Flexible device peeling method

Abstract

The present invention discloses a method for peeling a flexible device. The flexible device comprises a stacked flexible substrate and a flexible functional layer, with the side of the flexible substrate facing away from the flexible functional layer being disposed on a carrier substrate. The peeling method comprises the following steps: scanning a first region of the flexible device through the carrier substrate using a first laser; and scanning a second region of the flexible device through the carrier substrate using a second laser; wherein the second region of the flexible device is located within the range of the first region. This method significantly reduces tearing of the flexible device caused by the strong adhesion of particles at their locations during the separation process, effectively improving the yield rate of the flexible device peeling process.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible film products, and in particular to a stripping method for a flexible device. Background Art

[0002] Foldable electronic devices can effectively reduce the area they occupy and offer a wider range of features. Foldable electronic devices require flexible or foldable display devices. Compared to conventional display devices, flexible display devices offer advantages such as greater impact and vibration resistance, adaptability to a wider range of working environments, rollability, and the ability to utilize a roll-to-roll printing process. With the continuous advancement of manufacturing processes and technologies, flexible display devices are becoming increasingly diverse in form factor, and display quality is improving as screen size continues to increase.

[0003] Traditional flexible display devices typically consist of the following structure: a flexible substrate, an electrode layer, a flexible thin-film transistor array, a flexible light-emitting functional layer, and an encapsulation layer. Flexible display devices require that each component has a consistent and similar bending radius and withstands bending without damage or detachment, achieving overall flexibility.

[0004] The traditional method for manufacturing flexible display devices is a bonding and removal process. The bonding process involves first fabricating the entire flexible display device on a rigid substrate. This approach is chosen because it minimizes manufacturing precision and requires similar equipment and processes to those used for traditional non-flexible displays, eliminating the need for significant adjustments. This makes it more suitable for mass production in the short term. The removal process involves peeling the flexible display device from the rigid substrate after the bonding process is complete.

[0005] Flexible display devices are typically peeled off using a laser lift-off process. Specifically, a laser is applied to the interface between the flexible device and the rigid substrate. High-energy laser treatment of the flexible substrate at this interface reduces the bonding strength between the two substrates, allowing the flexible device to be peeled off. However, flexible devices produced using the laser lift-off process often exhibit surface damage, resulting in a low yield. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to reduce the damage to the surface of the flexible device during the laser lift-off process, so as to improve the production yield of the flexible device.

[0007] According to one embodiment of the present invention, a method for peeling a flexible device includes a flexible substrate and a flexible functional layer stacked together, wherein a side of the flexible substrate away from the flexible functional layer is disposed on a carrier substrate. The peeling method includes the following steps:

[0008] Scanning a first area of ​​the flexible device through the carrier substrate using a first laser;

[0009] Scanning a second area of ​​the flexible device through the carrier substrate using a second laser;

[0010] The second area on the flexible device is located within the range of the first area.

[0011] In one embodiment, when the first area of ​​the flexible device is scanned with the first laser, a focal plane of the first laser is located at an interface between the flexible substrate and the carrier substrate.

[0012] In one embodiment, when the second region of the flexible device is scanned with the second laser, a focal plane of the second laser is shifted toward the flexible substrate relative to an interface between the flexible substrate and the carrier substrate.

[0013] In one embodiment, the focus plane of the second laser is offset from the interface toward the flexible substrate by a distance of 3 μm to 5 μm.

[0014] In one embodiment, the energy density of the first laser is 120 mJ / cm 2 ~130mJ / cm 2 .

[0015] In one embodiment, the energy density of the second laser is 150 mJ / cm 2 ~160mJ / cm 2 .

[0016] In one embodiment, the laser emitting the first laser is selected from an excimer laser with an emission wavelength of 308 nm or a semiconductor laser with an emission wavelength of 405 nm.

[0017] In one embodiment, the laser emitting the second laser is selected from an excimer laser with an emission wavelength of 308 nm or a semiconductor laser with an emission wavelength of 405 nm.

[0018] In one embodiment, the flexible substrate is made of polyimide.

[0019] In one embodiment, the method further comprises the step of scanning the second area with the second laser one or more times, wherein the focal plane of the second laser is different in each step of scanning with the second laser.

[0020] In one embodiment, the orthographic projection of the first area on the flexible substrate covers the entire surface of the flexible substrate;

[0021] The orthographic projection of the second region on the flexible functional layer covers at least the entire surface of the flexible functional layer.

