WO2016081337A1

WO2016081337A1 - Methods of processing including peeling

Info

Publication number: WO2016081337A1
Application number: PCT/US2015/060799
Authority: WO
Inventors: Eric Lewis ALLINGTON; Robert Alan Bellman; Robert George MANLEY; Karan MEHROTRA
Original assignee: Corning Incorporated
Priority date: 2014-11-19
Filing date: 2015-11-16
Publication date: 2016-05-26
Also published as: CN107210247A; JP2017537857A; KR20170086593A; SG11201704108YA; TW201628958A

Abstract

Methods include processing a first substrate with a first major surface of the first substrate removably bonded to a first major surface of a second substrate. The methods comprise the step (I) of bonding a flexible membrane to a second major surface of the first substrate, wherein the flexible membrane includes a tab that extends off a leading peripheral edge of the first substrate. The methods further include the step (II) of peeling the leading peripheral edge of the first substrate from the second substrate by applying a force to the tab.

Description

METHODS OF PROCESSING INCLUDING PEELING

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 62/081,892 filed on November 19, 2014, the content of which is relied upon and incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates generally to methods of processing including peeling and, more particularly, to methods of processing including the step of peeling a leading peripheral edge of a first substrate from a second substrate wherein at least one of the substrates may comprise a glass substrate and/or a silicon wafer.

BACKGROUND

[0003] There is interest in using thin, flexible glass in the fabrication of flexible electronics or other devices. Flexible glass can have several beneficial properties related to either the fabrication or performance of electronic devices, for example, liquid crystal displays (LCDs), electrophoretic displays (EPD), organic light emitting diode displays (OLEDs), plasma display panels (PDPs), touch sensors, photovoltaics, etc. One component in the use of flexible glass is the ability to handle the glass in a sheet format and not in a roll format.

[0004] To enable the handling of flexible glass during processing of the flexible glass, the flexible glass is typically bonded to a relatively rigid carrier substrate using a polymer binding agent. Once bonded to the carrier substrate, the relatively rigid characteristics and size of the carrier substrate allow the bonded structure to be handled in production without undesired bending or causing damage to the flexible glass. For example, thin-film transistor (TFT) components may be attached to the flexible glass in the production of LCDs.

[0005] After processing, the flexible glass is removed from the carrier substrate. However, given the delicate nature of the flexible glass, the force applied to detach the flexible glass from the carrier substrate can damage the flexible glass. Moreover, the separation process, which typically includes the insertion of an implement to the flexible glass-carrier interface, can often damage the carrier substrate as well, rendering the carrier substrate unusable for future use. Accordingly, there is a need for practical solutions for detaching thin, flexible glass from a carrier substrate, that reduce the potential for damaging the flexible glass and/or carrier substrate. SUMMARY

[0006] The following presents a simplified summary of the disclosure in order to provide a basic understanding of some example aspects described in the detailed description.

[0007] In an aspect of the disclosure, a method is provided for processing a first substrate with a first major surface of the first substrate removably bonded to a first major surface of a second substrate. The method comprises the step (I) of bonding a flexible membrane to a second major surface of the first substrate, wherein the flexible membrane includes a tab that extends off a leading peripheral edge of the first substrate. The method further includes the step (II) of peeling the leading peripheral edge of the first substrate from the second substrate by applying a force to the tab.

[0008] In one example of the aspect, the first substrate comprises a substrate selected from the group consisting of: a glass substrate and a silicon wafer.

[0009] In another example of the aspect, the first substrate includes a thickness of from about 100 microns to about 300 microns.

[0010] In still another example of the aspect, the second substrate comprises a carrier substrate including a thickness of from about 300 microns to about 700 microns.

[0011] In yet another example of the aspect, the second substrate comprises a carrier substrate including a footprint that is larger than a footprint of the first substrate.

[0012] In a further example of the aspect, prior to step (II), the method further comprises the step of processing the first substrate while the first substrate is bonded to the second substrate. In one particular example, the step of processing the first substrate occurs prior to step (I).

