CN1648750A - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

The invention discloses a structure of a liquid crystal display device. After the transparent conducting layer (and the buffer layer) and the reflecting metal layer are laminated, a halftone image exposure technology is used, the film thickness of the photosensitive resin pattern formed on the reflecting electrode forming area is thicker than that of the film formed on the penetrating electrode forming area, after the reflecting electrode is formed by using the photosensitive resin pattern and matching the sizes of the penetrating electrode and the reflecting electrode, the film thickness of the photosensitive resin pattern is reduced, and the penetrating electrode is formed after the reflecting metal layer (and the buffer layer) on the penetrating electrode is removed.

Description

Liquid crystal display device and manufacturing method thereof

technical field

The present invention relates to a liquid crystal display device with a color image display function, and in particular, to a semi-transmissive liquid crystal display device.

Background technique

In recent years, due to advances in microfabrication technology, liquid crystal material technology, and high-density assembly technology, liquid crystal display devices with a diagonal of 5 to 50 cm have been widely used in television images or various image displays by commercial standards. In addition, on one side of the two glass substrates that make up the liquid crystal panel, the RGB coloring layer is formed in advance, and the color can be easily realized. In particular, the built-in switch component in each pixel, that is, the active liquid crystal panel, can not only reduce low-order distortion, but also speed up the response speed and ensure high image contrast.

The above-mentioned liquid crystal display device (liquid crystal panel) generally has 200-1200 scanning lines and 300-1600 signal lines arranged in a matrix. Recently, in order to support the expansion of display capacity, large-screen and high-definition are being simultaneously pursued.

Fig. 7 shows the assembly state of the liquid crystal panel, using a conductive adhesive to connect the semiconductor integrated circuit chip 3 that provides the driving signal to one of the transparent insulating substrates that constitute the liquid crystal panel 1, such as the scanning lines formed on the glass substrate 2 The COG (Chip-On-Glass) method of the electrode terminal group 5, or the TCP with metal or solder-plated copper foil terminals is based on a polyimide film-based resin film and uses an appropriate adhesive containing a conductive medium. The thin film 4 is press-welded to the electrode terminal group 6 of the signal line, and is fixed with a mounting method such as TCP (Tape-Carrier-Package) so as to supply an electric signal to the image display unit. For the convenience of explanation, the above two assembly methods are shown in diagrams, but in fact, either method can be appropriately selected.

The wiring lines 7, 8 between the electrode terminals 5, 6, which are located approximately in the center of the liquid crystal panel 1 and connect pixels, scanning lines, and signal lines in the display unit, are not necessarily made of the same conductive material as the electrode terminal groups 5, 6. 9 is a transparent conductive opposite electrode commonly used in all liquid crystal cells, and an opposite glass substrate or color filter of another sheet of transparent insulating substrate on its opposite surface.

8 shows an equivalent circuit diagram of an active liquid crystal display device in which an insulated gate type thin film transistor 10 is arranged for each pixel as a switch component, 11 (7 in FIG. 7 ) is a scanning line, 12 (7 in FIG. 7 is that 8) is a signal line, and 13 is a liquid crystal cell, and the liquid crystal cell 13 is used as an electrical capacity component. Components drawn in solid lines are formed on one glass substrate 2 constituting the liquid crystal panel, and counter electrodes 14 common to all liquid crystal cells 13 drawn in dotted lines are formed on the opposite main plane of the other glass substrate 9 . When the OFF resistance of the insulated gate type thin film transistor 10 or the resistance of the liquid crystal cell 13 becomes low, or when the gray scale of the displayed image is emphasized, an auxiliary storage capacitor 15 can be applied side by side to the liquid crystal cell 13, etc., in the circuit A little ingenuity is applied to expand the time constant of the liquid crystal cell 13 as a load, and 16 is the storage capacitor formed by the common bus of the storage capacitor 15 .

Fig. 9 shows the sectional view of the important parts of the image display part of the liquid crystal display device. The two glass substrates 2, 9 that constitute the liquid crystal panel 1 are formed on the same columnar shape by resinous fibers, hollow particles or color filters 9. Spacers such as spacers (not shown in the figure) are formed at predetermined pitches of a few μm, and around the glass substrate 9, a sealing material and a sealing material (not shown in any diagram) made of organic resin are used to seal the gap ( Gap) forms a closed space, and fills the closed space with liquid crystal 17 .

When realizing color display, use any one or both of dyes or pigments called coloring layer 18, and coat the closed space of glass substrate 9 with an organic thin film with a thickness of about 1-2 μm, which will have a color-developing function. The glass substrate 9 at this time is commonly known as a color filter (Color Filter, CF for short). According to the properties of the liquid crystal material 17, the liquid crystal panel 1 can function as an electro-optical component after the polarizer 19 is pasted on either the upper surface of the glass substrate 9 or the lower surface of the glass substrate 2, or both surfaces. At present, most of the liquid crystal panels on the market are made of TN (Twist Nematic) liquid crystal materials, which generally require two polarizers 19 . Although not shown in the figure, the transmissive liquid crystal panel is equipped with a back light source as a light source, and illuminates white light from below.

