Therefore, the display area of the pixel area is reduced, and the aperture ratio, which is the ratio of the area of the transmissive area for display to the entire area of the display area, cannot be increased. In a display device using this thin film transistor substrate, display Has the problem of darkening.

  The present invention has been made to solve such a problem, and includes performing a process of forming a first through hole in an interlayer insulating film of a thin film transistor substrate and a process of forming a channel region in a semiconductor film in a series of processes. Thus, an insulating film can be formed as a protective film in the channel region without taking into account the size shift and the position shift between the first through hole and the channel region. Therefore, a transmissive region of a pixel is not wasted, and in a display device using this thin film transistor substrate, a bright liquid crystal display device with a high aperture ratio can be obtained.

  The liquid crystal display device of the present invention includes a transparent substrate made of a transparent material, a gate electrode made of a first metal film formed on the transparent substrate, a first insulating film covering the gate electrode, and a first insulating film A semiconductor film covering the gate electrode, an n + semiconductor film covering the semiconductor film, a second metal film covering the n + semiconductor film, an interlayer insulating film covering the second metal film, an interlayer insulating film, A first through hole penetrating the second metal film, the n + semiconductor film, and a part of the semiconductor film; a surface exposed at a bottom surface of the first through hole; and a gate electrode through the first insulating film A channel region of the facing semiconductor layer; a thin film transistor portion comprising: a semiconductor film formed on the first insulating film; a second metal film covering the n + semiconductor film; the n + semiconductor film; and a second metal film. Covering interlayer insulating film, interlayer insulating film, second metal film, n + semiconductor film, and half A pixel contact hole portion including a second through hole penetrating a part of the body film, a connection region formed on a bottom surface of the second through port, and a connection region of the pixel contact hole portion; A first display electrode formed on the interlayer insulating film via the two through holes, and a second insulation covering the channel region of the thin film transistor portion and covering the first display electrode via the first through hole. The display unit includes a film and a second display electrode that covers the second insulating film.

  In the liquid crystal display device of the present invention, since the through hole formed in the interlayer insulating film of the thin film transistor substrate and the channel region formed in the semiconductor film are directly connected without deviation, the positional deviation between the through hole of the interlayer insulating film and the channel region of the thin film transistor, In consideration of the size shift, a bright display with a high aperture ratio can be obtained without wasting the transmission region of the pixel.

It is a top view of the pixel which concerns on Embodiment 1 and 2 of this invention. It is a cross-sectional schematic diagram of the thin-film transistor substrate which concerns on Embodiment 1 of this invention. It is process drawing of the thin-film transistor substrate which concerns on Embodiment 1 of this invention. It is process drawing of the thin-film transistor substrate which concerns on Embodiment 1 of this invention. It is a cross-sectional schematic diagram of the thin-film transistor substrate which concerns on Embodiment 2 of this invention. It is process drawing of the thin-film transistor substrate which concerns on Embodiment 2 of this invention. It is process drawing of the thin-film transistor substrate which concerns on Embodiment 2 of this invention.

  In the description of the embodiments and the respective drawings, the portions denoted by the same reference numerals indicate the same or corresponding portions.

Embodiment 1 FIG.
<Structure of thin film transistor substrate>
Embodiments of the present invention will be described below with reference to the drawings. First, the structure of the thin film transistor substrate used in the liquid crystal display device according to the present invention will be described.

  FIG. 1 is a plan view showing a pixel portion of a fringe field switching (FFS) mode liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a transparent substrate on which a thin film transistor of line AA in FIG. It is the cross-sectional schematic diagram which showed the figure typically. In the case of forming a liquid crystal display device, a structure in which a transparent substrate on which a thin film transistor is formed and a transparent substrate on which a color filter or the like is formed as a counter substrate is used, an alignment film is formed on the surfaces of both substrates, and the liquid crystal material is sandwiched between them. Is necessary.

  It is also necessary to perform an alignment treatment that imparts a function of aligning the liquid crystal material to the alignment film. However, since the present invention is characterized by the thin film transistor substrate among the liquid crystal display devices, the thin film transistor substrate will be described in detail here, and only the outline of the structure and the like of the liquid crystal display device will be described.

