KR20210131059A - Producing method of support substrate for supproting flexible substrate - Google Patents

Abstract

A method of manufacturing a support substrate for supporting a flexible substrate is disclosed. The method for manufacturing the support substrate according to the present invention temporarily and adhesively fixes the flexible substrate in a manufacturing process of a flexible display, and makes it easy to separate the flexible substrate and the support substrate by mechanical force after the production of the flexible display is completed.

Description

Method for manufacturing a support substrate for supporting flexible substrates {PRODUCING METHOD OF SUPPORT SUBSTRATE FOR SUPPROTING FLEXIBLE SUBSTRATE}

The present invention relates to a method for manufacturing a support substrate for supporting a flexible substrate. More specifically, it relates to a method of manufacturing a support substrate for supporting a flexible substrate that can temporarily adhesively fix the flexible substrate during the manufacturing process of the flexible display and can be easily separated by mechanical force after the manufacturing of the flexible display is completed.

In recent years, studies on flexible substrates, rollable substrates, etc., which are flexible substrates in accordance with miniaturization, weight reduction, and thinning, have been actively conducted in the field of display and electronics industries.

A flexible substrate instead of a glass substrate used in the manufacture of a conventional display has a disadvantage in that it is not easy to transport because of its flexibility. In order to solve this problem, the manufacturing is performed by transferring the flexible substrate to a support substrate such as glass or plastic in the form of a hard and thick flat plate, and a method of detaching it from the support substrate in the last step is used. At this time, if the flexible substrate is simply placed on the support substrate, deformation such as bending or bending of the flexible substrate occurs in the manufacturing process such as heat treatment. There was a problem in that non-uniform process results occurred.

Therefore, it has been proposed to form an adhesive capable of temporarily adhesively fixing the flexible substrate on the support substrate, and after the production of the flexible display on the support substrate is completed, a process of detaching the support substrate and the flexible display is required.

When describing the process of manufacturing a conventional flexible display, first, a support substrate to support the flexible substrate is introduced into the entry part. Next, the cleaning unit performs cleaning and drying of the support substrate. Subsequently, the flexible substrate is coated on the support substrate in the coating unit, and the volatile material of the flexible substrate is partially volatilized in the drying unit and the moisture is dried to adjust the thickness of the flexible substrate. Then, after the support substrate and the flexible substrate stand by in the buffer unit, one or a plurality of heat treatment units volatilize the volatile material of the flexible substrate and adjust the hardness of the flexible substrate through heat treatment. Next, a detachment process of the flexible substrate is performed with respect to the support substrate that has entered the laser detachment unit through the transfer unit. A pixel forming process, a TFT forming process, etc. may be performed on the flexible substrate before entering the laser detachment unit.

In the system for manufacturing a conventional flexible display as described above, by irradiating a laser such as an excimer laser to the adhesive on the support substrate in the laser detachment unit and heating the adhesive on the support substrate, the adhesive strength of the adhesive is weakened, and the flexible substrate is removed from the support substrate. detach

However, the laser detachable unit including the laser device has a disadvantage in that the equipment price is remarkably high and the maintenance cost is also high. It is a situation in which tens or hundreds of billions of billions of dollars are required only for the equipment price and maintenance cost of the laser detachment unit.

In addition, since the laser has to irradiate the laser to all parts of the large-area adhesive corresponding to the large-area support substrate, the process time becomes long, and when non-uniform laser irradiation occurs, the adhesive force is maintained strongly in some parts of the adhesive, making it flexible There is a problem of causing damage when the substrate is detached. In addition, a problem in that the flexible substrate is burned/damaged by the laser having high energy may also occur.

In addition, conventionally, the pressure-sensitive adhesive on the support substrate is formed by a method of coating two or more materials including organic materials by electrostatic force through a wet process. This method requires a high heat treatment temperature of 400° C. or higher to remove organic matter, and since several materials are coated in a wet process, materials are mixed during the process in a single chamber, making recycling difficult and waste is generated. In addition, the contaminated material may contaminate even the substrate, which may cause a problem in that productivity is deteriorated.

The present invention has been devised to solve the problems of the prior art as described above, and it is possible to manufacture at a low heat treatment temperature, and to provide a method of manufacturing a support substrate for supporting a flexible substrate that minimizes the possibility of generating contamination of the substrate The purpose.

Moreover, this invention aims at providing the manufacturing method of the support board|substrate for flexible board|substrate support which can reduce the cost and maintenance cost of an apparatus remarkably.

In addition, the present invention is to provide a method of manufacturing a support substrate for supporting a flexible substrate that can temporarily adhesively fix the flexible substrate in the manufacturing process of the flexible display and can be easily separated by mechanical force after the manufacturing of the flexible display is completed. The purpose.

In addition, an object of the present invention is to provide a method of manufacturing a support substrate for supporting a flexible substrate capable of minimizing defects and damage of the flexible display and improving productivity.

However, these problems are exemplary, and the scope of the present invention is not limited thereto.