On the two glass substrates 2 and 9 connecting the liquid crystal 17, a polyimide film-based resin film 20 with a thickness of about 0.1 μm is formed, which is an alignment film that determines the direction of the liquid crystal molecules. 21 is a drain (wiring) connecting the drain of the insulated gate thin film transistor 10 and the transparent conductive pixel electrode 22 , and is usually formed simultaneously with the signal line (source line) 12 . Located between the signal line 12 and the drain 21 is a semiconductor layer 23 , which will be described in detail later. On the boundary of the colored layer 18 that is in contact with the color filter 9, a Cr film layer 24 with a thickness of about 0.1 μm is formed, which is a light-shielding component for preventing external light sources from irradiating the semiconductor layer 23, the scanning line 11, and the signal line 12. , which is commonly known as the Black Matrix frame (Black Matrix for short BM), which is a common technology at present.

The structure of an insulated gate type thin film transistor as a switching element and a related manufacturing method will be described below. At present, there are two types of insulated gate thin film transistors widely used, one of which is called the etch stop layer type, which will be explained in detail with previous examples. Fig. 10 is a plan view of a unit pixel of an active substrate (semiconductor device for a display device) constituting a liquid crystal panel in the past. 11, the following briefly describes its manufacturing process.

First, as shown in Figure 10(a) and Figure 11(a), a glass substrate 2 with a thickness of about 0.5-1.1 mm is used as an insulating substrate with excellent heat resistance, chemical resistance and transparency, for example On one main plane of CORNING company/trade name 1737, use a vacuum film forming device such as SPT (sputtering) to coat the first metal layer with a film thickness of about 0.1 to 0.3 μm, and selectively form it through microfabrication technology It also serves as the scanning line 11 of the gate 11A and the storage capacitor line 16 . After comprehensively reviewing the material of the scanning line, the materials with heat resistance, chemical resistance, fluorine acid resistance and electrical conductivity are selected. Generally, Cr, Ta, MoW alloy and other metals or alloys with excellent heat resistance are used.

In order to reduce the resistance value of the scanning line, it is reasonable to use Al (aluminum) as the material of the scanning line in order to reduce the resistance value of the LCD panel, but the heat resistance of Al alone is not good, so the above-mentioned heat-resistant metal Cr, Ta, Mo are laminated with silicide, or an oxide layer (Al ₂ O ₃ ) is applied on the surface of Al by anodic oxidation, all of which are commonly used technologies at present. That is to say, the scanning line 11 is composed of more than one metal layer.

Secondly, on the whole glass substrate 2, using a PCVD (plasma) device, for example, with a film thickness of about 0.3-0.05-0.1 μm, sequentially coat the first SiNx (silicon nitride) layer that constitutes the gate insulating layer 30, and almost no impurities, the first amorphous silicon (A-Si) layer 31 is formed by the channel of the insulated gate type thin film transistor, and the second SiNx layer 32 and three kinds of thin film layers are formed by the insulating layer of the protection channel , as shown in FIG. 10(b) and FIG. 11(b), the width of the second SiNx layer on the gate 11A is selectively kept narrower than that of the gate 11A through microfabrication technology, as a protection The insulating layer (etching stop layer or channel protection layer) 32D, and exposes the first amorphous silicon layer 31 .

Next, use the same PCVD device to coat impurities such as the second amorphous silicon layer 33 containing phosphorus with a film thickness of about 0.05 μm, as shown in Figure 10(c) and Figure 11(c), use a vacuum such as SPT The film forming device is sequentially covered with a heat-resistant metal layer with a film thickness of about 0.1 μm, such as Ti, Cr, Mo and other thin film layers 34, and a low-resistance wiring layer, an Al thin film layer 35 with a film thickness of about 0.3 μm, and a thin film The thickness is about 0.1 μm, and the Ti thin film layer 36 as the middle conductive layer, through microfabrication technology, these three thin film layers 34A, 35A and 36A belonging to the source/drain wiring material are laminated and selectively formed to insulate The drain 21 of the gate type TFT and the signal line 12 as the source. Use the photosensitive resin pattern used to form the source/drain wiring as a photomask, etch the Ti thin film layer 36, Al thin film layer 35, and Ti thin film layer 34 in sequence, and remove the gap between the source/drain electrodes 12 and 21. The second amorphous silicon layer 33 is exposed to the protective insulating layer 32D, and at the same time, the first amorphous silicon layer 31 is also removed in other regions to expose the gate insulating layer 30, and the above selective pattern can be formed. In this way, under the second SiNx layer 32D where the channel protection layer exists, the etching of the second amorphous silicon layer 33 will automatically end, and this manufacturing method is called an etching stop layer type.

The source/drain electrodes 12, 21 overlap with a part (several μm) of the protective insulating layer 32D in a planar manner, so as to avoid structural deviation of the insulated gate type TFT. This overlap will generate electrical effects with parasitic capacity. Although the smaller the better, it still needs to be determined according to the adjustment accuracy of the exposure machine, the accuracy of the mask board, the expansion coefficient of the glass substrate, and the temperature of the glass substrate during exposure. Practical The value is about 2 μm.

After removing the above-mentioned photosensitive resin pattern, on the overall glass substrate 2, the gate insulating layer as a transparent insulating layer is also covered by a PCVD device with a SiNx layer with a film thickness of about 0.3 μm as a passivation insulating layer 37, as shown in the tenth (d) Figure and the passivation insulating layer 37 shown in Figure 11 (d), on the drain electrode 21 and in the area outside the image display part, the area where the electrode terminals of the scanning line 11 and the signal line 12 are formed, respectively Form the openings 62, 63, 64, remove the passivation insulating layer 37 and the gate insulating layer 30 in the openings 63, expose part of the scanning lines in the openings 63, and remove the passivation in the openings 62, 64 at the same time. The insulating layer 37 is removed to expose part of the drain electrode 21 and part of the signal line. Similar to the scanning lines 11 , openings 65 are formed on the storage capacitor lines 16 (electrode patterns bundled in parallel), exposing part of the storage capacitor lines 16 .

