JP2014041187A - Method of manufacturing display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut a cell structure including a sheet-like thin film and a glass substrate, at a low cost.SOLUTION: A method of manufacturing a display device includes a step of forming a sheet-like thin film on a substrate so that the sheet-like thin film can be peeled off the substrate, a step of forming a plurality of active elements on the sheet-like thin film, a step of irradiating the sheet-like thin film and the substrate with a laser beam having a wavelength of 700 to 1100 nm to cut the sheet-like thin film into a plurality of parts and forming cutting grooves on a surface of the substrate, a step of cutting the substrate into a plurality of parts along the grooves, and a step of peeling the substrate off from the sheet-like thin film.

Description

  Embodiments described herein relate generally to a method for manufacturing a display device.

  A substrate used in a conventional active matrix display device is a material that does not bend such as glass, and it is difficult to satisfy the need for a display device that can be deformed into a shape according to a user's request such as a flexible display. For this reason, attempts have been made to form a display on flexible plastic or sheet material, and there are many reports at academic societies and the like. However, since flexible materials cause expansion due to thermal expansion and moisture absorption, when this material is used as a substrate and a thin film transistor is formed thereon, the pattern that was originally formed and the pattern that is newly formed as the lithography process is repeated. Will be inconsistent with each other.

  Currently, in a TFT-LCD thin film transistor manufacturing process using a glass substrate of about 1 m square, magnification correction to cope with expansion and contraction of the base substrate can be performed by an exposure apparatus, but it is about ± 20 ppm. Yes. A typical film value of hygroscopic expansion of 1% (weight increase) is 300 ppm, for example, a size increase of about 0.3 mm in the case of 1 m square, and is not an amount that can be handled by the exposure apparatus.

  On the other hand, a gel-like polyimide is applied on a substrate such as glass to produce a sheet-like thin film, a thin film transistor is formed thereon, and then the above substrate is peeled off to avoid the above problem. it can. This is because the expansion / contraction amount of the film material such as polyimide forming the sheet-like thin film is determined by the expansion / contraction amount of the base substrate.

  In a conventional active matrix display device, a substrate used for manufacturing a thin film transistor is a hard material such as glass. In the manufacturing process, for example, a panel of about 1 m square on which a plurality of thin film transistors are formed is a desired panel. When cutting into sizes, a technique called scribe break is used. This technique is a process of “splitting” a desired shape by scratching the glass surface and cutting by applying pressure from the non-scratched side. This is effective in the conventional structure in which a thin thin film is laminated on a hard and thick glass substrate, but it is difficult to cut a sheet-like thin film that is difficult to cut simultaneously with the cutting of the glass substrate.

  In the case of the liquid crystal display device, the cause is that the liquid crystal is sealed between the two substrates (cell structure), but the sheet-like thin film is also located between the two substrates. Although the sheet-like thin film can be cut if it can be directly scratched, it is difficult to touch it directly because it is between two substrates.

  In order to solve this problem, a method of patterning a sheet-like thin film in advance may be considered, but the process for manufacturing the thin film transistor increases, and in particular, the lithography process increases, resulting in a significant increase in cost. There is a problem of bringing about.

JP 2009-265542 A

  An object of an embodiment of the present invention is to provide a manufacturing method of a display device that cuts a cell structure including a sheet-like thin film and a glass substrate at a low cost.

According to the embodiment, forming a sheet-like thin film that can be peeled from the substrate on the substrate;
Forming a plurality of active elements on the sheet-like thin film;
Irradiating the sheet-like thin film and the substrate with a laser beam having a wavelength of 700 to 1100 nm to cut the sheet-like capsule into a plurality of parts, and forming a cut on the substrate surface;
Cutting the substrate along the notches and dividing the substrate into a plurality of parts;
And a step of peeling the substrate from the sheet-like thin film.