[0022] In one embodiment, the flexible substrate has an edge portion protruding from a boundary of the flexible functional layer, and the peeling method further comprises:

[0023] The step of separating the edge portion from the carrier substrate comprises inserting a blade into the interface between the edge portion and the carrier substrate, and moving the blade away from the carrier substrate to separate the edge portion from the carrier substrate.

[0024] In one embodiment, after separating the edge portion from the carrier substrate, the method further comprises:

[0025] The flexible functional layer and the edge portion are adsorbed by an adsorption method, so as to peel the flexible device from the carrier substrate.

[0026] In one embodiment, the adsorption device comprises:

[0027] a device adsorption portion for adsorbing the flexible functional layer and an edge adsorption portion for adsorbing the edge portion;

[0028] Wherein, the height of the adsorption surface of the edge adsorption portion gradually decreases in a direction away from the device adsorption portion.

[0029] For flexible devices prepared on a carrier substrate, the traditional method of peeling the flexible device usually only uses a laser focused on the interface between the flexible substrate and the carrier substrate for irradiation to etch the flexible substrate material at the interface, weakening the bonding force between the flexible substrate and the carrier substrate at the irradiated area, thereby facilitating the subsequent separation process.

[0030] However, in the traditional laser lift-off process, the flexible substrate often tears when separating it from the carrier substrate. This is because during the actual preparation process, the material itself will absorb some particles, or some materials will shed particles during the process, resulting in the presence of particles between the flexible substrate and the carrier substrate. The particle size of these particles is very small, usually only a few microns, and therefore difficult to remove in the early process technology. The particles left at the interface will absorb the energy of the laser when the laser irradiates the interface, resulting in strong adhesion between the flexible substrate material and the particles in the area where the particles are located, and between the particles and the carrier substrate. This results in a strong adhesion between the flexible substrate and the carrier substrate in the area where the particles are located when separating the flexible device and the carrier substrate, and when subjected to external force, the flexible device is prone to tearing at this location.

[0031] The flexible device peeling method of the above embodiment includes scanning a first region of the flexible device with a first laser and scanning a second region of the flexible device with a second laser. If the second region is located within the first region, the adhesion between the flexible device and the carrier substrate in the second region, after two laser scans, is effectively weakened. This effectively prevents cracks in the flexible device caused by excessive localized adhesion during the subsequent peeling process. This flexible device peeling method significantly reduces tearing of the flexible device caused by strong adhesion at the locations where particles are located during the separation process, effectively improving the yield rate of the flexible device peeling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the process of laser peeling of flexible devices in traditional technology;

[0033] Figure 2 Schematic diagram of a manufacturing process of a flexible display device according to an embodiment of the present invention;

[0034] Figure 3 for Figure 2 A top view of the flexible display device is shown;

[0035] Figure 4 For the first laser scanning Figure 2 A schematic diagram of a flexible display device is shown;

[0036] Figure 5 For the second laser scanning Figure 2 A schematic diagram of a flexible display device is shown;

[0037] Figure 6 Schematic diagram of peeling the flexible display device from the carrier substrate after laser scanning.

[0038] The reference numerals are as follows:

[0039] 110: Carrier substrate; 111: Particles; 120: Flexible substrate; 121: Crack defect; 130: Flexible display functional body; 201: First region; 202: Second region; 210: Carrier substrate; 211: Interface particles; 220: Flexible substrate; 221: Interface; 222: Plane of second laser focus; 230: Flexible functional layer; 231: Barrier layer; 232: Driving element; 233: Light-emitting device; 234: Encapsulation layer; 235: Polarizer; 300: Blade; 400: Adsorption device. DETAILED DESCRIPTION

[0040] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. "Multiple" as used herein refers to a combination of two or more items. If not expressly stated or if a person skilled in the art does not have a common understanding of this, the concepts of proportion or concentration in this application should be considered to be mass proportion or mass concentration.