Finally, use a vacuum film-forming device such as SPT to coat a transparent conductive layer with a film thickness of about 0.1-0.2 μm, such as ITO (Indium-Tin-Oxide) or IZO (Indium-Zine-Oxide), as shown in Figure 10(e ) and FIG. 11( e ), through microfabrication technology, the pixel electrode 22 is selectively formed on the passivation insulating layer 37 including the opening 62 , that is, the active substrate 2 is completed. The part of the scanning line 11 exposed in the opening 63 is used as the electrode terminal 5, and the part of the signal line 12 exposed in the opening 64 can also be used as the electrode terminal 6. Electrode terminals 5A, 6A made of ITO are selectively formed on the passivation insulating layer 37, and a transparent conductive short-circuit line 40 connecting the electrode terminals 5A, 6A is usually formed at the same time. The reason is that, although not shown in the figure, since the electrode terminals 5A, 6A and the short-circuit line 40 form long and thin strips and become high resistance, it can be used as a high resistance for static electricity countermeasures. Similarly, although no number is assigned, the inclusion of the opening 65 forms an electrode terminal for the storage capacitor line 16 .

When the wiring resistance of the signal line 12 does not cause a problem, the low-resistance wiring layer 35 made of Al is not necessarily required. 12 and 21 can be simplified into a single layer. In this way, the most important thing is to use a heat-resistant metal layer for the source/drain wiring and ensure electrical connection with the second amorphous silicon layer. Regarding the heat resistance of the insulated gate type thin film transistor , the prior example of the Japanese Patent Application Publication No. Ping 7-74368 has been described in detail. In addition, in FIG. 10(c), the storage capacitor line 16 and the drain electrode 21 pass through the gate insulating layer 30, and the storage capacitor 15 is formed by the plane overlapping region 50 (towards the lower right oblique line). Detailed description is omitted.

Patent Document 1 JP-A-7-74368

Although the detailed processing of the five photomasks is omitted above, due to the rationalization of the striping process of the semiconductor layer and the deletion of the contact point formation process, about 7 to 8 photomasks were originally required, and because of the dry etching technology The introduction, now reduced to 5 wafers, is expected to significantly reduce processing costs. In order to reduce the production cost of liquid crystal display devices, firstly, the processing cost of the active substrate must be reduced, and secondly, the component cost must be reduced in the panel assembly process and module assembly process, which is also a well-known development goal.

In recent years, mobile phones have been popularized rapidly. In the beginning, only the caller ID function was needed, and a segment type liquid crystal display panel that could display black and white was enough. Nowadays, not only color display, high-definition, but also animation display and its functions are required. Every day. At present, one of the problems faced by mobile phones is the service life of the battery, the light brightness of the use environment and the limited backlight because there is no power to consume, so the demand for reflective LCD panels is becoming more and more urgent. In order for the liquid crystal display panel to perform the reflective function, the reflective electrode is of course required. The manufacturing method of the semi-transmissive liquid crystal panel with two functions of the transmissive type and the reflective type is briefly described below. However, as for the insulated gate type transistor, an insulated gate type transistor employing a channel etching type will be described below.

First, as with the treatment of five photomasks, on one main plane of the glass substrate 2, use a vacuum film-forming device such as SPT to coat the first metal layer with a film thickness of about 0.1-0.3 μm, as shown in Figure 12(a) and As shown in FIG. 13( a ), the scanning line 11 and the storage capacitor line 16 serving as the gate 11A are selectively formed through microfabrication technology.

Next, using a PCVD device on the whole glass substrate 2, with a film thickness of about 0.3-0.2-0.05 μm, the SiNx layer 30 that constitutes the gate insulating layer is sequentially covered, and the SiNx layer 30 that is almost free of impurities is made of an insulating gate type film. The first amorphous silicon layer 31 composed of the channel of the transistor, the second amorphous silicon layer 33 containing impurities and composed of the source/drain of the insulated gate type thin film transistor, and three thin film layers.

Next, as shown in FIG. 12(b) and FIG. 13(b), the second amorphous silica gel layer 33A is laminated with the first amorphous silicon layer 31A on the gate 11A through microfabrication technology. The striped semiconductor layer exposes the gate insulating layer 30 .

Use a vacuum film forming device such as SPT to sequentially cover a heat-resistant metal layer with a film thickness of about 0.1 μm, such as a Ti film layer 34, and an Al film layer 35 with a film thickness of about 0.3 μm for a low-resistance wiring layer, and the film thickness The middle conductive layer of about 0.1 μm, such as the Ti thin film layer 36 , covers the source/drain wiring material in sequence. Next, through microfabrication technology, the source/drain wiring material, the second amorphous silicon layer 33A, and the first amorphous silicon layer 31A composed of the three-layer film are sequentially etched by photosensitive resin patterns, and the gate electrode is exposed. Pole insulating layer 30, as shown in Fig. 12(c) and Fig. 13(c), overlaps part of gate 11A, and 34A, 35A, and 36A are stacked to form drain 21 of an insulated gate transistor. And the signal line 12 as the source is selectively formed. When the source/drain wiring 12, 21 is formed, the photosensitive resin pattern is used as a mask plate, and after the etching of the Ti film layer 34Al, the film layer 35 and the Ti film layer 36, the source/drain wiring 12 is sequentially etched. , 21 (channel formation region) and the second amorphous silicon layer 33A, and the first amorphous silicon layer 31A, the first amorphous silicon layer 31A is etched with about 0.05-0.1 μm left. The source/drain wiring 12, 21 is formed by etching the first amorphous silicon layer 31A with about 0.05~0.1 μm left after the metal layer is etched. Transistors are called channel etched. In addition, in terms of the structure of the source/drain wiring 12, 21, Ta, Cr, MoW, etc. can be simplified to a single layer as long as the restriction on the resistance value is relaxed.

