JPH03107128A - Active matrix display and production thereof - Google Patents

Abstract

PURPOSE:To prevent the disconnection of the drain electrodes, etc., of TFT elements formed on a glass surface formed with black stripes by forming the substrate to have a flat surface having no steps. CONSTITUTION:A resist 2 having the reversal patterns of the black stripes 3 is formed on the glass substrate 1. The surface of the glass substrate 1 which is not coated with the resist 2 is then etched by using the buffer hydrofluoric acid of a hydrofluoric acid etchant and is thereby formed with etching grooves 25 having grating patterns. The depth of the grooves 25 is equaled to the layer thickness of the stripes 3. A Cr film is deposited by evaporation as a metallic film 26 to form the stripes 3 over the entire surface on the substrate 1. The resist 2 on the substrate 1 is dissolved by an org. solvent and the resist 2 and the metallic film 26 on the resist are removed. The remaining metallic film 26 is patterned to form the stripes 3. The stripes 3 are thereby embedded into the etching grooves 25 formed on the surface of the glass substrate 1, by which the flat surface of the substrate 1 having no steps is obtd. The disconnection of the picture element electrodes 9 and drain electrodes 10b is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an active matrix display device and a method for manufacturing the same, and in particular, the present invention relates to an active matrix display device and a method for manufacturing the same, and in particular, the display contrast is improved by black stripes that shield light between picture element electrodes, and the black The present invention relates to an active matrix display device and a method for manufacturing the same, in which electrodes such as switching elements are not disconnected due to stripes.

(Prior Art) FIG. 4 is a sectional view schematically showing a display panel portion of a conventional active matrix display device.

The display panel uses TFT (Th) as a switching element.
The device includes a TFT-side substrate 45 on which an in-film transistor (in-film transistor) element 35 is formed, and a color filter-side substrate 46, with a liquid crystal layer 41 between these substrates. The TFT side substrate 45 has picture element electrodes 36 connected to the TPT element 35 and arranged in a matrix on the surface of the glass substrate 32 on the liquid crystal layer 41 side, and a source pass line (not shown) connected to the TFT element 35. and a gate pass line (not shown), and an alignment film 37 formed on the entire surface of the substrate so as to cover all of them. On the other hand, the color filter side substrate 46 includes the liquid crystal layer 4 of the glass substrate 34.
A color filter 40, a transparent electrode 39, and an alignment film 38 are provided on the surface of the first side in this order from the glass substrate 34 side. In addition, the TFT side substrate 45 and the color filter side substrate 4
6 has a polarizing plate 42 on the surface facing the surface on the liquid crystal layer 41 side.

A backlight source 31 is disposed on a side of the TPT side substrate 45 that is different from the liquid crystal layer 41 side. Backlight light emitted from the backlight light source 31 toward the liquid crystal display panel is transmitted to the TFT side substrate 45, the liquid crystal layer 41. After passing through the color filter side substrate 46 and the like, it is visually recognized as a display pattern. The display pattern is created by sending a signal from the source pass line to the picture element electrode 36 by switching the TPT element 35, and transmitting a signal to the liquid crystal layer 4 between the picture element electrode 36 and the transparent electrode 39.
The liquid crystal layer 41 is formed by applying a voltage to the liquid crystal layer 41 and modulating the optical characteristics of the liquid crystal layer 41. The backlight light transmitted through the color filters 40 has the color of each color filter, and the display pattern is visually recognized as a color image.

FIG. 5 is a plan view schematically showing the surface of the color filter side substrate 46 on the liquid crystal layer 41 side. On the color filter side substrate 46, there are red (R), green (G), and blue (B) color filters 4 as picture elements for creating a color display pattern.
0's are arranged in a matrix. Each color filter 4
A black stripe 33 is formed between 0 and 0 to prevent transmission of backlight light. The black stripe 33 is made of a light-shielding metal film such as Cr (chromium), and is provided to prevent a decrease in display contrast caused by backlight light passing between picture elements.

(Problems to be Solved by the Invention) However, the above-mentioned conventional technology has the following problems.

