TWI468092B - Method of detaching for flexible substrate and flexible substrate structure - Google Patents

Description

Separation method of flexible substrate and flexible substrate structure

The present invention relates to a method of separating a flexible substrate, and more particularly to a method of separating a flexible display substrate.

At present, the common flexible display process technology is to transfer the display process technology that is conventionally performed on glass to a flexible substrate. In order to fix the flexible substrate on the glass substrate, the flexible substrate can be smoothly formed on the glass substrate by the adhesive material on the glass substrate, and is not processed in the subsequent thin film transistor array process. Will fall off, and can withstand the high temperature of the process without deterioration.

However, when the process is completed, the flexible substrate needs to be easily separated on the glass substrate without damaging the tiny circuits in the thin film transistor array, so that the flexible display can be truly soft and bendable. Therefore, in the current flexible substrate manufacturing process, how to remove the flexible substrate is an important issue.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for separating a flexible display substrate by forming a release layer on a rigid (e.g., glass) substrate, and modifying the release layer from surface nanoparticles or crystals. Formed by nano-particles, and then formed into flexibility (example For example, the polymer substrate completely covers the surface of the release layer, and the subsequent process is fabricated on the flexible substrate. The subsequent process includes at least one of the following processes, such as a thin film transistor process and a color filter layer. Process, self-illuminating element (eg, organic light emitting diode (OLED), etc.) process, photoelectric conversion element (eg, PN or PIN diode, etc.) process or a combination of one of the foregoing processes. The separation process is performed on the flexible substrate, and the release layer is easily separated directly from the hard substrate by surface-modified nanoparticles or crystalline nanoparticles.

The surface modified nanoparticle has a diameter substantially less than 100 nanometers and may be an inorganic material comprising a metal, an alloy, a metal oxide, a metal nitride, a metal oxynitride, an alloy oxide, an alloy nitride, Alloy oxynitride or other suitable material, the invention is preferably a metal oxide, such as cerium oxide, titanium dioxide, aluminum oxide (Alumina), other suitable materials, or a combination of at least one of the foregoing, but is not limited thereto this. The release layer composed of surface-modified nano-particles forms a weak first interface and a second interface with the hard substrate and the flexible substrate respectively, and the separation process is based on the surface characteristics of different materials, and the adhesion is relatively good. The weak interface is separated. When the flexible display substrate separation process is performed, the area of the non-release layer can be completely removed from the rigid substrate without any other process steps or temperature restrictions.

Crystalline nanoparticles having a diameter of less than 100 nanometers but greater than 0, and may be inorganic materials, including metals, alloys, metal oxides, metal nitrides, metal oxynitrides, alloy oxides, alloy nitrides, alloys Nitrogen oxides or other suitable materials, the invention is based on metal oxides as preferred embodiments, such as anatase or rutile phase, alumina (Alumina) or other high temperature crystalline oxides. a release layer composed of crystalline nanoparticles, which can form a weak interface between the first substrate and the second interface of the rigid substrate and the flexible substrate, respectively, and the separation process is according to the surface characteristics of different materials, from the adhesion The weaker interface is separated. When the flexible display substrate separation process is performed, after cutting the area of the non-release layer, it is not necessary to apply any other process steps. The temperature or temperature limit can be completely removed from the hard substrate.

The invention proposes a nano-particle composition of surface modification or a release layer of crystalline nano-particles, which can be applied to a subsequent high-temperature film process, and the film process is not limited to before or after the separation process, nor does it affect the release layer. The advantage of being able to completely separate directly.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

1, 10‧‧‧ glass substrate (hard substrate or load substrate)

2, 12‧‧‧ release layer

2'‧‧‧Remaining nanoparticle layer after separation

3, 13‧‧‧flexible substrate

4, 14‧‧‧ component structure layer

5‧‧‧ cutting line

F1‧‧‧First surface adhesion

F2‧‧‧Second surface adhesion

1 is a cross-sectional view showing a flexible display substrate developed for experimental comparison in this case.

2 is a cross-sectional view showing a flexible display substrate of the present invention.

3 is a schematic view showing the cutting of the flexible display substrate of the present invention.

4A is a cross-sectional view showing the separation of the flexible display substrate of the present invention.