After the source/drain wiring 12, 21 is formed, on the overall glass substrate 2, as a transparent insulating layer, coat the second SiNx layer with a film thickness of about 0.3 μm and use it as a passivation insulating layer 37, continue As a transparent insulating layer, apply a transparent and highly heat-resistant photoacrylic resin with a film thickness of about 3 μm and use it as a concave-convex layer 39, as shown in Figure 12(d) and Figure 13(d), Using a photomask and selectively irradiating ultraviolet rays, openings 62, 63, and 64 are formed on the drain electrode 21, a part 5 of the scanning line, and a part 6 of the signal line. After the development process, the concave-convex layer 39 will be heated hardening. Next, the passivation insulating layer 37 in the openings 62, 64 is removed, and at the same time, the gate insulating layer 30 is removed together with the passivation insulating layer 37 in the opening 63, and the openings 62, 63 and 64 are respectively exposed. A part of the drain electrode 21, a part 5 of the scanning line, and a part 6 of the signal line. Similarly, an opening 65 is formed on the storage capacitor line 16 to expose a part of the storage capacitor line 16 .

As literally stated, the surface of the uneven layer 39 has unevenness with a height of 1 μm or less, and the metal electrode formed on the uneven layer 39 can function as a diffusion electrode. According to the description in FIG. 12( d ), one of the patterns matching the concavo-convex is represented by 70 and distributed evenly. The size of the pattern 70 is usually about a few μm. In order to avoid light interference caused by the fixed pattern, the pattern 70 is generally randomly distributed in the central position. Irradiate short-wavelength ultraviolet rays on the surface of photosensitive acrylic resin 39 to strengthen the hardening of the surface layer. After thermal hardening, unevenness can be formed on the surface layer. Similarly, soak it in strong alkali to soften the surface layer. When thermosetting, it can form unevenness on the surface layer, or form photosensitive acrylic resin 39 in two layers, one side is photosensitive acrylic resin with fluidity, so that it has an arc equivalent to thermosetting without fluidity After lamination of photosensitive acrylic resin, the concave-convex and other related technologies have been described in the previously disclosed examples. Since the purpose of the present invention is not the technology of forming concave-convex, the details are omitted here.

Such a channel-etching type insulated gate transistor usually needs to cover the active substrate 2 with a passivation insulating layer 37 made of SiNx, and then the concave-convex layer 39 can be formed with acrylic resin. The insulated gate transistor has a protective insulating layer 32D on the channel, even if acrylic resin is formed on the passivation layer of the active substrate 2 , the electrical properties of the insulated gate transistor will not change.

After the concave-convex layer 39 is formed, the entire glass substrate 2 is coated with a transparent conductive layer 91 with an ITO film thickness of about 0.1-0.2 μm, such as ITO, using a vacuum film-forming device such as SPT, as shown in Figure 12(e) and Figure 13(e) As shown, the connecting electrode 22A including the opening 62 , the pixel electrode 22 penetrating the electrode, the scanning line electrode terminal 5A including the opening 63 , and the signal line electrode terminal 6A including the opening 64 are formed by microfabrication technology. The connecting electrode 22A formed by the penetrating electrode and the reflective electrode is connected and formed as a part of the pixel electrode 22 . Although it is not necessary to have the connecting electrode 22A, in order to avoid a part of the drain electrode 21 being damaged due to a subsequent manufacturing process and causing poor contact, it is preferably provided between subsequent reflective electrodes.

Finally, a vacuum film-forming device such as SPT is used to coat a buffer layer 92 with a film thickness of about 0.1 μm, such as Mo, and a high-reflectivity metal layer 93 with a film thickness of about 0.1-0.2 μm, such as aluminum, as shown in Figure 12 ( f) and Figure 13(f). In order to encourage a part to overlap with the transparent conductive pixel electrode 22, the buffer layer 92 (41) and the aluminum layer 93 (41) are laminated to form the reflective electrode 41, so that the active substrate 2 of the transflective liquid crystal display device can be completed . Although it is necessary to avoid the battery effect that the buffer layer 92 (41) directly contacts aluminum or ITO, the ITO is reduced due to alkaline developing solution and photoresist stripping solution, and the aluminum is peeled off together. Potential, the aluminum alloy Al(Nd) containing a few percent of Nd does not require the buffer layer 92 (41).

As shown in FIG. 12(c), through the gate insulating layer 30, the storage capacitor line 16 and the drain electrode 21 are overlapped in the plane area 50 (the oblique line facing downward to the right) to form the storage capacitor 15. The scanning line 11 and the storage electrode formed on the scanning line 11 can also form the storage capacitor 15 after planar overlapping of the insulating layer including the gate insulating layer 30 . At this time, although the penetrating electrode 22 or the reflective electrode 41 connected to the drain electrode 21 must be connected to the storage electrode, detailed description is omitted here.

