CN103325734B - Flexible substrate separation method and flexible substrate structure - Google Patents

Abstract

A method for separating a flexible substrate and a flexible substrate structure, wherein a release layer is formed on a hard substrate, and the release layer is composed of surface-modified nanoparticles or crystalline nanoparticles, and then a flexible substrate is formed to completely cover the surface of the release layer. The release layer is separated from the flexible substrate, and can be easily removed from the glass substrate without any other process steps or temperature restrictions. The surface of the separated flexible substrate selectively has nanoparticles attached.

Description

Separation method of flexible substrate and structure of flexible substrate

【Technical field】

The present invention relates to a method for separating a flexible substrate, and in particular to a method for separating a flexible display substrate.

【Background technique】

The current common flexible display process technology is to transfer the display process technology known to be performed on glass to a flexible substrate. Among them, in order to fix the flexible substrate on the glass substrate, the flexible substrate can be smoothly formed on the glass substrate through the setting of the adhesive material on the glass substrate, and it will not be used in the subsequent TFT array manufacturing process. Shedding, and can withstand the high temperature of the process without deterioration.

But when the manufacturing process is completed, the flexible substrate needs to be easily separated from the glass substrate without damaging the tiny circuits in the thin film transistor array, so that the flexible display can truly achieve the characteristics of softness and bendability. Therefore, in the current flexible substrate manufacturing process, how to remove the flexible substrate technology is an important issue.

【Content of invention】

The object of the present invention is to provide a method for separating flexible display substrates. This method is to form a release layer on a hard (for example: glass) substrate, and the release layer is made of surface-modified nanoparticles or Composed of crystalline nanoparticles, a flexible (for example: polymer) substrate is formed to completely cover the surface of the release layer, and the subsequent process is made on the flexible substrate. The subsequent process includes at least one of the following processes For example: thin film transistor process, color filter layer process, self-luminous element (such as: organic light emitting diode (OLED), etc.) process, photoelectric conversion element (such as: PN or PIN diode, etc.) process or the aforementioned process A combination of one of the processes. The separation process is carried out on the flexible substrate, and the release layer is easily and directly separated from the hard substrate by means of the surface-modified nanoparticles or crystalline nanoparticles.

The surface-modified nanoparticles are substantially less than 100 nanometers in diameter and can be inorganic materials, including metals, alloys, metal oxides, metal nitrides, metal oxynitrides, alloy oxides, alloy nitrides, alloy nitrogen Oxide or other suitable materials, the present invention takes metal oxide as the best embodiment, such as silicon dioxide, titanium dioxide, aluminum oxide (Alumina), other suitable materials, or a combination of at least one of the above, but not limited thereto . The release layer composed of surface-modified nanoparticles forms the surface adhesion with the hard substrate and the flexible substrate respectively to form a weak first interface and a second interface. The separation process is based on the surface characteristics of different materials. Weak interface for separation. When performing the flexible display substrate separation process, after cutting the non-release layer area, it can be completely removed from the hard substrate without any other process steps or temperature restrictions.

Crystalline nanoparticles have a diameter less than 100 nanometers (nanometer) but greater than 0, and can be inorganic materials, including metals, alloys, metal oxides, metal nitrides, metal oxynitrides, alloy oxides, alloy nitrides, and alloy oxynitrides or other suitable materials. The present invention takes metal oxides as the best embodiment, such as high-temperature crystalline titanium dioxide (anatase or rutile phase), aluminum oxide (Alumina) or other high-temperature crystalline oxides. The release layer composed of crystalline nanoparticles can form the first interface and the second interface with weak surface adhesion with the hard substrate and flexible substrate respectively. The separation process is based on the surface characteristics of different materials, from the adhesion Weaker interface for separation. When performing the flexible display substrate separation process, after cutting the non-release layer area, it can be completely removed from the hard substrate without any other process steps or temperature restrictions.

Because the present invention proposes surface-modified nanoparticle composition or a release layer of crystalline nanoparticles, it can be applied to subsequent high-temperature thin-film manufacturing processes, and the thin-film manufacturing process is not limited to the production before or after the separation process, nor does it affect the integrity of the release layer. Advantages of direct separation.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

【Description of drawings】

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

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

FIG. 3 is a schematic diagram of cutting the flexible display substrate of the present invention.

