TW201412554A - Processing of flexible glass substrates and substrate stacks including flexible glass substrates and carrier substrates - Google Patents

Abstract

A method of processing a flexible glass substrate includes providing a substrate stack comprising the flexible glass substrate bonded to a carrier substrate using a carbon bonding layer. The flexible glass substrate is then separated from the carrier substrate.

Description

Processing of a flexible glass substrate and substrate stacking comprising the flexible glass substrate and the carrier substrate

The present application claims priority rights in U.S. Provisional Application No. 61/691,899 filed on Aug. 22, 2012, which is hereby incorporated by reference in its entirety in its entirety in its entirety in in.

This invention relates to apparatus and methods for processing flexible glass substrates on a carrier substrate.

Conventional flexible electronic devices associated with PV, OLED, LCD, and patterned thin film transistors (TFTs) are fabricated by processing device structures on the surface of a glass substrate. The thickness of the substrates can be, for example, between 0.3 mm and 0.7 mm. LCD panel device manufacturers have made significant capital investments in equipment for producing such device structures on the surface of glass substrates in the thickness range of 0.3 mm and 0.7 mm.

Glass substrates in flexible electronic applications have become thinner and lighter. For some display applications, especially portable electronic devices (such as laptops) Glass, hand-held devices, etc., glass substrates having a thickness of less than 0.5 mm, such as less than 0.3 mm, such as 0.1 mm or even thinner, may be desirable. These low-thickness glass substrates are typically formed by fabricating a device structure on a thicker glass substrate and then further processing the glass substrate (eg, via chemical and/or mechanical etching) to thin the glass substrate. While this thinning process is effective, it will be desirable to fabricate the device structure directly on a thinner glass substrate, thereby eliminating any glass thinning steps after the device structure is formed on the glass substrate.

What is needed is a carrier process that utilizes the manufacturer's existing capital infrastructure and enables processing of thin flexible glass substrates, i.e., glass having a thickness of no greater than about 0.3 mm.

The present concept relates to bonding a sheet (eg, a flexible glass substrate) to a carrier substrate using a carbon bonding layer that changes structure after the carbon bonding layer receives an energy input, such as thermal energy, and/or the carbon bonding The layer is brittle, which promotes crack propagation through the carbon bonding layer for layering the flexible glass substrate from the carrier substrate.

A commercial advantage of the method is that the manufacturer will be able to utilize the existing capital investment of the manufacturer on the processing equipment while obtaining, for example, photovoltaic devices (PV), organic light emitting diodes (OLEDs), liquid crystal displays (LCDs), The advantages of touch sensors and thin glass sheets for patterned thin film transistor (TFT) electronics.

According to a first aspect, a method of processing a flexible glass substrate comprises the steps of: A substrate stack is provided, the substrate stack comprising a flexible glass substrate bonded to the carrier substrate using a carbon bonding layer; and separating the flexible glass substrate from the carrier substrate.

According to a second aspect, the method of aspect 1, wherein the carbon bonding layer is brittle, the method further comprising the step of: cracking the crack in the carbon bonding layer.

According to a third aspect, the method of Aspect 1 or Aspect 2 is provided, the method further comprising the step of providing energy input to the carbon bonding layer to introduce a structural change in the carbon bonding layer.

According to a fourth aspect, the method of aspect 3, wherein the energy input is thermal energy, the method comprising the step of heating the carbon bonding layer to a temperature of at least about 250 °C.

According to a fifth aspect, the method of aspect 3 or aspect 4, wherein the energy input is light energy that heats the carbon bonding layer to a temperature of at least about 250 °C.

The method of any of aspects 3 to 5, wherein the structural change comprises increasing the porosity of the carbon bonding layer.

A method according to any one of aspects 1 to 6, wherein the carbon bonding layer is positioned along a periphery of the flexible glass substrate.

The method of any one of aspects 1 to 7, wherein the laser is used to locally heat the carbon bonding layer.

According to a ninth aspect, the method of any of aspects 1 to 8, wherein the carbon bonding layer is heated using an LED or a flash lamp source.

According to a tenth aspect, the method of any of aspects 1 to 9, the method further comprising the step of applying an electronic component to the flexible glass substrate.

The method of any of aspects 1 to 10, wherein the flexible glass substrate has a thickness of no greater than about 0.3 mm.

The method of any one of aspects 1 to 11, wherein the carrier substrate comprises glass.

The method of any one of aspects 1 to 12, wherein the carrier substrate has a thickness greater than a thickness of the flexible glass substrate.

