Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
  • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/06—Interconnection of layers permitting easy separation
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/20—Uniting glass pieces by fusing without substantial reshaping
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
  • C03C23/007—Other surface treatment of glass not in the form of fibres or filaments by thermal treatment

Definitions

• the present invention relates to apparatuses and methods for processing thin substrates on carrier substrates, and more specifically, to thin substrates of flexible glass on carrier substrates.
• Flexible glass substrates offer several technical advantages over flexible plastic technology.
• One technical advantage is the ability of the glass to serve as a moisture or gas barrier, a primary degradation mechanism in OLED displays, OLED lighting and organic photovoltaic devices.
• a second advantage is in its potential to reduce overall package size (thickness) and weight through the reduction or elimination of one or more package substrate layers.
• Other advantages of flexible glass substrates include benefits in optical transmission, dimensional stability, thermal capability and surface quality.
• the present concept for extraction involves heating only a portion of a flexible glass substrate (e.g., a perimeter) through a carrier substrate with a heating device.
• the heating device creates a sufficient temperature gradient between a device portion of the flexible glass substrate and the perimeter portion of the flexible glass substrate without overheating the device portion to separate the device portion from the perimeter portion of the flexible glass substrate.
• One commercial advantage to the present approach is that manufacturers will be able to utilize their existing capital investment in processing equipment while gaining the advantages of the thin glass sheets for PV, OLED, LCDs, touch sensors, flexible electronics and patterned Thin Film Transistor (TFT) electronics, for example.
• TFT Thin Film Transistor
• a method of processing a flexible glass substrate comprises:
• the method of aspect 1 further comprising heating the heating fixture using a heat source, the heating fixture transmitting heat to the carrier substrate.
• any one of aspects 1 - 3 further comprising inhibiting heating of the device portion during heating of the perimeter portion using a thermal insulating shield.
• any one of aspects 1-4 further comprising scoring the flexible glass substrate along a boundary between the perimeter portion and the device portion.
• a seventh aspect there is provided the method of aspect 6, comprising bonding the flexible glass substrate to the carrier substrate within the perimeter portion, a bond strength between the flexible glass substrate and the carrier substrate in the perimeter portion being greater than a bond strength between the flexible glass substrate and the carrier substrate in the device portion.
• the step of heating the perimeter portion of the flexible glass substrate to the temperature greater than that of the device portion includes heating the perimeter portion to a temperature of greater than about 100 °C, the device portion having a temperature of less than 100 °C.
• a method of processing a flexible glass substrate comprises:
• scoring the flexible glass substrate along a score line the score line defining a perimeter portion and a device portion of the flexible glass substrate
• the step of heating the perimeter portion of the flexible glass substrate comprises heating a heating fixture using a heat source, the heating fixture transmitting heat to the carrier substrate.
• the method of aspect 13 comprising bonding the flexible glass substrate to the carrier substrate within the perimeter portion, a bond strength between the flexible glass substrate and the carrier substrate in the perimeter portion being greater than a bond strength between the flexible glass substrate and the carrier substrate in the device portion.
• a method of processing a flexible glass substrate comprises:
• the heating fixture including at least one wall member having at least one lower support surface in contact with the heating plate and at least one upper support surface;
• the method of aspect 15 wherein the step of heating the perimeter portion of the flexible glass substrate is by convection.
• the method of aspect 15 or aspect 16 further comprising inhibiting heating of the device portion during heating the perimeter portion using a thermal insulating shield.
• any one of the aspects 15-17 further comprising scoring the flexible glass substrate along a boundary between the perimeter portion and the device portion.
• the method of aspect 19 comprising bonding the flexible glass substrate to the carrier substrate within the perimeter portion, a bond strength between the flexible glass substrate and the carrier substrate in the perimeter portion being greater than a bond strength between the flexible glass substrate and the carrier substrate in the device portion.
• the method of any one of aspects 15-20 wherein the step of heating the perimeter portion of the flexible glass substrate to the temperature greater than that of the device portion includes heating the perimeter portion to a temperature of greater than about 100 °C, the device portion having a temperature of less than 100 °C.
