JPH1010505A - Production of plane type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a display device which is thin and light by using substrates having the thickness enough to sufficiently withstand the warpage by the stresses and heat of films by etching one of the substrates to reduce its thickness after formation of wirings, etc., on the substrates. SOLUTION: The TFT(thin-film transistor) substrate 15 is obtd. by forming gate wirings 1 as scanning wirings, Cs wirings 4 for formation of auxiliary capacitors and source wirings 2 as signal wirings via gate insulating films 6 interposed therebetween on a substrate consisting of glass, etc., in the form of intersecting the respective wirings with each other. Pixel electrodes 5 are formed of transparent conductive films, such as ITO, in the case of a transmission type and of aluminum, etc., in the case of a reflection type. The wirings 1, 2 and the TFTs 3 connected to the electrodes 5 are arranged respectively near these electrodes 5. Next, the wirings 1, 2, the TFTs 3, etc., are coated with a resist 7 so as to protect the wirings, etc., (b). Etching is thereafter executed to reduce the thickness of the rear surface (the side not coated with the resist) of the substrate 15 and the resist is peeled (c). As a result, the display which is small in the thickness and is light in the weight is inexpensively obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a flat display device such as a liquid crystal display device.

[0002]

2. Description of the Related Art A conventional flat display device will be described by using a TFT.
This is performed using a (thin film transistor) type liquid crystal display device as an example. FIG. 1 is a plan view of one pixel portion of the TFT substrate, and FIG.
FIG. 1A shows a cross-sectional view between FIG. First, a TFT substrate 15 is formed by placing a gate wiring 1 as a scanning wiring of aluminum or tantalum, a Cs wiring 4 for forming an auxiliary capacitance, and a gate insulating film 6 of silicon nitride or the like on an insulating substrate such as glass. The source wirings 2 are formed as signal wirings by using aluminum, tantalum, ITO or the like so as to intersect each other. The pixel electrodes 5 are formed of a transparent conductive film such as ITO in the case of a transmission type and aluminum or the like in the case of a reflection type, and are arranged in a matrix form. 2 and a TFT 3 connected to the pixel electrode 5. These include a photolithography process after forming a conductive film or an insulating film,
It is formed by patterning in an etching step.

[0003] Then, as shown in FIG.
An FT substrate 15 and a counter substrate 16 having a counter electrode (not shown) are bonded together, and a gap is made constant with a spacer 13.
The liquid crystal 12 is sealed with a sealant 14 to form a TFT type liquid crystal display device.

[0004]

In recent years, flat display devices have been required to be further reduced in weight and thickness, and it has been necessary to manufacture a flat display device using a thinner substrate than before. . In addition, in order to reduce costs, it is necessary to use a multi-paneling technique for manufacturing a plurality of flat display devices using a large substrate called a mother substrate. In the past, thin and large substrates were used from the beginning of the process, so the substrate warped due to the stress and heat of the deposited film, and the patterning accuracy decreased in the photolithography process, etc. Was causing the problem.

For example, if the size of the substrate is doubled, the warpage of the substrate due to the stress of the film is also doubled, and if the thickness of the substrate is halved, the warpage due to the stress of the film is further doubled. Become. As described above, in order to make a flat display device using a large and thin substrate, much higher patterning accuracy and substrate transfer accuracy are required than in the past, so the size and thickness of the substrate are limited by the capacity of the manufacturing apparatus. Was determined by the limitations of

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a flat display device having a small thickness and a light weight at a low cost.

[0007]

According to a method of manufacturing a flat display device of the present invention, at least a plurality of scanning wirings and signal wirings intersecting each other are provided between a pair of substrates. And forming a wiring on at least the substrate, and etching at least one substrate surface of the substrate to reduce the thickness.

According to this manufacturing method, at the time of forming the scanning wiring and the signal wiring, a thin and light flat type display device is manufactured using a substrate having a thickness enough to withstand the stress of the film and the warpage due to heat. can do.

Further, the etching step may be performed after a pair of substrates are bonded.

According to this manufacturing method, not only can the process be shortened, but also the strength of the substrate can be maintained during bonding.

Further, after forming a plurality of flat display devices having at least a plurality of scanning wirings and signal wirings which intersect each other between a pair of mother substrates, the flat display devices are divided into individual flat display devices. The method of manufacturing a flat display device described above is characterized in that a pair of mother substrates are attached to each other and then etched to make the substrate thinner, and then divided into individual flat display devices.