According to a fourteenth aspect, a method of processing a flexible glass substrate, comprising the steps of: providing a carrier substrate having a glass support surface; providing a flexible glass substrate having a first wide surface And a second wide surface; bonding the first wide surface of the flexible glass substrate to the glass support surface of the carrier substrate using a carbon bonding layer; and initiating cracks in the carbon bonding layer for removing the flexible from the carrier substrate Glass substrate.

According to a fifteenth aspect, the method of aspect 14 is provided, the method further comprising the steps of: providing energy input to the carbon bonding layer for changing the structure of the carbon bonding layer and reducing the flexible glass substrate and the carrier substrate The strength of the joint between.

According to a sixteenth aspect, the method of aspect 15, wherein the energy input is thermal energy, the method comprising the step of heating the carbon bonding layer to a temperature of at least about 250 °C.

According to a seventeenth aspect, the method of aspect 15 or aspect 16, wherein the energy input is light energy that causes the carbon bonding layer to be heated to a temperature of at least about 250 °C.

The method of any one of aspects 14 to 17, wherein the carbon bonding layer is positioned along a periphery of the flexible glass substrate.

The method of any one of aspects 14 to 18, wherein the laser is used to locally heat the carbon bonding layer.

A method according to any one of aspects 14 to 20, wherein the carbon bonding layer is locally heated using an LED or a flash lamp source.

The method of any one of aspects 14 to 20, wherein the flexible glass substrate has a thickness of no greater than about 0.3 mm.

According to a twenty-second aspect, a substrate stack includes: a carrier substrate having a glass support surface; a flexible glass substrate supported by a glass support surface of the carrier substrate; and a carbon bonding layer, The carbon bonding layer bonds the flexible glass substrate to the carrier substrate, the carbon bonding layer being brittle to promote crack propagation through the carbon bonding layer.

According to a twenty-third aspect, the substrate stack of aspect 22 is provided, wherein the flexible glass substrate has a thickness of no greater than about 0.3 mm.

The substrate stack of any of the aspects 22 or 23, wherein the carbon bonding layer has a thickness of no greater than about 0.1 mm, in accordance with the twenty-fourth aspect.

Additional features and advantages will be set forth in the <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> </ RTI> <RTIgt; This invention is understood by the invention as defined in the appended claims. It is to be understood that both the foregoing general description and the claims of the invention

The accompanying drawings are included to provide a further understanding of the invention The drawings illustrate one or more embodiments, and are in the It is to be understood that the various features of the invention disclosed in this specification and in the drawings may be used in any and all combinations.

10‧‧‧Substrate stacking

12‧‧‧ Carrier substrate

14‧‧‧glass support surface

16‧‧‧ Relative support surface

Around 18‧‧

20‧‧‧Flexible glass substrate

22‧‧‧First wide surface

24‧‧‧ second wide surface

25‧‧‧ thickness

26‧‧‧around

28‧‧‧ thickness

30‧‧‧ joint layer

32‧‧‧ thickness

40‧‧‧Releasable joint method

42‧‧‧Steps

44‧‧‧Steps

46‧‧‧Steps

47‧‧‧Energy input

48‧‧‧Steps

50‧‧‧ steps

52‧‧‧The surrounding area

54‧‧‧Parts

60‧‧‧Discrete joints

100‧‧‧Stacking

102‧‧‧Device unit

104‧‧‧around

140‧‧‧Device unit

142‧‧‧ joint area

144‧‧‧ Non-joined area

145‧‧‧Electrical installation

Around 146‧‧

150‧‧‧ required equipment

152‧‧‧ perimeter joint

154‧‧‧ joint area

156‧‧‧non-joined area

158‧‧‧Laser

160‧‧‧Ray beam

A ₁ ‧‧‧Area

A ₂ ‧‧‧Area

A ₃ ‧‧‧Area

F‧‧‧ force

P‧‧‧ plane

R‧‧‧non-joined area

1 is a side view of an embodiment of a substrate stack including a flexible glass substrate carried by a carrier substrate; FIG. 2 is an exploded perspective view of the substrate stack of FIG. 1; 4 is a top view of an embodiment of a substrate stack, wherein the flexible glass substrate and the carrier substrate have different sizes; 5 is a top plan view of another embodiment of a substrate stack in which the flexible glass substrate and the carrier substrate have different shapes; and FIG. 6 is an implementation of the substrate stack having a bonding layer coated over the glass supporting surface of the carrier substrate. A top view of an example; Figure 7 is a top plan view of another embodiment of a substrate stack having a bonding layer overlying a glass support surface of a carrier substrate; and Figure 8 is a view having a bond over a glass support surface coated on a carrier substrate A top view of another embodiment of a substrate stack of layers; Figure 9 illustrates the absorbance of a carbon-based bonding layer; and Figure 10 is an embodiment of a substrate stack having a bonding layer coated over a glass support surface of a carrier substrate Top view; FIG. 11 is a plan view of an embodiment of a substrate stack for forming a plurality of desired portions; and FIG. 12 illustrates an embodiment of a method of releasing a flexible glass substrate from a carrier substrate.

