JP2002357848A - Reflective liquid crystal display device, image display device, and portable information terminal device - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To produce an array substrate of a reflective or transflective thin film transistor for a liquid crystal display device, a reflective electrode or a concavo-convex layer for scattering reflected light in a process of manufacturing a transmissive thin film transistor array substrate. It is necessary to add a step of forming a slab, which is a major problem in terms of cost. SOLUTION: At the same time as forming a contact hole for contacting a 13b semiconductor film contact layer of an A transistor portion with a 17a source electrode film and a 17b drain electrode,
By forming a hole also in the B pixel electrode portion, a 16b scattering uneven film is formed. At this time, a good selectivity can be obtained by using a 13b semiconductor film contact layer as an etching stopper for forming holes in the 16b scattering uneven film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, an image display application device using the same, and a portable information terminal device.

[0002]

2. Description of the Related Art Heretofore, several configurations of transmission type, reflection type and transflective type thin film transistor array substrates for liquid crystal display devices have been proposed. In a general manufacturing process of an array substrate of a thin film transistor, a pixel electrode portion is formed after a transistor forming process. In the transmission type, a transparent electrode is formed in order to form a pixel electrode. On the other hand, in the reflection type, a concave and convex shape for reflected light scattering is formed on the reflective electrode and an insulating film material having a thickness of 0.5 to 3 μm below the reflective electrode. It is necessary to form a layer. In the case of the transflective type, it is necessary to further form a transparent electrode after forming the reflective electrode. Here, the reason why the uneven film for scattering the reflected light is formed is to increase the viewing angle of the reflective liquid crystal display device by scattering and reflecting the light incident on the pixel electrode from the outside.

FIG. 2 shows a cross-sectional structure of an A transistor portion, a B pixel electrode portion, and a C storage capacitor portion of a conventional transflective thin film transistor array substrate. Here, an example using a top gate type polysilicon thin film transistor will be described. I do.
In FIG. 2, the manufacturing process of the A transistor portion is such that a base insulating film 22 and a semiconductor film 23 are deposited on a glass substrate 21,
23 A pattern of a semiconductor film is formed. Next, a 24 gate insulating film and a 25a gate electrode film are formed. In an ordinary polysilicon thin film transistor, an N-type or P-type transistor is formed by separating a 23 semiconductor film into a 23b contact layer formed by ion doping of phosphorus or boron using a 23a channel layer and a 25a gate electrode film as a mask. Next, after the formation of the 26 interlayer insulating film, a contact hole is formed by etching in order to contact the 23b semiconductor film contact portion with the 27a source electrode film and the 27b drain electrode. After the formation of the source electrode film 27, an insulating film 28a (protective film) for protecting electrodes and transistors is formed.
The transistor section is completed. Further, the B pixel electrode portion is formed to have irregularities for scattering the reflected light of the pixel portion.
b Insulating film (concavo-convex film for scattering) is formed, 29 reflection electrode film,
It is obtained by forming a 30 transmission electrode film. Since the example of FIG. 2 is a semi-transmissive type, 29 reflective electrode films and 30 transmissive electrode films are mixed in the B pixel electrode portion. . In the case of a general top gate transmission type thin film transistor array substrate, a transparent electrode film is formed as a final step on the 28 protective insulating film in FIG. The C storage capacity part is 25
b. It is composed of 26 interlayer insulating films between the adjacent pixel gate electrode and the 29 reflecting electrode film and the 30 transmitting electrode film.

[0004]

However, in order to fabricate a reflective or semi-transmissive thin film transistor array substrate for a liquid crystal display device, it is necessary to include a reflective electrode and unevenness for scattering reflected light in the manufacturing process of the transmissive thin film transistor array substrate. It is necessary to add a step of forming a layer, which is a major issue in terms of cost.

In view of such circumstances, the present invention greatly simplifies the number of steps for manufacturing an array substrate of a reflection type and a transflective type thin film transistor for a liquid crystal display device as compared with the conventional structure, and reduces the materials used. Accordingly, it is an object of the present invention to provide a reflective liquid crystal display element capable of forming an inexpensive thin film transistor array substrate having a short lead time and a display device using the same.

[0006]

In order to solve the above-mentioned problems, an uneven film for scattering reflected light of a pixel electrode portion for reflection is formed simultaneously with formation of a contact hole in a transistor portion and the like. Further, the reflective electrode film of the reflective pixel electrode portion is formed simultaneously with the source electrode film.