According to this manufacturing method, at the time of forming the scanning wiring, the signal wiring, and the driving element, a thin and light flat display device is formed by using a substrate having a thickness enough to withstand the warpage due to the stress or heat of the film. Can be manufactured. At this time, according to the size of the mother glass, the thickness of the mother glass can be determined to a thickness that can withstand the size at the same time, so it is possible to further increase the size of the mother glass Thus, the cost of the flat display device can be reduced.

[0013] In the etching step, the 1
The external circuit connection terminal may be protected between the pair of substrates.

Thus, it is not necessary to protect the external circuit connection terminals with a resist or the like, and the process can be shortened.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to the same portions as those in the related art, and the description is simplified. (Embodiment 1) Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of one pixel portion of a TFT (thin film transistor) substrate, and FIG. 2 is a cross-sectional view taken along the line AA of FIG. First, the TFT substrate 15 is formed on a substrate of glass, plastic, or the like by interposing a gate wiring 1 as a scanning wiring of aluminum, tantalum, or the like, a Cs wiring 4 for forming an auxiliary capacitance, and a gate insulating film 6 of silicon nitride or the like. The source wirings 2 are formed as signal wirings by using aluminum, tantalum, ITO or the like so as to intersect each other. And
The pixel electrodes 5 are formed of a transparent conductive film such as ITO in the case of the transmission type and aluminum or the like in the case of the reflection type, and are arranged in a matrix. The gate lines 1, the source lines 2 and T connected to the pixel electrode 5
FT3 is arranged. These are formed by forming a conductive film or an insulating film and then patterning the same in a photolithography step and an etching step (FIG. 2A). Then, an alignment film (not shown) is formed as necessary. Up to this point, it is formed in the same manner as in the prior art.

Next, a gate wiring 1, a source wiring 2, a TF
Cover with a resist 7 etc. to protect T3 etc.
(B)). After that, the TFT substrate 15 is etched.
2 is thinned, and the resist 7 is peeled off (FIG. 2C). For example, when wet etching is performed using glass as the substrate 15, an acid such as hydrofluoric acid (HF), hydrochloric acid (HCl), or sulfuric acid, or an alkaline liquid such as sodium hydroxide (NaOH) may be used alone or as an etchant. , A mixture thereof can be used. Needless to say, the etching may not be completed by one etching but may be divided into two or more. For example, a highly concentrated hydrochloric acid is used as the first etching solution, and a diluted mixture of hydrochloric acid and hydrofluoric acid is used as the second etching.

At this time, when transmitting light such as a transmission type liquid crystal display device is used, one substrate (1 in FIG. 3) on the display side is used.
6) and the other substrate (15 in FIG. 3) which is not the display side, and the display side substrate (1 in FIG. 3) in a reflection type liquid crystal display device or a plasma display.
In the case of use in 6), it is desirable that the light scattering characteristics of the substrate are not changed so as to be seen. Light scattering is less than 1.0% so that haze (ground glass state) is not visible,
Preferably, it is less than 0.5%. Here, it is desirable that the resist 7 can be selectively etched with the TFT substrate 15. For example, when plastic is used for the TFT substrate 15, the selective etching may not be possible depending on the selection of the material. ,
The wiring and the TFT 3 can be protected. Also, TFT
A film that can be selectively etched with the substrate 15 may be formed so as to protect the wiring and the TFT 3, and the TFT substrate 15 may be etched and then removed. If an alignment film is provided and the alignment film can be used as a protective film, a step for forming a protective film such as the resist 7 is not required.

Then, as shown in FIG.
5 and a counter substrate 16 provided with a counter electrode, a color filter and the like (not shown) are adhered to each other, a gap is made constant by a spacer 13, and a liquid crystal 12 is sealed with a sealing material 14, whereby a TFT type liquid crystal display device is formed. Thus, for example, a glass substrate having a thickness of 1.1 mm is used as the TFT substrate 15, the thickness is changed to 0.7 mm by etching, and
When using a glass substrate with a thickness of mm,
0% reduction in thickness and weight can be realized.
Calculated using two 1 mm thick glass substrates. Hereinafter, the following embodiments are calculated under the same conditions).