[0042] The traditional method for peeling flexible devices from carrier substrates is mainly laser lift-off. However, during the laser lift-off process, particles inevitably present at the interface between the flexible substrate and the carrier substrate during the production process will significantly affect the yield of the flexible device. These particles are usually contaminants adsorbed on the surface of the carrier substrate or powders that fall off during the flexible device manufacturing process. For example, please refer to Figure 1 The carrier substrate 110 has the prepared flexible substrate 120 and the flexible display function body 130 attached to its surface. During the production process, particles 111 inevitably form between the carrier substrate 110 and the flexible substrate 120. These particles 111 significantly affect the local energy during laser etching, preventing effective destruction of the interface where the particles 111 are located. Consequently, during the subsequent separation process, crack defects 121 may form on the flexible substrate 120 and even on the flexible display function body 130 at the locations corresponding to the original particles, affecting the peeling yield.

[0043] To address the above-mentioned problem, one embodiment of the present invention provides a method for peeling a flexible device, wherein the flexible device includes a flexible substrate and a flexible functional layer stacked together, and the side of the flexible substrate away from the flexible functional layer is disposed on a carrier substrate. The peeling method includes the following steps:

[0044] Scanning a first area of ​​the flexible device through a carrier substrate using a first laser;

[0045] Scanning a second area of ​​the flexible device through the carrier substrate using a second laser;

[0046] The second area on the flexible device is located within the range of the first area.

[0047] Further, scanning a first area of ​​the flexible device with a first laser to weaken the bonding force between the flexible substrate and the carrier substrate in the first area;

[0048] A second laser is focused on scanning a second area of ​​the flexible device to eliminate the adhesive force between the flexible substrate and the carrier substrate in the second area.

[0049] The flexible substrate is used to support the flexible functional layer thereon. During subsequent peeling or other transfer processes, the flexible substrate can be manipulated to avoid direct manipulation of the flexible functional layer. Furthermore, the flexible functional layer is also attached to the surface of the carrier substrate via the flexible substrate. In one specific example, the flexible substrate is made of polyimide.

[0050] Among them, there are particles on the interface between the flexible substrate and the carrier substrate. The presence of the particles hinders the scanning of the interface between the flexible substrate and the carrier substrate by the first laser, so that after the first laser scan, there is still a large adhesion force between the flexible substrate and the carrier substrate in the area where the particles are located. If the flexible device is peeled off at this time, the flexible device will easily crack. Therefore, in one specific example, the focal plane of the second laser focus is offset toward the flexible substrate relative to the interface of the first laser focus, and the surface of the second laser focus passes through the particles, or passes through the interface between the particles and the flexible substrate. Furthermore, the distance that the focal plane of the second laser focus is offset toward the flexible substrate relative to the interface is 3μm to 5μm.

[0051] In one specific example, the carrier substrate is a hard transparent substrate, the material of which can be selected from glass. The microparticles placed on the hard transparent substrate tend to be embedded in the flexible substrate.

[0052] In one specific example, the thickness of the carrier substrate is 0.1 mm to 10 mm.

[0053] In order to facilitate understanding of the basic structure of the flexible device in this embodiment, in one specific example, please refer to Figure 2 , a flexible device can be manufactured by a preparation method including the following preparation process.

[0054] Step S1 : preparing a flexible substrate 220 on a surface of a carrier substrate 210 .

[0055] In one specific example, the flexible substrate 220 is made of polyimide. Polyimide has excellent bending resistance and is particularly suitable as a substrate material for flexible display devices. The flexible substrate 220 can be prepared, for example, by applying a polyimide solution to the surface of the carrier substrate 210, followed by high-vacuum drying to rapidly evaporate and remove the majority of the solvent in the polyimide. Heat and drying are then used to further remove the solvent from the polyimide solution and crosslink and solidify the polyimide material, ultimately forming a flexible substrate with good thickness uniformity.

[0056] In one specific example, the thickness of the flexible substrate 220 is 10 μm to 50 μm. More specifically, the thickness of the flexible substrate 220 may be 20 μm.

[0057] Step S2 : preparing a flexible functional layer 230 on a side of the flexible substrate 220 away from the carrier substrate 210 .

[0058] The flexible functional layer 230 is the functional body of the flexible device, used to perform the functions of the flexible device. In this specific example, the flexible device is a flexible display device, and correspondingly, the functional body of the flexible display device is a light-emitting diode. Furthermore, optionally, the functional body of the flexible display device is an active-matrix organic light-emitting diode. In other specific examples, the flexible device can also be similarly fabricated on a carrier substrate, requiring the flexible substrate and the carrier substrate to be separated.