When bonding the TFT side substrate 45 and the color filter side substrate 46, the position of the picture element electrode 36 on the TFT side substrate 45 and the position of the color filter 40 and black stripe 33 on the color filter side substrate 46 are precisely aligned. There must be. At this time, in order to reliably shield light between the picture element electrodes 40 even if some positional deviation occurs, it is necessary to form black stripes 3 on the color filter side substrate 46.
3 needs to be made wider than the interval between the picture element electrodes 36 on the TFT side substrate 45 by a length corresponding to alignment accuracy. Currently, the accuracy of this alignment is about 10 μm, so the width of the black stripe 330 is
The spacing must be at least 20μ wider than the spacing of 6. In this way, as the width of the black stripe 330 becomes wider, the area of the picture element through which the backlight light passes is reduced, and the brightness of the display pattern is reduced.

An improved version of the above conventional technique will be described below. 6th
The figure is a sectional view showing the improved active matrix display device. In this device, an amorphous silicon (a-Sl) TPT element 69 is used as a switching element. This display device has a TFT side substrate 70
and a color filter side substrate 71, and a TFT side substrate 70.
A liquid crystal layer 64 is provided between the color filter side substrate 71 and the color filter side substrate 71. In the color filter side substrate 71, a color filter 66, a transparent electrode 67, and an alignment film 68 are formed in this order from the glass substrate 65 side on the surface of the glass substrate 65 on the liquid crystal layer 64 side. On the other hand, in the TFT side substrate 70, an etching stopper insulating film 54 is formed on a glass substrate 51 on which black stripes 53 are formed by a method described later, and an area where backlight light is blocked by the black stripes 53 is formed. On the insulating film 54 of
A gate electrode 55 of the element 69 and a gate pass line (not shown) connected to the gate electrode 55 are formed.

A gate insulating film 56 is formed over the entire surface of the glass substrate 51 so as to cover the gate electrode 55 and the gate pass line. T is applied on the gate electrode 55 via the gate insulating film 56.
A non-doped a-SL semiconductor layer 57 that becomes a channel portion of the FT element 69 is formed. On the non-doped 8l semiconductor layer 57, an etching stopper layer 61 for protecting the channel portion from etching and a contact layer 58 separated into the source side and the drain side are formed in this order. A source electrode 60a is formed on the contact layer 58 on the source side, and a source electrode 60a is formed on the contact layer 58 on the drain side.
A drain electrode 60b is formed on top. The source electrode Boa is connected to a source pass line (not shown) formed on the gate insulating film 56, and the drain electrode Bob is connected to the insulating film 56.
The pixel electrode 59 is connected to the pixel electrode 59 formed on the pixel electrode 6 . A protective insulating film 62 and an alignment film 63 are formed on the entire surface of the glass substrate 51 so as to cover all of them.

In this device, the black stripe 53 is located on the glass substrate 51.
is placed above. Therefore, even if the positions of the TFT-side substrate 70 and the color filter-side substrate 71 are misaligned when they are bonded together, the black stripe 53 will remain on the pixel electrode 59.
Make sure to block light between the areas. Therefore, there is no need to increase the width of the black stripe 53 depending on the bonding accuracy.

In this way, the black stripes 53 can reliably block light between the picture element electrodes 59 without reducing the area of the picture elements, and a display pattern with high brightness and high contrast can be obtained.

However, as shown in FIG. 6, a step is formed on the surface of the glass substrate 51 because of the black stripe 53. For this reason, there is a problem in that the picture element electrode 59 and the drain electrode 6ob are likely to be disconnected at the portion indicated by A in FIG. Disconnection of the electrodes causes display defects and lowers the manufacturing yield of the device. Further, even if no wire breakage occurs during manufacturing, the electrode becomes thinner at the gap portion. Therefore, the resistance value of the thinned portion increases, and wire breakage is likely to occur during use of the device, resulting in a significant decrease in the reliability of the device.

Next, a method for forming the black stripes 53 will be explained with reference to FIG.

First, as shown in FIG. 7(a), a metal film (such as Cr) that becomes a black stripe 53 on the entire surface of the glass substrate 51 (
A film thickness of 2000A) 76 is deposited.

After this, a black stripe 53 is placed on the glass substrate 51.
A resist 52 having a pattern of (7th m) is formed.
(b)").Metal film 76 not covered by resist 52
The metal film 76 is patterned into a predetermined shape by etching to form black stripes 53 (
Figure 7(C)). After that, if the resist 52 is removed, the process of forming the black stripes 53 is completed (seventh
Figure (d)). On the surface of the glass substrate 51 on which the black stripes 53 are formed in this way, a step difference of 2000 people is formed because of the black stripes 53.