[0013] In still a further example of the aspect, the leading peripheral edge includes a length defined between a first lateral edge and a second lateral edge of the first substrate, and step (I) includes bonding the flexible membrane to the second major surface of the first substrate such that the flexible membrane extends along substantially the entire length of the leading peripheral edge. In one particular example, step (II) uniformly applies the force to the tab along the length of the leading peripheral edge. In another particular example, step (II) peels the leading peripheral edge of the first substrate from the second substrate substantially simultaneously along the entire length of the leading peripheral edge.

[0014] In yet another example of the aspect, after step (II), further comprising the step of completely removing the first substrate from the second substrate. In one particular example, the step of completely removing the first substrate from the second substrate comprises completely peeling the first substrate from the second substrate.

[0015] In another example of the aspect, the method can also optionally include the steps of preselecting a minimum bend radius of the first substrate and selecting a flexible membrane to increase the effective stiffness of the first substrate to maintain a bend radius of the first substrate above the minimum bend radius while peeling the first substrate from the second substrate.

[0016] In still another example of the aspect, the method further comprises the step of controlling a bend radius of the first substrate while peeling the first substrate from the second substrate.

[0017] In yet another example of the aspect, step (I) bonds the flexible membrane to cover substantially the entire second major surface of the first substrate.

[0018] In a further example of the aspect, step (I) bonds the flexible membrane to the second major surface of the first substrate such that the tab extends a distance of from about 5 cm to about 20 cm off the leading peripheral edge of the first substrate.

[0019] In yet a further example of the aspect, after step (II), the method further comprises the step of removing the flexible membrane from the first substrate. In one particular example, the step of removing the flexible membrane from the first substrate includes exposing the flexible membrane to ultraviolet light to release the flexible membrane from the second major surface of the first substrate.

[0020] In still a further example of the aspect, step (II) includes vacuum attaching the tab to a vacuum attachment member and then applying the force to the tab with the vacuum attachment member.

[0021] In another example of the aspect, the method further comprises the step of determining a bond strength between the leading peripheral edge of the first substrate and the second substrate based on information obtained during step (Π).

[0022] The aspect may be carried out alone or with one or any combination of the examples of the aspect discussed above.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] These and other aspects are better understood when the following detailed description is read with reference to the accompanying drawings, in which:

[0024] FIG. 1 is a schematic side view of an example peeling apparatus; [0025] FIG. 2 is a front view of the peeling apparatus along line 2-2 of FIG. 1;

[0026] FIG. 3 is a top view of a vacuum plate of the peeling apparatus along line 3 -3 of FIG.

2;

[0027] FIG. 4 is a bottom view of a vacuum attachment member and an arm of the peeling apparatus along line 4-4 of FIG. 2;

[0028] FIG. 5 is a schematic side view of the peeling apparatus of FIG. 1 in an open orientation;

[0029] FIG. 6 is a schematic side view of the peeling apparatus of FIG. 1 in an open orientation with a carrier substrate vacuum attached to the vacuum plate;

[0030] FIG. 7 is a schematic side view of the peeling apparatus of FIG. 1 in a closed orientation with the carrier substrate vacuum attached to the vacuum plate and the attachment member vacuum attached to a tab extending off a leading peripheral edge of a first substrate;

[0031] FIG. 8 schematically illustrates a force being uniformly applied to the tab along a length of the leading peripheral edge;

[0032] FIG. 9 is an enlarged partial cross section of the peeling apparatus along line 9-9 of FIG. 8;

[0033] FIG. 10 is a partial view of FIG. 9 illustrating the step of peeling the leading peripheral edge of the first substrate from the carrier substrate by applying a force to the tab;

[0034] FIG. 11 illustrates a step of controlling a bend radius of the first substrate while peeling the first substrate from the carrier substrate;

[0035] FIG. 12 illustrates the first substrate being completely peeled from the carrier substrate;

[0036] FIG. 13 is a schematic side view of the peeling apparatus of FIG. 1 in an open orientation with a first substrate vacuum attached to the vacuum plate;

[0037] FIG. 14 is a schematic side view of the peeling apparatus of FIG. 1 in a closed orientation with the first substrate vacuum attached to the vacuum plate and the attachment member vacuum attached to a tab extending off a leading peripheral edge of a carrier substrate;

[0038] FIG. 15 illustrates a step of controlling a bend radius of the carrier substrate while peeling the carrier substrate from the first substrate;