It is a figure for demonstrating the cutting scissors used for embodiment. It is a figure for demonstrating the manufacturing process of the liquid crystal display device concerning embodiment. It is a figure showing the relationship between the injection | throwing-in power of a laser beam, and cutting edge. It is a figure showing the relationship between the frequency of a laser beam, and cutting edge. It is a figure for demonstrating the manufacturing process of the liquid crystal display device concerning embodiment. It is a figure showing the relationship between the frequency of a laser beam, and cutting edge. It is a figure for demonstrating the manufacturing process of the liquid crystal display device concerning embodiment. It is a figure for demonstrating the manufacturing process of the liquid crystal display device concerning embodiment. It is a figure for demonstrating the manufacturing process of the organic electroluminescent display element concerning embodiment. It is a figure for demonstrating the manufacturing process of the organic electroluminescent display element concerning embodiment. It is a figure showing the relationship between the wavelength of the irradiated light, and the light absorption amount.

  The flat display device manufacturing method according to the embodiment includes a step of forming a sheet-like thin film that can be peeled from the substrate on the substrate, a step of forming a plurality of active elements on the sheet-like thin film, a laser beam on the sheet-like thin film and the substrate. And cutting the sheet-like film into a plurality of pieces, and forming a cut on the surface of the substrate, cutting the substrate along the cut and dividing it into a plurality of pieces, peeling the substrate from the sheet-like thin film The process to comprise.

  The laser light used has a wavelength of 700 to 1100 nm.

  According to the embodiment, in the case of a configuration in which a sheet-like thin film is sandwiched between glass substrates as in a liquid crystal display, the wavelength on the order of 700 nm to 1100 nm is such that the absorption at the glass substrate is small and the sheet-like thin film can be sufficiently reached. Is used.

  As the laser light having a wavelength of 700 to 1100 nm, for example, laser light using a light source such as yttrium aluminum gallium (YAG), yttrium aluminum gallium-palladium (YAG-Pd) can be used.

  In particular, by using a laser having a short irradiation time, such as a femtosecond laser, the thermal diffusion length when cutting the glass is shortened, and it is possible to cut with a small cutting edge.

  FIG. 1 is a diagram for explaining cutting paper.

  As shown in the figure, here, the maximum width w of the actual cut end portions 102 and 103 with respect to the line 101 to be originally cut is referred to as cutting.

  Examples of the display device according to the embodiment include a liquid crystal display device and an organic EL display element.

  The sheet-like thin film used in the embodiment has flexibility, and for example, a polyimide film or the like can be used.

Example Hereinafter, an example is shown and an embodiment is described concretely.

Example 1
2A to 2J are views for explaining a manufacturing process of the liquid crystal display device according to the first embodiment.

  First, as shown in FIG. 2A, for example, a glass array substrate 1 having a size of 550 mm × 670 mm, and a glass counter substrate 2 having a size of 550 mm × 670 mm as shown in FIG. prepare.

  A polyimide (PI) coating solution is formed on the array substrate 1 by a slit coating method, pre-baked at 150 ° C. for 5 minutes, and then cured at 350 ° C. for 30 minutes to form a PI sheet-like thin film 3 having a thickness of about 10 μm. Formed.

On the PI sheet-like thin film 3, SiH ₄ + NH ₃ + N ₂ was used as a source gas, and plasma CVD was performed at a substrate temperature T _{sub of} 350 ° C. to form a SiN _x moisture diffusion prevention film (not shown).

Subsequently, a plurality of IGZO-TFTs (not shown) arranged regularly are formed on the SiN _x moisture diffusion barrier film.

  In this example, an IGZO-TFT is used, but a poly Si TFT and an amorphous (α-) Si TFT can be formed instead of the IGZO-TFT.

  Further, a lower electrode (not shown) was formed on each IGZO-TFT, an alignment film (not shown) was formed, and a rubbing process was performed.

  Further, an alignment film (not shown) was formed on the glass counter substrate 2 in the same manner as the lower electrode, and the alignment film was subjected to a rubbing treatment.

