KR20120018701A - Laser lift-off method and laser lift-off apparatus - Google Patents

Abstract

PURPOSE: A laser lift-off method and a laser lift-off apparatus are provided to easily separate a thin film electronic device from a substrate by removing a sacrificial layer with a laser beam. CONSTITUTION: A sacrificial layer(200) is formed on a substrate(100). An adhesive layer(300) is formed on the sacrificial layer. A flexible substrate(400) is laminated on the adhesive layer. A thin film electronic device(500) is formed on the flexible substrate. A laser beam is irradiated to the sacrificial layer to separate the thin film electronic device from the substrate.

Description

Laser lift-off method and laser lift-off apparatus

The present invention relates to a laser liftoff method and apparatus, and more particularly, to a laser liftoff method and apparatus for peeling a carrier substrate by irradiating a laser beam output from a laser source in a suitable wavelength band to remove the sacrificial layer. will be.

Due to the development of the information society, display devices capable of displaying information have been actively developed. The display device includes a liquid crystal display device, an organic electro-luminescence display device, a plasma display panel, and a field emission display device.

Recently, flexible display devices that can be bent by enhancing flexible performance have been actively studied. In particular, the flexible organic light emitting display device does not require a backlight unit, unlike a liquid crystal display device, thereby minimizing thickness and reducing power consumption.

Forming various device parts including a thin film transistor (TFT), an LCD, and an OLED on a flexible plastic substrate is an important core process in manufacturing a flexible display panel (FDP).

Therefore, as an alternative to using the existing panel fabrication process and equipment, a sacrificial layer and an adhesive layer are formed on a carrier substrate such as a glass substrate, a flexible substrate having flexibility including plastic is laminated thereon, and a flexible substrate. After directly fabricating the device portion including the thin film transistor array, a step of peeling the carrier substrate from the flexible substrate is performed.

However, in the process of detaching the carrier substrate, the intermolecular bonding force of the sacrificial layer is about 3.5 eV (electron volt), while the laser beam irradiated to the sacrificial layer is a gas type excimer laser. It is about 5.5eV or more.

Therefore, as the laser beam of energy higher than the intermolecular bonding force of the sacrificial layer is irradiated more than necessary, the sacrificial layer as well as the soluble substrate on which the thin film transistor array is generated may be affected and degrade in performance.

Accordingly, an object of the present invention is to solve such a conventional problem, and by separating the sacrificial layer by irradiating a laser beam of energy capable of releasing the intermolecular bonding force of the sacrificial layer to facilitate separation of the substrate and the thin film electronic device. It is an object of the present invention to provide a laser liftoff method and apparatus to be achieved.

In order to achieve the above object, the laser lift-off method of the present invention includes a plane including a substrate made of a transparent material, a thin film electronic device formed on the substrate, and a sacrificial layer formed between the substrate and the thin film electronic device. In the display device, a laser beam is irradiated to the sacrificial layer through the substrate to separate the substrate from the thin film electronic device, and the laser source from which the laser beam is output is a DPSS (Diode Pumped Solid State) laser or LPSS ( Lamp Pumped Solid State) and the laser beam is characterized in that having a wavelength in the range of 300 ~ 600nm.

In addition, in order to achieve the above object, the laser lift-off apparatus of the present invention includes a substrate of a light transmissive material, a thin film electronic element formed on the substrate, and a sacrificial layer formed between the substrate and the thin film electronic element. An apparatus for processing a flat panel display device, the apparatus comprising: a laser source for outputting a laser beam irradiated to the substrate side to separate the substrate and the thin film electronic device, wherein the laser source is a diode pumped solid state (DPSS) laser. Or LPSS (Lamp Pumped Solid State) laser, the laser source is characterized in that for outputting a laser beam having a wavelength in the range of 300 ~ 600nm.

The laser lift-off method and apparatus of the present invention have an effect of easily separating the substrate and the thin film electronic device by removing the sacrificial layer by irradiating a laser beam to release the intermolecular bonding force of the sacrificial layer.

In addition, by using a solid-state laser source instead of the excimer laser using a conventional toxic gas, the configuration of the device is simplified, there is an effect that the equipment can be operated easily and safely and safely.

In addition, since only the minimum energy is output from the DPSS laser source in the range of releasing the intermolecular binding force between the sacrificial layers, power consumption can be saved, and the damage to the flexible substrate disposed under the sacrificial layer can be prevented to the maximum. .