The above object of the present invention is a method of manufacturing a support substrate for temporarily adhesively fixing a flexible substrate in a flexible display manufacturing process. forming the adhesion-inducing thin film by applying plasma; forming an adhesion layer on the adhesion-inducing thin film, and supplying an adhesion solution containing a two-dimensional plate-shaped inorganic material that is electrostatically coupled to an adhesion-inducing material included in the adhesion-inducing thin film to form the adhesion layer; Heat-treating the adhesion-inducing thin film and the adhesion layer formed on the support substrate; is achieved by a method of manufacturing a support substrate for supporting a flexible substrate, including a.

In addition, according to one embodiment of the present invention, in the step of forming the adhesive layer, positive charges are generated in the adhesion-inducing thin film by the contact between the adhesion-inducing thin film and the adhesive solution, and the negative charge of the adhesive solution can be electrostatically coupled. .

Further, according to an embodiment of the present invention, the adhesion-inducing thin film and the adhesion layer may be alternately formed a plurality of times on the adhesion layer.

In addition, according to an embodiment of the present invention, in the step of forming the adhesion-inducing thin film, the plasma treatment may be performed by including at least one gas of oxygen, nitrogen, and argon.

In addition, according to an embodiment of the present invention, in the step of forming the adhesion-inducing thin film, the plasma treatment may be performed under normal pressure.

In addition, according to an embodiment of the present invention, the transmittance of the support substrate for supporting the flexible substrate after the heat treatment may be at least 92% to 99%.

In addition, according to an embodiment of the present invention, the adhesion inducing material of step (a) is (3-Aminopropyl)triethoxysilane, (3-Aminopropyl)trimethoxysilane, 3-Aminopropyl(diethoxy)methylsilane, ( 4-Aminobutyl)triethoxysilane, N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane, N ¹ -(3-Trimethoxysilylpropyl)diethylenetriamine, (2-Aminoethyl)triethoxylsilane, 4-(Diethoxymethylsilyl)butylamine, 2-(Triethoxysilyl)propylamine, 2 It may include at least one of -(Aminopropyl)triethoxysilane and 3-(Aminopropyl)tributoxysilane.

In addition, according to an embodiment of the present invention, the two-dimensional plate-like inorganic material of step (b) is, montmorillonite (montmorillonite), graphene oxide (Graphene oxide), kaolinite (Kaolinite), serpentine (serpentine), dickite ( dickite), talc, and vermiculite.

In addition, according to an embodiment of the present invention, when the adhesive solution is sprayed onto the adhesion-inducing thin film in the step of forming the adhesion layer, NH ₂ of the amine-based silicone included in the adhesion-inducing thin film changes to NH ₃ ^+, , the pH difference of the pressure-sensitive adhesive derived material containing the pKa and the two-dimensional plate-shaped inorganic material of the pressure-sensitive adhesive inducing thin film with an adhesive solution the larger a positive value becomes larger the concentration of NH ₃ ^+, NH ₃ ⁺ and the two-dimensional plate-shaped An amount of electrostatic coupling of negative charges included in the inorganic material may increase.

In addition, according to an embodiment of the present invention, the difference between the pKa of the adhesion-inducing thin film including the adhesion-inducing material and the pH of the adhesion solution including the two-dimensional plate-shaped inorganic material may be greater than at least 0.5.

Further, according to an embodiment of the present invention, after forming the adhesive layer, the adhesive solution may be spread on the adhesion inducing thin film by applying physical energy to the adhesive layer.

Also, according to an embodiment of the present invention, the physical energy may be gas injection.

According to the present invention configured as described above, the present invention can be manufactured at a low heat treatment temperature and has the effect of minimizing the possibility of generating contamination of the substrate.

In addition, there is an effect that can significantly reduce the cost and maintenance cost of the device.

In addition, the present invention has an effect that can be easily separated by mechanical force after the production of the flexible display is completed.

In addition, the present invention has the effect of minimizing the possibility of defects and damage to the flexible display, and improving productivity.

Of course, the scope of the present invention is not limited by these effects.

1 and 2 are schematic views showing a manufacturing process of a support substrate for supporting a flexible substrate according to an embodiment of the present invention.
3 is a structural formula showing the components of the adhesion-inducing material according to an embodiment of the present invention.
4 is a schematic diagram illustrating a reaction mechanism for forming a first layer on a support substrate according to an embodiment of the present invention.
5 is a schematic diagram illustrating the behavior of an adhesion-inducing material/adhesive solution by gas injection according to an embodiment of the present invention.
6 is a graph showing the abundance ratio _{of NH 2} and NH ₃ ⁺ to pH of the first layer according to an embodiment of the present invention.
7 is a schematic view showing a support substrate for supporting a flexible substrate according to various embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0023] Reference is made to the accompanying drawings, which show by way of illustration specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention are different but need not be mutually exclusive. For example, certain shapes, structures, and characteristics described herein with respect to one embodiment may be embodied in other embodiments without departing from the spirit and scope of the invention. In addition, it should be understood that the location or arrangement of individual components within each disclosed embodiment may be changed without departing from the spirit and scope of the present invention. Accordingly, the following detailed description is not intended to be taken in a limiting sense, and the scope of the present invention, if properly described, is limited only by the appended claims, along with all scope equivalents to those claimed. In the drawings, like reference numerals refer to the same or similar functions in various aspects, and the length, area, thickness, and the like may be exaggerated for convenience.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to enable those of ordinary skill in the art to easily practice the present invention.