(Embodiment 2) In this embodiment, the substrate surface of the first embodiment is polished in order to suppress scattering of light after using an etching solution having a high concentration. As described above, when the surface is polished last, light scattering can be suppressed, and the display quality is improved. Of course, the thickness may be reduced by polishing from the beginning, but since it takes time, it is preferable to perform polishing after etching if the process can be shortened. However, when a device such as a TFT which is sensitive to static electricity is formed on the substrate, it is necessary to take measures against static electricity such as grounding.

(Embodiment 3) FIG. 4 shows Embodiment 3 of the present invention.
This will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. FIG. 4 is a plan view of one pixel portion of the counter substrate 16, and FIG.
FIG. First, a light-shielding film 10 of chromium, chromium oxide, resin or the like, a color filter 9 of R, G, B, etc., a counter electrode 8 of ITO or the like, and an orientation film (not shown) are formed on a substrate 16 as necessary. (FIG. 5 (a)).

Next, the color filter 9, the counter electrode 8 and the like are covered with a resist 7 and the like to protect them (FIG. 5).
(B)). Thereafter, etching is performed as described in the first and second embodiments, the back surface (the side not covered with the resist) of the counter substrate 16 is thinned, and the resist 7 is peeled off (FIG. 5C).

Then, as shown in FIG.
5 and the opposing substrate 16 are adhered to each other, the gap is made constant by the spacer 13, and the liquid crystal 12 is sealed with the sealing material 14 to form a TFT type liquid crystal display device. Thus, for example, a glass substrate having a thickness of 1.1 mm is used as the counter substrate 16, the thickness is adjusted to 0.5 mm by etching, and 1.
When a glass substrate having a thickness of 1 mm is used, the thickness and weight can be reduced by about 30% as compared with the related art.

(Embodiment 4) In this embodiment, both the TFT substrate 15 and the opposing substrate 16 are thinned and adhered, instead of making only one substrate thin as described in Embodiments 1 to 3 above. Match. Specifically, the TFT-side substrate 1
A glass substrate having a thickness of 1.1 mm is used as both substrates of the counter substrate 5 and the counter substrate 16, and as described in Embodiments 1 to 3, both substrates are etched to a thickness of 0.7 mm. In that case,
It is possible to realize a reduction in thickness and weight of about 40% as compared with the related art.

(Embodiment 5) FIG. 7 shows Embodiment 5 of the present invention.
This will be described with reference to FIG. The same parts as those in the first to fourth embodiments are denoted by the same reference numerals, and description thereof will be omitted. First, as in the first to fourth embodiments, first, as the TFT substrate 15,
On a substrate such as glass, a gate wiring, a source wiring, a TFT, a pixel electrode, and the like (not shown) are formed. And
As a counter substrate 16, a light-shielding film (not shown), a color filter, a counter electrode, and the like are formed on a substrate such as glass.
After that, the TFT substrate 15 and the counter substrate 16 are bonded together, the gap is made constant by the spacer 13, and the liquid crystal 12 is sealed with the sealing material 14.
(FIG. 7A). Then, the external circuit connection terminal 11 is protected by the resist 7 or the like (FIG. 7B). Thereafter, the TFT substrate 15 and the opposite substrate 16 are etched to make the surfaces of both substrates thinner, and the resist 7 is peeled off (FIG. 7C).

According to such a manufacturing process, the TFT substrate 1
5 and the color filter substrate 16 can be simultaneously etched, so that an increase in the number of steps can be minimized.

(Embodiment 6) FIG. 8 shows Embodiment 6 of the present invention.
This is performed using The same parts as those in the first to fifth embodiments are denoted by the same reference numerals, and description thereof will be omitted. Generally, TF
A flat display device such as a T-type liquid crystal display device is manufactured using a technique called multi-paneling, which is to form a plurality of display device substrates from one large substrate (hereinafter, referred to as a mother substrate). The embodiment can be applied to the above-described multi-panning.

First, as in the first to fifth embodiments, first, a gate wiring, a source wiring, a TFT, a pixel electrode, and the like (not shown) are formed as a mother TFT substrate 17 on a substrate such as glass. Then, a light-shielding film (not shown), a color filter, a counter electrode, and the like are formed on a substrate such as glass as the mother counter substrate 18. Thereafter, the mother TFT substrate 17 and the mother opposing substrate 18 are bonded together, the gap is made constant by the spacer 13, and the liquid crystal 12 is sealed with the sealing material 14 (FIG. 8A). At this time, FIG.
As shown in (a), a plurality of TFT liquid crystal display devices are formed on one set of substrates. Then, the mother TFT substrate 1
7 and the mother opposite substrate 18 are etched to make the substrate surface thinner (FIG. 8B). After that, the liquid crystal display is divided into individual TFT type liquid crystal display devices (not shown).