1 is a schematic diagram showing a laser liftoff process according to the present invention laser liftoff apparatus,
2 is a schematic view showing one embodiment of the laser liftoff device of the present invention;
3 is a schematic view showing another embodiment of the laser liftoff device of the present invention;
4 is a schematic view showing another embodiment of the laser liftoff device of the present invention;
5 is a graph showing an energy distribution of a laser beam according to the present invention;
6 is a view for explaining an embodiment of the laser liftoff method of the present invention;
7 is a view for explaining another embodiment of the laser liftoff method of the present invention;
8 illustrates another embodiment of the laser liftoff method of the present invention.

Hereinafter, the configuration and operation of the laser lift-off device and method of the present invention according to the accompanying drawings in more detail.

1 is a schematic diagram showing a laser liftoff process according to the laser liftoff apparatus of the present invention.

The present invention is a flexible laminated to the substrate 100, the sacrificial layer 200 formed on the substrate 100, the adhesive layer 300 formed on the sacrificial layer 200, and the adhesive layer 300 The substrate 100 may be removed from the planar display device 10 including the substrate 400 and the thin film electronic device 500 formed on the flexible substrate 400 to remove the sacrificial layer 200. In the laser lift-off device for irradiating a laser beam to the laser beam, the laser beam is output from a laser source that outputs a wavelength in the range of 300 ~ 600nm.

First, the substrate 100 is preferably formed of an insulating material while having light transmittance such as glass.

The sacrificial layer 200 may be formed of a material selected from the group consisting of a transparent metal compound, an alkali water soluble polymer compound, and an acidic water soluble polymer compound. Representative examples of the transparent metal compound include indium tin oxide (ITO), indium zinc oxide (IZO), and zinc oxide (ZnO).

Alkali water-soluble polymer compounds are polymer compounds having an anion in a polymer chain dissolved in an aqueous alkali solution, and typically include copolymers containing polyacrylic acid or polyacrylic acid, copolymers containing polystyrene or polystyrene, and polysulfone. Copolymers comprising polysulfate or polysulfite and copolymers comprising polyamic acid or polyamic acid are used.

Acidic water-soluble polymer compounds are polymer compounds having a cation in a polymer chain by dissolving in an acidic aqueous solution. Typically, a copolymer containing polyamine or polyamine, polyvinyl alcohol (PVA), polyallylamine and poly Acrylic acid (polyacrylic acid) is used.

In addition, an amorphous silicon (a-Si: H, a-SiC: H, etc.) thin film may be used as the sacrificial layer 200.

The sacrificial layer 200 is capable of laser transmission, and may be formed to a thickness of 200 nm or less. When the thickness of the sacrificial layer 200 exceeds 200 nm, the sacrificial layer 200 does not completely detach by the laser irradiation and remains, resulting in defects in the display device. It is preferable to form at 200 nm or less.

In addition, the adhesive layer 300 may be formed of a polymer material such as polyimide and photoresist capable of laser detachment. The thickness of the adhesive layer 300 is preferably formed within 20nm to 50nm. The adhesive layer 300 has a thickness of 20 nm to 20 nm, considering the role of the adhesive to assist the detachment of the substrate 100 after the adhesion of the substrate 100 and the flexible substrate 400 and completion of the display device. It is preferable to form within 50 nm.

In addition, the adhesive layer 300 may use a polyimide excellent in heat resistance, and may be used by mixing a polyimide and a coupler.

The adhesive layer 300 as described above may be formed by a printing method, a slit coating method, a spin coating method, a dipping method, or the like.

The polyimide used in the adhesive layer 300 may be formed of a transparent polyimide and an opaque polyimide.

The transparent polyimide may be used as a color filter substrate in manufacturing a color electrophoretic display, and the opaque polyimide may be used in a thin film transistor substrate of an electrophoretic display and a color electrophoretic display.

The flexible substrate 400 may be formed by a lamination method using a roll. The flexible substrate 400 includes kapton, polyethersulphone (PES), polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyethylene naphthalate ( It is preferable to include a material selected from the group consisting of polyethylenenaphthalate (PEN), polyacrylate (PAR), fiber reinforced plastic (FRP) and the like.