4B is a cross-sectional view showing another embodiment of the separation of the flexible display substrate of the present invention.

4C is a cross-sectional view showing another embodiment of the separation of the flexible display substrate of the present invention.

FIG. 5 is a cross-sectional view showing the flexible display substrate of the present invention after being separated.

From the experimental comparative example shown in Fig. 1, when the release layer 12 formed on the surface of a hard substrate (e.g., glass substrate) 10 is a non-particulate type of fluoroalkyl silanes (FAS) and a poly pair In the case of dimethyl benzene (Parylene), the material cost of the FAS is high, and the coverage of the glass surface modification and the reaction time are uncertain. In addition, the glass is modified with fluorine-containing decane to form a single-layer film bond with the glass, because of its low surface. The surface energy, so the surface is not easy to apply polymer materials. As for the high-temperature process of parylene, the organic material is prone to breakage or volatilization, which causes difficulty in the subsequent process of the flexible substrate 13 and the thin film transistor array structure 14.

To this end, the present invention relates to a method for separating a flexible substrate. As shown in FIG. 2, first, a release layer 2 is formed on a substrate 1 of a hard material (for example, glass, quartz or germanium substrate, etc.). Layer 2 consists of surface modified nanoparticles. In a preferred embodiment of the invention, the nanoparticles may be composed of an inorganic material having a diameter substantially less than 100 nanometers but greater than 0, for example, cerium oxide nanoparticles, wherein the cerium oxide is passed through the medium. The rice particles are surface modified.

The surface modification reaction process may be to change the original hydrophilicity of the ceria surface to hydrophobicity, since the functional group on the surface of the ceria is mainly composed of a hydrophilic hydroxy functional group (-OH), which is intended to be hydrophilic. The functional group is modified to a hydrophobic functional group, and the functional group can be replaced by a Sol gel method. For detailed steps of the sol-gel method, refer to CJ Brinker's 1990 work "Sol Gel Science: The physics and chemistry of sol gel processing". The sol-gel reaction can be divided into hydrolysis and condensation, hydrolyzing the reaction formula shown in the following (1), and condensing the reaction formulas shown below (2a) and (2b):

If TriMethylChloroSilane (TMCS) is used as an example, the chemical mechanism for modifying nano-cerium oxide is as shown in the following reaction formula (3), wherein the physical or chemical properties of trimethylchlorocyclohexane, View material safety data sheet (MSDS)

The surface modified medium comprises at least one alkoxy group, a halogen functional group (F, Cl, Br, I) or an amine decane such as trimethylchloromethane (TMCS, TriMethylChloroSilane). , dimethyl chloride (DMCS, DiMethylChloroSilane) hexamethyldioxane, (HMDS, Hexamethyldisilazane), polydimethylsiloxane (PDMS, polydimethylsiloxane), dimethyldiethoxysilane (DMDES, dimethyldiethoxysilane And the trimethylethoxysilane, etc., wherein the physical or chemical properties of the above modified materials can be viewed by a material safety data sheet (MSDS). The decane and the cerium oxide nanoparticle are dispersed in a liquid phase or a gas phase to carry out a hydrolysis condensation reaction, and the organic functional group is grafted onto the cerium oxide nanoparticle, as shown in the above reaction formula 3, resulting in hydrophobicity For the detailed steps of this surface modification, please refer to Proc. SPIE Sol-Gel Optics II, vol. 1758, p396-538 (1992) or the Fraunhofer ISC website www.isc.fraunhofer.de , and therefore will not be described here. Only the surface modified dielectric material is not limited to this.

The modified cerium oxide nanoparticle is coated on the glass substrate 1 by a coating solution, and the coating liquid is selected according to the compatibility with the modified cerium oxide nanoparticle. The cloth liquid comprises: a solvent (for example, acetone, ethanol, isopropanol, alcohol, ether, ester or a mixture of at least two kinds of the above solvents), but other additives may be added if a stable coating liquid is obtained. For example: a dispersant, wherein the dispersant comprises a polymer, Methanes and surfactants (including anionic, cationic, nonionic and diionic). Furthermore, the coated modified cerium oxide nanoparticle layer is subjected to baking at about 350 ° C to about 500 ° C to remove excess medium and coating liquid, so that the release layer 2 is finally modified by cerium oxide. Composition of rice particles.