[0059] In one specific example, the flexible substrate 220 is arranged to protrude from the edge of the flexible functional layer 230. For example, the area of ​​the flexible substrate 220 protrudes from the edge of the flexible functional layer 230 by 10 mm to 50 mm. Figure 3 , which shows a top view of the flexible device, with the flexible functional layer 230 located within the area of ​​the flexible substrate 220. The flexible substrate 220 measures 730 mm x 460 mm, and the flexible functional layer 230 disposed on the flexible substrate 220 measures 690 mm x 400 mm. The flexible functional layer 230 is disposed in the center of the flexible substrate 220, with its long side 30 mm from the long sides of the flexible substrate 220, and its short side 20 mm from the short sides of the flexible substrate 220. For ease of understanding and description, the area of ​​the flexible substrate 220 where the flexible functional layer 230 is located is the device portion, and the portion protruding from the flexible functional layer 230 is the edge portion.

[0060] Providing a flexible substrate 220 with a larger area can reserve sufficient space for the flexible functional layer 230. In the subsequent manufacturing process, the flexible device can be operated through the edge portion of the flexible substrate 220, and the edge portion can be finally cut off.

[0061] The flexible functional layer 230 specifically includes a barrier layer 231, a driving element 232, a light-emitting device 233, an encapsulation layer 234, and a polarizer 235, stacked in sequence. The barrier layer 231 serves to block water and oxygen; the driving element 232 is a thin-film transistor (TFT) and its bonding area leads. The TFT drives the light-emitting device 233 thereon to emit light. The light-emitting device 233 is an organic light-emitting diode. The TFT drives the pixelated light-emitting device 233 to emit light, thereby displaying a pattern.

[0062] In one specific example, the specific preparation process of the flexible functional layer 230 may include sequentially preparing a barrier layer 231, a driving element 232, a pixelated light-emitting diode 233, an encapsulation layer 234, and a polarizer 235. Since the water and oxygen permeability of the flexible substrate 220 may be high, the barrier layer 231 is required during the fabrication of the flexible functional layer 230 to isolate water and oxygen. The barrier layer 231 can have an alternating organic / inorganic structure, such as a stacked arrangement of parylene / silicon nitride / parylene / silicon nitride, or an alternating inorganic / inorganic structure, such as a stacked arrangement of silicon nitride / silicon dioxide / silicon nitride. Then, a TFT array for driving the light-emitting devices and bonding area leads connecting the TFT array are fabricated on the barrier layer 231. Depending on the TFT process temperature, the material of the flexible substrate 220 with different temperature resistance can be selected. Next, the light-emitting diode 233 is fabricated, and thin-film encapsulation is performed to prepare the encapsulation layer 234, followed by the polarizer 235. The light emitting diode 233 can be prepared by a printing process or an evaporation process.

[0063] Typically, during the laser lift-off process for flexible devices, the carrier substrate 210 is positioned above the flexible substrate 220 ("above" in this context refers to the position relative to the ground). This is because the laser light must pass through the carrier substrate 210 to reach the interface between the two substrates. If the carrier substrate 210 is positioned lower, it will require support. If the support is a fixture securing the sides of the carrier substrate 210, the center of the carrier substrate will bend due to gravity, making it difficult to align the laser's focal plane with the interface. Alternatively, if the support supports the center of the carrier substrate, it will block or weaken the laser intensity, significantly affecting the laser's scanning of the flexible substrate 220 at the interface. Therefore, during laser scanning, the laser light is typically directed from top to bottom, with the carrier substrate 210 facing upward and the flexible device facing downward. Consequently, after the flexible device is fabricated, the carrier substrate 210 and the flexible device must be transferred, maintaining the carrier substrate 210 facing upward and the flexible device facing downward.

[0064] In one specific example, before the first laser focus scanning is performed, the following steps are also included.

[0065] Step S3 is a step of transferring the carrier substrate provided with the flexible device to the area where the laser irradiation equipment is located.

[0066] For example, a robot can be used to transfer the flexible device to the area where the laser irradiation equipment is located. Furthermore, the robot simultaneously absorbs the carrier substrate 210 and the bonding area leads of the driving element 232 by suction, preventing relative displacement between the flexible device and the carrier substrate 210 and preventing the bonding area leads of the driving element 232 from falling off and causing poor bonding.

[0067] For ease of illustration, this embodiment illustrates the structure and preparation process of a specific flexible device. The following describes the peeling method provided by the embodiment of the present invention by peeling off the flexible device. The peeling method includes the following steps S4 and S5. It is understood that other flexible devices with similar structures can also be peeled off using the peeling method provided by the embodiment of the present invention, depending on actual needs.