Also, when etching the metal film 76, the glass substrate 5
The area where the metal film 76 is etched on the surface of
It is damaged by etching and becomes cloudy. Since the part through which the backlight light should pass becomes cloudy, the transmittance of light in that part decreases, resulting in a decrease in display brightness.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide an active matrix display device that prevents electrodes from being disconnected due to black stripes and has high display brightness, and the like. The purpose is to provide a manufacturing method.

(Means for Solving the Problems) An active matrix display device of the present invention includes: a pair of transparent substrates; a display medium inserted between the substrates and whose optical characteristics are modulated in response to an applied voltage; A picture element electrode formed in a matrix and a switching element connected to the picture element electrode are provided on the inner surface of one of the pair of substrates, and the picture element electrode is provided on the inner surface of the substrate on which the switching element is formed. A groove is formed in an area corresponding to an area where no elementary electrode is formed, and the groove is filled with a layer having a light-shielding property, thereby achieving the above object.

The method for manufacturing an active matrix display device of the present invention includes:
A pair of transparent substrates, a display medium inserted between the substrates and whose optical characteristics are modulated in response to an applied voltage, and formed in a matrix on the inner surface of one of the pair of substrates. A method for manufacturing an active matrix display device comprising a picture element electrode and a switching element connected to the picture element electrode, the area comprising: a region on an inner surface of a substrate on which the switching element is formed; a step of forming a resist in a region corresponding to the surface of the substrate, a step of etching the region on the inner surface of the substrate where the resist is not formed to form a groove on the inner surface of the substrate, and a step of forming a layer having a light shielding property on the entire surface of the inner surface of the substrate. and a step of removing the resist and the layer formed on the resist, thereby achieving the above object.

(Example) The present invention will be described below with reference to Examples.

As shown in FIG. 1, the display device of this embodiment includes a TFT-side substrate 20 having a light-transmitting property on which a TPT element 19 etc. are formed as a switching element, and a light-transmitting TFT-side substrate 20 having a light-transmitting property on which a color filter etc. are formed. A color filter side substrate 21 is provided, and a liquid crystal layer 14 is provided between the TFT side substrate 20 and the color filter side substrate 21.

In the color filter side substrate 21, a color filter 16, a transparent electrode 17, and a distribution film 18 are formed in this order from the glass substrate 21 side on the surface of the glass substrate 15 on the liquid crystal layer 14 side.

A black stripe (layer thickness: 2000 layers) 3 is formed on the surface of the glass substrate l of the TFT side substrate 20 using Cr as a material. As shown in Figure 2, black stripe 3
is formed in a lattice shape, and its width, indicated by B in the figure, is 36 mm.
It is μm. The interval between the picture element electrodes 9 arranged in a matrix (indicated by C in FIG. 2) is 30 μm. Since the black stripe 3 is provided on the TFT side substrate 20,
The bonding accuracy between the TFT side substrate 20 and the color filter side substrate 21 does not affect the misalignment between the position of the picture element electrode 9 and the position of the black stripe 3.

Therefore, the width of the black stripe 3 required to completely shield light between the picture element electrodes is determined by considering the accuracy of alignment between the picture element electrode 9 and the black stripe 3 when patterning the picture element electrode 9. Enough. The accuracy of the alignment is about ±3 μm. For this reason, the width of the black stripe 3 is made 20 mm wider than the interval between the picture element electrodes 9 as in the conventional case.
There is no need to make it wider than μ notation.

In addition to metals such as Cr, materials for the black stripe 3 include a-S! A semiconductor or a resin with a large light absorption coefficient may also be used. The layer thickness required to obtain sufficient light-shielding properties as the black stripe 3 varies depending on the material. When the material is metal, if the layer thickness is approximately 0.01 to 1.0 μm or more, 99% or more of light can be absorbed, and excellent light-shielding properties can be obtained. To obtain similar light blocking properties, the material should be a-S! In the case of semiconductors, 0. 2～1゜0
A layer thickness of approximately μm or more is required. When the material is resin, a layer thickness of approximately 0.05 to 2.0 μm or more is required.

