KR102170175B1 - Method for manufacturing temporarily bonded carrier glass-metal foil assembly for fabricating flexible display device - Google Patents

Abstract

The present invention relates to a method of manufacturing a temporarily bonded carrier glass-metal foil assembly, including: (a) forming a coating layer containing glass powder on a carrier glass; (b) preparing a carrier glass-metal foil assembly by contacting the glass powder-containing coating layer with one surface of the metal foil; and (c) applying an electron beam to the carrier glass-metal foil assembly to temporarily bond the carrier glass and the metal foil. According to the present invention, a glass powder layer is interposed between a carrier glass and a metal foil, and an electron beam is irradiated to prepare a temporary bonded glass-metal bonded body, so that glass and metal are rapidly and effectively bonded without requiring a heat treatment process that consumes a relatively large amount of time and energy for the bonding process as in the related art.

Description

Manufacturing method of a temporary bonding carrier glass-metal foil bonded body for manufacturing a flexible display device {METHOD FOR MANUFACTURING TEMPORARILY BONDED CARRIER GLASS-METAL FOIL ASSEMBLY FOR FABRICATING FLEXIBLE DISPLAY DEVICE}

It relates to a method of manufacturing a temporary bonded carrier glass-metal foil bonded body that can be used in the manufacture of a flexible display device.

Since 1896 Charles Eduouard Guillaume discovered invar, a unique iron-nickel alloy with a very low coefficient of thermal expansion (CTE), Invar has received much attention. Invar has high dimensional stability and flexibility, and exhibits mechanical properties equivalent to stainless steel. Due to these special properties, invar foil is very attractive as a substrate for manufacturing flexible display devices in the display industry.

Meanwhile, in order to be able to use a flexible substrate in a display device manufacturing line, it is necessary to temporarily dock a flexible substrate to a rigid carrier that suppresses bending of the flexible substrate during the manufacturing process. It relates to a method of bonding and separating glass to a carrier glass and platic to a glass substrate. On the other hand, studies related to docking metal foils to rigid glass are very rare.

Korean Patent Publication No. 10-2013-0024385 (Publication date: 2013.03.08)

Hoehla, S., Garner, S., Hohmann, M., Kuhls, O., Li, X., Schindler, A., and Fruehauf, N.:'Active Matrix Color-LCD on 75 μm Thick Flexible Glass Substrates' , J. Disp. Technol., 2012, 8, (6), pp.309-316 , J.,, S.,, G.B.,, B.D., and, D.:'Temporary bond-debond process for manufacture of flexible electronics: Impact of adhesive and carrier properties on performance', J. App. Phy., 2010, 108, (11), 114917 Haq, J., Vogt, B.D., Howard, E., and Loy, D.:'Temporary bond-debond technology for high-performance transistors on flexible substrates', J. Soc. Inf. Disp., 2010, 18, (11), pp. 884-891 Choi, Y.S.,, J.U.,, S.E.:'Flat panel display glass: Current status and future',, 2016, 431, pp. 2-7 Lee, C.C., Chang Y.Y., Cheng, H.C., Ho, J.C.:'' J. Soc. Inf. Disp., 2010, 41, (1), pp. 810-813 O'Rourke, SM, Venugopal, SM, Raupp, GB, Allee, DR, Ageno, S., Bawolek, EJ, Loy, DE, Kaminski, JP, Moyer, C., O'Brien, B., Long, K ., Marrs, M., Bottesch, D., Dailey, J., Trujillo, J., Cordova, R., Richards, M., Toy, D., Colaneri, N.:'Active Matrix Electrophoretic Displays on Temporary Bonded Stainless Steel Substrates with 180 ㅀC a-Si:H TFTs', J. Soc. Inf. Disp., 2008, 39, (1), pp. 422-424 Kern, W.:'The Evolution of Silicon Wafer Cleaning Technology', J. Electrochem. Soc., 1990, 137, (6), pp. 1887-1892

The technical problem to be solved by the present invention is to provide a method of manufacturing a carrier glass-metal foil bonded body temporarily bonded by docking a flexible metal foil to a rigid glass sheet.