  Note that the drawings used in the description in this specification, including these drawings, do not accurately indicate the film thickness, length, etc., but are simplified for easy understanding. In addition, the scales in the vertical and horizontal directions do not necessarily reflect the actual configuration and dimensions.

  FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. 1, and corresponds from the bottom to the top of the line AA in FIG. 1 from the left to the right in FIG. Therefore, in FIG. 2, the left side is a thin film transistor portion that is a switching element, and shows the first through hole 4 of the thin film transistor portion, and the center is a second region that connects the connection region 18 of the drain electrode 2 and the pixel electrode 3. The pixel contact hole portion in which the through-hole 6 is formed, and the right side shows a display portion in which a slit shape is formed in the uppermost common electrode 5. Although not shown in FIG. 2, as shown in FIG. 1, the common wiring 7 is formed in the horizontal direction above the pixel region, and the slit-shaped common electrode 5 and the common electrode opening at the top of the pixel are formed. 8 is electrically connected.

  As shown in the schematic sectional view of FIG. 2, a gate electrode 9 made of a first metal film is formed on a glass substrate, and a gate insulating film 10 as a first insulating film is formed on the entire surface thereof. . The gate electrode 9 was made of Mo / Al, and the gate insulating film 10 was made of silicon nitride. A semiconductor film 11 made of an amorphous silicon (a-Si) layer and an n + semiconductor film 17 (n + a-Si layer) are formed on the gate insulating film 10, and a source connected to the signal wiring 12 is formed above the semiconductor film. A drain electrode 2 for applying a voltage to the electrode 13 and the pixel electrode 3 is formed.

  An interlayer insulating film 15, which is a photosensitive organic material, is formed on the substrate surface, and the interlayer insulating film 15 is exposed and developed to connect the first through hole 4 and the drain electrode 2 at a position corresponding to the channel region 14. A second through-hole 6 is formed at a position corresponding to the region 18, and a common electrode opening 8 for connecting the common wiring 7 and the common electrode 5 (not shown in FIG. 2) is formed.

  Using the first through-hole 4 and the second through-hole 6 as an etching mask, a channel region 14 and a connection region 18 are formed, respectively. Next, a first electrode (pixel electrode 3) is formed on the interlayer insulating film 15 from the connection region 18 through the second through-hole 6 and covered with the second insulating film. Since the process of forming the first through hole 4 in the interlayer insulating film 15 and the process of forming the channel region 14 in the semiconductor film 11 and the like are performed in series, the first through hole 4 and the channel region 14 are the same. It can be set as the structure penetrated by the diameter.

  A common electrode 5 is formed on the uppermost layer. In the present embodiment, the common electrode 5 is used as a slit shape in which a plurality of windows are formed. However, the common electrode 5 can also be used as a comb shape, and is not limited to a slit shape or a comb shape. Any shape can be used.

  A voltage for driving the liquid crystal material is applied between the pixel electrode 3 and the common electrode 5, and a fringe electric field is applied to the peripheral portion of the slit-shaped electrode through a window formed in the common electrode 5. A liquid crystal display device can be obtained by sandwiching a liquid crystal material using the thin film transistor substrate described above and a counter substrate on which a color filter or the like is formed, and the liquid crystal material is caused to respond by the fringe electric field to obtain a display. Can do.

<Configuration of liquid crystal display device>
The thin film transistor substrate thus manufactured and the color filter substrate, which is a counter substrate, are arranged to face each other, an alignment film is formed on the inner surface side of each substrate, a rubbing process is performed in a predetermined direction, and a liquid crystal material is sandwiched between them. Thus, a liquid crystal display device was obtained. Since this liquid crystal display device can display in FFS mode, the viewing angle is very wide, and the channel region 14 is covered with silicon nitride through the first through-hole 4 and protected, so that the reliability is high. high. Further, since the channel region 14 and the first through hole 4 of the interlayer insulating film 15 and the connection region 18 of the drain electrode 2 and the second through hole 6 are formed in a series of steps, misalignment and size deviation are considered. There is no need to use the pixel transmissive region, and a bright display with a high aperture ratio can be obtained.