As shown in FIG. 1, the black stripe 3 is a groove (width: 36 μm) formed on the inner surface of the glass substrate 1.

The surface of the glass substrate l is flattened. black stripe 3
An etching stopper insulating film 4 is formed on the entire surface of the glass substrate l so as to cover the glass substrate l, and a TPT element 19 is provided on the insulating film 4 in the area where the black stripe 3 is formed.

Similar to the TPT element 19, the source pass line 22 and gate pass line 23 connected to the TPT element 19 are also formed on the region where the black stripe 3 is formed (see FIG. 2). The gate electrode 5 of the TPT element 19 is formed on the insulating film 4 using Ta (tantalum), and the gate insulating film 6 is formed on the entire surface of the glass substrate 1 so as to cover the gate electrode 5. The non-doped Mi3i semiconductor layer 7 which becomes the channel portion of the TPT element 19 is formed on the gate electrode 5 with the gate insulating film 6 interposed therebetween.

On the non-doped a--SI semiconductor layer 7, an etching stopper layer 11 for protecting the channel portion from etching, and a contact layer (phosphorous doped 31 layer) 8 separated on the source side and the drain side are formed in this order. ing. The source electrode 10a is formed on the source side contact layer 8, and is connected to the source pass line 22 (see FIG. 2) on the gate insulating film 6. On the other hand, the drain electrode 10b is formed on the contact layer 8 on the drain side, and is connected to a picture element electrode 9 made of a transparent conductive film such as ITO formed on the gate insulating film θ. 5I is applied to the entire surface of the glass substrate 1 so as to cover all of these.
A protective insulating film 12 made of Nx and an alignment film 13 are formed.

In this embodiment, since the surface of the glass substrate 1 on which the black stripe 3 is formed is substantially flat with no steps, the drain electrode 10b of the TPT element 19 and the pixel electrode 9 formed thereon are etc. will not be disconnected. Therefore, the yield of non-defective products and the reliability of display devices have improved.

In addition, the area of the picture element was not significantly reduced by the black stripes 3, and the space between the picture element electrodes 9 could be reliably shielded from light, making it possible to obtain a display pattern with high brightness and contrast.

Next, we will explain the method for forming the black stripes 3 in the third section.
This will be explained with reference to the figures.

First, as shown in FIG. 3(a), a resist 2 having an inverted pattern of black stripes 3 was formed on a glass substrate 1. Next, by etching the surface of the glass substrate 1 that is not covered with the resist 2 using a hydrofluoric acid etchant such as buffered hydrofluoric acid or hydrofluoric nitric acid, etching grooves having a grid pattern (depth 2000 mm, width 36 μm) 25 was formed (FIG. 3(b)). The depth of the etching groove 25 at this time was set to a value equal to the desired layer thickness of the black stripe 3 to be formed in a later step. Next, a Cr film (thickness: 2,000 yen) was deposited on the entire surface of the glass substrate 1 as a metal film 26 to form the black stripe 3 (FIG. 3(C)). Thereafter, the resist 2 on the glass substrate 1 was dissolved with an organic solvent or the like, and the metal film 26 on the resist 2 was removed together with the resist 2. In this way, by leaving the metal film 26 only in the area where the resist 2 is not formed on the glass substrate 1, the metal film 26 is patterned to form the black stripe 3.
Figure (d)). The black stripe 3 was embedded in an etching groove 25 formed on the surface of the glass substrate 1.

According to the method of this example, the surface of the glass substrate 1 on which the black stripe 3 was formed could be made flat without any steps. For this reason, the picture element electrode 9 formed in a later process
This also eliminates the possibility of disconnection of the drain electrode 10b. Further, the etched portion of the glass substrate 1 is within the area where the backlight light should be blocked, and the portion where the backlight light should be transmitted is not damaged by etching. Therefore, the brightness of the display pattern in the display device formed in this example was higher than the brightness of the display pattern in the display device formed by the conventional method shown in FIG.

In addition, although the embodiment has been described with respect to a device that performs color display, the present invention can also be applied to a monochrome display device that does not include a color filter.