In the transflective liquid crystal display device described above, reflective electrodes are additionally formed on the transmissive liquid crystal display device, and the number of mask plates is increased from 5 to 6, which will inevitably increase its manufacturing cost. In order to control manufacturing costs, it is important to reduce the number of manufacturing processes in addition to reducing costs through mass production.

In view of the relevant status quo, in order to achieve the purpose of using a photomask to process the striping process of the semiconductor layer and the source/drain wiring formation process, the present invention develops a method similar to the halftone image exposure technology, using a photomask The plate handles the reflective electrodes and the through electrodes, that is, implements the subtractive manufacturing process.

The present invention does not use a mask plate different from the previous penetrating electrodes and reflective electrodes, which are manufactured in different processes. In the present invention, the transparent conductive layer and the reflective metal layer are laminated first, and the reflective electrodes are formed through the halftone image exposure technology. The thickness of the film on the region forms a photosensitive resin pattern that is thicker than the film thickness on the penetrating electrode region. The photosensitive resin pattern is used to form the reflective electrode in conjunction with the size of the penetrating electrode and the reflective electrode, so that the photosensitive resin pattern is reduced. Film thickness, after removing the reflective metal layer on the penetrating electrode to form the penetrating electrode.

Contents of the invention

According to one aspect of the present invention, there is provided a liquid crystal display device, on the main plane of a first transparent insulating substrate, there are at least an insulated gate type thin film transistor, which can be used as a scanning line for the gate of the insulated gate type thin film transistor , the signal line that can be used as the source wiring, and the unit pixel formed by the pixel electrode connected to the drain wiring are arranged in a two-dimensional matrix on the first transparent insulating substrate, and the liquid crystal is filled in the opposite to the first transparent insulating substrate. Between the second transparent insulating substrate or the color filter, it is characterized in that: on the main plane of the first transparent insulating substrate, an insulated gate type transistor, a scanning line and a signal line are formed; at least there is an opening on the drain part, the concave-convex transparent insulating layer on the surface of a part of the area is formed on the first transparent insulating substrate; The reflective electrode and other areas, including the opening, are formed continuously with the transparent conductive layer as a transparent conductive penetrating electrode.

According to another aspect of the present invention, there is provided a method for manufacturing a liquid crystal display device. On the main plane of a first transparent insulating substrate, at least an insulated gate type thin film transistor is formed, which can be used as the insulated gate type thin film transistor. The scanning line of the gate of the transistor can be used as the signal line of the source wiring, and the unit pixel formed by the pixel electrode connected to the drain wiring is arranged in a two-dimensional matrix on the first transparent insulating substrate, and the liquid crystal is filled with the Between the second transparent insulating substrate or the color filter opposite to the first transparent insulating substrate, it is characterized in that it includes the step of: forming an insulated gate type transistor, a scanning line and a signal line, on the main plane of the first transparent insulating substrate On the top; at least an opening is provided on the drain electrode and on the first transparent insulating substrate, a concave-convex transparent insulating layer is formed on the surface of a partial area; after forming a transparent conductive layer and more than one metal layer, including the opening Inside, the reflective electrode formed with a concave-convex transparent insulating layer area cooperates with a transparent and conductive penetrating electrode outside the concave-convex area, and the film thickness on the reflective electrode will form a photosensitive resin pattern that is thicker than the film thickness on the penetrating electrode; Using the photosensitive resin pattern as a mask plate, after selectively removing the metal layer, the transparent conductive layer is exposed; reducing the film thickness of the photosensitive resin pattern, and exposing the metal layer in the penetrating electrode formation area to reduce the film thickness The photosensitive resin pattern, and the metal layer in the penetrating electrode formation region are used as a mask plate, and after the transparent conductive layer is selectively removed, the transparent insulating layer is exposed; and the photosensitive resin pattern that reduces the thickness of the film is used as a mask plate, The metal layer in the area where the penetrating electrode is formed is removed to expose a transparent and conductive penetrating electrode.

As mentioned above, when the present invention manufactures a transflective liquid crystal display device, after the transparent conductive layer and (and the buffer layer) reflective metal layer are stacked, the thickness of the film on the reflective electrode formation area is formed by half-tone image exposure technology. A photosensitive resin pattern that is thicker than the thickness of the film on the penetrating electrode formation area. The photosensitive resin pattern is used to match the size of the penetrating electrode and the reflective electrode to form a reflective electrode, and the film thickness of the photosensitive resin pattern is reduced to remove the penetration. The reflective metal layer on the electrode is mainly based on the rationalization technology of forming the penetrating electrode. Based on this structure, various active substrate schemes are proposed. Therefore, compared with the past manufacturing method, it is expected to reduce the number of photo-etching processes, contributing to a significant cost reduction.

In addition, since the penetrating electrode and the reflective electrode are formed at the same time, the adjustment accuracy of the mask plate between these electrodes will become 0. Although it is very small, the pixel electrode can be enlarged, so the aperture ratio can be increased and bright images can be obtained. Display the image. Moreover, since the precision of the process graphics is not high, it will not have a great impact on the yield or quality, and it is easy to manage production.