Further, on the release layer 2, a flexible substrate 3 is formed to cover the release layer 2, and the material of the flexible substrate 3 is, for example, an organic polymer having good flexibility. Materials, for example, Polyimide (PI), Polyethylene (PE), PolyVinyl Chloride (PVC), Polypropylene (PP), Polystyrene (PS), Poly(methyl methacrylate), PMMA, Polycarbonate (PC), Polyethylene terephthalate (PET), Polyethylene naphthalate (Polyethylene naphthalate, PEN), Polytetrafluoroethylene (PTFE), Polyethersulfone (PES), Phenol formaldehyde resin (PF), Unsaturated polyester resin (UP), Epoxy Resins, Silicone Resins, Melamine Resins, Urea formaldehyde, but not limited to the above materials, if you need to withstand high temperature process (about more than 400 ° C), this implementation Polyimine Preferred embodiment. Among them, the physical or chemical properties of the flexible substrate 3 can be viewed from a material safety data sheet (MSDS). The subsequent process of the element structure layer 4 is performed on the flexible substrate 3. After the completion, the separation between the flexible substrate 3 and the glass substrate 1 is performed. Generally, the process of the component structure layer 4 is, for example, a thin film transistor process, a color filter process, a black matrix process, a self-luminous component (for example, an organic light emitting diode (OLED), an inorganic light emitting diode, etc.) Process, photoelectric conversion component (eg, PN, PIN diode, photo-sensor, solar cell, etc.) process or a combination of one of the foregoing processes. For example, when the process of the component structure layer 4 performed is a thin film transistor process, the thin film transistor formed on the flexible substrate 3 can be It is called an active device array; when the component structure layer 4 is a color filter process, the color filter formed on the flexible substrate 3 can be referred to as a color filter array. On the other hand, when the component structure layer 4 is performed to include both the thin film transistor process and the color filter process, the array formed on the flexible substrate 3 can be referred to as a color filter on the thin film transistor ( The array structure or thin film transistor of COA, color filter on array is located in an array structure of an AOC (array on color filter). In another direction, when the component structure layer 4 is simultaneously included in the thin film transistor process and the black matrix in the color filter process, the array formed on the flexible substrate 3 can be referred to as a black matrix in the thin film transistor. An array structure of BOA (black on array) or a thin film transistor is placed on an array structure of an AOB (array on color filter). In the above, the thin film transistor process is, for example, an amorphous germanium thin film transistor process, a polycrystalline germanium thin film transistor process, an oxide semiconductor thin film transistor process, or an organic semiconductor thin film transistor process.

During the separation process, the surface of the modified cerium oxide nanoparticle has hydrophobic characteristics, and one of the modified cerium oxide nano particles and the glass substrate or the flexible substrate is weak. . Therefore, the release layer 2 has a first surface adhesion F1 between the interface of the glass substrate (or the carrier substrate) 1 and the interface between the flexible substrate 3 and the release layer 2 The second surface adhesion force F2, the first surface adhesion force F1 is substantially greater than the second surface adhesion force F2. It should be noted that the adhesion (not shown) between the flexible substrate and the interface of the hard substrate at this time is much larger than the first surface adhesion F1 and the second surface adhesion F2. Therefore, as shown in FIG. 3, when the release layer 2 is used to separate the flexible substrate 3 from the glass substrate 1, the region of the non-release layer 2 is cut along the cutting line 5, and no further application is required. The flexible substrate 3 can be completely removed from the glass substrate by any other process steps or temperature limitation, and the release layer 2 remains on the glass substrate 1, as shown in Fig. 4A. As shown in FIG. 4B , the second surface adhesion F2 between the flexible substrate 3 and the interface of the release layer 2 is substantially greater than the interface between the release layer 2 and the glass substrate 1 . When a surface adhesion force F1, after separation, the release layer 2 It will remain on the surface of the flexible substrate 3, and the release layer 2 will not remain on the glass substrate 1. In other embodiments, the second surface adhesion F2 between the flexible substrate 3 and the interface of the release layer 2 is substantially the same as the first surface adhesion F1 between the interface of the release layer 2 and the glass substrate 1, When the second surface adhesion F2 between the flexible substrate 3 and the interface of the release layer 2 is also substantially greater than the adhesion between the nanoparticles, the release layer 2 remains on the glass substrate 1 and away after separation. Another portion of the type layer 2 remains on the surface of the flexible substrate 3, as shown in Fig. 4C. Wherein, the non-detached region means that only the end of the release layer 2 or the edge, only the overlapping structure of the flexible substrate 3 and the glass substrate 1 does not exist in the release layer 2; The area means that the end surface or edge of the release layer 2 has an overlapping structure of the flexible substrate 3, the glass substrate 1 and the release layer 2, and the projected area of the element structure layer 4 can be selected. The projected area of the property and the release layer 2 is substantially the same or smaller. In addition, it must be noted that, preferably, the cutting line 5 is aligned and cut on the trailing end or edge of the release layer 2, but if there is a problem in accuracy during cutting, the cutting line 5 will be aligned very well. The flexible substrate 3 can still be removed near the end of the release layer 2 or near the edge.