• FIG. 1 is a side view of an embodiment of a substrate stack including a flexible glass substrate that is carried by a carrier substrate;
• FIG. 2 is an exploded, perspective view of the substrate stack of FIG. 1 ;
• FIG. 3 illustrates an embodiment of a method of processing the flexible glass substrate and substrate stack of FIG. 1 ;
• FIG. 4 illustrate an exemplary embodiment of a heating apparatus
• FIG. 5 illustrates a perspective view of the heating apparatus of FIG. 4 in isolation
• FIG. 6 is a schematic illustration of operation of the heating apparatus of FIG. 4.
• FIG. 7 illustrates an exemplary glass temperature distribution using the heating apparatus of FIG. 4.
• Embodiments described herein generally relate to processing of flexible glass substrates, sometimes referred to herein as device substrates.
• the flexible glass substrates may be part of a substrate stack that generally includes a carrier substrate and the flexible glass substrate bonded thereto.
• a portion of the flexible glass substrate e.g., a perimeter
• the heating device creates a sufficient temperature gradient between a device portion of the flexible glass substrate and the perimeter portion of the flexible glass substrate without overheating the device portion.
• the device portion of the flexible glass substrate is protected from a certain amount of heating and kept at a relatively low temperature to avoid damage to the device portion, while the perimeter portion of the flexible glass substrate is heated to induce expansion and tensioning around the device portion for extraction from the carrier substrate.
• the perimeter portion need not be coextensive with the periphery at the outer bounds of the flexible glass sheet, although in some instances, it may be.
• a 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 opposite support surface 16 and a periphery 18.
• the flexible glass substrate 20 has a first broad surface 22, an opposite, second broad surface 24 and a periphery 26.
• the flexible glass substrate 20 may be "ultra-thin" having a thickness 28 of about 0.3 mm or less including but not limited to thicknesses of, for example, about 0.01-0.05 mm, about 0.05-0.1 mm, about 0.1-0.15 mm and about 0.15-0.3 mm, or for example, 0.3, 0.29, 0.28, 0.275, 0.27, 0.26, 0.25, 0.24, 0.23, 0.225, 0.20, 0.21, 0.20, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11, 0.10, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01 mm.
• the flexible glass substrate 20 is bonded at its first broad surface 22 to the glass support surface 14 of the carrier substrate 12 using a bonding layer 30.
• the bonding layer may be formed of any suitable bonding materials, for example, organic or inorganic bonding materials.
• the bonding material of the bonding layer 30 is located about the periphery 18 and 26 of the carrier substrate 12 and the flexible glass substrate 20.
• the location of the bonding material can define a perimeter portion 32 of the flexible glass substrate 20 above the bonding material and a central or device portion 34 located inside of the perimeter portion 32.
• the combined thickness 25 of the substrate stack 10 may be the same as single glass substrate having increased thickness as compared to the thickness of the flexible glass substrate 20 alone, which may be suitable for use with existing device processing infrastructure.
• thickness of the carrier substrate 12 may be selected to be something no greater than 0.4 mm, depending, for example, on thickness of the bonding layer 30. In some embodiments, however, no bonding layer 30 may be used.
• the flexible glass substrate 20 may be bonded directly to the carrier substrate 12 using electrostatic, covalent, or van der Waals forces.
• the carrier substrate 12 may be surface modified (e.g., etching, scoring, etc.), spacers, or other materials, for example various coatings (e.g., adhesives or other materials having a reduced adhesion to the flexible glass substrate 20) may be applied at selected locations (e.g., beneath the device portion(s) 32) to inhibit bonding between the flexible glass substrate 20 and the carrier substrate 12 in those areas.
• the carrier substrate 12 may be of any suitable material including glass, glass- ceramic or ceramic, as examples, and may or may not be transparent. If made of glass, the carrier substrate 12 may be of any suitable composition including alumino-silicate, boro- silicate, alumino-boro-silicate, soda-lime-silicate, and may be either alkali containing or alkali- free depending upon its ultimate application.