The embodiments described herein are generally directed to the treatment of flexible glass substrates (sometimes referred to herein as device substrates). The flexible glass substrate can be part of a substrate stack that generally includes a carrier substrate and a flexible glass substrate joined to the carrier substrate by an inorganic bonding layer. As used herein, the term "inorganic material" refers to a compound that is not a hydrocarbon or a hydrocarbon derivative. As will be described in more detail below, the bonding layer includes an inorganic bonding material that provides a brittle bonding layer, or a bonding layer that can otherwise be relatively easily separated, the bonding layer being compatible with device (eg, TFT) processing. And providing a peeling strength that enables separation of the flexible glass substrate from the carrier substrate.

Referring to FIGS. 1 and 2, the substrate stack 10 includes a carrier substrate 12 and a flexible glass substrate 20. The carrier substrate 12 has a glass support surface 14, an opposing support surface 16 and a perimeter 18. The flexible glass substrate 20 has a first wide surface 22, an opposite second wide surface 24, and a perimeter 26. The flexible glass substrate 20 can be "ultra-thin" having a thickness 28 of about 0.3 mm or less, including but not limited to, for example, about 0.01 mm to 0.05 mm, about 0.05 mm to 0.1 mm, and about 0.1 mm to 0.15. Mm and a thickness of about 0.15 mm to 0.3 mm.

The flexible glass substrate 20 is bonded to the glass support surface 14 of the carrier substrate 12 with the first wide surface 22 of the flexible glass substrate 20 using the bonding layer 30. The bonding layer may be an inorganic bonding layer containing an inorganic bonding material. When the carrier substrate 12 and the flexible glass substrate 20 are bonded to each other by the bonding layer 30, the combined thickness 25 of the substrate stack 10 can be compared to a single glass having an increased thickness compared to the thickness of the individual flexible glass substrate 20. The substrate is the same and this thickness may be suitable for existing device processing infrastructure. For example, if the processing device of the device processing infrastructure is designed for a 0.7 mm piece and the flexible glass substrate 20 has a thickness 28 of 0.3 mm, the thickness of the carrier substrate 12 is based on, for example, the thickness of the bonding layer 30. 32 can be selected to be no greater than 0.4 mm.

As an example, carrier substrate 12 can have any suitable material, including glass, glass ceramic, or ceramic, and carrier substrate 12 can be transparent or non-transparent. If the carrier substrate 12 is made of glass, the carrier substrate 12 can have any suitable composition, including aluminosilicate, borosilicate, aluminoboronate, sodium calcium citrate, and according to the carrier substrate 12 For the end application, the carrier substrate 12 may or may not contain a base. The thickness 32 of the carrier substrate 12 can be from about 0.2 mm Up to 3 mm, such as 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.65 mm, 0.7 mm, 1.0 mm, 2.0 mm or 3 mm, and as described above, the thickness can be seen as the thickness 28 of the flexible glass substrate 20. And set. Moreover, as shown, the carrier substrate 12 can be made from one or more layers (including a plurality of sheets) that are joined together to form a portion of the substrate stack 10.

As an example, the flexible glass substrate 20 can be formed from any suitable material, including glass, glass ceramic, or ceramic, and the flexible glass substrate 20 can be transparent or non-transparent. When the flexible glass substrate 20 is made of glass, the flexible glass substrate 20 can have any suitable composition, including aluminosilicate, borosilicate, aluminoboronate, sodium calcium citrate, And depending on the final application of the flexible glass substrate 20, the flexible glass substrate 20 may or may not contain a base. The thickness 28 of the flexible glass substrate 20 can be about 0.3 mm or less, such as about 0.2 mm or less, such as about 0.1 mm, as described above. As described herein, the flexible glass substrate 20 can have the same size and/or shape or a different size and/or shape as the carrier substrate 12.

Referring to FIG. 3, a releasable bonding method 40 is illustrated as part of processing a flexible glass substrate 20. At step 42, the carrier substrate 12 and the flexible glass substrate 20 are selected based on, for example, the size, thickness, material, and/or end use of the carrier substrate 12 and the flexible glass substrate 20. Once the carrier substrate 12 and the flexible glass substrate 20 are selected, the bonding layer 30 can be applied to one or both of the glass support surface 14 and the first wide surface 22 of the flexible glass substrate 20 at step 44. The bonding layer 30 can be applied using any suitable method, such as, for example, one or more of boost coating, spreading, melting, spin casting, spraying, dipping, vacuum or atmospheric deposition, etc. via a nozzle.