  Next, as shown in FIG. 2B, spacers 4 were formed on the alignment film of the PI sheet-like thin film 3.

  Further, as shown in FIG. 2C, the liquid crystal 5 was dropped on the alignment film.

  Subsequently, as shown in FIG. 2 (e), the counter substrate 2 of FIG. 2 (d) was bonded onto the array substrate 1 via the spacer 4, and the liquid crystal 5 was sealed to obtain an assembly.

  Next, as shown in FIG. 2 (f), a YAG laser with a wavelength of 1064 nm is irradiated on the counter substrate 2 made of glass under the conditions of 50 kHz and 100 μJ / shot, and as shown in FIG. The PI sheet-like thin film 3 was cut and the array substrate 1 was cut.

  Here, notches are provided for cutting out 55 array substrates 1 ′ having a size of 94.5 mm × 56.2 mm, for example, from the array substrate 1 having a size of 550 mm × 670 mm.

  Subsequently, as shown in FIG. 2H, the array substrate 1 was cut at the notch by applying an impact near the notch using, for example, a break bar 11 or the like. Here, since the PI sheet-like thin film 3 is cut in advance, the array substrate 1 can be easily cut.

  As shown in FIG. 2 (i), the cut array substrate 1 'was peeled from the PI sheet-like thin film 3, and a plurality of liquid crystal display devices 10 were obtained as shown in FIG. 2 (j).

In addition, using the assembly shown in FIG.
The cutting edge was measured when the input power was changed at kHz.

  FIG. 3 shows a relationship between the laser beam input power and the cutting force.

  In FIG. 3, 101 indicates a scribe line after laser beam irradiation, 102 indicates a cutting scissor after breaking the glass substrate, and 103 indicates a polyimide scissor.

  FIG. 3 shows that when a YAG laser (wavelength: 1064 nm) is used, if it is smaller than 100 μJ / shot at 50 kHz, there is no scribe line in the glass, and the cutting becomes larger during breaks. Moreover, when it becomes high energy, the surface side roughness will become large at the time of irradiation. The polyimide sheet can be cut between 80 μJ and 120 μJ. Under this condition, 100 μJ / shot is good.

Further, by using the assembly shown in FIG. 2 (e), a YAG laser having a wavelength of 1064 nm was measured by changing the frequency at 100 μJ / shot.

  FIG. 4 is a diagram showing the relationship between the frequency of the laser light and the cutting edge.

  Here, 201 indicates a scribe line after laser irradiation.

  When a YAG laser (wavelength 1064 nm) is used, the cutting force is the same up to 50 kHz. If the frequency exceeds 50 kHz, surface roughness increases during irradiation. This is probably due to heat accumulation. It can be seen that 50 kHz is good under this condition.

Example 2
5A to 5J are views for explaining a manufacturing process of the liquid crystal display device according to the second embodiment.

  First, as shown in FIG. 5 (a), an array substrate similar to that of the first embodiment and a counter substrate 2 similar to that of the first embodiment as shown in FIG. 5 (d) are prepared.

  A PI sheet-like thin film 3 was formed on the array substrate 1 in the same manner as in Example 1.

On the PI sheet-like thin film 3, a SiN _x moisture diffusion blocking film (not shown) and a plurality of IGZO-TFTs (not shown) arranged regularly are formed.

  Note that a poly-Si TFT and an α-Si TFT can be formed instead of the IGZO-TFT as in the first embodiment.

  Further, a lower electrode (not shown) was formed on each IGZO-TFT, an alignment film (not shown) was formed, and a rubbing process was performed.

  Further, an alignment film (not shown) was formed on the glass counter substrate 2 in the same manner as the lower electrode, and the alignment film was subjected to a rubbing treatment.

  Next, as shown in FIG. 5B, the spacer 4 was formed on the alignment film of the PI sheet-like thin film 3 in the same manner as in Example 1.