1 and 2 are schematic views illustrating a manufacturing process of a support substrate 100 for supporting a flexible substrate according to an embodiment of the present invention.

The support substrate 100 for supporting the flexible substrate (see FIG. 2 ( g ) ) may be understood as a temporary adhesive portion 120 formed on the support substrate 110 . The support substrate 110 may be used to flatly support a flexible substrate (not shown). The temporary adhesive part 120 may be used for a purpose in which the flexible substrate is temporarily adhesively fixed to the support substrate 110 , and the flexible substrate can be detached from the support substrate 110 by applying a mechanical force at the last stage of the process. have.

The manufacturing method of the support substrate 100 for supporting the flexible substrate of the present invention is a method of manufacturing the support substrate 100 for temporarily adhesively fixing the flexible substrate in the flexible display manufacturing process, (a) one surface of the support substrate 110 . Forming the first layer 130 by supplying an adhesion-inducing material and plasma containing an amine-based material and silicon (Si) thereon, (b) negative (-) on the first layer 130 Forming the second layer 150 by spraying an adhesive solution having an electric charge, (c) may include heat-treating the support substrate 110 , the first layer 130 , and the second layer 150 . . Hereinafter, the manufacturing process of the support substrate 100 for supporting the flexible substrate will be described in detail.

First, referring to FIG. 1A , the support substrate 110 may be prepared. The size of the support substrate 110 may be a size corresponding to an integer multiple of the size of the flexible substrate to be used, or at least a size larger than this.

The support substrate 110 may include a material such as glass or quartz. As an example, the support substrate 110 may use a pure glass substrate that does not have an electric charge on the surface without a separate treatment on the surface. Alternatively, as the support substrate 110 , a tempered glass substrate such as low iron glass, soda lime glass, or alumina silicate glass having excellent hardness may be used. The tempered glass substrate is advantageously reusable by preventing the occurrence of aspiration, damage, and the like.

Next, the support substrate 110 may be cleaned by a known cleaning method. For example, cleaning may be performed with DI water, ethanol, or the like using a sonicator. After washing, drying may be performed using an air gun.

Next, referring to FIG. 1B , an adhesion-inducing material (G) and plasma (P) containing an amine-based material and silicon (Si) are supplied on at least one surface of the support substrate 110 . Thus, the first layer 130 ′ may be formed. The process of forming the first layer 130 ′ may be performed as a dry process in which a gaseous adhesion-inducing material (G) is supplied and plasma (P) is simultaneously supplied in a plasma facility. Plasma P may use atmospheric pressure O ₂ plasma, and plasma treatment may be performed under atmospheric pressure, so that the process is simple.

_{A carrier gas such as Ar or N 2} may be supplied to the adhesion-inducing material (G) stored in a liquid state, and the adhesion-inducing material (G) may be vaporized while passing through an evaporator and a heater. Thus, it is possible to supply the adhesion-inducing material (G) in a gaseous state simultaneously with the plasma (P) to the support substrate 110 disposed in the plasma facility. The supply path of the carrier gas for plasma formation and the supply path of the adhesion-inducing material (G) may be variously changed.

The adhesion-inducing material (G) may be an amine-based silicone including amine and silicon (Si). The silicon (Si) component may contribute to bonding ^{with OH −} formed on the surface of the support substrate 110 when plasma P is supplied. The amine component is combined with the silicon (Si) component so that the adhesion-inducing material (G) can be deposited on the support substrate 110 and, at the same time, positively charged as _{NH 3} ^{+ in the adhesive solution having a negative charge to be described later.} may play a role in providing

3 shows a structural formula of an aminosilane-based material including an amine and silicon (Si). The adhesion-inducing material (G) is (3-Aminopropyl)triethoxysilane [Fig. 3(a)], (3-Aminopropyl)trimethoxysilane [Fig. 3(b)], 3-Aminopropyl(diethoxy)methylsilane [Fig. 3(c)], (4-Aminobutyl)triethoxysilane [Fig. 3(d)], N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane [Fig. 3(e)], N ¹ -(3-Trimethoxysilylpropyl)diethylenetriamine [Fig. 3(f)], (2-Aminoethyl)triethoxylsilane [Fig. 3(g)], 4-(Diethoxymethylsilyl)butylamine [Fig. 3(h)], 2-(Triethoxysilyl)propylamine [Fig. 3(i)], 2-(Aminopropyl)triethoxysilane [Fig. 3(j)], 3-(Aminopropyl)tributoxysilane [Fig. 3(k)], etc. may be used. Hereinafter, an example of using (3-Aminopropyl)triethoxysilane (or 'APTES') as the adhesion-inducing material (G) will be described.