[0068] Please refer to Figure 2 , for ease of understanding, Figure 2 The first region 201 and the second region 202 of the flexible device of this embodiment are marked with dotted lines.

[0069] Please also refer to Figure 4 In step S4 , a focal plane of the first laser is positioned at the interface between the flexible substrate 220 and the carrier substrate 210 , and the first area 201 is scanned.

[0070] It can be understood that the laser can act on the bond formed between the flexible substrate 220 and the surface of the carrier substrate 210 , thereby weakening or eliminating the adhesive force between the flexible substrate 220 and the carrier substrate 210 .

[0071] The focal plane of the first laser is the interface between the flexible substrate 220 and the carrier substrate 210 . Therefore, during the first laser scanning, the portion of the flexible substrate 220 that absorbs laser energy and breaks the bond with the carrier substrate 210 is located at the interface.

[0072] In one specific example, the portion of the first region 201 on the flexible substrate 220 can cover the entire surface of the flexible substrate 220. This can also be understood as the orthographic projection of the first region 201 on the flexible substrate 220 covering the entire surface of the flexible substrate 220. Furthermore, the first laser is focused on the interface between the flexible substrate 220 and the carrier substrate 210. At this point, the flexible substrate 220 at this interface absorbs the energy of the first laser, destroying the interfacial bond between the flexible substrate 220 material and the carrier substrate 210. The material of the flexible substrate 220 at this interface also partially decomposes and carbonizes, thereby weakening the bonding force between the entire flexible substrate 220 and the carrier substrate 210.

[0073] At the same time, the presence of the particles affects the absorption of laser energy by the flexible substrate 220 in the area where the particles are located, resulting in a relatively strong bond between the flexible substrate 220 and the carrier glass 210 at that location. At this point, the flexible substrate 220 and the carrier glass 210 remain bonded together due to the residual bonding force and the strong bonding force between the flexible substrate 220 and the carrier glass 210 in the area where the particles are located, so the two are not separated.

[0074] Furthermore, the energy density of the first laser is 120 mJ / cm 2 ~130mJ / cm 2 Alternatively, the energy density of the first laser can be 120 mJ / cm 2 、122mJ / cm 2 、124mJ / cm 2 、126mJ / cm 2 、128mJ / cm 2 or 130 mJ / cm 2 The energy density of the first laser is selected to be 120mJ / cm 2 ~130mJ / cm 2 , while reducing the bonding force between the flexible substrate 220 and the carrier substrate 210, it is possible to better maintain the bonding force between the flexible substrate 220 and the carrier substrate 210, so that the two remain in a bonded state, thereby ensuring that the flexible substrate 220 and the carrier substrate 210 do not fall off or shift.

[0075] In one specific example, the first laser beam is a linear laser beam, the width of which is set based on the size of the flexible substrate 220. For example, for a flexible substrate 220 measuring 730 mm x 460 mm, the width of the first laser beam can be set to 730 mm. Furthermore, the beam can be translated along the surface of the flexible substrate 220, from one side of the flexible substrate 220 to the opposite side, so that the entire area of ​​the flexible substrate 220 is illuminated by the first laser beam.

[0076] As a parameter of the actual manufacturing process of this specific example, the distance between the light source of the linear laser beam and the focal plane is 13.5 mm. At this time, the focal plane is accurately positioned at the interface between the flexible substrate 220 and the carrier substrate 210 .

[0077] Please also refer to Figure 5 In step S5 , the second laser is focused on the flexible substrate, scanning the second area 202 to eliminate the adhesive force between the flexible substrate and the carrier substrate in the second area 202 .

[0078] Specifically, in the presence of interface particles 211, the interface particles 211 make it difficult for the flexible substrate 220 at their location to receive the energy of the first laser beam, thereby preventing the flexible substrate 220 from receiving the energy. In one specific example, the focal plane of the second laser beam is offset relative to the interface 221 toward the flexible substrate 220. Furthermore, the offset distance is 3 μm or 5 μm. Specifically, the second laser beam is focused on the surface where the particles are located or on the interface between the particles and the flexible substrate, scanning the second region 202.

[0079] The laser can act on the bond formed between the flexible substrate 220 and the surface of the microparticles, thereby weakening or eliminating the adhesive force between the flexible substrate 220 and the carrier substrate 210 .