According to the description, the essentials of the present invention can be clearly understood. The key point is that when manufacturing a semi-transparent liquid crystal display device, after the transparent conductive layer and (and buffer layer) reflective metal layer are laminated, through the half-tone image exposure technology, The thickness of the film on the region where the reflective electrode is formed will form a photosensitive resin pattern that is thicker than the thickness of the film on the region where the penetrating electrode is formed. By using this photosensitive resin pattern, after forming the reflective electrode in accordance with the size of the penetrating electrode and the reflective electrode, this can be reduced. The film thickness of the photosensitive resin pattern can form the penetrating electrode by removing the reflective metal layer on the penetrating electrode. , Including scanning lines, signal lines, pixel electrodes, gate insulating layers and other materials or film thicknesses of completely different liquid crystal display devices, or differences in their manufacturing methods, it is not difficult to understand that these all belong to the scope of the present invention. In addition, it is more certain that the semiconductor layer of the insulated gate type thin film transistor is not limited to amorphous silicon.

Description of drawings

1 is a plan view of an active substrate according to Embodiment 1 of the present invention;

2 is a cross-sectional view of the active substrate manufacturing process according to Embodiment 1 of the present invention;

3 is a plan view of an active substrate according to Embodiment 2 of the present invention;

4 is a cross-sectional view of an active substrate according to Embodiment 2 of the present invention;

5 is a plan view of an active substrate according to Embodiment 3 of the present invention;

6 is a cross-sectional view of an active substrate according to Embodiment 3 of the present invention;

Fig. 7 is a perspective view showing the assembled state of a liquid crystal panel in the prior art;

8 is an equivalent circuit diagram of a liquid crystal panel in the prior art;

9 is a cross-sectional view of a liquid crystal panel in the prior art;

10 is a plan view of an active substrate of the prior art;

FIG. 11 is a cross-sectional view of an active substrate manufacturing process in the prior art;

FIG. 12 is a plan view of the active substrate of the semi-transmissive liquid crystal display device in the prior art; and

Fig. 13 is a cross-sectional view of the active substrate manufacturing process mainly based on the transflective liquid crystal display device.

Symbol Description

1: LCD panel

2: Active substrate (glass substrate)

3: Semiconductor integrated circuit chip

4: TCP film

5: A part of the metallic scanning line or an electrode terminal

5A: Transparent conductive scanning line electrode terminal

6: A part of a metallic signal line or an electrode terminal

6A: Transparent conductive signal line electrode terminal

9: Color filter (opposite glass substrate)

10: Insulated gate transistor

11: scan line

11A: Gate wiring, gate

12: Signal line (source wiring, source)

14: (on the color filter) opposite electrode

16: storage capacitor line

17: LCD

19: polarizer

20: Orientation film

21: Drain (drain wiring, drain)

22: Transparent conductive pixel electrodes, penetrating electrodes

30: Gate insulating layer

31: (first) amorphous silicon layer free of impurities

32 D: Protective insulation layer (etch stop layer, channel protection layer)

33: (second) amorphous silicon layer containing impurities

34: heat-resistant metal layer

35: Low resistance metal layer (AL)

36: middle conductive layer

37: passivation insulating layer

38: Forming the opening of the penetrating region in the concave-convex layer

39: (made of photosensitive acrylic resin) concave-convex layer

41: (highly reflective metal) reflective electrode

50, 52: storage capacitor formation area

62: opening (on the drain)

63: opening (on the scanning line or on the scanning line electrode terminal)

64: Opening (on signal line or signal line electrode terminal)

65: opening (on the counter electrode)

72: storage electrode

81A, 81B: (formed after halftone image exposure) photosensitive resin pattern

91: transparent conductive layer

92: buffer layer

93: (highly reflective) metal layer

Detailed ways

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6 . FIG. 1 shows a plan view of a semiconductor device (active substrate) for a display device according to Embodiment 1 of the present invention, and FIG. 2 shows the AA' line, BB' line, and CC' line of the first (h) figure. A cutaway view of the manufacturing process in-line. Similarly, after changing part of the design of the liquid crystal display device, FIG. 3 and FIG. 4 show reference example 1, and FIG. 5 and FIG. 6 show the plan view and cross-sectional view of the active substrate of reference example 2. The same symbols are assigned to the same parts as those in the conventional examples, and detailed explanations are omitted. Regardless of whether it is an insulated gate type transistor or a storage capacitor, the present invention adopts any structure or form, and the characteristics of the present invention exist in the manufacturing process after forming a transparent resin layer with a concave-convex layer (for applying diffusivity to the reflective electrode). Although Embodiment 1 adopts the channel etching type 5-piece reticle processing and explains in detail, even if the etch-stop type 5-piece reticle processing is adopted, or even the rationalized channel-etching type 4-piece reticle processing, Doesn't have any effect either.

In Embodiment 1, as shown in FIG. 1(d) and FIG. 2(d), openings 62, 63 are respectively formed on the drain electrode 21, a part 5 of the scanning line, and a part 6 of the signal line. And 64 of the concave-convex layer 39, before exposing a part of the electrode, the manufacturing process carried out is the same as the previous embodiment.

Next, use a vacuum film-forming device such as SPT to include a transparent conductive layer 91 with a film thickness of about 0.1-0.2 μm, such as ITO, and a buffer layer 92 with a film thickness of about 0.1 μm, such as Mo, and a film thickness of about 0.1 μm. After ~0.2 μm highly reflective metal layer 93, such as aluminum, use half-tone image exposure technology to form a film thickness of 3 μm for example 81A (41) matching the reflective electrode forming area, 81B (22) matching the penetrating electrode forming area and 81B (5A) corresponding to the electrode terminal formation area, and photosensitive resin patterns 81A, 81B thicker than 81B (6A) with a film thickness of 1.5 μm.