The thin film electronic device 500 is formed on the flexible substrate 400. Referring to the thin film electronic device 500 as an example, a thin film transistor array is formed on the flexible substrate 400. The thin film transistor array may include a gate line, a data line, a thin film transistor connected to the gate line and the data line, and a first electrode connected thereto. However, the first electrode may be connected to the gate line and the data line via the plurality of thin film transistors.

The thin film transistor supplies the data voltage supplied from the data line to the first electrode in response to the scan signal supplied from the gate line. The thin film transistor may include a gate electrode, a source electrode, a drain electrode, an active layer, and an ohmic contact layer.

In addition, a display layer and an opposing substrate may be formed on the thin film transistor array.

The display layer may include a liquid crystal layer, an electrophoretic layer or an organic light emitting layer.

The opposing substrate includes a second electrode and is formed of a transparent material. For example, the opposing substrate may be formed in the form of a film using a plastic or glass material.

The second electrode is formed on the opposing substrate to face the first electrode. The second electrode is formed of a transparent material to transmit incident light like the counter substrate. For example, the second electrode may be formed of a material such as indium tin oxide (ITO), indium zinc oxide (IZO), and carbon nanotube (CNT). The second electrode may receive a constant voltage such as a common voltage. Here, the opposing substrate may further include a substrate protective film.

The first electrode charges the voltage according to the data voltage supplied from the thin film transistor to generate a potential difference with the second electrode. By this potential difference, the display layer located between the flexible substrate and the counter substrate is driven to display an image.

In addition, it should be noted that a central processing unit (CPU), a memory, a thin film battery, a controller, and the like, which form a system for realizing a display, may be further mounted on the flexible substrate 400.

The laser beam is irradiated onto the substrate 100 to peel the substrate 100 and remove the sacrificial layer 200 from the flat panel display configured as described above. In the laser lift-off device of the present invention, the laser beam is 300 to 600 nm. And output from a laser source that outputs a range of wavelengths.

In general, conventional laser beams have used laser beams having a wavelength of about 248 nm output from an excimer laser.

However, while the laser beam output from the excimer laser as described above has an energy of 5.5 eV, the intermolecular bonding force of the sacrificial layer 200 is 3.5 eV, which is more than the energy required to release the intermolecular bonding force of the sacrificial layer 200. The laser beam of a large quantity is irradiated above.

Therefore, in the present invention, the wavelength of the laser beam output from the laser source is limited to the range of 300 to 600 nm so that the laser beam has an energy of 3.6 eV, so that an appropriate energy consumption can be achieved in the laser lift-off method.

According to a preferred embodiment of the invention, the laser source is a Diode Pumped Solid State (DPSS) laser.

DPSS laser is a solid-state laser is a niobium YIG (Yittrium Aluminum Garnet) (YAG), Vanadate (YVO4), YLF (YLF) laser, is a laser that is excited by diode laser pumping to generate a laser light source.

When the DPSS laser is used as the laser source as described above, it is not necessary to use a mask that was previously required to mask the cross-sectional shape of the laser in the gas type excimer laser due to the characteristics of the DPSS laser as a solid laser. The advantage is that the configuration is simplified.

In addition, in the case of the conventional excimer laser, the frequency is usually 20 to 100 Hz and the cross-sectional area is large so that the laser is irradiated in the form of a line beam.

However, the DPSS laser has a high frequency of 20 to 100 kHz, and has a circular spot beam shape with a small cross-sectional area. As a result, the energy per pulse is significantly reduced.

On the other hand, the laser source of the present invention may be a LP Pump (Lamp Pumped Solid State) laser that is excited by lamp pumping to generate a laser light source.

The laser beam of the present invention is characterized by having an energy density in the range of 0.3 ~ 0.9 J / cm 2.

According to a preferred embodiment of the present invention, the substrate 100 is at least one glass material selected from the group consisting of sapphire, quartz, borosilicate glass and fused silica glass It includes.

In addition, according to a preferred embodiment of the present invention, the adhesive layer 300 is formed by including a polyimide or photoresist that can be removed by laser irradiation as mentioned above.

According to a preferred embodiment of the present invention, the thin film electronic device 500 is any one unit selected from an organic light-emitting diode (OLED), a thin film transistor (TFT) LCD, and an electrophoresis display (EPD). Consists of elements.