4 is a schematic diagram illustrating a reaction mechanism for forming a first layer 130 ′ on a support substrate 110 according to an embodiment of the present invention. When the adhesion-inducing material (G) and plasma (P) are supplied on the support substrate 110, two mechanisms for forming the first layer 130' (or the adhesion-inducing thin film 130') will be described below. same.

Referring to FIG. 4A as the first mechanism, OH ⁻ may be formed on the surface of the support substrate 110 by plasma P. At the same time or sequentially with the formation of OH ⁻ , the adhesion-inducing material G affected by the plasma P may be plasma-deposited on the surface of the support substrate 110 . Si of the adhesion inducing material (G) forms a bond with O ^{2 -} of OH - on the support substrate 110, and H ^{+ of OH -} and C, H, O components of the adhesion inducing material (G) are generated as ethanol. can Si of the adhesive inducer (G) is able to form a first layer 130 ', as by maintaining a state in combination with NH _2, place an NH ₂ on the surface of the support substrate 110. The

Referring to (b1) of FIG. 4 as a second mechanism, the adhesion-inducing material (G) may be influenced by plasma (P), so that the bonds around Si may be changed to Si-OH bonds instead of Si-O bonds (G - >G'). ^{OH −} may be formed on the surface of the support substrate 110 by plasma P.

Then, as shown in FIG. 4 (b2), Si of the adhesion inducing material (G') forms a bond with O ^{2 -} of OH - on the support substrate 110, and H ^{+ of OH -} and the adhesion inducing material (G) O, H components can be produced as water. Adhesive inducer (G ') is Si of the first layer (130 as to maintain a state in combination with NH _2, place an NH ₂ on the surface of the support substrate 110, it is possible to form a).

Next, referring to FIG. 1C , a second layer 150 ′ (or an adhesive layer 150 ′) may be formed on one surface of the support substrate 110 . The second layer 150 ′ may be formed by spraying an adhesive solution. Since the injection of the adhesive solution is a wet process, it is preferable to proceed in a chamber separate from the supply of the adhesion inducing material (G), but the present invention is not limited thereto and may be continuously performed in one chamber. In the present invention, since the formation of the first layer 130 by the adhesion inducing material (G) is a dry process and the spraying of the adhesion solution is a wet process, the two materials are mixed to contaminate the support substrate 110 and the inside of the chamber. has the advantage of being resolved.

The adhesive solution is a two-dimensional plate-shaped inorganic material, including montmorillonite, negative graphene oxide (nGO), positive graphene oxide (pGO), kaolinite, serpentine, dickite, and talc. , vermiculite, etc. may be used. In order to prevent aggregation of molecules in the adhesive solution, it is preferable to continuously mix the adhesive solution using a stirrer, a circulation pump, or the like.

The adhesive solution may be sprayed from the adhesive solution spraying unit (not shown). As long as the adhesive solution spraying unit is for the purpose of spraying fine droplets, known devices such as a two-fluid nozzle, a sprayer, a spin coater, and a brush may be used without limitation. A two-fluid nozzle is a nozzle that creates a fine jet shape by mixing and jetting gas and liquid. When the pressure-sensitive adhesive solution is injected into the two-fluid nozzle and sprayed, fine droplets may be sprayed as the liquid molecules are destroyed using gas. The two-fluid nozzle has advantages in that the cost is as low as hundreds of thousands of won, there is no need to configure a separate power supply line, and the amount of spray can be controlled in a small amount. Accordingly, the adhesive solution may be uniformly and thinly sprayed on the support substrate 110 at the nm level.

On the other hand, the adhesive solution spraying unit is disposed at a position spaced apart from one surface of the support substrate 110 in the z-axis direction, and in a direction from one end of the support substrate 110 to the other end (eg, the x-axis direction, the y-axis direction). direction, diagonal direction, etc.) while scanning can be performed. For example, a plurality of double-fluid nozzles arranged to be spaced apart from each other in the horizontal direction (for example, the x-axis direction) are disposed at positions spaced apart from the support substrate 110 in the z-axis direction, and scanned in the y-axis direction. While the adhesive solution can be sprayed. After spraying the adhesive solution while scanning, the adhesive solution spraying unit is preferably moved to a position that does not overlap in the vertical direction of the support substrate 110 .

Conversely, spraying is performed by fixing the adhesive solution spraying unit at a position spaced apart from one surface of the support substrate 110 in the z-axis direction, and spraying is performed while moving the support substrate 110 in the x-axis direction, the y-axis direction, etc. can do. For example, a plurality of double-fluid nozzles arranged to be spaced apart from each other in a horizontal direction (for example, in the x-axis direction) are fixedly disposed at positions spaced apart from the support substrate 110 in the z-axis direction, and the support substrate 110 is disposed. ) may move the loaded support means in the y-axis direction to spray the adhesive solution on the support substrate 110 .