[0080] The purpose of scanning the second region 202 with the second laser is to eliminate the adhesive force between the flexible substrate and the particles in the second region 202. The second region 202 is located within the range of the first region 201.

[0081] In this specific example, the portion of the second region 202 on the flexible functional layer 230 may cover the entire surface of the flexible functional layer 230. This can also be understood as the orthographic projection of the second region 202 on the flexible functional layer 230 covering at least the entire surface of the flexible functional layer 230. Furthermore, the portion of the second region 202 on the flexible functional layer 230 overlaps with the flexible functional layer 230.

[0082] In the actual preparation process, the size of the particles is mostly 3μm to 5μm. Therefore, the distance between the focal plane of the second laser and the focal plane of the first laser can be set to be greater than 3μm. As a result, the second laser energy is mainly received by the particles or the portion of the flexible substrate 220 greater than 3μm at the interface between the particles and the flexible substrate (i.e., the focal plane of the first laser). The particles and the portion of the flexible substrate 220 bonded to the particles are separated, thereby separating the flexible substrate 220 and the carrier substrate 210 in the second area 202 that is scanned by the first and second lasers at the same time.

[0083] In one specific example, the focal plane of the second laser is shifted from the interface to the direction of the flexible substrate by 3μm to 5μm. The particle size of the microparticles is generally 3μm to 5μm, and therefore, the interface between the microparticles and the flexible substrate 220 is mostly located at this position. By aligning the focal plane of the second laser with the interface between the microparticles and the flexible substrate 220, the second laser can act on the microparticles or accurately act on the interface between the microparticles and the flexible substrate 220. The organic microparticles that absorb the laser energy will deteriorate, or the flexible substrate 220 at the interface in contact with the microparticles will absorb the laser energy, the surface adsorption bonds will break, and the bonding force will be eliminated. This avoids the situation in which the flexible substrate 220 and the carrier substrate 210 are difficult to fully separate in the traditional laser lift-off process, which leads to local tearing of the flexible substrate 220 and affects the flexible functional layer 230.

[0084] In one specific example, the second region 202 is the area on the flexible substrate 220 corresponding to the area where the flexible functional layer 230 is located. The second laser utilizes a linear laser beam, and the width of the linear laser beam is set according to the size of the flexible functional layer 230. For example, if the size of the flexible functional layer 230 is 690 mm × 400 mm, the width of the second laser beam can be set to 690 mm. Furthermore, the second laser beam can be translated along the focal plane of the second laser beam so that the entire area on the flexible substrate 220 corresponding to the flexible functional layer 230 is scanned by the second laser beam.

[0085] As a parameter of the actual preparation process of this specific example, the distance between the light source of the linear laser beam and the focusing plane is 13.503-13.505 mm. At this time, the focusing plane is accurately positioned at the interface between the flexible substrate 220 and the carrier substrate 210 .

[0086] Furthermore, by setting a relatively high and appropriate laser energy density, the flexible substrate 220 material located in the second laser focusing plane can absorb the laser energy and be decomposed or carbonized, and the flexible substrate 220 in this area is separated from the carrier substrate 210 .

[0087] In one specific example, the energy density of the second laser is 20 mJ / cm higher than that of the first laser. 2 ~40mJ / cm 2 At the energy density of the first laser, the bonding force between the flexible substrate and the carrier substrate at the irradiated location is weakened; at an energy density higher than 20 mJ / cm 2 ~40mJ / cm 2 Under the energy density of the second laser, the bonding force between the flexible substrate 220 and the carrier substrate 210 at the irradiated location can be further weakened or eliminated.

[0088] The energy density of the second laser is 150 mJ / cm 2 ~160mJ / cm 2 Specifically, the energy density of the second laser is 150 mJ / cm 2 、152mJ / cm 2 、154mJ / cm 2 、156mJ / cm 2 、158mJ / cm 2 or 160 mJ / cm 2 Set the energy density of the second laser to 150mJ / cm 2 ~160mJ / cm 2 The area irradiated by the second laser can be sufficiently separated from the carrier substrate 210 without damaging the flexible device itself. The above laser energy density range is particularly suitable for flexible polyimide substrates.