  Subsequently, as shown in FIG. 5C, the counter substrate 2 of FIG. 5D was bonded onto the array substrate 1 via the spacer 4.

  Next, as shown in FIG. 5E, a short pulse laser with a wavelength of 800 nm is irradiated on the glass counter substrate 2 under the conditions of 100 μJ / shot and 70 fs, as shown in FIG. The PI sheet-like thin film 3 was cut, and the array substrate 1 was cut in the same manner as in Example 1.

  Subsequently, as shown in FIG. 5G, the array substrate 1 was cut in the same manner as in Example 1. Here, since the PI sheet-like thin film 3 is cut in advance, the array substrate 1 can be easily cut.

  As shown in FIG. 5 (h), the cut array substrate 1 'is immersed in a container containing liquid crystal. After injecting liquid crystal by osmotic pressure due to capillary action between the array substrate 1 and the counter substrate 2, the opening was closed with a sealing material and sealed.

  Thereafter, the cut out array substrate 1 ′ was peeled from the PI sheet-like thin film 3 to obtain a plurality of liquid crystal display devices 20 as shown in FIG.

  Furthermore, using the assembly shown in FIG. 5C, a short pulse laser having a wavelength of 800 nm was measured while changing the irradiation time per shot.

  A diagram showing the relationship between the frequency of the laser beam and the cutting edge is shown in FIG.

  In the figure, reference numeral 301 denotes a scribe line after laser light irradiation, and 302 denotes a cutting slit of polyimide.

  When a short pulse laser (wavelength 800 nm) is used, the cutting time of the plastic substrate becomes smaller as the irradiation time is shorter. This is probably due to heat accumulation. It can also be seen that the cutting margin of the sheet (polyimide film) is smaller than the substrate under any conditions. If the cutting depth is better, the condition of 70 femtoseconds is the best.

Example 3
7A to 7J are views for explaining the manufacturing process of the liquid crystal display device according to the third embodiment.

  First, as shown in FIG. 7A, an array substrate 1 similar to that in Example 1 is prepared.

  Also, as shown in FIG. 7F, a flexible counter substrate 6 having a size corresponding to each liquid crystal display device is prepared.

  A PI sheet-like thin film 3 was formed on the array substrate 1 in the same manner as in Example 1.

On the PI sheet-like thin film 3, a SiN _x moisture diffusion blocking film (not shown) and a plurality of IGZO-TFTs (not shown) arranged regularly are formed.

  Note that a poly-Si TFT and an α-Si TFT can be formed instead of the IGZO-TFT as in the first embodiment.

  Further, a lower electrode (not shown) was formed on each IGZO-TFT, an alignment film (not shown) was formed, and a rubbing process was performed.

  Further, an alignment film (not shown) was formed on the flexible counter substrate 6 similarly to the lower electrode, and the alignment film was rubbed.

  Next, as shown in FIG. 7B, a spacer 4 was formed on the alignment film of the PI sheet-like thin film 3 in the same manner as in Example 1.

  Thereafter, as shown in FIG. 7C, a short pulse laser with a wavelength of 800 nm is irradiated on the PI sheet-like thin film 3 under the conditions of 100 μJ / shot and 70 fs, and as shown in FIG. The sheet-like thin film 3 was cut, and the array substrate 1 was cut in the same manner as in Example 1.

  Subsequently, as shown in FIG. 7E, the array substrate 1 was cut in the same manner as in Example 1. Here, since the PI sheet-like thin film 3 is cut in advance, the array substrate 1 can be easily cut.

  Further, as shown in FIG. 7 (g), the flexible counter substrate 6 shown in FIG. 7 (f) was bonded to the cut out array substrate 1 'via the spacer 4 while being opposed thereto. The obtained structure is immersed in a container containing liquid crystal. After injecting liquid crystal by osmotic pressure due to capillary action between the array substrate 1 and the counter substrate 2, the opening was closed with a sealing material and sealed.