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

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

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

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

【Symbol Description】

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

2, 12: release layer

2': Residual nanoparticle layer after separation

3, 13: flexible substrate

4, 14: Component structure layer

5: Cutting line

F1: First Surface Adhesion

F2: Second Surface Adhesion

【detailed description】

From the experimental comparative ratio shown in Fig. 1, when the release layer 12 material formed on the surface of the hard substrate (for example: glass substrate) 10 is non-particle type fluorine-containing silane (fluoroalkylsilanes, referred to as FAS) and poly When using dimethylbenzene (Parylene), because the material cost of FAS is high, and the coverage and reaction time for glass surface modification are uncertain. In addition, glass modified by fluorine-containing silane forms a bond with glass to form a single-layer film. Because of its low surface energy, it is difficult to coat the surface with polymer materials. As for parylene (Parylene), its organic material tends to break bonds or volatilize during the high-temperature process, which causes difficulties in subsequent processes of the flexible substrate 13 and the thin film transistor array structure layer 14 .

For this reason, the present invention proposes a method for separating a flexible substrate. As shown in FIG. The release layer 2 is composed of surface-modified nanoparticles. In a preferred embodiment of the present invention, nanoparticles may be composed of inorganic materials with a diameter substantially smaller than 100 nanometers (nanometer), but greater than 0, for example, silica nanoparticles, wherein the silica nanoparticles are surfaced via a medium Upgrading.

The reaction process of surface modification can change the original hydrophilicity of the silica surface to hydrophobicity. Since the functional groups on the surface of silica are mainly hydrophilic hydroxyl functional groups (-OH), it is desired to change this A hydrophilic functional group is modified into a hydrophobic functional group, and the functional group can be replaced by a sol-gel (SolGel) method, and the detailed steps of the sol-gel method can be referred to C.J.Brinker's 1990 book "SolGelScience : the physics and chemistry of solgel processing". The sol-gel reaction can be divided into hydrolysis and condensation. The reaction formula shown in (1) for hydrolysis and the reaction formula shown in (2a) and (2b) for condensation are as follows:

If taking trimethylchlorosilane (TriMethylChloroSilane, TMCS) as an example, the chemical mechanism used to modify nano-silicon dioxide is shown in the following reaction formula (3), wherein the physical or chemical properties of trimethylchlorosilane can be View Material Safety Data Sheet (material safety data sheet, MSDS)

(3)

The medium for surface modification contains at least one silane of alkoxy group, halogen group (F, Cl, Br, I) or amine group, such as trimethylchlorosilane (TMCS, TriMethylChloroSilane), Dimethylchlorosilane (DMCS, DiMethylChloroSilane) Hexamethyldisilazane, (HMDS, Hexamethyldisilazane), Polydimethylsiloxane (PDMS, polydimethylsiloxane), Dimethyldiethoxysilane (DMDES, dimethyldiethoxysilane) and trimethylethoxysilane TMES (trimethylethoxysilane), etc., wherein, the physical or chemical properties of the above-mentioned modified materials can be found in the Material Safety Data Sheet (MSDS). Silanes and silica nanoparticles are dispersed in the liquid phase or gas phase for hydrolysis and condensation reaction, so that the organic functional groups are grafted onto the silica nanoparticles, as shown in the above reaction formula 3, resulting in a hydrophobic effect. For the detailed steps of surface modification, please refer to Proc.SPIESol-GelOpticsII, vol.1758, p396-538 (1992) or refer to the website of FraunhoferISC www.isc.fraunhofer.de , so it is not repeated here. However, the dielectric material for surface modification is not limited thereto.

The modified silicon dioxide nanoparticles are covered on the glass substrate 1 by means of coating through the coating solution. The choice of the coating solution is based on compatibility with the modified silicon dioxide nanoparticles. The coating solution Contains: solvents (such as acetone, ethanol, isopropanol, alcohols, ethers, esters or a mixture of at least two of the above solvents), but other additives can also be added to obtain a more stable coating solution, such as: Dispersants, wherein the dispersants include polymers, organosilanes and surfactants (including anionic, cationic, nonionic and diionic). Furthermore, the coated modified silica nanoparticle layer is baked at about 350°C to about 500°C to remove excess medium and coating liquid, so that the release layer 2 is finally made of modified silica composed of nanoparticles.