2 is a schematic view showing an embodiment of the laser lift-off device of the present invention, FIG. 3 is a schematic view showing another embodiment of the laser lift-off device of the present invention, and FIG. 4 is a laser lift-off device of the present invention. A schematic diagram showing another embodiment of.

According to a preferred embodiment of the present invention as shown in FIGS. 2 to 4, the first galvanometer scanner 610 reflects the incident laser beam toward the substrate 100 so that the laser beam is irradiated onto the substrate 100. ), And a second galvanometer scanner 620.

The first galvanometer scanner 610 includes a mirror 611 for reflecting the incident laser beam in a direction different from the incident direction, and a driving source 612 for rotating the mirror 611. The mirror 611 is a reflecting means for reflecting a laser beam and irradiating the substrate 100 while repeatedly rotating at a predetermined angle. The mirror 611 has a polygonal flat plate shape and has a reflecting surface that reflects a laser beam output from a laser source. do. Here, the mirror 611 is irradiated while feeding the laser beam by repeatedly rotating at a predetermined angle by a driving means such as a motor. The laser beam incident on the mirror 611 is reciprocated along the virtual X axis on the substrate 100 as the mirror 611 is rotated.

The second galvanometer scanner 620 includes a mirror 621 for reflecting the incident laser beam in a direction different from the incident direction, and a driving source 622 for rotating the mirror 621. The laser beam incident on the mirror 621 is reciprocated along the virtual Y axis crossing (orthogonally) the X axis on the substrate 100 as the mirror 621 is rotated.

As such, the laser beam is reciprocated along the X axis on the substrate 100 by the first galvanometer scanner 610 and reciprocated along the Y axis on the substrate 100 by the second galvanometer scanner 620. The laser beam may be irradiated on the entire surface of the substrate 100.

Referring to FIG. 3, which is another embodiment of the present invention, the laser lift-off apparatus of the present invention includes a laser scanner 630 for reflecting an incident laser beam toward the substrate 100 so that the laser beam is irradiated onto the substrate 100; Galvanometer scanner 640.

The laser scanner 630 has a plurality of reflective surfaces and includes a polygon mirror 631 for reflecting an incident laser beam in a direction different from the incident direction, and a driving source 632 for rotating the polygon mirror 631. do. The polygon mirror 631 has a polygonal pillar shape, and a mirror is attached to the side surface of the polygonal pillar. The mirror attached to each side rotates in one direction about an axis, and is rotated by a driving means such as a motor, thereby changing the reflection angle of the light incident by the rotation, and transporting the laser beam to the substrate 100. The laser beam incident on the polygon mirror 631 is reciprocated along the virtual X axis on the substrate 100 as the polygon mirror 631 is rotated.

The galvanometer scanner 640 includes a mirror 641 for reflecting the incident laser beam in a direction different from the incident direction, and a driving source 642 for rotating the mirror 641. The laser beam incident on the mirror 641 is reciprocated along the virtual Y axis crossing (orthogonally) the X axis on the substrate 100 as the mirror 641 is rotated.

The polygon mirror 631 rotates to reflect the laser beam to the mirror attached to the side to irradiate the laser beam along the X axis, and the mirror 641 rotates at a predetermined angle to reflect the laser beam to reflect the laser beam along the Y axis. By irradiating, the laser beam may be irradiated on the entire surface of the substrate 100.

Referring to FIG. 4, which is another embodiment of the present invention, the laser lift-off device of the present invention includes a laser scanner 650 for reflecting an incident laser beam toward the substrate 100 so that the laser beam is irradiated onto the substrate 100. The substrate transfer part 700 is included.

The laser scanner 650 has a plurality of reflecting surfaces and includes a polygon mirror 651 for reflecting an incident laser beam in a direction different from the incident direction, and a driving source 652 for rotating the polygon mirror 651. do. The laser beam incident on the polygon mirror 651 is reciprocated along the virtual X axis on the substrate 100 as the polygon mirror 651 is rotated.

The substrate transfer part 700 reciprocates the substrate 100 along a virtual Y axis crossing the X axis on the substrate. The polygon mirror 651 rotates to reflect the laser beam to the mirror attached to the side to irradiate the laser beam along the X axis, and the substrate transfer part 700 is connected to the driving means to transfer the substrate 100 along the Y axis, The laser beam may be irradiated on the entire surface of the substrate 100.