  Thereafter, the cut out array substrate 1 ′ was peeled off from the PI sheet-like thin film 3 to obtain a plurality of liquid crystal display devices 30 as shown in FIG.

Example 4
8A to 8J are views for explaining a manufacturing process of the liquid crystal display device according to the fourth embodiment.

  First, as shown in FIG. 8A, an array substrate 1 similar to that of Example 1 is prepared.

  Further, as shown in FIG. 8F, a flexible counter substrate 6 having a size corresponding to each liquid crystal display device is prepared.

As shown in FIGS. 8A to 8D, in the same manner as in FIGS. 4A to 4D of Example 3, the PI sheet-like thin film 3 on the array substrate 1 and SiN _x moisture diffusion prevention (not shown) are prevented. A plurality of IGZO-TFTs (not shown) arranged in a film and regularly were formed.

  Note that a poly-Si TFT and an α-Si TFT can be formed instead of the IGZO-TFT as in the first embodiment.

  Further, a lower electrode (not shown) was formed on each IGZO-TFT, an alignment film (not shown) was formed, and a rubbing process was performed.

  Further, an alignment film (not shown) was formed on the flexible counter substrate 6 similarly to the lower electrode, and the alignment film was rubbed.

  Next, as shown in FIG. 8B, a spacer 4 was formed on the alignment film of the PI sheet-like thin film 3 in the same manner as in Example 1.

  Thereafter, as shown in FIG. 8C, a short pulse laser with a wavelength of 800 nm is irradiated on the PI sheet-like thin film 3 under the conditions of 100 μJ / shot and 70 fs, and as shown in FIG. The sheet-like thin film 3 was cut, and the array substrate 1 was cut in the same manner as in Example 1.

  Subsequently, as shown in FIG. 8E, the array substrate 1 was cut in the same manner as in Example 1. Here, since the PI sheet-like thin film 3 is cut in advance, the array substrate 1 can be easily cut. Subsequently, liquid crystal was dropped on the alignment film of the PI sheet-like thin film 3.

  Subsequently, as shown in FIG. 8 (g), the flexible counter substrate 2 shown in FIG. 8 (f) is bonded to the array substrate 1 via the spacer 4 to close the opening, thereby liquid crystal. 5 was sealed.

  Thereafter, as shown in FIG. 8 (h), the cut out array substrate 1 'was peeled from the PI sheet-like thin film 3 to obtain a plurality of liquid crystal display devices 40 as shown in FIG. 8 (i).

Example 5
9A to 9I are views for explaining a manufacturing process of the organic EL display element according to the fifth embodiment.

  First, as shown in FIG. 9A, an array substrate similar to that of the first embodiment and an opposing substrate 2 similar to that of the first embodiment as shown in FIG. 9C are prepared.

  A PI sheet-like thin film 3 was formed on the array substrate 1 in the same manner as in Example 1.

On the PI sheet-like thin film 3, a SiN _x moisture diffusion blocking film (not shown) and a plurality of IGZO-TFTs (not shown) arranged regularly are formed.

  Note that a poly-Si TFT and an α-Si TFT can be formed instead of the IGZO-TFT as in the first embodiment.

  Furthermore, as shown in FIG. 9B, electrodes (not shown) and the organic EL light emitting layer 7 were formed on each IGZO-TFT.

  Subsequently, as shown in FIG. 9 (d), a spacer 4 is formed on the PI sheet-like thin film 3, and the PEN or PET film shown in FIG. 9 (c) can be formed on the array substrate 1 via the spacer 4. A flexible counter substrate 2 was placed opposite to be bonded.

  A filler 8 can be filled in a gap between the counter substrate 2 and the organic EL light emitting layer 7.