At step 46, the flexible glass substrate 20 is adhered or otherwise bonded to the carrier substrate 12 using the bonding layer 30. In order to achieve the desired bonding strength between the flexible glass substrate 20 and the carrier substrate 12, the bonding material forming the bonding layer 30 may be heated, cooled, dried, mixed with other materials, and a pressure for inducing a reaction or the like may be applied. As used herein, "joint strength" refers to any one or more of dynamic shear strength, dynamic spall strength, static shear strength, static spall strength, and combinations of the above. For example, the peel strength is the per-unit width necessary to initiate a fault (static) and/or maintain a specific failure rate (dynamic) by the stress applied to one or both of the flexible glass substrate and the carrier substrate in the peeling mode. Force. The shear strength is in the shear mode by means of the stress applied to one or both of the flexible glass substrate and the carrier substrate to initiate a failure per unit (static) and/or to maintain a specific failure rate (dynamic) The force of the width. Any suitable method can be used to determine the bond strength, including any suitable peel and/or shear strength test.

Steps 48 and 50 relate to releasing or separating the flexible glass substrate 20 from the carrier substrate 12 such that the flexible glass substrate 20 can be removed from the carrier substrate 12. Prior to and/or after release of the flexible glass substrate 20 from the carrier substrate 12, the flexible glass substrate 20 can be processed, for example, in the formation of a display device such as an LCD, OLED or TFT electronic device. For example, an electronic component or color filter can be applied to the second wide surface 24 of the flexible glass substrate 20. Further, the final electronic component can be assembled or combined with the flexible glass substrate 20 before the flexible glass substrate 20 is released from the carrier substrate 20. For example, an additional film or glass substrate can be laminated to the surface of the flexible glass substrate 12, or an electronic component such as a flexible circuit or IC can be bonded. Once processed flexible glass The glass substrate, that is, the energy input 47 can be applied to the bonding layer 30 that changes the structure of the bonding layer 30 at step 48. As will be described below, the structural change reduces the bonding strength of the bonding layer 30 to promote separation of the flexible glass substrate 20 from the carrier substrate 12 as compared to before the energy input at step 46. Alternatively, as will be described below, the bonding layer 30 may include an inorganic material that does not undergo structural changes, but forms a bonding layer 30 that is susceptible to, for example, cracking to promote peeling of the flexible glass substrate 20. At step 50, the flexible glass substrate 20 is removed from the carrier substrate 12. For example, the extraction can be completed by peeling off a portion of the flexible glass substrate 20 or the flexible glass substrate 20 from the carrier substrate 20. The spalling force is generated by applying a force F to one or both of the substrates at an angle to one of the planes P extending through the bonding layer 30.

Carrier substrate and flexible glass sheet selection

The carrier substrate 12 and the flexible glass substrate 20 may be formed of the same, similar or different materials. In some embodiments, the carrier substrate 12 and the flexible glass substrate 20 are formed from a glass, glass ceramic, or ceramic material. The carrier substrate 12 and the flexible glass substrate 14 can be formed using the same, similar or different forming processes. For example, a melt process (eg, a melt down process) forms a high quality thin glass sheet that can be used in various devices, such as flat panel displays. In the case of using different materials, it may be necessary to match the coefficient of thermal expansion coefficient. When compared to glass sheets produced by other methods, the glass sheets produced in the melt process have surfaces with higher flatness and smoothness. The melting process is described in U.S. Patent Nos. 3,338,696 and 3,682,609. Other suitable glass sheet forming methods include a float process, a draw process, and a slit draw process. The flexible glass substrate 20 (and/or the carrier substrate 12) may also be included on the flexible glass substrate A temporary or permanent protective or other type of coating on one or both of the first wide surface 22 and the second wide surface 24 of 20.

One or more of the size and/or shape of the carrier substrate 12 and the flexible glass substrate 20 may be about the same and/or different. For example, referring briefly to FIG. 4, a carrier substrate 12 having substantially the same shape as the flexible glass substrate 20 but having one or more larger than the flexible glass substrate 20 is illustrated. Size. This configuration allows the peripheral region 52 of the carrier substrate 12 to extend outward beyond the flexible glass substrate 20 about the entire perimeter 26 of the flexible glass substrate 20 or at least a portion of the perimeter 26. As another example, FIG. 5 illustrates an embodiment in which the flexible glass substrate 20 has a different shape, and the flexible glass substrate 20 has a size different from that of the carrier substrate 12. This configuration may allow only a portion 54 of the perimeter 18 of the carrier substrate 12 to extend outward beyond the perimeter 26 of the flexible glass substrate 20. Although rectangular and circular are illustrated, any suitable shape, including irregular shapes, can be used depending on the desired stack configuration. Further, the carrier substrate 12 can round, trim, and/or grind the edges of the carrier substrate 12 to withstand impact and facilitate processing. Surface features such as grooves and/or holes may also be provided on the carrier substrate 12. The grooves, holes, and/or other surface features can promote and/or inhibit the positioning and/or adhesion of the bonding material.