In this case, when manufacturing the substrate for liquid crystal display devices, the photosensitive resin patterns 81A and 81B are usually made of a general positive photoresist photosensitive resin, and the reflective electrode formation area 81A is black, that is, after the Cr thin film is formed, the penetrating electrode is formed. The region and the electrode terminal forming region 81B are gray, for example, a Cr pattern with a width of about 0.5-1.5 μm is formed, and the other regions are white, that is, a mask plate with a Cr film removed can be used. In the gray area, because the resolution of the exposure machine is not enough, it is impossible to analyze the subtle lines and spaces (Line And Space). The light source from the display can penetrate about half of the mask plate to irradiate light, which matches the characteristics of the remaining film of positive photoresist photosensitive resin. , as shown in FIG. 2(e), photosensitive resin patterns 81A and 81B having cross-sectional shapes can be obtained. As long as a certain amount of ultraviolet light penetration is ensured in the gray area, not only Line And Space, but Cr and other films with thin film thicknesses can also be equipped with light absorption after formation. , the reticle technology for halftone images should be more and more advanced.

As shown in FIG. 1(e) and FIG. 2(e), the highly reflective metal layer 93 and the buffer layer 92 are etched sequentially or simultaneously to expose the transparent conductive layer 91 using the photosensitive resin pattern 81A, 81B as a mask. Specifically, chemical solution treatment (addition of phosphoric acid to nitric acid of a few percent or less) can be performed simultaneously with etching.

After the oxygen plasma treatment, the film thickness of the photosensitive resin patterns 81A, 81B is reduced by 1.5 μm, the photosensitive resin pattern 81B disappears, and the highly reflective metal layers 93(22), 93(5A), 93( 6A) While being exposed, the photosensitive resin pattern 81C (41) with reduced film thickness can be directly left in the reflective electrode forming region. During the oxygen plasma treatment, it can be found that the transparent conductive layer 91 can be protected by reducing the film thickness of the concave-convex layer 39 formed by the organic insulating layer. As shown in Figure 1 (f) and Figure 2 (f), the photosensitive resin pattern 81C (41) and the highly reflective metal layers 93 (22), 93 (5A), and 93 (6A) are used as the mask board to selectively remove the The transparent conductive layer 91 exposes the concave-convex layer 39 .

Continue as shown in Figure 1(g) and Figure 2(g), use the photosensitive resin pattern 81C(41) as a mask plate to remove the high reflective metal layer 93(22) exposed on the penetrating electrode and the high reflective metal layer on the electrode terminal. Reflective metal layers 93(5A), 93(6A). At the same time, the buffer layers 92 ( 22 ), 92 ( 5A), and 92 ( 6A) are also removed to expose the penetrating electrodes 22 and the electrode terminals 5A, 6A, respectively.

Finally, as shown in FIG. 1(h) and FIG. 2(h), the photoresist pattern 81C (41) is removed by using a photoresist stripper, exposing the buffer layer 92 (41) and the highly reflective metal layer 93 (41) stacked The finished reflective electrode 41 can complete the manufacturing process of the active substrate 2 . In the photoresist stripping process, since the concave-convex layer 39 made of organic resin is exposed on the active substrate 2 , it is not necessary to use oxygen plasma. As explained in previous examples, when the high reflective metal layer 93 is selected from the aluminum alloy Al(Nd), the buffer layer 92 does not need to be introduced. The liquid crystal panel is formed after the active substrate 2 manufactured at this stage is coated with color filters, and the implementation example 1 of the present invention is completed. In addition, although omitted in FIG. 1( h), as described in previous examples, including the transparent conductive scanning line electrode terminal 5A, the electrode terminal 6A of the signal line 12 and the short-circuit circuit 40 disposed on the periphery of the active substrate 2, The pattern of the transparent conductive layer connecting the terminal and the circuit is in the shape of a long and thin line, which can be used as a high-resistance wiring when anti-static measures are taken.

In Embodiment 1, although the electrode terminals of this type of scanning lines and the electrode terminals of the signal lines will have restrictions on the device structure of the transparent conductive layer, devices can also be used to solve the restrictions. related information. However, the manufacturing process is still the same without any changes, and ultimately only the plan and cross-sectional views of the active substrate are recorded.

According to Embodiment 2, as shown in FIG. 1(e) and FIG. 2(e), when the photosensitive resin pattern is formed by using the halftone image exposure technique, the film thickness of the electrode terminal forming region becomes thicker as that of the reflective electrode forming region, Metallic electrode terminals can be made. In other words, the structure of the electrode terminals can be changed by changing the graphic design. As a result, the structure of the electrode terminal becomes the same as that of the reflective electrode. As shown in FIG. 3(h) and FIG. 6A) and the highly reflective metal layers 93 (5A), 93 (6A) can be stacked to obtain electrode terminals, while the active substrate 2 is exposed as the high reflective metal layer 93 (5A) of the scanning line electrode terminals 5, and The highly reflective metal layer 93 as the signal line electrode terminal 6 is exposed (6A).

Although not shown in the figure, in Embodiment 2, when the short circuit 40 is formed on the periphery of the active substrate 2, the thickness of the photosensitive resin pattern film in the short circuit forming area will be as thin as that in the penetrating electrode forming area.