  Furthermore, since the number of steps can be reduced as compared with the conventional manufacturing steps, a low-cost liquid crystal display device can be obtained. In addition, since the first through-hole 4 and the channel region 14 of the interlayer insulating film 15 are formed in a series of steps, the first through-hole 4 and the channel region 14 are directly connected without deviation, and a step, unevenness, etc. are formed at the boundary portion. Since the protective film of the channel region 14 made of silicon nitride can be formed with good adhesion, the reliability of the channel region 14 is significantly higher than that of the normal insulating film.

  In the present embodiment, the structure in which the pixel electrode 3 is the lower layer and the common electrode 5 is formed on the upper layer through the interelectrode insulating film 16 is shown. However, the positional relationship between the pixel electrode 3 and the common electrode 5 is not limited to this, and the same effect can be obtained by forming the slit shape in the pixel electrode 3 with the common electrode 5 as the lower layer and the upper layer.

<Manufacture of thin film transistor substrate>
FIGS. 3A to 3E and FIGS. 4F to 4H show a method for manufacturing the thin film transistor substrate shown in FIG. A method of manufacturing a thin film transistor substrate will be described in order with reference to FIGS.
First, a first metal film composed of a two-layer film of Mo / Al is formed on one surface of a glass substrate which is a transparent insulating substrate. A photoresist made of a photosensitive resin is applied onto the first metal film by spin coating and then dried to form a photoresist film, and the photoresist is patterned by exposure and development. Using this patterned photoresist as an etching mask, the first metal film is patterned to form a gate electrode 9 made of a Mo / Al two-layer film (first photolithography process: FIG. 3A). Although not shown in FIG. 3A, the common wiring 7 connected to the common potential is also formed in the same process.

Next, a gate insulating film 10 made of silicon nitride, a semiconductor film 11 made of amorphous silicon (a-Si), and phosphorus-doped amorphous silicon (n) are formed by plasma CVD so as to cover the glass substrate on which the gate electrode 9 and the like are formed. ^An n + semiconductor film 17 made of a ( ⁺ a-Si) film is successively formed. A photoresist having photosensitivity is applied by spin coating on the semiconductor film 11 and the like, dried, further exposed and developed to pattern the photoresist film. The semiconductor film 11 and the like are etched using the patterned photoresist as an etching mask (second photolithography process: FIG. 3B).

  A three-layer second metal film made of Mo / Al / Mo is formed by sputtering so as to cover the glass substrate on which the pattern of the semiconductor film 11 and the like is formed. A photoresist film having photosensitivity is formed on the second metal film, and exposure and development are performed to pattern the photoresist film. The second metal film is etched using the patterned photoresist film as an etching mask, and the source electrode 13 and the drain electrode 2 are formed on the semiconductor film 11 and the like (the source electrode 13 and the drain electrode 2 remain integrated at this stage). (Third photolithography step: FIG. 3C). Although not shown in the drawing in this step, the signal wiring 12 is formed at the same time.

  A planarizing film (interlayer insulating film 15) made of acrylic resin having photosensitivity is applied by spin coating so as to cover the glass substrate on which the drain electrode 2 (including the source electrode 13) is formed and dried (FIG. 3). (D)). Further, exposure and development are performed to form the first through hole 4 corresponding to the channel region 14 formed in the semiconductor film 11 and the second through hole 6 corresponding to the connection portion 18 formed in the drain electrode 2.

The drain electrode 2, the n + semiconductor film 17 (n ⁺ a-Si film), and the semiconductor film 11 exposed through the first through-hole 4 and the second through-hole 6 in the interlayer insulating film 15 are etched (fourth fourth). Photolithographic process: FIG. 3 (e)). In this step, although not shown in the drawing, the common electrode opening 8 is also formed in the common wiring 7 portion.