Bonding layer selection and coating

The bonding layer 30 can include one or more bonding materials that undergo structural changes upon receipt of an energy input. For example, the bonding layer 30 may include an inorganic material and may include materials such as glass, glass ceramic, ceramic, and carbonaceous materials. In some embodiments, the bonding layer 30 can be composed of carbon that forms a carbon bonding layer. Various exemplary bonding materials are described below. Can be applied using any suitable method The bonding layer 30 is coated, for example, one or more of pressurized coating, spreading, melting, spin casting, spraying, dipping, vacuum or atmospheric deposition, etc. via a nozzle.

Bonding layer 30 can be applied in any suitable pattern and/or shape. Referring to Figure 6, the entire region of A ₁ bonded over coating 30 in the region of the glass support surface 14 of the region A ₁ of the area covered by the flexible substrate 20 A ₂ glass is at least about 50%, such as substantially A ₂ . In some embodiments, A ₁ A ₂ may be less than approximately 50%, such as at most of about 25% A _2. The bonding layer 30 may extend beyond the perimeter of the flexible glass substrate 20 or the bonding layer 30 may be contained within the perimeter of the flexible glass substrate 20. Referring to Figure 7, may be coated with the bonding layer 30 continuously (i.e., continuously engaging the periphery) along a predetermined path (such as in region A extends around the periphery of the ₃ A _2), leaving the definition of the bonding layer 30 is not bonded Area R. Referring to Fig. 8, the bonding layer 30 may be formed of discrete bonding portions 60 spaced apart from each other. In the embodiment of Figure 8, the discrete joint portions are in the form of separate lines. Any other suitable shape may be used, such as a circle, a dot, a random shape, and a combination of various shapes.

Energy input can be provided to the bonding layer 30, which changes or serves to alter the structure of the bonding layer 30. The structural change reduces the bonding strength of the bonding layer 30 to promote separation of the flexible glass substrate 20 from the carrier substrate 12 as compared to before energy input. This type of energy input depends, at least in part, on the bonding material used in bonding layer 30. Non-limiting examples of bonding materials for providing bonding layer 30 and input energy are provided below and are not meant to be limiting.

Instance

A bonding layer including carbon is formed from the phenol resin solution. This process utilizes a phenol formaldehyde copolymer and produces samples in a spin casting and thermal curing process. Process step The steps include the following steps: a. Spin casting 70% by weight of resin and 30% by weight of deionized (DI) water diluted phenolic resin solution on the carrier substrate for 30 seconds at 3k rpm to produce a bonding layer of no more than 10 μm thick. .

b. The carrier substrate having the bonding layer and the device substrate placed on the carrier substrate are placed on a hot plate at room temperature. A weight that produces a maximum joint pressure greater than 100 kPa is applied.

c. Heat the hot plate to 150 ° C for about 10 minutes and then cool back to room temperature.

d. The stack was circulated in the furnace under air for up to 400 ° C for one hour and then the stack was cooled.

Using this process, the device substrate is bonded to a carrier substrate that survives the shear tensile test and can be separated upon application of the peeling force, at least in part due to the carbon bonding layer left behind after heating and Increased porosity formed in the bonding layer during heating. Both the device substrate and the carrier substrate were formed from a 0.7 mm thick EAGLE 2000® (a trade name of an alkali-free aluminoborosilicate glass available from Corning Incorporated, Corning, NY) (8 cm x 12 cm) substrate.

Additional screening tests were performed on the stacks formed according to the examples. The stack was cycled in air for one hour in a 500 ° C furnace, which resulted in severe oxidation of the joint layer. This oxidation of the carbon bonding layer can be used to strip the device substrate from the carrier substrate. Since the oxidized carbon evaporates, the carbon bonding layer can be easily removed to clean the carrier substrate for reuse.

The bonding strength between the flexible glass substrate 20 and the carrier substrate 12 can be reduced by oxidizing the carbon-based bonding layer. For example, in an example, heating the bonding layer 30 to a temperature of about 500 ° C in the presence of oxygen can result in carbon oxidation. In the presence of ozone, oxidation of the carbon bonding layer can occur at temperatures less than 500 °C. While it may be unacceptable to heat a fully assembled device substrate up to 500 °C, in some embodiments, the bonding layer may be locally heated using a laser to a temperature that promotes oxidation.