If, instead of spraying in a scan method, it is sprayed with the adhesive solution spraying part fixedly arranged on the xy plane, the adhesive solution liquid droplets formed on the nozzle after spraying fall to the upper surface of the support substrate 110, and uniformly and thinly produced. It may be an obstacle to forming the second layer 150'. Of course, in a later step, the gas injection means 50 (see FIG. 1(d) ) may spray the gas A to form the second layer 150 ′ uniformly and thinly, but it is not a micro-droplet but a large liquid. It is undesirable for the enemy to fall on the support substrate 110 in terms of thickness uniformity.

Next, referring to FIG. 1D , physical energy may be applied to the second layer 150 ′. By applying physical energy to move molecules in the adhesive solution of the second layer 150 ′, the adhesive solution may be evenly spread on the entire surface of the support substrate 110 . The application of physical energy may be performed by injecting the gas A with the gas injection means 50 . By applying physical energy to move the molecules in the adhesive solution of the second layer 150 ′, the adhesive solution is evenly spread on the front surface of the support substrate 110 , so that the first layer 130 and the second layer 150 ′ may increase the amount of charge binding.

5 is a schematic diagram illustrating the behavior of an adhesion-inducing material/adhesive solution by gas injection according to an embodiment of the present invention. 6 is a graph showing the abundance ratio _{of NH 2} and NH ₃ ⁺ to pH of the first layer according to an embodiment of the present invention. 5 and 6 , it will be further described that the first layer 130 has a (+) charge and the second layers 150' and 150" have a (-) charge.

Physical energy may be applied to the second layer 150 ′ by spraying the gas A through the gas injection means 50 . As the molecules of the adhesive solution of the second layer 150 ′ are moved by the application of physical energy, the adhesive solution may be evenly spread on the first layer 130 . Alternatively, the adhesive solution may be evenly spread on the first layer 130 as molecules in the adhesive solution of the second layers 150' and 150" are moved by the application of physical energy. In other words, the gas (A) By the injection of (+) and (-) charges of the upper and lower layers, it is possible to increase the amount of charge coupled by electrostatic attraction in the form of 1:1, 1:many. The gas (A) injection of the gas injection means 50 may be a movement process of the mixture molecules in the adhesive solution for generating a uniform (+), (-) bonding layer.

Referring to (a) of FIG. 5 , when the gas A is sprayed while the gas spraying means 50 is scanned (S), the pressure-sensitive adhesive solution of the second layer 150 ′ thickly formed on the first layer 130 . this can be pushed out Molecular leveling may proceed while the second layer 150 ′ is pushed while maintaining a minimum thickness to be coupled to the first layer 130 directly below by electrostatic attraction. The adhesive solution that is not coupled by electrostatic attraction may be pushed to the outside (outside the support substrate 110 ) along the injection direction of the gas A.

Referring to (b) of FIG. 5 , the second layer 150 ″ is not formed on the entire surface of the first layer 130 , and an empty portion V may exist. When the gas A is sprayed while scanning (S), the adhesive solution of the second layer 150 ″ may be pushed out. As the second layer 150" is pushed out, the vacant portion V of the adhesive solution may be filled. At this time, the adhesive solution is emptied by the minimum thickness to be coupled with the first layer 130 directly below by electrostatic attraction. Molecular alignment may proceed while filling the portion V. The adhesive solution that is not bound by electrostatic attraction may be pushed to the outside (outside the support substrate 110) along the spraying direction of the gas A.

As the adhesive solution is pushed out by the gas A sprayed from the gas spraying means 50 , residual moisture is removed, and molecular alignment of the solution may proceed. The gas A injected from the gas injection means 50 may be used not only with an inert gas such as Ar, but also N ₂ , O _{2 ,} etc. that do not react with the first layer 130 / second layer 150 .

In addition, it is preferable that the temperature of the gas A injected by the gas injection means 50 is 0 °C to 80 °C. Accordingly, as the gas A is sprayed, the residual moisture in the adhesive solution may be removed. A gas (A) having a temperature higher than this may heat-treat the first layer 130 and the second layer 150 , and the gas (A) having a lower temperature than this may be the first layer 130 and the second layer 150 . It is preferable to maintain a temperature sufficient to remove the residual moisture, since it can freeze moisture.

As described above in FIG. 4 , before spraying the adhesive solution, the first layer 130 _{contains only NH 2} , so it is neutral or has insufficient (+) charge. However, as the adhesive solution is sprayed onto the first layer 130 , a (+) charge may be generated in the first layer 130 .