[0039] FIG. 16 is a schematic side view of the peeling apparatus of FIG. 1 in an open orientation with a second carrier substrate vacuum attached to the vacuum plate; [0040] FIG. 17 is a schematic side view of the peeling apparatus of FIG. 1 in a closed orientation with the second carrier substrate vacuum attached to the vacuum plate and the attachment member vacuum attached to a tab extending off a leading peripheral edge of a first carrier substrate;

[0041] FIG. 18 illustrates a step of controlling a bend radius of the first carrier substrate while peeling the first carrier substrate from an intermediate substrate and the second carrier substrate; and

[0042] FIG. 19 illustrates example steps in methods of processing a first substrate with a first major surface of the first substrate removably bonded to a first major surface of a second substrate.

DETAILED DESCRIPTION

[0043] Examples will now be described more fully hereinafter with reference to the accompanying drawings in which example embodiments are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, aspects may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0044] Peeling apparatus of the disclosure can be used to facilitate removal of a first substrate bonded to a second substrate. In one example, the peeling apparatus can facilitate initial or complete separation of a silicon wafer or a glass substrate from a carrier substrate. For instance, the peeling apparatus can be useful in initially or completely peeling a glass substrate from a carrier substrate although the carrier substrate can be initially or completely peeled from the glass substrate and/or another carrier substrate in further examples.

[0045] Flexible glass sheets are often used to manufacture liquid crystal displays (LCDs), electrophoretic displays (EPD), organic light emitting diode displays (OLEDs), plasma display panels (PDPs), touch sensors, photovoltaics, etc. To enable the handling of flexible glass sheet during processing, the flexible glass sheet may be bonded to a rigid carrier substrate using a binding agent, for example a polymer binding agent. The carrier substrate may be fabricated from glass, resin or other materials capable of withstanding conditions during processing of the substrate (e.g., glass substrate, silicon wafer, etc.) removably bonded to the carrier substrate. In some examples, the carrier substrate and the substrate bonded to the carrier substrate can each include a thickness defined between the respective major surfaces of the substrates. The carrier substrate can optionally introduce a desired level of rigidity by providing the carrier substrate with a thickness that is greater than the thickness of the substrate removably bonded to the carrier substrate. Furthermore, in some examples, the carrier substrate can be selected with a thickness wherein the overall thickness of the carrier substrate and the substrate bonded to the carrier substrate is within a range that can be used with existing processing machinery configured to process relatively thick glass substrates having a thickness within the range of the overall thickness of the carrier substrate and the substrate bonded to the carrier substrate.

[0046] In some examples, the first substrate can comprise a glass substrate or a silicon wafer with a thickness of from about 100 microns to about 300 microns. In further examples, the carrier substrate can include a thickness of from about 300 microns to about 700 microns. In such examples, the carrier substrate may include a thickness that is greater than the thickness of the substrate (e.g., glass substrate or silicon wafer) bonded to the carrier substrate.

[0047] The rigid characteristics and size of the carrier substrate allow the bonded glass sheet to be handled in production without significant bending that may otherwise cause damage to the flexible glass sheet and/or components mounted to the flexible glass sheet. After processing (e.g., handling, adding components, treating, etc.), a peeling apparatus of the disclosure may be used to initially or completely peel the carrier substrate from the bonded substrate (e.g., glass substrate or silicon wafer) or the bonded substrate(s) from the carrier substrate.

[0048] Turning to FIGS. 1 & 2, there is shown an example peeling apparatus 101 configured to peel a first substrate from a second substrate. Throughout the disclosure, the first substrate can comprise a silicon wafer, glass substrate (e.g., a thin, flexible glass substrate), or other substrate removably bonded to a second substrate such as a carrier substrate. In further examples, the second substrate can comprise the silicon wafer, glass substrate, or other substrate removably bonded to the first substrate comprising the carrier substrate.