Referring to Figure 9, the absorbance of the carbon-based bonding layer 30 is illustrated. A laser can be used to locally heat and oxidize the carbon-based bonding layer 30 (or any one or more of the bonding materials described herein). The carbon-based bonding layer 30 can be applied as a perimeter bond (Figs. 7 and 8) to promote localized heating of the carbon-based bonding layer 30 by the laser, whereby the carbon-based bonding layer 30 is nearly flexible The periphery of the glass substrate 20 provides more use of the carbon-based bonding layer 30. Fig. 9 is a view showing the absorption spectrum of the carbon-based bonding layer 30 produced from the phenol resin described in the above examples. As can be seen, the absorbance is increased in the visible and UV spectra to enable heating of the bonding material that can be used for thermal oxidation. A dopant can be added to the bonding layer to increase the amount of radiation absorbed.

It should be noted that the optimization of the bonding material should occur for the particular device fabrication process used. For example, for an a-Si or p-Si TFT process having a fabrication temperature of about 250 ° C or higher, such as about 350 ° C or higher, such as between about 250 ° C and about 450 ° C, The thermally exposed bonding material is stripped to greater than 250 ° C or higher (such as 350 ° C or higher, such as 450 ° C or higher) to reduce any undesired peeling potential. However, thermal exposure should be selected to be less than thermal exposure that can damage any device electronics or other components. In some In embodiments, the bond strength of the bond layer 30 may not substantially decrease or decrease until the target peel heat exposure (eg, less than about 50%, such as less than about 25%, such as less than about 10%, such as less than about 5%, such as less than about 1%). Therefore, the stripping material can be optimized for different device manufacturing scenarios. Likewise, the application of energy 47 to bonding layer 30 can be localized to bonding layer 30 itself. For example, the energy source can be optimized such that the bonding layer 30 absorbs most of the energy 47, which results in reduced thermal effects on the flexible substrate 20, the carrier substrate 12, or any device layer on the flexible substrate 20. .

The bonding layer 30 may include an inorganic material that does not undergo a structural change that causes a decrease in bonding strength (for example, between about 250 ° C and about 450 ° C), but the inorganic material forms a bonding layer 30 that is susceptible to, for example, cracking, The peeling of the flexible glass substrate 20 is promoted. Without wishing to be bound by theory, both types of rupture include ductile rupture and brittle rupture. In applications where a strong and durable bond is important between the substrates, ductile fracture is generally preferred in view of the plastic deformation associated with the use of the ductile material, which typically retards crack propagation through the ductile material. On the other hand, brittle fracture generally results in rapid crack propagation through the brittle material or along the interface between the bonding layer 30 and the flexible glass substrate 20 and/or the carrier substrate 12, which is typically nearly perpendicular to the applied The direction of stress. Thus, in the releasable applications described herein, brittle fracture may preferably have associated rapid crack propagation. As used herein, a brittle bonding layer can be the thickness of the bonding layer 30 therein (eg, no more than about 100 μm, such as up to about 50 μm, such as up to about 25 μm, such as up to about 10 μm, such as up to about 5 μm, such as in a plastic zone formed around the crack tip in the bonding layer compared to between about 5 μm and about 50 μm) A brittle bonding layer that is small in size (eg, no more than about 25% or less). Some materials, such as glass, may not have a plastic zone at zero or a near-zero plastic zone, and thus constitute a brittle bond layer. Another exemplary brittle bonding layer can be a carbon bonding layer formed, for example, using a phenol formaldehyde copolymer and a thermal curing process in a manner similar to that described in the examples above.

Release flexible glass substrate

The flexible glass substrate 20 can be released from the carrier substrate 12 by any suitable method. As an example, the stress for delamination can occur due to the movement of the overall tensile compression neutral axis during formation of the final device that utilizes the flexible glass device 20. For example, joining the flexible glazing unit 20 and the carrier substrate 12 together may first place the joint plane near the stress neutral axis. However, when it is joined near the neutral axis, the mechanical tensile stress can be minimized. After the device is fully assembled (possibly assembled with cover glass) with the flexible glass substrate 20 bonded to the carrier substrate 12, the stress neutral axis can be moved, which greatly increases the tensile stress and bending along the joint plane. Stress, resulting in at least some stratification. Any number of devices (such as seesaws, lasers, knives, scoring wheels) can also be used to initiate and/or complete delamination, and the etchant and/or flexible glass substrate can be manually removed.