In order to achieve the above technical problem, the present invention, as shown in Figure 1 (a) forming a glass powder-containing coating layer on a carrier glass; (b) manufacturing a carrier glass-metal foil assembly by contacting the glass powder-containing coating layer with one surface of the metal foil; And (c) temporarily bonding the carrier glass and the metal foil by irradiating an electron beam onto the carrier glass-metal foil assembly.It proposes a method of manufacturing a temporary bonding carrier glass-metal foil assembly.

In addition, a method of manufacturing a temporary bonding carrier glass-metal foil bonded body, characterized in that the coating layer containing glass powder is formed by spin coating in the step (a).

In addition, in the step (b), the glass powder is an alkaline earth boro-aluminosilicate (alkaline earth boro-aluminosilicate) glass, characterized in that it is made of a temporary bonding carrier glass-proposes a method of manufacturing a metal foil bonded body.

In addition, it is proposed a method of manufacturing a temporary bonding carrier glass-metal foil bonded body, characterized in that the metal foil is a foil made of invar.

In another aspect of the present invention, after preparing a temporary bonding carrier glass-metal foil bonded body according to the method, (d) forming an element on the other surface of the metal foil, and then peeling the carrier glass. A method of manufacturing a flexible device including a metal substrate is proposed in which a flexible device is manufactured by performing additionally.

At this time, it is proposed a method of manufacturing a flexible device including a metal substrate, characterized in that the carrier glass is peeled off by laser irradiation or mechanical stress application in step (d).

In another aspect of the invention, the present invention proposes a flexible display device manufactured by the method of manufacturing a flexible device including a metal substrate.

According to the manufacturing method of a temporary bonded carrier glass-metal foil bonded body for manufacturing a flexible display device according to the present invention, a glass-metal bonded bonded body was prepared by interposing a glass powder layer between the carrier glass and a metal foil and then irradiating an electron beam. Thus, glass and metal can be quickly and effectively bonded without requiring a heat treatment process that consumes a relatively large amount of time and energy for the bonding process as in the prior art.

1 is a process flow diagram showing each step of a method of manufacturing a temporary bonding carrier glass-metal foil bonded body according to the present invention.
2(a) to 2(c) are photographs of the carrier glass-invar foil assembly exposed to the electron beam for 1 minute, 2 minutes, and 3 minutes, respectively, in the present embodiment, and FIG. 2(d) is the electron beam exposure process completed. It is a photograph of the later carrier glass-invar foil conjugate.
3 is a cross-sectional TEM image of a carrier glass-invar foil conjugate exposed to an electron beam for 2 minutes (inset is an EDS spectrum of each point).
4 is a cross-sectional TEM image of a carrier glass-invar foil conjugate exposed to an electron beam for 2 minutes (inset is a diffraction pattern of each point).

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

Since the embodiments according to the concept of the present invention can apply various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiments according to the concept of the present invention to a specific form of disclosure, and it should be understood that all changes, equivalents, and substitutes included in the spirit and scope of the present invention are included.

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of a set feature, number, step, action, component, part, or combination thereof, but one or more other features or numbers It is to be understood that the possibility of addition or presence of, steps, actions, components, parts, or combinations thereof is not preliminarily excluded.

Hereinafter, the present invention will be described in more detail with reference to examples.

The embodiments according to the present specification may be modified in various forms, and the scope of the present specification is not construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely describe the present specification to those of ordinary skill in the art.