In order to positively charge the first layer 130 , NH ₂ must be changed to NH ₃ ^{+ .} That is, NH ₂ may _{be ionized as NH 3} ⁺ , or may be protonated. Referring to FIG. 6 , _{the ratio of NH 2} ↔ NH ₃ ^{+ in} the solution (adhesive solution) is determined by the pH of the solution. When the pH of the solution is lowered around pKa, _{the concentration of NH 3} ⁺ may increase to 50% or more. For example, when the adhesion-inducing material (G) is APTES and the adhesion solution is montmorillonite, pKa is 7.6. The pKa of the aminosilane-based material is present at pH 6 to pH 9, and according to the graph of FIG. 6 , as the pH value of the adhesive solution is lower than the pKa in the solution, that is, the difference between the pKa and the pH of the adhesive solution is a positive value. As NH ₃ ⁺ increases, the concentration of NH 3 + may increase. Therefore, _{in order to make the concentration of NH 3} ⁺ 90% or more, it is preferable to maintain the pH of the adhesive solution at pH 5 to pH 8. According to one embodiment, _{when the concentration of NH 3} ⁺ is 70% or more, the second layer 150 may be formed to have an appropriate adhesive force for detachment of the flexible substrate. In addition, _{when the concentration of NH 3} ⁺ is 90% or more, a series of processes for effectively forming the temporary adhesive portion 120 may be possible. For this purpose, it is preferred that the difference between the pKa and the pH of the adhesive solution is at least greater than 0.5. For example, when pKa = 7.6, pH = 7.1, _{the concentration of NH 3} ^{+ corresponds} to 76%, when pKa = 7.6, pH = 6.6, _{the concentration of NH 3} ⁺ corresponds to 91%. However, the present invention is not limited thereto, and even if the pH of the solution is higher than pKa, that is, even if _{the concentration of NH 3} ⁺ is as low as about 30%, the second layer 150 may be formed, and the first layer 130 and It turns out that the pH can be adjusted within the range in which the second layer 150 is bonded.

Accordingly, when the gas injection means 50 is scanned (S) to distribute the second layers 150 ′ and 150 ″ on the first layer 130 as shown in FIG. 5 , the first layer 130 is NH ₃ ⁺ It has a (+) charge due to an increase in the concentration of can be combined with The adhesive solution remains to a minimum thickness to be coupled with the first layer 130 directly below by electrostatic attraction to constitute the second layer 150 .

Again, referring to (d) of FIG. 1 , the gas injection unit 50 injects the gas A while scanning (S) in at least one direction, such as the x-axis and the y-axis, similarly to the above-described adhesive solution injection unit. can be performed. For example, the gas ejection means 50 formed to extend in a horizontal direction (for example, the x-axis direction) is disposed at a position spaced apart from the support substrate 110 in the z-axis direction, and scans in the y-axis direction ( S) while the gas (A) can be sprayed.

The adhesive solution of the second layer 150 ′ is pushed along the scan (S) direction of the gas spraying means 50 by the gas A sprayed from the gas spraying means 50 . As the adhesive solution is pushed out, residual moisture is removed, and the adhesive solution may be aligned. However, not all of the adhesive solution is pushed out, and the adhesive solution remains as thick as the range in which the adhesive solution is subjected to electrostatic attraction on the first layer 130 having an opposite charge. The pushed adhesive solution has the advantage of being collected and reused.

On the other hand, when the pressure of the gas A is too strong, residual moisture on the surface of the support substrate 110 is removed in the form of a stain, and when the pressure is too weak, the moisture on the surface cannot be removed. In consideration of this, the pressure of the gas A injected from the gas injection means 50 should be adjusted so as not to be strong enough to release the mutual electrostatic attraction of the first layer 130 having an opposite charge to the adhesive solution. The vertical distance between the gas injection means 50 and the support substrate 110 may also be adjusted to correspond to the pressure of the gas A.

Next, referring to FIG. 2E , residual moisture in the adhesive solution of the second layer 130 may be removed and alignment may be completed. The first layer 130 having a charge opposite to that of the adhesive solution is subjected to electrostatic attraction to form a minimum thickness.

Meanwhile, referring to (f) of FIG. 2 , heat treatment (H) may be further performed. The heat treatment (H) may be performed in advance in order to prevent the generation of pores due to volatile components in the temporary adhesive part 120 during the heat treatment of the flexible substrate in a subsequent process.

The heat treatment (H) may be performed in a first temperature range of 200°C to 270°C. In the heat treatment (H) process, the moisture of the second layer 150 is removed, and at the same time, the amine group (-NH ₂ ) of the first layer 130 may be removed.

As described above, as the heat treatment is performed on the support substrate 100 , it is possible to prevent bubbles from being generated in the temporary adhesive part 120 due to outgassing in the heat treatment process of the flexible substrate, which is a subsequent step. In addition, while the conventional organic material requires heat treatment at 400° C. or higher, the present invention can perform heat treatment in a low temperature range of 200° C. to 270° C., so the effect of reducing the possibility of defects in the support substrate 100 is have.

As shown in (g) of Figure 2, after the heat treatment, the first layer 130 is removed and the second layer 150 may be left in a state in which the temporary adhesive portion 120 can be configured.