The reflection type liquid crystal display element of the present invention is characterized in that the underlying layer forming the uneven shape for scattering the reflected light of the reflection type pixel electrode portion is an interlayer insulating film between the gate electrode and the source electrode. .

Further, the reflection type liquid crystal display element of the present invention is characterized in that the shape of the underlayer of the reflection type pixel electrode according to the first aspect is formed simultaneously with the formation of a contact hole of a transistor or the like.

Further, the reflection type liquid crystal display element of the present invention is characterized in that the reflection type pixel electrode according to claim 1 is formed simultaneously with the formation of the source electrode.

In the reflection type liquid crystal display device of the present invention, the semiconductor film or the gate electrode film is used as an etching stopper when forming the shape of the underlayer of the reflection type pixel electrode. It is characterized by.

Further, according to the present invention, in the reflective pixel electrode and the interlayer insulating film according to the first to third aspects, a pixel storage capacitor is formed by the interlayer insulating film between the reflective pixel electrode and the gate electrode film. A liquid crystal display device and a reflective liquid crystal display device characterized by the above.

Further, a reflection type liquid crystal display element according to the present invention is characterized in that the semiconductor layer of the display element according to any one of the first to fifth aspects is formed of polysilicon.

Further, the present invention is an image display application device or an information portable terminal device having the reflective display element according to any one of claims 1 to 6.

[0014]

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

(Embodiment 1) First, Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of a top gate type polysilicon thin film transistor array substrate of a reflection type liquid crystal display device according to Embodiment 1 of the present invention, which is composed of an A transistor portion, a B pixel electrode portion, and a C storage capacitor portion. . Here, even if a bottom gate type is used instead of the top gate, the same configuration and effect as those described below can be obtained. The A transistor portion is a known formation method, in which a 12 base insulating film of an oxide film or a nitride film is formed on a 11 glass substrate, and a 13 semiconductor film is formed of amorphous silicon or the like. The 13 semiconductor film is not limited to amorphous silicon or polysilicon. After the pattern formation of the 13 semiconductor film, a 14 gate insulating film is formed with an oxide film, and a 15a gate electrode film is formed with a metal or alloy such as molybdenum or tungsten. Here, when polysilicon is used for the 13 semiconductor film, boron or phosphorus ion doping is generally performed using the 15 gate a electrode film as a mask, and the 13 semiconductor film is
It is divided into a 3a channel layer and a 13b contact layer. Next, a 16a interlayer insulating film is formed using an oxide film or a nitride film. 1
To obtain contact between the 7a source electrode and 17b drain electrode and the 13b semiconductor film contact layer, the 16a interlayer insulating film and the 14 gate insulating film are etched to form contact holes. Finally, a 17a source electrode and a 17b drain electrode are formed of a metal or an alloy such as titanium or aluminum to complete the A transistor portion.

Next, the configuration of the B pixel electrode portion of the present invention will be described. Conventionally, the uneven film for reflected light scattering is formed of an insulating material of about 0.5 to 3 μm after the formation of the source electrode of the transistor portion. In this embodiment, the 17a source electrode and the 17b drain electrode of the A transistor portion and the like are used. And 13
At the same time that a contact hole for contacting the b semiconductor contact layer is formed, a hole is also formed in the B pixel electrode portion to form a 16b scattering uneven film. At this time, a good selectivity can be obtained by using a 13b semiconductor film contact layer as an etching stopper for forming holes in the 16b scattering uneven film of the B pixel electrode portion. A 15a gate electrode film may be used as an etching stopper. Also, in order to increase the level difference of the 16b scattering uneven film, or to use the conventional pattern of the 13 semiconductor film as it is, the underlying insulating film may be barely etched without using an etching stopper to form a hole. I do not care. As described above, it is possible to omit the uneven film forming step without requiring any special material change, addition, and step change.

(Embodiment 2) Next, Embodiment 2 of the present invention will be described with reference to FIG. On the surface of the 16b scattering unevenness film of the B pixel electrode portion formed in the first embodiment and the like, a 17c reflection electrode film is formed simultaneously with the formation of the 17a source electrode and the 17b drain electrode of the A transistor portion. This makes it possible to omit the step of forming the reflective electrode film, which is conventionally required separately. In addition, by using this configuration, a thin film transistor array substrate for a transflective liquid crystal display device can be manufactured at low cost by replacing a part of the 17c reflective electrode film region of the B pixel electrode portion with a transparent electrode.