[0089] In this specific example, after the second laser scan, second region 202 lies within first region 201, thus undergoing both the first and second laser scans. During the first laser scan, the adhesion between flexible substrate 220 and carrier substrate 210 at the interface in first region 201 was significantly weakened, but separation did not occur. During the second laser scan, the focal plane of the second laser shifted slightly relative to the focal plane of the first laser, and the laser irradiation energy was increased. The focal plane of the second laser irradiated the location of the microparticles, resulting in complete separation between flexible substrate 220 and carrier substrate 210 at the location of the microparticles.

[0090] In one specific example, different lasers are selected based on the absorption degree of different wavelengths of laser light by a specific material. For example, for a polyimide material, it is preferred that the laser emitting the first laser light be selected from an excimer laser with an emission wavelength of 308 nm or a semiconductor laser with an emission wavelength of 405 nm. In another specific example, the laser emitting the second laser light be selected from an excimer laser with an emission wavelength of 308 nm or a semiconductor laser with an emission wavelength of 405 nm.

[0091] In one specific example, if the particle sizes differ greatly and a single second laser scan is insufficient to completely eliminate the adsorption force between the particles and the flexible substrate 220, the step of scanning the second region 202 with a second laser one or more times may be included to focus the second laser on the surface where the particles are located or on the interface between the particles and the flexible substrate.

[0092] Furthermore, when the second laser is used to scan the second area 202 , each second laser is focused on a different focusing plane.

[0093] Furthermore, when the second laser is used to scan the second area 202 multiple times, the focal plane of the second laser gradually moves from the interface to the flexible substrate 220 .

[0094] For example, the second laser can be repeatedly focused on a plane that is at least 3 μm away from the interface and is located toward the flexible substrate. For another example, the second laser can be focused on a different plane each time the second laser is scanned. Furthermore, the second laser can be scanned starting from a plane that is at least 3 μm away from the interface and toward the flexible substrate, and then sequentially scanned toward surfaces further from the interface.

[0095] In one specific example, after the laser scanning process including the above-mentioned step S4 and step S5 is completed, a step of separating the flexible substrate 220 and the carrier substrate 210 is further included.

[0096] like Figure 6 As shown, in step S6 , the flexible substrate 220 and the carrier substrate 210 are separated.

[0097] Dislocation or displacement should not occur between the flexible device 220 and the carrier substrate 210, otherwise it will cause defects such as local adhesion, deformation and damage of the flexible device. Therefore, after completing the laser scanning process, a step of mechanically assisting the separation of the substrate 220 and the carrier substrate 210 can also be included.

[0098] Specifically, the flexible functional layer 230 can be adsorbed by the adsorption device 400, and the blade 300 can be inserted into the interface between the edge portion of the flexible substrate 220 and the carrier substrate 210, and the blade 300 can be moved away from the carrier substrate 210 to move the edge portion away from the carrier substrate 210. Figure 6 In the orientation shown, a blade 300 is used to press down on the edge of the flexible substrate 220. Because the edge is not scanned by the second laser, adhesion between the flexible substrate 220 and the carrier substrate 210 still exists at the edge. Inserting the blade 300 into this edge region completely separates the flexible substrate 220 from the carrier substrate 210, allowing the flexible functional layer 230 to be transferred to the surface of the adsorption device 400.

[0099] Optionally, the adsorption device 400 has multiple evenly distributed ventilation holes, and air is evacuated from the ventilation holes to achieve vacuum adsorption of the flexible functional layer 230. Furthermore, the adsorption device 400 includes a device adsorption portion for adsorbing the flexible functional layer 230 and an edge adsorption portion for adsorbing the flexible substrate 220 in the edge region. After the blade 300 is inserted into the flexible substrate 220 in the edge region, the blade 300 is pressed down onto the surface of the edge adsorption portion, so that the flexible substrate 220 in that region is also adsorbed by the adsorption device 400. Figure 6 The sizes and proportions of the components are for illustration only and are not intended to be used in actual production.

[0100] In one specific example, the edge suction portion is connected to the device suction portion, and the suction surface gradually decreases in height as it moves away from the device suction portion. In practice, both the flexible substrate 220 and the flexible functional layer 230 are very thin. Therefore, setting the suction surface of the edge suction portion to gradually decrease in height provides ample space for the blade to press down on the edge of the flexible substrate 220.

[0101] Through the above steps, the flexible device can be basically peeled off from the surface of the carrier substrate 210 .