  The etching of the channel region 14 exposed through the first through hole 4 of the interlayer insulating film 15 will be described in detail. Using the first through hole 4 as an etching mask, the drain electrode 2 (including the source electrode 13) is first etched by a wet etching method, and then the semiconductor film 11 and the like are etched by a dry etching method to form a channel region 14. . In the dry etching process of the semiconductor layer 11 and the like, the inner wall of the first through hole 4 is slightly etched and retreats simultaneously. Therefore, a slight step is formed between the interlayer insulating film 15 in the first through hole 4 and the drain electrode 2 (including the source electrode 13) on the semiconductor film 11.

  That is, the size of the first through-hole 4 is larger than that of the channel region 14 at the portion where the first through-hole 4 and the channel region 14 are in contact with each other. However, the difference is slight, which is very small compared to the positional deviation and size deviation when the formation of the first through-hole 4 and the channel region 14, which is the subject of the present invention, is a separate process. Not enough to change. In other words, the size of the first through hole 4 and the size of the channel region 14 can be found by performing precise measurement, but can be said to be substantially the same size within the scope of the object of the present invention. .

  Similarly, the second through hole 6 has a connection region 18 formed in the drain electrode using the second through port 6 as an etching mask, and the connection region 18 of the drain electrode 2 and the pixel electrode 3 are connected to each other. The size of the connection region 18 between the through hole 6 and the drain electrode 2 is substantially the same within the scope of the object of the present invention.

  Therefore, the opening length in the channel direction of the first through-hole 4 of the interlayer insulating film 15 can be said to be the same as the channel length, and the opening length of the first through-hole 4 in the direction perpendicular to the channel direction is Can be said to be the same as the channel width. Therefore, in consideration of misalignment and the like, the first through hole 4 larger than necessary is not formed, and the transmission region of the pixel is not wasted, so that a display with a high aperture ratio can be obtained.

  In the process of etching the drain electrode 2 and the etching of the semiconductor film 11, an ashing process is additionally performed, the interlayer insulating film 15 is retracted by ashing, and the upper surface of the drain electrode 2 is exposed. By opening the second through hole 6 slightly larger, the pixel electrode 3 connected to the drain electrode 2 to be formed in the next step is not only the end side surface of the connection region 18 formed in the drain electrode 2 but also the drain electrode. 2 can be connected to the upper surface portion, and the contact area can be increased, so that the reliability of connection of the pixel electrode 3 can be increased.

  A first transparent conductive film is formed by sputtering so as to cover the entire surface of the transparent substrate in which the second through-hole 6 and the like are formed in the interlayer insulating film 15. As the transparent conductive film material, ITO (Indium Tin Oxide) was used. IZO (Indium Zinc Oxide) or the like can also be used. A photosensitive photoresist is applied on the transparent conductive film, dried, exposed and developed, and the transparent conductive film is etched using the patterned photoresist as an etching mask (fifth photolithography step: FIG. 4F). ). In this process, the pixel electrode 3 can be formed.

  Next, a second insulating film is formed by plasma CVD so as to cover the entire surface of the transparent substrate on which the pixel electrode 3 made of a transparent conductive film is formed. This second insulating film was made of silicon nitride. A photosensitive photoresist film was formed on the second insulating film, an etching mask patterned by exposure and development was formed, and the second insulating film was patterned (sixth photolithography process: FIG. 4 ( g)). This second insulating film functions as an interelectrode insulating film 16 between the pixel electrode 3 and the common electrode formed in the next step, and at the same time, covers the channel region 14 and functions as a channel protective film to improve reliability. Have

  Next, a second transparent conductive layer was formed by a sputtering method so as to cover the transparent substrate on which the second insulating film was formed. This transparent conductive layer also used ITO. A photoresist film was formed on the second transparent conductive layer, patterned by exposure and development, and an etching mask was formed to pattern the second transparent conductive layer (seventh photolithography step: FIG. 4 ( h)). Through this process, the slit-shaped common electrode 5 for applying an electric field to the pixel electrode is formed.