Referring to FIG. 5, after the flexible substrate 3 is subjected to a separation process as shown in FIG. 4B or FIG. 4C, the surface of the separated flexible substrate 3 has the ruthenium dioxide nanoparticle layer 2 remaining in the release layer 2. ' Attached. It is assumed that the flexible substrate 3 to which the ceria nanoparticle layer 2' is attached is a substrate applied to a self-luminous display panel, and the self-illuminating element is a downward-emitting element (not shown). The light can be penetrated by adjusting the thickness of the cerium oxide nanoparticle 2' attached to the surface of the flexible substrate and the porosity of the cerium oxide nanoparticle film layer (adjusting the refractive index of the material, n) In the case of a flexible substrate, it reduces the reflection of light at the interface, so that the light energy can be used more efficiently. If the protective film (not shown) is attached after the ruthenium dioxide nanoparticle 2', the flexibility can also be used. The refractive index value (n value) of the substrate 3 and the protective film further adjusts the film thickness of the cerium oxide nanoparticle 2' and its n value.

Further, in this embodiment, the release layer 2 is composed of modified cerium oxide nano particles and is applied on the glass substrate 1 in a wet manner, which is simple in process and time-saving. Furthermore, the release layer 2 composed of the modified cerium oxide nano particles is composed of Si-O and Si-C due to its organic portion, and has a higher temperature resistant process than the organic material composed of the general CC. The characteristics can overcome the disadvantages of producing a broken or volatile gas in a subsequent high-temperature process to cause gas release, and failing to complete the fabrication of the thin film transistor.

In another embodiment of the present invention, the release layer 2 is composed of crystalline nano particles, such as an anatase or rutile phase or an aluminum oxide (Alumina) having a size of less than about 100 nm. (nanometer) but greater than 0, the crystalline titanium dioxide nanoparticle may be the product ST-01 supplied by Ishihara Sanyo Co., Ltd. Only product materials are not limited to this.

Both the coating method and the baking to remove the coating liquid are not different from the manner disclosed in the above embodiment of the present invention, and therefore will not be described again, but the release layer 2 is finally composed of crystalline titanium dioxide nanoparticles. The crystalline titanium dioxide nanoparticle has a high recrystallization temperature and is not easily melted with the glass substrate 1 even after a high temperature process. Moreover, the surface adhesion between the release layer 2 composed of the crystalline titanium dioxide nanoparticles and the glass substrate 1 can be compared with the between the release layer 2 composed of the crystalline titanium dioxide nanoparticles and the flexible substrate 3. The surface adhesion is weak. It should be noted that the adhesion between the flexible substrate and the interface of the rigid substrate (not shown) is far greater than the surface adhesion between the release layer 2 and the glass substrate 1 and between the flexible substrate 3 Surface adhesion.