Figure 5 is a graph showing the energy distribution of the laser beam according to the present invention, according to a preferred embodiment of the present invention, the laser beam is irradiated in the form of a circular beam having a cross-sectional energy distribution Gaussian distribution, by the laser beam irradiated In order to keep the amount of energy accumulated in any area uniformly, laser beams in the form of neighboring circular beams may be irradiated to overlap each other. More preferably, the adjacently irradiated laser beams may be irradiated at least 50% of each other.

First, the laser beam can be irradiated with a DPSS laser and has a high frequency of about 1000 irradiations per second. The laser beam has a Gaussian distribution, especially when measuring the energy distribution irradiated once.

Therefore, in order to maintain a uniform energy intensity, the energy distribution of the laser beam irradiated adjacently is irradiated at least 50% or more.

For example, the nth irradiated laser beam is irradiated such that the energy distribution overlaps with the n-1th irradiated laser beam by 50% or more, and the n + 1th irradiated laser beam has the energy distribution with the nth irradiated laser beam. Irradiation over 50% overlap.

That is, when the maximum point of the nth laser beam energy is located at the center of the time when the nth laser beam is irradiated, when the n-1th irradiated laser beam is the maximum point, the nth laser beam starts to be irradiated, and the nth irradiation When the energy of the laser beam becomes the maximum point, the n + 1 th laser beam starts to be irradiated.

Therefore, although the nth irradiated laser beam has a Gaussian energy distribution, the energy of the two laser beams is overlapped at the portion where the n-1th irradiated laser beam and the n + 1th irradiated laser beam overlap on both sides. When the energy amounts are added together because they overlap, the energy equal to the maximum point of the nth laser beam energy is maintained and a uniform energy distribution is achieved.

As described above, the reason why the laser lift-off method is possible by using a DPSS laser that irradiates relatively little pulse energy is because the laser is focused by focusing on a small circular beam, specifically, an excimer laser. This is because the energy per area can be obtained by overlapping the entire area while maintaining a much faster scan rate with a much larger pulse repetition rate of about 1000 times and a galvanometer scanner or polygon scanner.

As such, the excimer laser irradiates the laser using a line beam with uniform energy at one time, but instead of providing the same energy at all positions simultaneously due to the characteristics of a process called lift-off, the energy accumulated in the unit area is the same. Good control of the overlapping ratio of the laser beam to produce a good enough lift-off result.

In particular, the Gaussian beam (Gaussian beam) can be ensured uniformly the total energy irradiated per area as the film separation quality uniformity is made by the cumulative energy uniformity when the overlapping method is irradiated.

Therefore, the laser lift-off method can be carried out even if the excimer laser and homogenizing optical system, which are expensive in maintenance, complicated and occupy a large space, are replaced with the DPSS laser and the scanning optical system.

On the other hand, the laser lift-off device may be configured with a DPSS laser, a homogenizing optical system and a scanning optical system.

In this configuration, the laser beam irradiated from the DPSS laser is irradiated in the form of a square beam in which the cross-sectional energy distribution forms a top hat distribution while passing through the homogenization optical system. Compared with the circular beam of the Gaussian distribution, the square beam of the top hat distribution does not need to superimpose the laser beam irradiated adjacently because the cross-sectional energy is homogeneous first. Therefore, since the pitch between the laser beam and the laser beam can be widened, the processing speed can be improved.

On the other hand, the DPSS laser has an excellent point in terms of the possibility of damaging the flexible substrate. Since the peak power of the DPSS laser is sufficient to process the sacrificial layer 200 without thermal influence and is low to process the flexible substrate 400, the laser beam output from the DPSS laser will damage the flexible substrate 400. The probability is quite low. On the other hand, since the peak power of the excimer laser is capable of processing not only the sacrificial layer 200 and the flexible substrate 400 but also a metal material, the laser beam output from the excimer laser may damage the flexible substrate 400. This is quite high. In view of this, it can be seen that the laser liftoff apparatus and method using a DPSS laser according to the present invention is superior to the conventional apparatus and method using an excimer laser.

Hereinafter, various embodiments of the laser liftoff method according to the present invention will be described with reference to FIGS. 6 to 8.

6 is a view for explaining an embodiment of the laser lift-off method of the present invention, Figure 7 is a view for explaining another embodiment of the laser lift-off method of the present invention, Figure 8 is a laser lift-off method of the present invention A diagram illustrating still another embodiment of.