[0049] The peeling apparatus 101 further includes a vacuum plate 103 configured to releasably secure one of the substrates in place. For example, the vacuum plate can be vacuum attached to a major surface of the second substrate to releasably secure the second substrate in place. The vacuum plate 103 includes a length "LI" (see FIG. 1) and a width "Wl" (see FIG. 2). In the illustrated example, the length "LI" is greater than the width

"Wl" although the length and width may be substantially equal or the width may be greater than the length in further examples. [0050] As shown in FIG. 3, the vacuum plate 103 can include one or more vacuum ports, such as the illustrated plurality of vacuum ports 301 open at a surface 303 (e.g., a substantially planar surface). The plurality of vacuum ports 301 may be in fluid

communication with a vacuum source 104 such as vacuum tank, vacuum pump, etc. As shown in FIGS. 1 and 9, a vacuum conduit 901, such as a flexible hose, may provide fluid communication between the plurality of vacuum ports 301 and the vacuum source 104. In one example, as shown in FIG. 9, a vacuum chamber 903 may be placed in fluid

communication with the plurality of vacuum ports 301 such that the plurality of vacuum ports 301 are in fluid communication with the vacuum conduit 901.

[0051] Although not shown, one or more standoffs may be provided to prevent actual engagement between the major surface of the substrate and the surface 303 of the vacuum plate 103. Such standoffs may comprise a peripheral standoff, such as a ring circumscribing the plurality of vacuum ports 301. In addition or alternatively, the standoffs can comprise pillars distributed between vacuum ports throughout the pattern of vacuum ports 301. The pillars can comprise various materials such as a polymeric material. The standoffs can extend a distance of about 1.6 mm (e.g., 1/16 of an inch) although other distances may be used in further examples.

[0052] Referring to FIG. 1, the vacuum plate 103 can optionally be configured to translate along a translation axis 105 in one of a first direction 107a and a second direction 107b opposite the first direction. For instance, as schematically illustrated, a plurality of bearings 109 may receive a translation rail 111 extending along the translation axis 105. In some examples, the vacuum plate 103 may freely translate in one of the directions 107a, 107b as the bearings glide along the translation rail 111. Optionally, a locking member, such as the illustrated set screw 113, may selectively lock the vacuum plate 103 relative to the translation rail 111. In a locked orientation, the vacuum plate 103 may be prevented from moving relative to the translation rail 111. Alternatively, in the unlocked orientation, the vacuum plate 103 may be able to translate relative to the translation rail 111 along one of the directions 107a, 107b. The vacuum plate 103 may be selectively locked or unlocked to accommodate different peeling procedures. In applications where only locked orientations are contemplated, the translation mechanism may be discarded altogether. In such examples, the vacuum plate 103 may be fixedly mounted relative to a support surface 115 such as a floor, table top, stand or other support surface. [0053] The peeling apparatus 101 further includes a vacuum attachment member 117 configured to be releasably vacuum attached relative to a leading peripheral edge of the first substrate. In order to facilitate the vacuum attachment, the vacuum attachment member can include one or more vacuum ports. For instance, as shown in FIG. 4, the one or more vacuum ports can comprise a plurality of vacuum ports 401 open at a surface 403 (e.g., a substantially planar surface) of the vacuum attachment member 117. In one example, the plurality of vacuum ports 401 may be arranged in a pattern to distribute force along a width "W2" of the vacuum attachment member 117.

[0054] The plurality of vacuum ports 401 may be in fluid communication with a vacuum source 118 such as vacuum tank, vacuum pump, etc. As shown in FIGS. 1 and 9, a vacuum conduit 905, such as a flexible hose, may provide fluid communication between the plurality of vacuum ports 401 and the vacuum source 118. In one example, as shown in FIG. 9, a vacuum chamber 907 may be placed in fluid communication with the plurality of vacuum ports 401 such that the plurality of vacuum ports 401 are in fluid communication with the vacuum conduit 905.

[0055] The vacuum attachment member 117 may further include a standoff that, in some examples, may prevent actual engagement between the vacuum attachment member 117 and a substrate surface. For instance, if the vacuum attachment member 117 is vacuum attached directly to the first substrate (e.g., glass substrate, silicon wafer, carrier substrate), the standoff can act as a bumper to protect the glass surfaces from damage due to direct contact between the vacuum attachment member and the first substrate. As schematically shown in FIG. 4, one example standoff, if provided, may comprise a peripheral ring-shaped standoff 405 that circumscribes the plurality of vacuum ports 401. The standoff 405 can comprise various materials such as a polymeric material and, in some examples, can extend a distance of about 1.6 mm (e.g., 1/16 of an inch) from the surface 403 of the vacuum attachment member 117.