• the thickness of the carrier substrate 12 may be from about 0.2 to 3 mm, for example 0.2, 0.3, 0.4, 0.5, 0.6, 0.65, 0.7, 1.0, 2.0, or 3 mm, and may depend upon the thickness 28 of the flexible glass substrate 20, as noted above. Additionally, the carrier substrate 12 may be made of one layer, as shown, or multiple layers (including multiple thin sheets) that are bonded together to form a part of the substrate stack 10.
• the flexible glass substrates 20 described herein may have a thickness of about 0.3 mm or less including but not limited to thicknesses of, for example, about 0.01 -0.05 mm, about 0.05-0.1 mm, about 0.1-0.15 mm, about 0.15-0.3 mm, including 0.3, 0.275, 0.25, 0.225, 0.2, 0.19, 0.18, 0.17, 0.16, 0.15, 0.14, 0.13, 0.12, 0.11 , 0.10, 0.09, 0.08 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, or 0.01 mm, for example.
• the flexible glass substrates may be formed of glass, a glass ceramic, a ceramic material or composites thereof; for the sake of convenience in reference only, the terms "flexible glass substrate” or “glass layer” may be used throughout the specification, wherein such a substrate or layer may instead be made from any of these other materials.
• a fusion process e.g., down draw process
• Flexible glass substrates produced in a fusion process may have surfaces with superior flatness and smoothness when compared to glass sheets produced by other methods. Fusion processes are described in U.S. Patent Serial Nos. 3,338,696 and 3,682,609.
• Other suitable flexible glass substrate forming methods include a float process, updraw and slot draw methods.
• the flexible glass substrates 20 may be the same size and/or shape or of a different size and/or shape as the carrier substrates 12.
• a bonding and device portion extraction method 40 is illustrated as part of the processing of the flexible glass substrate 20.
• the carrier substrate 12 and the flexible glass substrate 20 are selected based on, for example, their sizes, thicknesses, materials and/or end uses.
• the bonding layer 30 may be applied to the peripheries (and/or other locations) to one or both of the glass support surface 14 and the first broad surface 22 of the flexible glass substrate 20 at step 44.
• the flexible substrate 20 may be bonded directly to the carrier substrate 12, as noted above. Any suitable methods may be used for applying the bonding layer 30, for example one or more of a pressurized application, for example, through a nozzle, spreading, melting, spin casting, spraying, dipping, vacuum or atmospheric deposition, etc.
• the flexible glass substrate 20 is adhered or otherwise bonded to the carrier substrate 12 using the bonding layer 30.
• bonding material forming the bonding layer 30 may be heated, cooled, dried, mixed with other materials, reaction induced, pressure may be applied, for example.
• any suitable releasable materials may be used or surface altering of the carrier substrate 12.
• bond strength refers to any one or more of dynamic shear strength, dynamic peel strength, static shear strength, static peel strength and combinations thereof.
• Peel strength for example, is the force per unit width necessary to initiate failure (static) and/or maintain a specified rate of failure (dynamic) by means of a stress applied to one or both of the flexible glass substrate and carrier substrate in a peeling mode.
• Shear strength is the force per unit width necessary to initiate failure (static) and/or maintain a specified rate of failure (dynamic) by means of a stress applied to one or both of the flexible glass substrate and carrier substrate in a shear mode. Any suitable methods can be used to determine bond strength including any suitable peel and/or shear strength test.
• Steps 48 and 50 relate to extracting devices from the flexible glass substrate 20 and/or de -bonding devices from the carrier substrate 12 so that the device portions of the flexible glass substrate 20 can be removed from the carrier substrate 12.
• the flexible glass substrate 20 may be processed, for example, in the formation of a display device, for example an LCD, OLED or TFT electronics or other electronic devices for example a touch sensor or photovoltaic.
• a display device for example an LCD, OLED or TFT electronics or other electronic devices for example a touch sensor or photovoltaic.