Embodiment 3 Next, Embodiment 3 of the present invention will be described with reference to FIG. The C pixel storage capacitor portion is formed at the same time by devising a mask pattern in the steps described in the first and second embodiments. That is, 1a formed simultaneously with the 15a gate electrode film
A pixel storage capacitor is formed by a 16a interlayer insulating film formed between a 5b adjacent pixel gate electrode film and an electrode on a further extension of the 17c reflection electrode film on the extension of the 17b drain electrode film. Although not shown in FIG. 2, by using a 13 semiconductor film under the 14 gate insulating film below the 15b adjacent pixel gate electrode film, the 14 gate insulating film can also be used for the storage capacitor.

[0019]

As is apparent from the above description, it is possible to obtain an effective effect of simplifying the number of manufacturing steps and reducing the cost as compared with the conventional reflective and transflective thin film transistor array substrates. It is possible and has great industrial value.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a reflection type thin film transistor array substrate of the present invention (an example of a top gate type polysilicon thin film transistor).

FIG. 2 is a cross-sectional view of a conventional transflective thin film transistor array substrate (an example of a top gate type polysilicon thin film transistor).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Glass substrate 12 Base insulating film 13 Semiconductor film 13a Semiconductor film channel layer 13b Semiconductor film contact layer 14 Gate insulating film 15 Gate electrode film 15a Gate electrode film 15b Adjacent gate electrode film 16 Interlayer insulating film 16a Interlayer insulating film 16b Irregular insulation for scattering Film 17 Source electrode film 17a Source electrode film 17b Drain electrode film 17c Reflective electrode film 21 Glass substrate 22 Base insulating film 23 Semiconductor film 23a Semiconductor film channel layer 23b Semiconductor film contact layer 24 Gate insulating film 25 Gate electrode film 25a Gate electrode film 25b Adjacent gate electrode film 26 Interlayer insulating film 27 Source electrode film 17a Source electrode film 17b Drain electrode film 28 Insulating film 28a Transistor protective film 28b Scattering unevenness film 29 Reflecting electrode film 30 Transmission electrode film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/30 338 G09F 9/30 338 9/35 9/35 H01L 21/336 H01L 29/78 612D 29 / 786 616T 616K F term (reference) 2H042 BA04 BA15 BA20 DA02 DA06 DA12 DB08 DC08 DD10 DE04 2H091 FA14Z GA13 LA30 2H092 GA29 JA25 JA34 JA37 JA41 JA46 JB61 KA04 KA05 KB25 MA27 NA25 PA01 PA12 5C094 AA43 A04 AA43 A04 AA43A04 ED11 ED13 FA01 FA02 FB12 FB14 FB15 GB10 5F110 AA16 BB01 CC02 CC07 DD02 DD13 DD14 EE04 EE06 EE50 GG02 GG13 GG15 HJ01 HJ12 HJ30 HL03 HL04 HL06 HL07 HM02 HM04 NN02 NN72 Q11 Q08

Claims (8)

[Claims] 1. A reflection type liquid crystal display device, wherein a base layer forming a concave / convex shape for reflection light scattering of a reflection type pixel electrode portion is an interlayer insulating film between a gate electrode and a source electrode. 2. A reflection type liquid crystal display device, wherein the shape of the base layer of the reflection type pixel electrode according to claim 1 is formed simultaneously with the formation of a contact hole of a transistor or the like. 3. A reflective liquid crystal display device, wherein the reflective pixel electrode according to claim 1 is formed simultaneously with the formation of the source electrode. 4. A reflection type liquid crystal display device, wherein a semiconductor film or a gate electrode film is used as an etching stopper when forming a shape of a base layer of a reflection type pixel electrode according to claim 1. 5. A reflective pixel electrode and an interlayer insulating film according to claim 1, wherein a pixel storage capacitor is formed by an interlayer insulating film between the reflective pixel electrode and the gate electrode film. Liquid crystal display device and reflective liquid crystal display device. 6. A reflective liquid crystal display device, wherein the semiconductor layer of the display device according to claim 1 is formed of polysilicon. 7. An image display application device comprising the reflective display element according to claim 1. Description: 8. An information portable terminal device comprising the reflective display element according to claim 1.