On the other hand, the transmittance of the temporary adhesive portion 120 after the heat treatment (H) may be at least 92% to 99%. In the thickness of this range, the temporary adhesive part 120 may have a predetermined adhesive force. That is, while the temporary adhesive part 120 adhesively fixes the flexible substrate, a predetermined adhesive force to the extent that the flexible substrate is detached according to the application of a mechanical force [for example, the adhesive force corresponding to the post-it degree of 3M Corporation] ] can be obtained. The adhesive force may be about 0.5 gf/in to 4.0 gf/in.

The transmittance of the temporary adhesive portion 120 may correspond to the number of molecular layers of the second layer 150 , and the transmittance per molecular layer of the second layer 150 decreases by about 0.4%. In order to have a predetermined adhesive force, about 3 to 20 molecular layers may be included, and preferably, 3 molecular layers may be included. The number of molecular layers may correspond to the total thickness of the temporary adhesive part 120. By measuring the transmittance that is relatively easy to measure than the total thickness of the temporary adhesive part 120, the adhesive force of the temporary adhesive part 120 can be set. there will be Transmittance can be measured using a UV wavelength of 250 nm to 300 nm through a UV spectrophotometer.

After the heat treatment (H), additional heat treatment may be applied to the temporary adhesive portion 120 including the second layer 150 . Additional heat treatment may be performed by raising the temperature to about 420°C. After the process of forming the temporary adhesive part 120 , there is a process of raising the temperature to about 420° C. a plurality of times in subsequent processes such as a process of forming/volatilizing a flexible substrate, a pixel forming process, and a TFT forming process. In order to prevent the second layer 150 from being deformed in the process, additional heat treatment is performed in advance. If aging is performed so that the second layer 150 has an appropriate stress-retained state through additional heat treatment, the second layer 150 may stably adhere and fix the flexible substrate even in a subsequent process.

7 is a schematic diagram illustrating support substrates 100 - 2 and 100 - 3 according to various embodiments of the present invention.

Referring to (a1) of FIG. 7 , steps (b) of FIG. 1 to (e) of FIG. 2 are repeated twice to form a first layer 130: 130a, 130b and a second layer 150: 150a, 150b. ) can be alternately formed in two layers. In addition, referring to (b1) of FIG. 7, by repeating steps (b) of FIG. 1 to (e) of FIG. 2 n times (n is an integer), the first layer 130: 130a, 130b, 130c and The second layers 150: 150a, 150b, and 150c may be alternately formed by n layers.

After further heat treatment (H) is performed, the first layer 130 is removed and the temporary adhesive part 120 is formed with the second layer 150 remaining ((a2), (b2) in FIG. 7]. can As described above, by adjusting the number of molecular layers of the second layer 150, the temporary adhesive unit 120 adhesively fixes the flexible substrate, while the detachment of the flexible substrate according to mechanical force is applied. It is possible to have a predetermined adhesive strength [eg, adhesive strength corresponding to the degree of Post-it notes manufactured by 3M]. The adhesive force may be about 0.5 gf/in to 4.0 gf/in.

A system (not shown) for manufacturing a flexible display according to an embodiment of the present invention may include an entry unit, a cleaning unit, a temporary adhesive coating unit, a coating unit, a drying unit, a buffer unit, a heat treatment unit, a conveying unit, etc. have. Compared with the conventional system, the laser detachable part is excluded in this system, and a temporary adhesive part coating part can be added.

The support substrate 110 to support the flexible substrate may be introduced into the entrance. Subsequently, cleaning and drying of the support substrate 110 may be performed in the cleaning unit.

Next, in the added temporary adhesive coating part, a series of processes of forming the temporary adhesive part 120 on the support substrate 110 described above with reference to FIGS. 1 to 2 may be performed.

Then, in the coating unit, the flexible substrate is coated on the support substrate 100 for supporting the flexible substrate, and in the drying unit, the volatile material of the flexible substrate is partially volatilized and the moisture is dried to adjust the thickness of the flexible substrate.

Then, after the support substrate 100 and the flexible substrate stand by in the buffer unit, the volatile material of the flexible substrate may be volatilized and the hardness of the flexible substrate may be adjusted through heat treatment in one or a plurality of heat treatment units. Next, a pixel forming process, a TFT forming process, etc. may be performed on the flexible substrate.

Finally, separation may be performed by applying a mechanical force to at least one of the flexible substrate and the support substrate.

Although the system of the present invention adds a temporary adhesive coating, the cost and maintenance cost of the device can be significantly reduced compared to the laser detachable part of the conventional system. In addition, in the system of the present invention, a process of applying a mechanical force is added in the last step, but the time can be significantly shortened compared to the process of irradiating a laser to a large-area support substrate by a laser. Accordingly, there is an advantage in that productivity and economy are remarkably increased.