Referring to FIG. 6, in the present invention, the laser beam L is defocused and irradiated onto the sacrificial layer 200.

The laser beam L is focused on or inside the substrate 100 and then irradiated to the sacrificial layer 200 in a defocused state through the substrate 100.

By using the laser beam in a defocused state, the present invention can prevent the risk of damage to the substrate and bring about a wide range of processing conditions. That is, in the image projection method of the excimer laser, since the beam quality (uniformity) is maintained only in the focused state, there is a high risk of damaging the flexible substrate 400 adjacent to the sacrificial layer 200 which is the focusing plane. However, by using the defocused laser beam in the lift-off method, damage to the substrate can be minimized as compared with a conventional excimer laser.

In addition, by using the defocused laser beam, the optimization range of the processing conditions can be variously changed while changing the laser power and the degree of defocus. The amount of energy per unit area of the laser beam changes depending on how defocused the focusing position is. For example, if the focus is relatively defocused slightly, the amount of energy per unit area of the laser beam is large, so that the laser power can be lowered and processed. On the contrary, if the focus is relatively defocused, the amount of energy per unit area of the laser beam is small, so that the laser power can be increased. As such, when the defocused laser beam is used, the amount of energy per unit area of the laser beam changes according to the defocused degree, and thus, an optimization range of processing conditions may be widened.

In addition, the defocused laser beam is less sensitive to the height variation of the substrate, and thus a more uniform liftoff process can be performed.

7, the laser lift-off method of the present invention can be processed by changing the power of the laser beam according to the processing line.

The laser lift-off method is performed while irradiating laser beams superimposed along a line. The laser beam is moved while being irradiated to overlap each other along the virtual first processing line L1 on the sacrificial layer 200, and when the processing for the first processing line L1 is completed, the laser beam is changed again by changing the moving direction. The layer 200 moves while being overlapped with each other along the second processing line L2 parallel to the first processing line L1. When the processing for the second processing line L2 is completed, the moving direction is changed again. The laser beam is moved while overlapping each other along the third processing line L3 parallel to the second processing line L2 on the sacrificial layer 200.

In order to separate the substrate 100 and the thin film electronic device 500, it is not necessary to remove the sacrificial layer 200 at all positions of the sacrificial layer 200. When only a portion of the sacrificial layer 200 is removed and a sufficient external force is provided to separate the substrate 100 from the thin film electronic device 500, the sacrificial layer 200 of the remaining portion, which is not removed, is also separated, thereby leaving the substrate with respect to the entire area. The separation between the 100 and the thin film electronic device 500 becomes possible.

Therefore, instead of maintaining the power of the same laser beam in all the processing lines, it is possible to change the power of the laser beam according to the processing line. For example, the power of the laser beam irradiated along the first processing line L1 is relatively high, the power of the laser beam irradiated along the second processing line L2 is relatively low, and the third processing line is relatively low. The power of the laser beam irradiated along (L3) is equal to the power of the laser beam irradiated along the first processing line (L1). The power pattern of can be processed repeatedly. In this case, the power of the laser beam irradiated along the second processing line L2 may be adjusted to zero.

In this way, by varying the power of the laser beam according to the processing line to prevent the unnecessary energy is transferred to the substrate, it is possible to prevent damage to the components used in the product, such as the flexible substrate 400 located below the sacrificial layer (200). Can be.

Referring to FIG. 8, the laser liftoff method of the present invention may selectively remove the sacrificial layer 200.

As shown in FIG. 8, the sacrificial layer 200 may be virtually divided into an inner region 201 and an edge region 202.

The laser beam L is irradiated only to the inner region 201 of the sacrificial layer 200 with respect to the partitioned sacrificial layer 200, such that the substrate 200 and the thin film electronic device 500 corresponding to the inner region 201 are exposed. ) Separates the areas of. In this case, the edge region 202 of the sacrificial layer 200 remains without being removed, and the substrate 100 corresponding to the edge region 202 and the regions of the thin film electronic device 500 remain bonded to each other.

As mentioned above, by selectively removing the sacrificial layer 200, the edge regions of the substrate 100 and the thin film electronic device 500 are bonded to each other, thereby providing a surface of the flexible substrate 400 in a subsequent process. Contamination or damage by this impurity can be prevented. The edge region may be maintained in a bonded state to block contact with external impurities as much as possible, and in the final process, an external force may be applied to completely separate the substrate 100 and the thin film electronic device 500.