Furthermore, on the release layer 2, a flexible substrate 3 is formed to cover the release layer 2. The material of the flexible substrate 3 is, for example, an organic polymer with good flexibility. Materials, for example, polyimide (Polyimide, PI), polyethylene (Polyethylene, PE), polyvinyl chloride (PolyVinylChloride, PVC), polypropylene (Polypropylene, PP), polystyrene (Polystyrene, PS), polypropylene Methyl methacrylate (Poly (methylmethacrylate), PMMA), polycarbonate (Polycarbonate, PC), polyethylene terephthalate (Polyethyleneterephthalate, PET), polyethylene naphthalate (Polyethylenenaphthalate, PEN), polytetrafluoroethylene (Polytetrafluoroethylene, PTFE), polyethersulfone (Polyethersulfone, PES), phenolic resin (Phenolformaldehydesin, PF), unsaturated polyester (Unsaturatedpolyesterresin, UP), EpoxyResins, silicone resin (SiliconeResins) , melamine resin (Melamine Resins), urea formaldehyde resin (Ureaformaldehyde), but not limited to the above materials, if it needs to withstand high temperature process (about greater than 400 ° C), then this embodiment takes polyimide as the best embodiment . Wherein, the physical or chemical properties of the flexible substrate 3 can be found in a material safety data sheet (MSDS). The subsequent manufacturing process of the device structure layer 4 is carried out on the flexible substrate 3 . And after the completion, the flexible substrate 3 and the glass substrate 1 are separated. Generally speaking, the manufacturing process of the element structure layer 4 is, for example, thin film transistor manufacturing process, color filter manufacturing process, black matrix manufacturing process, self-luminous element (such as: organic light emitting diode (OLED), inorganic light emitting diode, etc.) manufacturing process, photoelectric conversion element (for example: PN, PIN diode, photo-sensor, solar cell, etc.) manufacturing process or a combination of one of the aforementioned manufacturing processes. For example: when the element structure layer 4 is a thin film transistor process, the thin film transistors formed on the flexible substrate 3 can be called an active element array; when the element structure layer 4 is a color filter During the manufacturing process, the color filters formed on the flexible substrate 3 can be called a color filter array. On the other hand, when the element structure layer 4 includes both the thin film transistor process and the color filter process, the array formed on the flexible substrate 3 can be called a color filter on the thin film transistor (COA, color filter on array ) array structure or a thin film transistor located in an array structure of color filters (AOC, array on color filter). In another direction, when the element structure layer 4 includes both the black matrix in the thin film transistor process and the color filter process, the array formed on the flexible substrate 3 can be called a black matrix on a thin film transistor (BOA). , blackonarray) array structure or thin film transistors on the black matrix (AOB, arrayoncolorfilter) array structure. Based on the above, the thin film transistor manufacturing process is, for example, an amorphous silicon thin film transistor manufacturing process, a polysilicon thin film transistor manufacturing process, an oxide semiconductor thin film transistor manufacturing process or an organic semiconductor thin film transistor manufacturing process.