The function of the reflective liquid crystal display device is to transmit the reflected light from the reflective electrode to the observer. Therefore, the optical path difference generated after passing through the liquid crystal cell of the same thickness is about twice that of the transmissive liquid crystal display device, and half The Δnd value obtained by the maximum brightness (reflectivity and transmittance) of the transmissive liquid crystal display device is also completely different. In order to avoid such a situation, both the conventional example and the first example form an opening 38 in the concave-convex layer 39 , remove the passivation insulating layer and the gate insulating layer in the opening, and increase the thickness of the liquid crystal cell in the penetrating region. The concave-convex layer 39 can be easily formed with a film thickness of about 3 μm. Therefore, the liquid crystal cell thickness of the reflective part and the transmissive part can be increased by about 2 times (multi gap), and this part belongs to the category of optical design.

However, since the penetrating electrode 22 is located at the bottom of the extremely deep opening 38, when using a flat grinding cloth for orientation treatment, it is easy to cause the surroundings of the opening 38 to become non-directional, and it is necessary to use BM as the light in the color filter. Shielding, the aperture ratio will thus decrease.

It is also possible to do an optical design that emphasizes reflection characteristics. At this time, the reflection part and the transmission part can adopt the same thickness of the liquid crystal cell, and the opening 38 is not needed. As shown in Figure 5 (h) and Figure 6 (h), in The penetrating electrode 22 is formed on the flat area of the concave-convex layer 39 , that is, it is located at the same height as the reflective electrode 41 (single gap).

In principle, Single gap is not easy to produce non-directional, so it is not necessary to use BM to shield the inner periphery of the penetrating electrode 22 and the reflective electrode 41 in the color filter. Therefore, Multi gap can increase the aperture ratio, and can also be supplemented Insufficient penetration characteristics.

The thickness of the liquid crystal cell belonging to the physical quantity depends on the penetrating electrode 22 on the active substrate 2, and the distance between the reflective electrode 41 and the opposite electrode 14 formed on the color filter 9. The value of Δnd can be changed according to the film thickness of the colored layer 18 . In the future, although the manufacturing cost of color filters will increase, it can expand the freedom of optical design. Therefore, various optical design technologies and component technologies should be developed to improve the optical properties of transflective liquid crystal display devices. characteristic.

To sum up, since the CMOS transmission signal does not require an additional DC bias voltage, it is easier to apply to a system with a low logic voltage (such as 1.8V) than a differential signal. The invention saves the wiring number of the display panel, reduces current consumption, and improves EMI characteristics.

The embodiments provided above have highlighted many features of the present invention. Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the scope of the present invention. Any person skilled in the art may make various modifications and modifications without departing from the spirit and scope of the present invention. In addition, the section titles mentioned in this specification are not used to limit the scope of the content, especially the background technology mentioned may not be the disclosed prior art, and the description of the invention is not used to limit the technical characteristics of the present invention . The novelty, progress and protection scope of the present invention shall be based on the scope defined by the appended claims.

Claims (2)

1. A liquid crystal display device, on the main plane of a first transparent insulating substrate, at least has an insulated gate type thin film transistor, which can be used as the scanning line of the gate of the insulated gate type thin film transistor, and can be used as the source The signal line of the wiring and the unit pixel formed by the pixel electrode connected to the drain wiring are arranged in a two-dimensional matrix on the first transparent insulating substrate, and the liquid crystal is filled in the second transparent insulating substrate opposite to the first transparent insulating substrate or Between color filters, characterized by: On the main plane of the first transparent insulating substrate, an insulated gate transistor, a scanning line and a signal line are formed; An opening is provided on at least the drain electrode, and a transparent insulating layer having unevenness on a part of the surface is formed on the first transparent insulating substrate; and On the region with the concave-convex transparent insulating layer, more than one layer of reflective metal layer and transparent conductive layer are laminated to form a reflective electrode, and on other regions, including the opening, a transparent electrode is continuously formed with the transparent conductive layer. Conductive penetrating electrodes. 2. A manufacturing method of a liquid crystal display device, on the main plane of a first transparent insulating substrate, forming at least a scanning line with an insulated gate type thin film transistor, which can be used as the gate of the insulated gate type thin film transistor, and can The signal line as the source wiring and the unit pixel formed by the pixel electrode connected to the drain wiring are arranged in a two-dimensional matrix on the first transparent insulating substrate, and the second transparent insulating substrate opposite to the first transparent insulating substrate is filled with liquid crystal. Between transparent insulating substrates or color filters, it is characterized in that it comprises steps: forming insulated gate transistors, scanning lines and signal lines on the main plane of the first transparent insulating substrate; At least an opening is provided on the drain electrode, and a transparent insulating layer with unevenness is formed on the surface of a partial area on the first transparent insulating substrate; After the transparent conductive layer and more than one metal layer are formed, including the opening, the reflective electrode formed in the area of the concave-convex transparent insulating layer cooperates with the transparent and conductive penetrating electrode outside the concave-convex area. The thickness of the film on the reflective electrode will be forming a photosensitive resin pattern thicker than the thickness of the film on the penetrating electrode; Using the photosensitive resin pattern as a mask plate, after selectively removing the metal layer, the transparent conductive layer is exposed; After reducing the film thickness of the photosensitive resin pattern and exposing the metal layer in the penetrating electrode formation region, the photosensitive resin pattern with reduced film thickness and the metal layer in the penetrating electrode formation region are used as a mask plate to selectively remove the Behind the transparent conductive layer, the transparent insulating layer is exposed; and The photosensitive resin pattern with reduced film thickness is used as a mask plate, and the metal layer in the region where the penetrating electrode is formed is removed to expose the transparent and conductive penetrating electrode.

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