  Thereafter, as shown in FIG. 9 (e), a short pulse laser with a wavelength of 800 nm is irradiated from above the counter substrate 2 under the conditions of 100 μJ / shot and 70 fs, and the PI sheet-like thin film as shown in FIG. 9 (f). 3 was cut, and the array substrate 1 was cut.

  Subsequently, as shown in FIG. 9G, the array substrate 1 was cut in the same manner as in Example 1. Here, since the PI sheet-like thin film 3 is cut in advance, the array substrate 1 can be easily cut.

  Thereafter, as shown in FIG. 9 (h), the cut out array substrate 1 'was peeled from the PI sheet-like thin film 3, and a plurality of organic EL display elements 50 were obtained as shown in FIG. 9 (i).

Example 6
FIGS. 10A to 10H are views for explaining a manufacturing process of the organic EL display element according to the sixth embodiment.

  First, as shown in FIG. 10A, an array substrate 1 similar to that in Example 1 is prepared.

  A PI sheet-like thin film 3 was formed on the array substrate 1 in the same manner as in Example 1.

On the PI sheet-like thin film 3, a SiN _x moisture diffusion blocking film (not shown) and a plurality of IGZO-TFTs (not shown) arranged regularly are formed.

  Note that a poly-Si TFT and an α-Si TFT can be formed instead of the IGZO-TFT as in the first embodiment.

  Furthermore, as shown in FIG. 10B, electrodes and organic EL light emitting layers 7 (not shown) were formed on each IGZO-TFT.

  Then, as shown in FIG.10 (c), the organic EL light emitting layer 7 was sealed by forming the thin film 9 on the PI sheet-like thin film 3 via the organic EL light emitting layer 7. Then, as shown in FIG.

  Thereafter, as shown in FIG. 10D, a short pulse laser with a wavelength of 800 nm is irradiated from above the thin film 9 under the conditions of 100 μJ / shot and 70 fs, and the PI sheet-like thin film 3 as shown in FIG. And the array substrate 1 was cut.

  Subsequently, as shown in FIG. 10 (f), the array substrate 1 was cut in the same manner as in Example 1. Here, since the PI sheet-like thin film 3 is cut in advance, the array substrate 1 can be easily cut.

  Thereafter, as shown in FIG. 10G, the cut out array substrate 1 ′ was peeled from the PI sheet-like thin film 3 to obtain a plurality of organic EL display elements 50 as shown in FIG.

  Further, the amount of light absorbed was measured by changing the wavelength of light irradiated on the polyimide film used in the organic EL display element described in Example 5 and the upper substrate (film) made of, for example, PET.

  FIG. 11 shows the relationship between the wavelength of the irradiated light and the amount of light absorbed.

  In the figure, 401 indicates the result of polyimide, and 402 indicates the result of the upper substrate.

  From FIG. 11, when the wavelength is longer than 1100 nm, the absorption of the polyimide (PI) film is lost. If it is shorter than 700 nm, the absorption of the upper substrate increases. In addition, since the absorption of the PI film also increases, it can be seen that the temperature of the irradiated portion changes due to fluctuations in the intensity of the laser beam, and the process margin becomes small.

  According to these embodiments or examples, it can be seen that the cell structure including the sheet-like thin film and the glass substrate can be cut at a low cost without increasing a new process.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 3 ... Sheet-like thin film 10, 20, 30, 40, 50, 60 ... Display apparatus

Claims (3)

Forming a sheet-like thin film peelable from the substrate on the substrate;
Forming a plurality of active elements on the sheet-like thin film;
Irradiating the sheet-like thin film and the substrate with a laser beam having a wavelength of 700 to 1100 nm to cut the sheet-like capsule into a plurality of parts, and forming a cut on the substrate surface;
Cutting the substrate along the notches and dividing the substrate into a plurality of parts;
And a step of peeling the substrate from the sheet-like thin film.   The method according to claim 1, wherein a light source of the laser light is mainly composed of yttrium aluminum gallium.   The method according to claim 1, wherein the laser beam is a femtosecond laser.

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