According to such a manufacturing process, wiring, TF
Since not only the T, the color filter and the counter electrode but also the external circuit connection terminal 11 are covered with the substrate, there is no need to protect the terminal with a resist or the like. Therefore, a resist forming / stripping step is not required. Further, the etching of the mother TFT substrate 17 and the mother opposing substrate 18 can be performed at the same time, so that the number of steps can be minimized.

Although the embodiment has been described with reference to the drawings, the present invention is not limited to the above-described embodiment. For example, as an etching method, a wet etching method has been described. A dry etching method using _four gases or the like may be used. Also, TFT
Although the description has been made by taking the liquid crystal display device as an example, the present invention is not limited thereto, and the present invention can be applied to a simple matrix liquid crystal display device, a plasma display device, and an electroluminescence display device.

[0030]

As described above, according to the method of manufacturing a flat display device of the present invention, at least a plurality of intersecting scanning wirings and signal wirings are provided between a pair of substrates. After forming wiring and switching elements on top,
At least one of the substrates has a step of etching and thinning, so that at the time of forming scanning wirings, signal wirings, and driving elements, a substrate having a thickness sufficient to withstand warpage due to film stress or heat is formed. By using this, a thin and light flat display device can be manufactured.

Further, when the present invention is applied to an active matrix type liquid crystal display device, the active matrix type liquid crystal display device having a complicated manufacturing process and large warpage due to film stress or heat can be made thin and lightweight.

Further, by performing the etching step after bonding a pair of substrates, not only the process can be shortened, but also the strength of the substrate can be increased at the time of bonding.

Further, a plurality of flat display devices having at least a plurality of scanning wirings and signal wirings crossing each other are formed between a pair of substrates, and the flat display devices are divided into individual flat display devices. In a method of manufacturing a type display device, after a pair of substrates are bonded together, the substrate is thinned by etching, and divided into individual flat type display devices to form scanning wiring, signal wiring, and driving elements. At this point, a thin and light flat display device can be manufactured using a substrate having a thickness enough to withstand film stress or warpage due to heat. At this time, according to the size of the mother glass, the thickness of the mother glass can be determined to a thickness that can withstand the size at the same time, so it is possible to further increase the size of the mother glass Thus, the cost of the flat display device can be reduced.

In the etching step, the 1
Since the external circuit connection terminals are protected between the pair of substrates, it is not necessary to protect the external circuit connection terminals with a resist or the like, and the process can be shortened.

[Brief description of the drawings]

FIG. 1 is a plan view of one pixel portion of a TFT substrate according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along a line AA in FIG. 1 and is an explanatory diagram of a manufacturing method according to the first embodiment.

FIG. 3 is a sectional view of the TFT liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a plan view of one pixel portion of an active matrix substrate according to a third embodiment of the present invention.

FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4 and is an explanatory view of a manufacturing method of the third embodiment.

FIG. 6 is a sectional view of a TFT type liquid crystal display device according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating a method for manufacturing a TFT-type liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 8 is a diagram illustrating a method for manufacturing a TFT liquid crystal display device according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gate wiring 2 Source wiring 3 Thin film transistor (TFT) 5 Pixel electrode 6 Gate insulating film 7 Resist 15 TFT substrate 16 Counter substrate 17 Mother TFT substrate 18 Mother counter substrate

Claims (4)

[Claims] 1. A method of manufacturing a flat display device having at least a plurality of scanning wirings and signal wirings intersecting each other between a pair of substrates, wherein at least wirings are formed on the substrates, A method for manufacturing a flat display device, comprising a step of etching at least one substrate surface to make it thinner. 2. The method according to claim 1, wherein the etching step is performed after bonding a pair of substrates. 3. After forming a plurality of flat display devices having at least a plurality of scanning wirings and signal wirings intersecting each other between a pair of mother substrates, the flat display devices are divided and individually separated. A method of manufacturing a flat display device, comprising: bonding a pair of mother substrates, etching the substrate, thinning the substrate, and dividing the substrate into individual flat display devices. Manufacturing method. 4. The method according to claim 3, wherein an external circuit connection terminal is protected between the pair of substrates during the etching step.