Although the present invention has been described with reference to the embodiments shown in the accompanying drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. There will be. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

100 substrate 200 sacrificial layer
300: adhesive layer 400: flexible substrate
500: thin film electronic device 610: first galvanometer scanner
620: second galvanometer scanner 630: laser scanner
640: galvanometer scanner 650: laser scanner
700: substrate transfer part

Claims (12)

A flat display device comprising a substrate made of a light transmissive material, a thin film electronic element formed on the substrate, and a sacrificial layer formed between the substrate and the thin film electronic element,
Irradiating a laser beam to the sacrificial layer through the substrate to separate the substrate from the thin film electronic device,
The laser source to which the laser beam is output is a Diode Pumped Solid State (DPSS) laser or a Lamp Pumped Solid State (LPSS) laser,
And the laser beam has a wavelength in the range of 300 to 600 nm. The method of claim 1,
And the laser beam is focused on or inside the substrate and then irradiated to the sacrificial layer in a defocused state through the substrate. The method of claim 1,
The laser beam is irradiated in the form of a circular beam having a cross-sectional energy distribution of Gaussian distribution,
The laser beam of the laser lift-off method characterized in that the laser beams in the form of neighboring circular beams are irradiated to overlap each other so that the amount of energy accumulated in any area by the irradiated laser beam is kept uniform. The method of claim 3,
The laser beam irradiated adjacently irradiated with at least 50% overlap each other laser liftoff method. The method of claim 1,
And the laser beam is irradiated in the form of a square beam having a top hat distribution in which the energy distribution of the cross section is homogeneous. The method of claim 1,
The laser beam is moved while overlapping each other along the virtual first processing line on the sacrificial layer,
The laser beam is moved while overlapping each other along the second processing line parallel to the first processing line on the sacrificial layer,
The power of the laser beam irradiated along the first processing line and the power of the laser beam irradiated along the second processing line are different. The method of claim 1,
The sacrificial layer is divided into an inner region and an edge region,
By irradiating a laser beam only to the inner region of the sacrificial layer, the substrate and the region of the thin film electronic element corresponding to the inner region are separated from each other, and the substrate and the region of the thin film electronic element corresponding to the edge region are separated from each other. The laser liftoff method of maintaining the bonded state. The method of claim 1,
And the laser beam has an energy density in the range of 0.3 to 0.9 J / cm 2. A flat display device comprising a substrate made of a transparent material, a thin film electronic device formed on the substrate, and a sacrificial layer formed between the substrate and the thin film electronic device.
In order to separate the substrate and the thin film electronic device, a laser source for outputting a laser beam irradiated to the substrate side,
The laser source is a diode pumped solid state (DPSS) laser or a lamp pumped solid state (LPSS) laser,
The laser source is a laser lift-off device, characterized in that for outputting a laser beam having a wavelength in the range of 300 ~ 600nm. 10. The method of claim 9,
A first galvanometer scanner having a mirror for reflecting the incident laser beam in a direction different from the incident direction, a driving source for rotating the mirror, and moving the laser beam along the virtual X axis on the substrate;
A second galvanometer for reflecting the incident laser beam in a direction different from the incident direction and a driving source for rotating the mirror, the second galvanometer for moving the laser beam along an imaginary Y axis crossing the X axis on the substrate; And a scanner further comprising a scanner. 10. The method of claim 9,
A polygon mirror having a plurality of reflective surfaces and reflecting an incident laser beam in a direction different from the incident direction, and a driving source for rotating the polygon mirror, wherein the laser beam is moved along the virtual X axis on the substrate; Laser scanner and
A galvanometer scanner having a mirror for reflecting the incident laser beam in a direction different from the incident direction and a driving source for rotating the mirror, the galvanometer scanner for moving the laser beam along an imaginary Y axis crossing the X axis on the substrate; Laser lift off device further comprising. 10. The method of claim 9,
A polygon mirror having a plurality of reflective surfaces and reflecting an incident laser beam in a direction different from the incident direction, and a driving source for rotating the polygon mirror, wherein the laser beam is moved along the virtual X axis on the substrate; Laser scanner and
And a substrate transfer part for moving the substrate along the virtual Y axis crossing the X axis on the substrate.

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