<Production of liquid crystal display device>
The thin film transistor substrate thus manufactured and the color filter substrate, which is a counter substrate, are arranged to face each other, an alignment film is formed on the inner surface side of each substrate, a rubbing process is performed in a predetermined direction, and a liquid crystal material is sandwiched between them. Thus, a liquid crystal display device was obtained. This liquid crystal display device can display in the FFS mode, so that the viewing angle is very wide, and the channel region 14 is covered and protected by silicon nitride, so that the reliability is high.

  The formation of the channel region 14 and the connection region 18 and the formation of the first through-hole 4 and the second through-hole 6 of the interlayer insulating film 15 are performed in a series of steps, and the first through-hole 4 and the second through-hole are formed. Since the channel region 14 and the connection region 18 are formed using the opening 6 as an etching mask, it is not necessary to consider a margin for alignment, and the transmission region of the pixel is not wasted, so that a high aperture ratio can be achieved. . Furthermore, since the number of steps can be reduced as compared with the conventional manufacturing steps, a low-cost liquid crystal display device can be obtained. In addition, the channel region 14 is protected by silicon nitride because the first through hole 4 and the channel region 14 of the interlayer insulating film 15 are formed in a series of steps. Since there is no step, unevenness, etc. at the boundary portion, and the protective film can be formed with good adhesion, the reliability is very high compared to the protection of the channel region by a normal insulating film.

Embodiment 2. FIG.
FIG. 5 is a schematic cross-sectional view schematically showing a cross-sectional view of the transparent electrode substrate on which the thin film transistor according to the present embodiment is formed, and shows the AA line portion of the plan view of the pixel portion shown in FIG. is there. 6 (a) to 6 (e) and FIGS. 7 (f) to (h) show steps for obtaining the structure shown in FIG.

  The cross-sectional schematic diagram (FIG. 5) of the thin film transistor substrate according to the present embodiment is different from the cross-sectional schematic diagram (FIG. 2) of the thin film transistor substrate of the first embodiment in the connection method of the drain electrode 2 and the pixel electrode 3. In the first embodiment, the pixel electrode 3 is connected to the connection region 18 of the etched drain electrode 2, whereas in the present embodiment, the drain electrode 2 is left as it is, and the pixel electrode 3 is formed thereon. Since they are formed, the contact area between the electrodes can be increased, and a stable connection can be achieved.

  Hereinafter, the manufacturing process of the thin film transistor substrate according to the present embodiment will be described with reference to FIGS.

  Since the process of forming the gate electrode 9 and the gate insulating film 10 on the transparent substrate is the same as that of the first embodiment, the details are omitted. As in the first embodiment, a first metal film is formed on a transparent substrate, and a gate electrode 9 is formed by a first photolithography process (FIG. 6A). A gate insulating film 10 made of silicon nitride is formed on the entire transparent substrate on which the gate electrode 9 is formed, and a semiconductor film 11, an n + semiconductor film 17, and a second metal film are formed on the gate insulating film 10. Here, the n + semiconductor film 17 refers to an impurity in order to form a good electrical connection by preventing generation of a Schottky barrier between the semiconductor film 11 and the second metal film. And is also referred to as an ohmic contact film.

  An etching mask is formed using a photosensitive photoresist, the second metal film, the n + semiconductor film 17 and the semiconductor film 11 are etched into the same shape, and the semiconductor film 11, the n + semiconductor film 17 and the drain electrode 2 thereon are formed. A second electrode to be the source electrode 13 is formed (second photolithography process: FIG. 6B).

  Next, a photosensitive resin made of an organic material is uniformly applied on the transparent substrate so as to cover the whole, and an interlayer insulating film 15 is formed (FIG. 6C). The interlayer insulating film 15 is exposed, The first through-hole 4 and the second through-hole 6 of the thin film transistor portion that are developed and the common electrode through-hole portion that is not shown in FIG. 5 but is in electrical contact with the common wiring 7 and the common electrode 5 8 are formed at the same time (third photolithography step: FIG. 6D).