[0056] Referring to FIGS. 1 and 4, the peeling apparatus 101 further includes an arm 119 supporting the vacuum attachment member 117. As shown, the arm 119 can comprise a plate although the arm may comprise a frame, beam, or other structure configured to support the vacuum attachment member 117. In some examples, the arm 119 can further include a length "L2" that is greater than the length "LI" of the vacuum plate 103. Providing the arm 119 with the relatively longer length "L2" can allow the vacuum attachment member 117 to be spaced laterally away from the surface 303 of the vacuum plate 103 and beyond a leading edge 121 of the vacuum plate. Spacing the vacuum attachment member 117 laterally away from the surface 303 of the vacuum plate 103 can allow the vacuum attachment member 117 to be vacuum attached to a tab without the tab being vacuum attached to the surface 303 of the vacuum plate 103.

[0057] Although not shown, in alternative examples the arm 119 may have a length "L2" that is equal to or less than the length "LI" of the vacuum plate 103. Such a configuration can allow the vacuum attachment member 117 to be vacuum attached directly to a major surface of the first substrate while the second substrate is vacuum attached to the vacuum plate 103.

[0058] The arm 119 is also pivotally attached relative to the vacuum plate 103. For example, as shown in FIG. 1, the trailing end 123 of the vacuum plate 103 can be pivotally attached relative to a trailing end 125 of the arm 119 with a hinge. In some example, the hinge can comprise a float hinge 127 although fixed hinge configurations may be used in alternative examples. The float hinge 127 can include a hinge pin 129 configured to translate and rotate within the slot 131. Consequently, the float hinge 127 can allow different thickness substrate stacks to be processed with the peeling apparatus 101.

[0059] As shown in FIG. 1, the peeling apparatus 101 can also include an actuator 133 configured to apply a force "F" to the vacuum attachment member 117 to lift the vacuum attachment member 117 and consequently cause the arm 119 to pivot in direction 135 about the float hinge 127. In just one example, the force "F" can be applied through a link 137 connected (e.g., with hook 138) to a flexible filament 139 (e.g., wire, cable, etc). For instance, as shown in FIG. 2, one end 139a of the filament 139 can be attached to a first pin 201a extending from a first side of the vacuum attachment member 117 while the other end 139b of the filament 139 can be attached to a second pin 201b extending from a second side of the vacuum attachment member 117. Application of the force "F" through the link 137 can result in application of tensile forces "Fl", "F2" to the first pin 201a and second pin 201b. Moreover, as shown in FIG. 1, the moment arm about the float hinge 127 is maximized since the pins 201a, 201b are positioned at the outermost leading end of the vacuum attachment member 117. As such the leverage may be maximized to more efficiently apply the force "F" to initiate peeling of the substrates.

[0060] As further illustrated in FIGS. 1 and 2, the peeling apparatus 101 may also include a load sensor 141 configured to sense the force "F" being applied by the actuator 133. Information from the load sensor 141 may be sent back to a control device 143 (e.g., programmable logic controller) by way of communication line 141a. The control device 143 can be configured to (e.g., "programmed to", "encoded to", designed to", and/or "made to") control the actuator 133 by way of communication line 133a and the vacuum sources 104, 118 by way of respective communication lines 104a, 118a.

[0061] Methods of processing will now be described with initial reference to FIG. 19. The method can start with step 1901 with a first substrate including a first major surface of the first substrate removably bonded to a first major surface of a second substrate. Throughout the application, the first substrate can be removably bonded to the second substrate by a polymer binding agent or other material that can withstand processing conditions while permitting the substrates to be subsequently peeled at least partially apart.