Referring now to Figure 10, an exemplary bonding layer 30 coating pattern is illustrated in which the flexible glass substrate 20 will be divided or cut into multiple portions, sometimes referred to as device units. Figure 10 illustrates a plan view of a stack 100 comprising a flexible glass substrate 20 bonded to a carrier substrate 12 as described above. The bonding layer (denoted by the region A ₁₎ may be coated on a glass support surface of the carrier substrate 12 of glass substrate 14 may be flexible entire (or less than all) of the coverage area 20. In the illustrated embodiment, the flexible glass substrate 20 is subdivided into device units 102 (also indicated by area A ₂ ) for further processing of the perimeter 104 having. By coating the bonding layer A ₁ under the device unit 102, process fluid can be minimized or prevented from leaking into the area defined by the device unit 102, which can contaminate subsequent processes, or the flexible glass can be prematurely The substrate 20 (or at least a portion of the flexible glass substrate 20) is separated from the carrier substrate 12.

Although illustrated as having one flexible glass substrate 20 bonded to the carrier substrate 12, a plurality of flexible glass substrates 20 may be bonded to one carrier substrate 12 or a plurality of carrier substrates 12. In such cases, the carrier substrate 12 can be separated from the plurality of flexible glass substrates 20 simultaneously or in some suitable order.

Any number of device units 102 can be separated from any number of other device units 102 by cutting along perimeter 104. Venting may be provided to reduce any expansion of the flexible glass substrate 20 or other adverse effects on the flexible glass substrate 20. A laser or other cutting device can be used for cutting the individual device unit 102 from the flexible glass sheet 20. Further, the cutting may be performed such that only the flexible glass substrate 20 is cut or scored instead of the carrier substrate 12, so that the carrier substrate 12 can be reused. Etching and/or any other cleaning process can be used to remove any residue left by the bonding layer 30. Etching may also be used to assist in removing the flexible glass substrate 20 from the carrier substrate 12.

Referring to Fig. 11, an embodiment of a method for removing a device unit 140 (e.g., having an electrical device 145 or other unit of other desired structures formed thereon) for removing the flexible glass substrate 20 from the carrier substrate 12 is illustrated. . Any number depending on the size of the flexible glass substrate 20 and the size of the device unit 140 The device unit 140 can be made of a flexible glass substrate 20 bonded to a carrier substrate. For example, the flexible glass substrate may have a Gen 2 size or larger, for example, Gen 3, Gen 4, Gen 5, Gen 8 or larger (for example, from 100 mm × 100 mm to 3 m × 3 m or more) Slice size). To allow the user to determine the configuration of the device unit 140 depending on the size, number, and shape of the device unit 140, for example, a configuration in which one of the flexible glass substrates 20 to be self-bonded to the carrier substrate 12 is generated; as shown in FIG. The flexible glass substrate 20 is supplied as shown. More specifically, a substrate stack 10 having a flexible glass substrate 20 and a carrier substrate 12 is provided. The flexible glass substrate 20 is bonded to the carrier substrate 12 in a bonding region 142 surrounding the non-bonding region 144.

The joint region 142 is disposed at the periphery of the flexible glass substrate 20, completely surrounding the non-joining region 144. This continuous bond region 142 can be used to seal any gap between the flexible glass substrate 20 and the carrier substrate 12 at the periphery of the flexible glass substrate 20 such that process fluid is not captured, otherwise the captured process fluid can become contaminated Subsequent processes are passed through the substrate stack 10. However, in other embodiments, discontinuous joint regions may be used.

The CO ₂ laser beam can be used to cut the perimeter 146 of the desired portion 140. The CO ₂ laser-enabled flexible glass substrate 20 is integrally cut (100% thick). For CO ₂ laser cutting, the laser beams into a circular shape of the small diameter of the beam on the surface of the flexible substrate 20 of glass 24, and the laser beam along a desired trajectory and may be followed coolant nozzle. The coolant nozzle can be an air nozzle that, for example, delivers a stream of compressed air through the small diameter aperture to the surface of the sheet. Water or gas mist can also be used. Once the perimeter 146 of the device unit 140 is cut, the device unit 140 can be removed from the remaining flexible glass substrate 20. Then, an energy input can be applied to the bonding layer 30 that changes the structure of the bonding layer 30. The structural change reduces the bonding strength of the bonding layer 30 to promote separation of the remaining flexible glass substrate 20 from the carrier substrate 12.