[0102] The method for stripping a flexible device in the above embodiment further includes a step of scanning the interface between the flexible substrate and the carrier substrate using a first laser focused on the surface where the particles are located or the interface between the particles and the flexible substrate using a second laser focused on the surface where the particles are located or the interface between the particles and the flexible substrate. The first laser irradiation is used to weaken the bonding force between the flexible substrate and the carrier substrate in the first area 201, so that the flexible substrate as a whole still remains connected to the carrier substrate. The second laser irradiation is used to eliminate the bonding force between the particles and the flexible substrate, and the flexible device in this area is completely separated from the carrier substrate. As a result, in the subsequent separation process, the bonding force between the flexible substrate as a whole and the carrier substrate is relatively weak, and the bonding force between the flexible substrate and the carrier substrate in the area where the flexible functional layer is located is eliminated. In the process of separating the flexible substrate from the carrier substrate, the tearing of the flexible device caused by the strong bonding force at the location where the particles are located is greatly reduced, effectively improving the yield rate of the flexible device stripping process.

[0103] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The above embodiment merely represents a preferred embodiment of the present invention. While the description is relatively specific and detailed, it should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for peeling a flexible device, characterized in that: The flexible device includes a flexible substrate and a flexible functional layer that are stacked, wherein a side of the flexible substrate away from the flexible functional layer is arranged on a carrier substrate, and the peeling method includes the following steps: Scanning a first area of ​​the flexible device through the carrier substrate using a first laser; Scanning a second area of ​​the flexible device through the carrier substrate using a second laser; Wherein, the second area on the flexible device is located within the range of the first area; Scanning the second area with the second laser one or more times, wherein the second laser is focused on a different focal plane in each step of scanning with the second laser; When the second laser is used to scan the second area multiple times, the focal plane of the second laser is gradually shifted toward the interface between the flexible substrate and the carrier substrate toward the flexible substrate.

2. The method for peeling a flexible device according to claim 1, wherein: When the first area of ​​the flexible device is scanned with the first laser, a focal plane of the first laser is located at an interface between the flexible substrate and the carrier substrate; and / or When the second area of ​​the flexible device is scanned with the second laser, a focal plane of the second laser is shifted toward the flexible substrate relative to the interface between the flexible substrate and the carrier substrate.

3. The method for peeling a flexible device according to claim 2, wherein: The distance that the focal plane of the second laser is offset relative to the interface toward the flexible substrate is 3 μm to 5 μm.

4. The method for peeling a flexible device according to claim 1, wherein: The energy density of the first laser light is lower than the energy density of the second laser light.

5. The method for peeling a flexible device according to claim 4, wherein: The energy density of the first laser is 120 mJ / cm 2 ~130mJ / cm 2 and / or The energy density of the second laser is 150 mJ / cm 2 ~160mJ / cm 2 .

6. The method for peeling a flexible device according to claim 1, wherein: The laser emitting the first laser light and the laser emitting the second laser light are each independently selected from an excimer laser emitting at a wavelength of 308 nm or a semiconductor laser emitting at a wavelength of 405 nm.

7. The method for peeling a flexible device according to any one of claims 1 to 6, characterized in that: The flexible substrate is made of polyimide.

8. The method for peeling a flexible device according to any one of claims 1 to 6, wherein: The orthographic projection of the first area on the flexible substrate covers the entire surface of the flexible substrate; The orthographic projection of the second region on the flexible functional layer covers at least the entire surface of the flexible functional layer.

9. The method for peeling a flexible device according to claim 8, wherein: The flexible substrate has an edge portion protruding from a boundary of the flexible functional layer, and the peeling method further includes: The step of separating the edge portion from the carrier substrate comprises inserting a blade into the interface between the edge portion and the carrier substrate, and moving the blade away from the carrier substrate to separate the edge portion from the carrier substrate.

10. The method for peeling a flexible device according to claim 9, wherein: After separating the edge portion from the carrier substrate, the method further comprises: The flexible functional layer and the edge portion are adsorbed by an adsorption method, so as to peel the flexible device from the carrier substrate.

11. The method for peeling a flexible device according to claim 10, wherein: The flexible functional layer is adsorbed by an adsorption device, wherein the adsorption device comprises: a device adsorption portion for adsorbing the flexible functional layer and an edge adsorption portion for adsorbing the edge portion; Wherein, the height of the adsorption surface of the edge adsorption portion gradually decreases in a direction away from the device adsorption portion.

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