As described above, the present invention has the effect of remarkably reducing the cost and maintenance cost of the device. In addition, since the flexible display can be easily separated by mechanical force after the manufacturing is completed, the possibility of defects and damage to the flexible display can be minimized, and productivity can be improved. _{And, since the NH 2} material can be removed at a low heat treatment temperature, the occurrence of defects on the substrate can be minimized, and since the plasma dry process and the wet process of spraying the adhesive solution are performed separately, the possibility of generating contamination of the substrate can be minimized. can have an effect. In addition, since the adhesive solution is not mixed, the reusability can be increased, and after the flexible display is separated, the support substrate 110 can be reused, thereby further contributing to reducing production costs.

Although the present invention has been illustrated and described with reference to preferred embodiments as described above, it is not limited to the above embodiments and is not limited to the above-described embodiments, and various methods can be made by those of ordinary skill in the art to which the invention pertains without departing from the spirit of the present invention. Transformation and change are possible. Such modifications and variations are intended to fall within the scope of the present invention and the appended claims.

50: gas injection means
100: a support substrate for supporting a flexible substrate
110: support substrate
120: temporary adhesive
130: first floor
150: second floor

Claims (12)

A method of manufacturing a support substrate for temporarily adhesively fixing a flexible substrate in a flexible display manufacturing process, the method comprising:
forming an adhesion-inducing thin film by supplying an adhesion-inducing material containing amine-based silicon on one surface of the support substrate, and forming the adhesion-inducing thin film by applying plasma;
forming an adhesion layer on the adhesion-inducing thin film, and supplying an adhesion solution containing a two-dimensional plate-shaped inorganic material that is electrostatically coupled to an adhesion-inducing material included in the adhesion-inducing thin film to form the adhesion layer;
heat-treating the adhesion-inducing thin film and the adhesion layer formed on the support substrate;
A method of manufacturing a support substrate for supporting a flexible substrate, comprising a. According to claim 1,
In the step of forming the adhesive layer, positive charges are generated in the adhesion-inducing thin film by contact of the adhesion-inducing thin film and the adhesive solution and electrostatically coupled to the negative charge of the adhesive solution. According to claim 1,
Forming an adhesion-inducing thin film and an adhesion layer alternately a plurality of times on the adhesion layer,
A method of manufacturing a support substrate for supporting a flexible substrate. According to claim 1,
In the step of forming the adhesion induction thin film, the plasma treatment is performed by including at least one gas of oxygen, nitrogen, and argon,
A method of manufacturing a support substrate for supporting a flexible substrate. 5. The method of claim 4,
In the step of forming the adhesion induction thin film, plasma treatment is performed under normal pressure,
Method for manufacturing a support substrate for supporting flexible substrates According to claim 1,
After the heat treatment, the transmittance of the support substrate for supporting the flexible substrate is at least 92% to 99%,
A method of manufacturing a support substrate for supporting a flexible substrate. According to claim 1,
The adhesion-inducing material of step (a) is an amine-based silicone material, such as (3-Aminopropyl)triethoxysilane, (3-Aminopropyl)trimethoxysilane, 3-Aminopropyl(diethoxy)methylsilane, (4-Aminobutyl)triethoxysilane, N-(2- Aminoethyl)-3-aminopropyltrimethoxysilane, N ¹ -(3-Trimethoxysilylpropyl)diethylenetriamine, (2-Aminoethyl)triethoxylsilane, 4-(Diethoxymethylsilyl)butylamine, 2-(Triethoxysilyl)propylamine, 2-(Aminopropyl)triethoxysilane, 3-(Aminopropyl) At least one of tributoxysilane,
A method of manufacturing a support substrate for supporting a flexible substrate. According to claim 1,
The two-dimensional plate-like inorganic material of step (b) is, montmorillonite, graphene oxide, kaolinite, serpentine, dickite, talc, vermiculite (vermiculite) comprising at least any one of,
A method of manufacturing a support substrate for supporting a flexible substrate. According to claim 1,
When the pressure-sensitive adhesive solution is supplied to the adhesion-inducing thin film in the step of forming the adhesion layer, NH ₂ of the amine-based silicone included in the adhesion-inducing thin film changes to NH ₃ ^{+ ,}
The pH difference of the pressure-sensitive adhesive derived material containing the pKa and the two-dimensional plate-shaped inorganic material of the pressure-sensitive adhesive inducing thin film with an adhesive solution The larger a positive value becomes larger the concentration of the NH ₃ ^+, the NH ₃ ⁺ and the two-dimensional The amount of electrostatic coupling of negative charges contained in the plate-shaped inorganic material increases,
A method of manufacturing a support substrate for supporting a flexible substrate. 10. The method of claim 9,
The difference between the pKa of the adhesion-inducing thin film including the adhesion-inducing material and the pH of the adhesion solution including the two-dimensional plate-shaped inorganic material is at least 0.5 or greater,
A method of manufacturing a support substrate for supporting a flexible substrate. According to claim 1,
After forming the adhesive layer, applying physical energy to the adhesive layer to spread the adhesive solution on the adhesion inducing thin film,
A method of manufacturing a support substrate for supporting a flexible substrate. 11. The method of claim 10,
wherein the physical energy is a gas jet,
A method of manufacturing a support substrate for supporting a flexible substrate.

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