Referring to Fig. 12, an embodiment of a method of releasing the flexible glass substrate 20 from the carrier substrate 12 is illustrated. Once the flexible glass substrate 20 is processed to include the desired device 150 (eg, an LCD, OLED, or TFT electronic device) and, for example, once the device unit 140 is removed, the remaining flexible glass substrate 20 is released from the carrier substrate 12 (or the entire Flexible glass substrate 20). In this embodiment, the bonding layer 30 can be formed to form a perimeter bond 152 of the bond region 154 and the non-bond region 156. Laser 158 directs laser beam 160 (e.g., having a wavelength between about 400 nm and 750 nm) between flexible glass substrate 162 and carrier substrate 12 to locally heat portions of bonding layer 30. It is also possible to tune the LED and flash source that is absorbed by the bonding layer 30. For example, laser 158 can also be used to locally heat and oxidize carbon-based bonding layer 30. The perimeter bond 152 can facilitate localized heating of the carbon-based bond layer 30 by the laser 158, thereby providing more use of the carbon-based bond layer 30 due to the carbon-based bond layer 30 and flexibility. The proximity of the perimeter of the glass substrate 20 and the relatively small cross-sectional area (e.g., as compared to the bonding across the entire width of the flexible glass substrate 12).

The bonding layer can provide an inorganic adhesion method that enables the use of a thin flexible glass substrate within existing equipment and manufacturing conditions. The carrier substrate can be reused with different flexible glass substrates. A stack comprising a carrier substrate, a flexible glass substrate, and a bonding layer can be assembled and then shipped for further processing. Alternatively, assemble some stacks or not stack them before shipping. Initially the carrier substrate does not need to be used as a carrier substrate. For example, carrier substrates may have been subjected to excessive binding or streaking that renders such carrier substrates unsuitable for use as display devices. The use of the carrier substrate avoids the problem of directly using the thin substrate, such as the problem of dimples and static electricity increase around the vacuum holes. The height of the bonding layer may be thin (eg, about 10 μm or less or between about 1 μm and 100 μm), which may minimize flatness issues (such as sagging) and promote continuous coating across the entire carrier substrate. Or the use of a film that is partially coated, such as around the perimeter.

In the foregoing detailed description, the exemplary embodiments of the invention It will be apparent, however, that the invention may be practiced in other embodiments of the specific embodiments disclosed herein. In addition, descriptions of well-known devices, methods, and materials may be omitted so as not to obscure the description of the various principles of the invention. Finally, wherever practicable, the same element symbol refers to the same element.

The directional terminology used herein (eg, top, bottom, right, left, front, back, top, bottom) is made with reference only to the drawings drawn, and such terms are not intended to imply an absolute orientation.

It is to be understood that the above-described embodiments of the present invention are intended to be illustrative of the embodiments of the invention. Many changes and modifications may be made to the above described embodiments of the invention without departing from the spirit and scope of the invention. All such modifications and variations are intended to be included within the scope of the present disclosure and the scope of the following claims.

10‧‧‧Substrate stacking

12‧‧‧ Carrier substrate

14‧‧‧glass support surface

16‧‧‧ Relative support surface

Around 18‧‧

20‧‧‧Flexible glass substrate

22‧‧‧First wide surface

24‧‧‧ second wide surface

25‧‧‧ thickness

26‧‧‧around

28‧‧‧ thickness

30‧‧‧ joint layer

32‧‧‧ thickness

Claims (10)

A method for processing a flexible glass substrate, the method comprising the steps of: providing a substrate stack comprising the flexible glass substrate, the flexible glass substrate bonded to a carrier substrate using a carbon bonding layer; And separating the flexible glass substrate from the carrier substrate. The method of claim 1, wherein the carbon bonding layer is brittle, the method further comprising the step of: creating a crack in the carbon bonding layer. The method of claim 1, the method further comprising the step of providing an energy input to the carbon bonding layer to introduce a structural change in the carbon bonding layer. The method of claim 3, wherein the energy input is light energy that heats the carbon bonding layer to a temperature of at least 250 °C. The method of claim 3, wherein the structural change comprises increasing a porosity of the carbon bonding layer. The method of claim 3, wherein the carbon bonding layer is heated using a laser, an LED or a flash light source. The method of any one of claims 1 to 6, further comprising the step of applying an electrical component to the flexible glass substrate. A substrate stack comprising: a carrier substrate having a glass support surface; a flexible glass substrate supported by the glass support surface of the carrier substrate; A carbon bonding layer bonding the flexible glass substrate to the carrier substrate, the carbon bonding layer being brittle to promote crack propagation through the carbon bonding layer. The substrate stack of claim 8, wherein the flexible glass substrate has a thickness of no greater than about 0.3 mm. The substrate stack of claim 8 or claim 9, wherein the carbon bonding layer has a thickness of no more than about 0.1 mm.