During the separation process, the surface of the modified silicon dioxide nanoparticles has a characteristic of hydrophobicity, and the bonding force between the modified silicon dioxide nanoparticles and the glass substrate or the flexible substrate is relatively weak. Therefore, the interface between the release layer 2 and the glass substrate (or called the carrier substrate) 1 has the first surface adhesion force F1, and the interface between the flexible substrate 3 and the release layer 2 has the first surface adhesion. Two surface adhesion forces F2, the first surface adhesion force F1 is substantially greater than the second surface adhesion force F2. It must be noted that at this time, the adhesion force (not shown) between the interface of the flexible substrate and the rigid substrate is much greater than the above-mentioned first surface adhesion force F1 and second surface adhesion force F2. Therefore, as shown in Figure 3, when the release layer 2 is used to separate the flexible substrate 3 from the glass substrate 1, after the area of the non-release layer 2 is cut along the cutting line 5, no further application is required. With any other process steps or temperature restrictions, the flexible substrate 3 can be completely removed from the glass substrate, while the release layer 2 remains on the glass substrate 1 , as shown in FIG. 4A . As for the separation sectional view shown in FIG. 4B , when the second surface adhesion F2 between the interface of the flexible substrate 3 and the release layer 2 is substantially greater than the second surface adhesion F2 between the interface of the release layer 2 and the glass substrate 1 When the surface adhesion is F1, the release layer 2 will remain on the surface of the flexible substrate 3 after separation, but the release layer 2 will not remain on the glass substrate 1 . In other embodiments, when the second surface adhesion force F2 between the interface of the flexible substrate 3 and the release layer 2 is substantially the same as the first surface adhesion force F1 between the interface of the release layer 2 and the glass substrate 1, And when the second surface adhesion force F2 between the interface of the flexible substrate 3 and the release layer 2 is also substantially greater than the adhesion force between the nanoparticles, the part of the release layer 2 will remain on the glass substrate 1 and the release layer after separation. Another part of the layer 2 will remain on the surface of the flexible substrate 3 , as shown in the isolated cross-sectional view of FIG. 4C . Wherein, the non-release area refers to the tail end or edge (edge) of the release layer 2, only the overlapping structure of the flexible substrate 3 and the glass substrate 1, and does not exist in the release layer 2; The area refers to the tail end or edge (edge) of the release layer 2, there is 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 property is substantially the same as or smaller than the projected area of the release layer 2. In addition, it must be noted that, preferably, the cutting line 5 is aligned and cut on the tail end or edge of the release layer 2, but if there is a problem with precision during cutting, the cutting line 5 will be aligned very quickly. Near the end of the release layer 2 or near the edge, the flexible substrate 3 can still be removed.

Referring to FIG. 5, after the flexible substrate 3 undergoes the separation process as shown in FIG. 4B or 4C, the surface of the separated flexible substrate 3 will have a silicon dioxide nanoparticle layer 2' remaining in the release layer 2. attached. Assuming that the flexible substrate 3 attached with the silicon dioxide nanoparticle layer 2' is a substrate used in a self-luminous display panel, and the self-illuminating element is a downward-emitting element (not shown in the figure), then it can By adjusting the thickness of the silicon dioxide nanoparticles 2' attached to the surface of the flexible substrate and the porosity of the silicon dioxide nanoparticle film layer (adjusting the refractive index of the material, n), the light can pass through the flexible substrate When the light is reflected at the interface, the light energy can be used more efficiently; if a protective film (not shown) is attached after the silicon dioxide nanoparticles 2', it can also be combined with the flexible substrate 3 and the protective film. The refractive index value (n value) of the film can be further adjusted to adjust the film thickness of the silica nanoparticles 2' and its n value.

To further illustrate, in this embodiment, the release layer 2 is composed of modified silicon dioxide nanoparticles, and is wet-coated on the glass substrate 1 , the manufacturing process is simple and time-saving. Furthermore, the release layer 2 composed of modified silicon dioxide nanoparticles is more resistant to high-temperature processes than organic materials composed of general C-C due to its organic parts, such as Si-O and Si-C. It can overcome the shortcoming that the production of thin film transistors cannot be completed due to the release of gas caused by broken bonds or volatilization in the subsequent high-temperature process.

In another embodiment of the present invention, the above-mentioned release layer 2 is made up of crystalline nanoparticles instead, such as high-temperature crystalline titanium dioxide (anataseorrutilephase) or aluminum oxide (Alumina), and the size is about less than 100 nanometers (nanometer) but greater than 0, the crystalline titanium dioxide nanoparticles can be the product ST-01 supplied by IshiharaSanyo Co., Ltd. However, the product material is not limited to this.