Furthermore, instead of directly forming a black stripe on the inner surface of the substrate on the side where the switching elements are formed, a transparent film such as a silicon nitride film that can be easily etched is formed on the inner surface of the substrate, and the above-mentioned embodiment Similar black stripes may be formed, and a
- Switching elements other than SiTFT elements, such as M
An IM element, diode, varistor, etc. may also be used.

(Effects of the Invention) As described above, in the device of the present invention, the groove formed on the inner surface of the light-transmitting substrate on the side where the switching element is provided is filled with the light-shielding layer (black stripe). In addition, since the surface formed by the surface of the substrate and the surface of the layer in the region where the groove is not formed is substantially flat with no step, the electrode of the switching element formed thereon is flat. There will be no disconnection of the pixel electrodes. Therefore, the yield of good products and reliability of the device are improved.

In addition, since the black stripe is formed on the substrate on the side where the switching elements and picture element electrodes are provided, the width of the black stripe varies depending on the bonding accuracy of this substrate and the other substrate facing the substrate. There is no need to make the spacing wider than the spacing between the picture element electrodes. Therefore, the black stripes can reliably block light between the picture element electrodes without reducing the area of the picture element, and a display pattern with high brightness and contrast can be obtained.

Therefore, according to the active matrix display device of the present invention, high brightness and high quality display can be obtained, and the manufacturing yield thereof is also good.

According to the method of the present invention, the surface formed by the surface of the layer having a light-shielding property formed on the inner surface of the substrate and the surface of the substrate in the area where the layer is not formed is flattened with substantially no steps. can be taken as a thing.

Therefore, the electrodes of switching elements and the like formed on the substrate will not be disconnected.

In addition, the substrate can be etched without damaging the parts through which the backlight light should pass.
The brightness of the backlight light transmitted through the substrate does not decrease.

Therefore, according to the manufacturing method of the present invention, a high-quality active matrix display device with high display brightness can be manufactured with a high yield.

4. Figure 1 is a sectional view showing an embodiment of the present invention, and Figure 2 is a cross-sectional view of the embodiment of the present invention.
A plan view showing the substrate on which PT elements etc. are formed, FIGS. 3(a) to 3(d) are cross-sectional views showing the method of forming black stripes in the example, and FIG. 4 is a conventional active matrix display. 5 is a plan view showing the color filter side substrate of the device, FIG. 6 is a sectional view showing an improved active matrix display device, and FIG.
a) to (d) are cross-sectional views showing a method of forming the black stripes.

1.15...Glass substrate, 2...Resist, 3...
・Black stripe, 4... Insulating film for etching stopper, 5... Gate electrode, 6... Gate insulating film,
7... Non-doped a-st semiconductor layer, 11... Etching stopper layer, 8... Funtact layer (phosphorous doped 8I layer), 9... Picture element electrode, loa... Source electrode, 10b... Drain electrode, 12... Protective insulating film, 13... Alignment film, 14... Liquid crystal layer, 16...
Color filter, 17... Transparent electrode, 18... Alignment film, 19... TFT element, 20... TPT side substrate,
21... Color filter side substrate, 22... Source pass line, 23... Gate pass line.

that's all

Claims (1)

[Claims] 1. A pair of transparent substrates; a display medium inserted between the substrates and whose optical characteristics are modulated in response to an applied voltage; and one of the pair of substrates. The inner surface of the substrate includes picture element electrodes formed in a matrix and switching elements connected to the picture element electrodes, and corresponds to the area where the picture element electrodes are not formed on the inner surface of the substrate where the switching elements are formed. An active matrix display device, wherein a groove is formed in the area where the light is formed, and the groove is filled with a layer having a light-shielding property. 2. a pair of transparent substrates; a display medium inserted between the substrates and whose optical characteristics are modulated in response to applied voltage;
A method for manufacturing an active matrix display device, comprising: a picture element electrode formed in a matrix on the inner surface of one of the pair of substrates, and a switching element connected to the picture element electrode, the switching element comprising: forming a resist on the inner surface of the substrate on which the element is formed, in a region corresponding to the region where the picture element electrode is formed; and etching the region on the inner surface of the substrate where the resist is not formed, and etching the inner surface of the substrate. An active matrix display device comprising: forming a groove; forming a layer having light-shielding properties over the entire inner surface of the substrate; and removing the resist and the layer formed on the resist. manufacturing method.