• electrical components or color filters may be applied to the second broad surface 24 of the flexible glass substrate 20 (FIGS. 1 and 2).
• final electronic components can be assembled or combined with the flexible glass substrate 20 before releasing the desired portions from the carrier substrate 12.
• additional films or glass substrates can be laminated to the surface of the flexible glass substrate 20 or electrical components for example flex circuits or ICs can be bonded.
• an energy input 47 may be selectively applied through the carrier substrate 12 thereby heating the perimeter portion 32 on the flexible glass substrate 20 at step 48.
• a heat shield component 49 may be used to limit heating of the device portion 34 of the flexible glass substrate 20.
• a temperature gradient is formed in the flexible glass substrate 20 between the device portion 34 and the perimeter portion 32 causing thermal expansion.
• a score or break line 60 may be provided in the flexible glass substrate 20 at a break location.
• the device portion 34 may be extracted from the perimeter portion 32 along the break line 60.
• the heating apparatus 100 includes a heat source 102, for example provided by a heat plate 104 and a heating fixture 106 that rests on the heat plate 104.
• the heating fixture 106 includes a heating and support member 108 having an upper support surface 110 and a lower support surface 112.
• the upper support surface 110 supports the substrate stack 10 thereon at the support surface 16.
• the lower support surface 112 may be in contact with the heat plate 104.
• An outer peripheral surface 1 14 and an inner peripheral surface 116 extend between the upper support surface 110 and the lower support surface 1 12.
• there may be any suitable number including a matching number of inner peripheral surfaces to heat perimeter portions that surround device portions on any given flexible glass sheet.
• the heating fixture 106 includes the heating and support member 108 that includes wall members 1 18.
• the heating and support member 108 includes wall members 1 18.
• a continuous circular or oval wall member may be used to form the upper support surface of the heating and support member.
• the wall members 118 may define any number of shapes, for example, an array of shapes. Stated another way, the configuration in FIG. 5 may be repeated across a larger area depending upon the size of the devices to be made, and the size of the flexible glass substrate.
• the thermal insulating shield 120 includes a support plate 122 that extends between and is integrally connected to the wall members 1 18, a first thermal insulating layer 124 that faces the flexible glass substrate 120 and a second thermal insulating layer 126 that faces the heat plate 104.
• the first and second thermal insulating layers 124 and 126 may extend over the entire opposite surfaces 128 and 130 of the support plate 122 and each may have conductive, convective and/or radiative insulating properties.
• the thermal insulating shield 120 may be located vertically between the upper and lower support surfaces 1 10 and 1 12. Such an arrangement can provide gaps 132 and 134 between the thermal insulating shield 120 and the heat plate 104 and the thermal insulating shield 120 and the carrier substrate 12 (or, in some cases, alternatively, the flexible glass substrate 20), which can serve to further insulate the device portion 34 of the flexible glass substrate 120 from the heat plate 104.
• the heating fixture 106 may be formed by any suitable method and of any suitable materials.
• the heating and support member 108 and the support plate 122 may be formed together from the same (e.g., aluminum) or different materials, for example through casting, stamping and/or machining.
• the first and thermal insulating layers 126 may be formed of any suitable insulating materials or combinations of materials, for example glass, polymers, foams, foils, etc.
• heating apparatus 100 to extract at least a portion of the flexible glass substrate 20 from the carrier substrate 12 is illustrated schematically.
• the heating fixture 106 is illustrated resting on the heat plate 104 of the heat source 102.
• the heating fixture 106 may be supported on the heat plate 104 upon the lower support surface 1 12 that is provided by the heating support member 108 and the wall members 118.
• a substrate stack 150 may be located on the upper support surface 110 that is provided by the heating and support member 108 including the wall members 118.
• the thermal insulating shield 120 extends between each of the wall members 118 and is located between and spaced vertically from both the upper support surface 1 10 and the lower support surface 112 thereby providing the gaps 132 and 134 both above and below the thermal insulating shield.
• Heating the heat plate 104 heats the heating and support member 108.