  In this photolithography process, the second through-hole 6 is controlled by using a gray tone mask so that the exposure does not proceed more than other portions. At this time, in the second through-hole 6 using the gray tone mask, the interlayer insulating film remains thin at the bottom. The remaining interlayer insulating film is removed by ashing to expose the surface of the drain electrode 2. The first through-hole 4 is etched under the same conditions as in the first embodiment, and the second metal film and the n + semiconductor film 17 are formed in a series of steps by producing the first through-hole 4 of the interlayer insulating film 15. (FIG. 6 (e)).

  Here, the gray tone mask is a general term for a mask using an intermediate transmittance, and includes a method of adjusting the aperture ratio with a fine pattern, a method of using a pattern in which the transmittance of the film itself is adjusted, and the like. It includes what is called a stack drain mask, a slit mask or the like.

  Since the formation of the through-hole 6 and the like of the interlayer insulating film 15 and the formation of the channel region 14 of the semiconductor layer 11 are performed in a series of steps, the alignment of the first through-hole 4 and the channel region 14 is not necessary, Since there is no need to consider a margin, a transmissive area of a pixel is not wasted and display with a high aperture ratio is possible.

  Next, a first transparent electrode film is formed by a sputtering method so as to cover the entire surface of the substrate, and is patterned by a fourth photolithography process (FIG. 7F) using a photosensitive photoresist to form pixel electrodes. 3 was formed. Here, ITO was used as the transparent electrode film. The connection area between the drain electrode 2 and the pixel electrode 3 is wide, and electrical reliability can be improved.

  Formation of the interelectrode insulating film 16 after the pixel electrode 3 is formed (fifth photolithography process: FIG. 7G), and formation of the common electrode 5 on the insulating film (sixth photolithography process: FIG. 7) Since h)) is the same as that of the first embodiment, it is omitted.

  The thin film transistor substrate thus manufactured and the color filter substrate, which is a counter substrate, are arranged to face each other, an alignment film is formed on the inner surface side of each substrate, a rubbing process is performed in a predetermined direction, and a liquid crystal material is sandwiched between them. Thus, a liquid crystal display device was obtained. This liquid crystal display device has a very wide viewing angle because it can perform FFS mode display, and has high reliability because the channel region is covered and protected by silicon nitride. In addition, since the formation of the first through-hole 4 and the channel region 14 in the interlayer insulating film 15 are performed in a series of the same process, it is not necessary to consider the alignment margin, and the transmission region of the pixel is wasted. Therefore, a high aperture ratio can be achieved, and the number of processes can be reduced as compared with the conventional manufacturing process, so that a low-cost liquid crystal display device can be obtained.

  Further, in the liquid crystal display device described in this embodiment, the connection between the drain electrode 2 and the pixel electrode 3 is highly reliable, and a highly reliable liquid crystal display device can be obtained. In addition, the channel region 14 is protected by silicon nitride because the first through hole 4 and the channel region 14 of the interlayer insulating film 15 are formed in a series of steps. Since there is no step, unevenness, etc. at the boundary portion, and the protective film can be formed with good adhesion, the reliability is very high compared to the protection of the channel region by a normal insulating film.

  In the present embodiment, the structure in which the pixel electrode 3 is the lower layer and the common electrode 5 is formed on the upper layer through the interelectrode insulating film 16 is shown. However, the positional relationship between the pixel electrode 3 and the common electrode 5 is not limited to this, and the same effect can be obtained by forming the slit shape in the pixel electrode 3 with the common electrode 5 as the lower layer and the upper layer.

  Within the scope of the present invention, the present invention can be freely combined with each other, or can be appropriately modified or omitted.