The method of coating and baking to remove the coating liquid are the same as those disclosed in the above embodiments of the present invention, so they will not be described again, but the release layer 2 is finally composed of crystalline titanium dioxide nanoparticles. The material characteristic of the crystalline titanium dioxide nanoparticles has a high recrystallization temperature, and it is not easy to melt with the glass substrate 1 even after a high-temperature process. Moreover, the surface adhesion between the release layer 2 composed of crystalline titanium dioxide nanoparticles and the glass substrate 1 is comparable to the surface adhesion between the release layer 2 composed of crystalline titanium dioxide nanoparticles and the flexible substrate 3. Weak. It must be noted that the adhesion (not marked) between the interface between the flexible substrate and the hard substrate is much greater than the surface adhesion between the release layer 2 and the glass substrate 1 and the surface adhesion between the flexible substrate 3 and the flexible substrate 3. between the surface adhesion.

In summary, the release layer 2 of the present invention is composed of modified nanoparticles or crystalline nanoparticles, which can respectively form the first interface F1 with weak surface adhesion with the hard substrate or flexible substrate Or the second interface F2 can be applied to the subsequent high-temperature thin film process, and the thin film process is not limited to the production before or after the separation process, nor does it affect the advantage that the release layer can be completely and directly separated. In addition, the above element 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, electrochromic display panels, electrochromic display panels, or other Suitable display panels, self-luminous display panels, such as: organic light-emitting display panels, inorganic light-emitting display panels, or other suitable display panels, and other applications, such as: three-dimensional display panels, grating panels, liquid crystal lenses (liquid crystallens), touch panels or other suitable applications), solar panels or a combination of at least one of the above panels.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The scope of protection of the invention shall be defined by the scope of the appended patent application.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the present invention The scope of protection should be defined by the claims.

Claims (8)

1. a separation method for flexible base plate, it comprises the following steps:

One hard substrate and a flexible base plate are provided;

A release layer is formed on this hard substrate;

This flexible base plate covers this hard substrate comprising this release layer, the nanoparticle that this release layer includes multiple crystal type nanoparticle or has a surfaction formed, and form one first interface between this hard substrate, and between this flexible base plate, form one second interface;

An element structure sheaf is formed on this flexible base plate; And

One separation processing procedure is carried out to this flexible base plate, cut the overlapping region of this hard substrate and this release layer and flexible base plate, and this flexible base plate is intactly directly intactly separated with this hard substrate from more weak this first interface of adhesive force or this second interface;

Wherein, this release layer is coated on this hard substrate with wet-format, and coating fluid at least comprises solvent, surfaction or crystal type nanoparticle and additive.

2. the separation method of flexible base plate as claimed in claim 1, it is characterized in that, this nanoparticle diameter is less than 100 nanometers (nanometer) but is greater than 0 nanometer.

3. the separation method of flexible base plate as claimed in claim 1, it is characterized in that, this nanoparticle material is inorganic material.

4. the separation method of flexible base plate as claimed in claim 3, it is characterized in that, the nanoparticle of this inorganic comprises the combination of metal, alloy, metal oxide, metal nitride, metal oxynitride, alloyed oxide, alloy nitride, alloy nitrogen oxide or above-mentioned material at least one.

5. the separation method of flexible base plate as claimed in claim 1, it is characterized in that, there is the nanoparticle of surfaction, wherein, the medium of this nano-particle surface upgrading can be made to comprise hexamethyldisiloxane (HMDS, Hexamethyldisilazane), dimethyl silicone polymer (PDMS, polydimethylsiloxane), dimethyldiethoxysilane (DMDES, dimethyldiethoxysilane) with trimethylethoxysilane (TMES, trimethylethoxysilane).

6. the separation method of flexible base plate as claimed in claim 1; it is characterized in that; the method forming this release layer comprises: impose baking to remove this coating fluid, and this release layer is finally made up of this crystal type nanoparticle or the nanoparticle with surfaction.

7. the separation method of flexible base plate as claimed in claim 1, it is characterized in that, this flexible base plate is a polymeric substrate.

8. the separation method of flexible base plate as claimed in claim 1, it is characterized in that, the processing procedure of this component structure layer is the combination of a thin-film transistor processing procedure, color filter producing process, black matrix" processing procedure, organic illuminating element processing procedure, photo-electric conversion element processing procedure or preceding process at least one.