• the heating of the heating and support member 108 may occur primarily through contact (i.e., conduction) between the wall members 118 and the heat plate 104.
• heating of the heating and support member 108 can occur using convection and/or radiation depending on the type of heat source used, and the material from which the wall members 1 18 are made.
• the wall members 118 being made from a thermally conductive material, for example aluminum, conduct heat along a path represented by arrow 152 toward a carrier substrate 154 of the substrate stack 150. The heat is further conducted through the carrier substrate 154 to a flexible glass substrate 156.
• the flexible glass substrate 156 is bonded directly to the carrier substrate 154 (e.g., using van der Waals or electrostatic bonding) at a perimeter portion 158 of the flexible glass substrate 156.
• a device portion 160 of the flexible glass substrate 156 may be relatively unbonded to the carrier substrate 154 such that separation of the flexible glass substrate 156 between the device portion 160 from the perimeter portion 158 of the flexible glass substrate 156 can allow the device portion 158 to be extracted from the carrier substrate 154.
• the flexible glass substrate 156 may be processed to include one or more desired devices 162 (e.g., LCD, OLED or TFT electronics) prior to extraction of the device portion 160.
• a break or score line 164 may be provided (e.g., using a scribe or score wheel, or via laser scribing) about the device portion 160, defining a boundary between the perimeter portion 158 and the device portion 160 to facilitate removal of the device portion 160 from the perimeter portion 158.
• a thermal gradient is created between the device portion 160 and the perimeter portion 158.
• This thermal gradient is due to increased heat transfer to the perimeter portion 158 of the flexible glass substrate 156 and reduced heat transfer to the device portion 160 due to the presence of the thermal insulating shield 120 and the gaps 132 and 134, which may be filled with a gas for example air.
• the thermal gradient causes thermal tensioning in the direction of arrows 170 and 172, which results in separation of the device portion 160 from the perimeter portion 158 along the score line 164.
• FIG. 7 illustrates an exemplary glass temperature distribution taken using a thermovision camera (FLIR) showing a high temperature perimeter in a perimeter portion of a 0.7 mm EAGLE XG ® glass substrate heated in a manner similar to that described above in FIG. 6.
• FLIR thermovision camera
• An aluminum heating fixture with thermal insulating shield was heated on a heat plate set at 350 °C.
• a relatively high temperature perimeter portion of about 150 °C is shown with a relatively low temperature central portion of approximately 64 °C.
• the above-described temperature assisted processing of flexible glass substrates utilizes a heating apparatus that induces thermal expansion of the perimeter portion of the flexible glass substrate to extract the device portion of the flexible glass substrate, which can reduce a possibility of edge damage to the device portion during the extraction process.
• the heating apparatus including the heating fixture can simplify the extraction process by reducing the force required to separate the device portion of the flexible glass substrate from the carrier substrate. Additionally, or alternatively, the heating apparatus and extraction process reduce edge damage on the extracted part caused by part edges otherwise rubbing against the opposite edges of the glass after cutting and during extraction. Thus the concepts described herein may minimize part edge rubbing, preserve the edge strength and increase extraction process reliability. Manufacturers can utilize their existing capital investment in processing equipment, while gaining advantages of the use of flexible glass substrates. Increased edge strength for the device portion of the flexible glass substrate can result from the extraction processes described herein. Use of the heating fixture can reduce the possibility of damage to the flexible glass substrate due to the type and design of the heat source.
• Ranges can be expressed herein as from “about” one particular value, and/or to "about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. [0059] Directional terms as used herein— for example up, down, right, left, front, back, top, bottom— are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Electroluminescent Light Sources (AREA)
• Joining Of Glass To Other Materials (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=51843863

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (5)

• 2014
  • 2014-04-24 WO PCT/US2014/035216 patent/WO2014179137A1/en active Application Filing
  • 2014-04-28 TW TW103115197A patent/TW201500189A/zh unknown

Patent Citations (5)

Also Published As

Similar Documents

Legal Events