  DESCRIPTION OF SYMBOLS 1 Thin-film transistor (TFT), 2 drain electrode, 3 pixel electrode, 4 1st through-hole, 5 common electrode, 6 2nd through-hole, 7 common wiring, 8 common electrode opening part, 9 gate electrode, 10 gate insulating film , 11 semiconductor film, 12 signal wiring, 13 source electrode, 14 channel region, 15 interlayer insulating film, 16 inter-electrode insulating film, 17 n + semiconductor film, 18 connection region, 19 gate wiring

Claims (16)

A transparent substrate made of a transparent material;
A gate electrode made of a first metal film formed on a transparent substrate;
A first insulating film covering the gate electrode;
A semiconductor film on the first insulating film and covering the gate electrode;
An n + semiconductor film covering the semiconductor film;
A second metal film covering the n + semiconductor film;
An interlayer insulating film covering the second metal film ,
A channel region formed through the second metal film, the n + semiconductor film, and a part of the semiconductor film;
A thin film transistor portion in which a first through hole penetrating the interlayer insulating film is formed in the interlayer insulating film continuously with the channel region ;
The semiconductor film formed on the first insulating film, the n + semiconductor film, the second metal film covering the n + semiconductor film, and an interlayer insulating film covering the second metal film ,
A connection region formed through the second metal film, the n + semiconductor film, and a part of the semiconductor film;
A second contact hole penetrating the interlayer insulating film is formed in the interlayer insulating film continuously with the connection region ;
Covering the connection area of the pixel contact hole portion, a first display electrode formed on the interlayer insulating film through said second through hole,
A second insulating film that covers the channel region of the thin film transistor portion and covers the first display electrode through the first through hole;
A liquid crystal display device comprising: a second display electrode that covers the second insulating film; and a display unit including the second display electrode. The liquid crystal display device according to claim 1, wherein the second display electrode has a comb shape. The liquid crystal display device according to claim 1, wherein the second display electrode has a slit shape. 4. The liquid crystal display device according to claim 1, wherein the interlayer insulating film is made of an organic insulating material. The liquid crystal display device according to claim 4, wherein the organic insulating material has photosensitivity. 6. The liquid crystal display device according to claim 1, wherein an opening length of the first through hole in a channel direction is the same as a channel length. 7. 7. The liquid crystal display device according to claim 1, wherein an opening length in a direction perpendicular to a channel direction of the first through-hole is the same as a channel width. The liquid crystal display device according to claim 1, wherein the first display electrode and the second display electrode are made of a transparent conductive material. Forming a first metal film on a transparent substrate and patterning to form a gate electrode;
Forming a first insulating film, a semiconductor film, and an n + semiconductor film covering the gate electrode in order, and patterning the semiconductor film and the n + semiconductor film;
Forming and patterning a second metal film;
Forming an interlayer insulating film covering the second metal film;
Forming a first through hole and a second through hole penetrating the interlayer insulating film;
Etching the second metal film, the n + semiconductor film, and a part of the semiconductor film under the first through hole to form a channel region at a position corresponding to the gate electrode;
Etching the second metal film, the n + semiconductor film, and a part of the semiconductor film under the second through hole to form a connection region where the second metal film is exposed;
A step of forming the connecting region covers, the second first display electrode through the through hole Ru is formed on the interlayer insulating film,
Forming a pre-Symbol covering the channel region, a second insulating film of the first through the through-hole covering the first display electrodes above,
Forming a second display electrode covering the second insulating film. A method for manufacturing a liquid crystal display device. The method for manufacturing a liquid crystal display device according to claim 9, wherein the second display electrode forms a comb-teeth shape. The method for manufacturing a liquid crystal display device according to claim 9, wherein the second display electrode forms a slit shape. The method of manufacturing a liquid crystal display device according to claim 9, wherein the interlayer insulating film is made of an organic insulating material having photosensitivity. The method for manufacturing a liquid crystal display device according to claim 9, wherein an opening length of the first through hole in a channel direction is the same as a channel length. 14. The liquid crystal display device manufacturing method according to claim 9 , wherein an opening length in a direction perpendicular to the channel direction of the first through holes is the same as a channel width. 15. Method. The method for manufacturing a liquid crystal display device according to claim 9, wherein the first display electrode and the second display electrode are formed using a transparent conductive material. The method according to any one of claims 9 to 15, characterized in that the formation of the connection region with the formation of the channel region at the same time.

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