In summary, the release layer 2 of the present invention is composed of modified nano particles or crystalline nano particles, which can respectively form a first interface with weak surface adhesion to a rigid substrate or a flexible substrate. F1 or the second interface F2 can be applied to the subsequent high-temperature film process, and the film process is not limited to the production before or after the separation process, and does not affect the advantages that the release layer can be completely separated directly. In addition, the above-mentioned component structure layer 4 can be used to complete various flexible display panels, such as non-self-luminous display panels, such as electrophoretic display panels, liquid crystal display panels, electro-display panels, electrochromic display panels, or other suitable Display panel, self-luminous display panel, for example: organic light emitting display panel, inorganic light emitting display panel, or Other suitable display panels have other uses, such as a stereoscopic display panel, a grating panel, a liquid crystal lens, a touch panel or other suitable application, a solar panel, or a combination of at least one of the above.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

1‧‧‧ glass substrate

2‧‧‧ release layer

3‧‧‧Flexible substrate

4‧‧‧Component structure layer

F1‧‧‧First surface adhesion

F2‧‧‧Second surface adhesion

Claims (14)

A method for separating a flexible substrate, comprising the steps of: providing a rigid substrate and a flexible substrate; forming a release layer between the rigid substrate and the flexible substrate, the release layer comprising a plurality of a surface-modified nano-particle composed of a first interface formed between the hard substrate and a second interface formed between the flexible substrate; and an element structure layer formed on the flexible substrate; Performing a separation process on the flexible substrate, cutting an overlapping area of the hard substrate with the release layer and the flexible substrate, and completely removing the flexible substrate from the first interface having weak adhesion or The second interface is completely separated from the rigid substrate directly; wherein the release layer is applied to the rigid substrate in a wet manner, and the coating liquid contains at least a solvent, surface modified or crystalline nano particles and an additive. The method of separating a flexible substrate according to claim 1, wherein the nanoparticle has a diameter of less than 100 nanometers but greater than 0 nanometers. The method for separating a flexible substrate according to claim 1, wherein the nanoparticle material is an inorganic material. The method for separating a flexible substrate according to claim 3, wherein the inorganic nanoparticle comprises a metal, an alloy, a metal oxide, a metal nitride, a metal oxynitride, an alloy oxide, or an alloy nitride. , alloy oxynitride, or a combination of at least one of the foregoing materials. The method for separating a flexible substrate according to claim 1, wherein the table has a table Surface modified nano particles, wherein the medium for modifying the surface of the nano particles comprises hexamethylene diazoxide (HMDS, Hexamethyldisilazane), polydimethylsiloxane (PDMS), dimethyl Dimethyl ethoxy silane (DMDES, dimethyldiethoxysilane) and trimethylethoxysilane (TMES, trimethylethoxysilane). The method for separating a flexible substrate according to claim 1, wherein the method of forming the release layer comprises: baking to remove the coating liquid, such that the release layer is ultimately composed of the crystalline type Rice particles or nanoparticles with surface modification. The method for separating a flexible substrate according to claim 1, wherein the flexible substrate is a polymer substrate. The method for separating a flexible substrate according to claim 1, wherein the component structure layer comprises a thin film transistor process, a color filter process, a black matrix process, an organic light emitting device process, a photoelectric conversion device process or At least one combination of the foregoing processes. A flexible substrate structure comprising: a flexible substrate having a first surface and a second surface; a nanoparticle layer consisting of a plurality of surface modified nano particles, the nano a layer of particles attached to the first surface of the flexible substrate; and an element structure layer disposed on the second surface of the flexible substrate; wherein the medium for modifying the surface of the nanoparticle comprises hexamethyl Hydrazine (HMDS, Hexamethyldisilazane), polydimethylsiloxane (PDMS), dimethyldiethoxydecane (DMDES, dimethyldiethoxysilane) or trimethylethoxysilane (TMES). . The flexible substrate structure according to claim 9, wherein the element structure layer is a combination of at least one of a thin film transistor, a color filter, a black matrix, an organic light emitting element, a photoelectric conversion element, or the foregoing element. The flexible substrate structure of claim 9, wherein the nanoparticle diameter is less than 100 nanometers but greater than 0 nanometers. The flexible substrate structure according to claim 9, wherein the nanoparticle material is an inorganic material. The flexible substrate structure according to claim 12, wherein the inorganic nanoparticle comprises a metal, an alloy, a metal oxide, a metal nitride, a metal oxynitride, an alloy oxide, an alloy nitride, or an alloy. A combination of at least one of nitrogen oxides or the above materials. The flexible substrate structure according to claim 9, wherein the flexible substrate is a polymer substrate.