<Example>

Invar (FeNi36) film and commercial alkaline earth boro-aluminosilicate glass (Corning 1737) having a thickness of 100 μm and 500 μm, respectively, were used. The coefficient of thermal expansion (CTE) of the glass plate was 37 × 10 ^-7 K ^-1 (α _20-300 ( ISO 7991)). The manufacturing process was carried out as follows. First, in order to thoroughly remove grease and organic contaminants to improve the adhesion between Invar and glass, both Invar foil and glass plate specimens were cleaned using a standard RCA cleaning process. Glass powder was used between the metal foil and the glass plate to improve adhesion. For this, spin coating was used to coat the glass surface with glass powder. The suspension used for spin coating was prepared by mixing 10 ml of deionized water and 4 mg of glass powder and performing ultrasonic treatment for 10 minutes. Spin coating was performed at 750 rpm for 15 seconds. Next, the assembly of the glass substrate and the Invar foil was irradiated with an electron beam using an Infovion system (Infovion Inc., Korea) to heat the assembly. To do this, place the specimen in the specimen holder of the chamber, lower the vacuum degree of the chamber to 7 x 10 ^-7 Torr, adjust the operating pressure to about 1 × 10 ^-5 Torr, and set the acceleration voltage to 4 kV and the distance between the beam source and the substrate to 20 cm After setting, an electron beam was irradiated while rotating the substrate at 5 rpm. 2(a) to 2(c) are photographs showing specimens exposed to an electron beam. The corresponding electron beam energy is sufficient to heat the metal layer and ensures a fast bonding process. When the glass substrate is assembled with the metal foil and exposed to the electron beam for 2 minutes, adhesion occurs between the glass and the metal, but the adhesion between the Invar and the glass is very weak, and the glass is easily separated from the Invar. This weak adhesion can be expected to be associated with insufficient surfaces involved in the diffusion process. To solve this problem, glass powder was used to increase the surface area (Fig. 2(d)). The amount of glass powder on the surface was adjusted by changing the concentration of the glass powder in the suspension. Accordingly, it is estimated that the adhesion between Invar and the glass increases significantly and reaches a maximum of 42 N/m (ASTM D1876) depending on the amount of glass powder.

In order to understand the adhesion mechanism, energy dispersive X-ray spectroscopy (EDS) analysis was performed on the cross section. 3 shows a cross-sectional image of Invar on glass after exposure to an electron beam. Table 1 below summarizes the EDS results for the glass, interfacial and metal regions. Trace amounts of Fe and Ni atoms (Fe: 0.04 at%, Ni: 0.01 at%) diffused to a depth of 500 nm, but were mainly concentrated at the interface. Interestingly, atoms originating from glass such as Si and O were not observed in the Invar foil. These elements were only detected at the interface, meaning that they could not diffuse for a short time. This is also related to the existing strong covalent bonds. Based on the EDS data, it can be concluded that electron beam exposure can bond metal and glass due to the diffusion of elements from metal to glass.

4 is a result of TEM analysis of the bonded interface, according to which it can be clearly observed that an interface without defects ensuring good adhesion was formed. The diffraction pattern of the glass shows that despite the diffusion of Fe and Ni into the glass, the structure of the glass remains amorphous without change (see the interpolation diagram in FIG. 4). In addition, in the case of Invar, there was no structural change, and it was confirmed that the crystal structure was very well developed from the diffraction pattern. That is, it can be concluded that the electron beam-treated invar foil will have the same characteristics as before the treatment. In short, when glass is assembled with metal foil and irradiated with an electron beam, metal and glass are successfully bonded, and the main cause of this successful bonding is presumed to be the diffusion of elements from metal to glass.

[Table 1] Element concentration in glass, metal and interface after electron beam treatment of Invar/glass assembly

Claims (7)

(a) forming a coating layer containing glass powder on a carrier glass;
(b) manufacturing a carrier glass-metal foil assembly by contacting the glass powder-containing coating layer with one surface of the metal foil; And
(c) Temporarily bonding the carrier glass and the metal foil by irradiating an electron beam to the carrier glass-metal foil assembly. A method of manufacturing a temporary bonded carrier glass-metal foil assembly comprising. The method of claim 1,
Method for producing a temporary bonding carrier glass-metal foil bonded body, characterized in that forming a glass powder-containing coating layer by spin coating in the step (a). The method of claim 1,
In the step (b), the glass powder is a method of manufacturing a temporary bonded carrier glass-metal foil bonded body, characterized in that it is made of alkaline earth boro-aluminosilicate glass. The method of claim 1,
The method of manufacturing a temporary bonding carrier glass-metal foil bonded body, characterized in that the metal foil is a foil made of invar. The method of claim 1,
(d) after forming the device on the other surface of the metal foil, the method of manufacturing a flexible device including a metal substrate further comprising the step of peeling the carrier glass. The method of claim 5,
The method of manufacturing a flexible device including a metal substrate, characterized in that the carrier glass is peeled off by laser irradiation or mechanical stress application in step (d). A flexible display device manufactured by the method according to claim 6.

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