[0062] In one example of step 1901, as shown in FIGS. 6-12, the method can start with a first substrate 601 comprising a glass substrate (e.g., a thin, flexible glass substrate) or a silicon wafer and a second substrate 603 comprising a carrier substrate (e.g., glass carrier substrate). As shown in FIG. 9, in some examples, the first substrate 601 can include a thickness Tl from about 100 microns to about 300 microns between a first major surface 601a and a second major surface 601b of the first substrate 601. As further shown in FIG. 9, in some examples, the second substrate 603 can include a thickness T2 from about 300 microns to about 700 microns between a first major surface 603a and a second major surface 603b of the second substrate 603. As further illustrated in FIG. 9, in some examples, the thickness T2 of the second substrate 603 (e.g., carrier substrate) can be greater than the thickness Tl of the first substrate 601. Providing a relatively thicker carrier substrate can help increase the effective stiffness of the first substrate (e.g., glass substrate or silicon wafer) to facilitate processing of the first substrate. A relatively thicker carrier substrate can also help significantly contribute to increasing the effective stiffness of the first substrate bonded to the second substrate.

[0063] As illustrated in FIG. 9, the first major surface 601a of the first substrate 601 can be removably bonded to the first major surface 603a of the second substrate 603. Moreover, as further shown in FIG. 9 the second substrate 603 can include a footprint that is larger than a footprint of the first substrate 601. Indeed, the leading peripheral edge 909 of the second substrate 603 extends beyond a leading peripheral edge 911 of the first substrate 601. In addition, the trailing peripheral edge 913 of the second substrate 603 can extend beyond a trailing peripheral edge 915 of the first substrate 601. In fact, in some examples, all of the peripheral edges of the second substrate 603 can optionally extend beyond the corresponding peripheral edges of the first substrate 601 by various distances, for example from about 0.5 mm to about 3 mm. Providing the second substrate 603 with a larger footprint than the first substrate 601 can help protect the relatively fragile peripheral edges of the first substrate from damage during processing. Indeed, any impact to the edges of the bonded substrates would tend to occur at the outwardly extending peripheral edges of the second substrate 603 that would act to protect the relatively fragile outer peripheral edges of the first substrate 601.

[0064] Although not shown in FIGS. 6-12, the footprint of the first substrate 601 and the second substrate 603 may be substantially equal in further examples. Providing substantially equal footprints may simplify manufacturing. For example, the first and second substrates may be first bonded together and then they may be separated along a common separation path wherein the substrates consequently have substantially identical footprints.

[0065] In still another example, although not shown in FIGS. 6-12, the first substrate may have a footprint that is larger than the second substrate such that one or all of the outer peripheral edges of the first substrate extend beyond the second substrate. Alternatively, regardless of the relative footprint size, although not shown, the leading peripheral edge 911 of the first substrate can optionally include an overhung portion (e.g., tab) that extends beyond the leading peripheral edge 909 of the second substrate, for example, from about 50 microns to about 150 microns such as about 100 microns. Such examples can be beneficial to help peel the leading peripheral edge of the first substrate from the second substrate.

[0066] As further shown in FIG. 19, any of the methods of the disclosure can optionally proceed along arrow 1903 to a step 1905 of processing the first substrate 601 while the first substrate 601 is bonded to the second substrate 603. The first substrate 601 can be processed, for example, to include electronics, color filters, touch sensors, liquid crystal wells and other electronics in display applications. In another example, processing can include etching of the glass or otherwise working the glass substrate. When using a silicon wafer, processing can include cutting the silicon wafer into smaller pieces or otherwise processing the silicon wafer to manufacture electronic components.

[0067] As shown by arrow 1907 in FIG. 19, after the step 1905 of processing, the method can optionally proceed to the step 1909 of bonding a flexible membrane to a second major surface of the first substrate, wherein the flexible membrane includes a tab that extends off a leading peripheral edge of the first substrate. For example, as shown in FIGS. 9 and 10, a flexible membrane 917 is bonded to the second major surface 601b of the first substrate 601. The flexible membrane 917 can have a wide range of thicknesses, for example, from about 75 microns to about 150 microns although other thicknesses may be provided in further examples. The flexible membrane can be fabricated from a resin (e.g., clear resin), such as a polymeric material. In one example, the flexible membrane can be fabricated from a polyimide material configured to resist high temperature and configured to transit a relatively high force in tension. In particular examples, the flexible membrane can be fabricated from PVC, polyolefin, polyethylene or other materials.

[0068] The flexible membrane can also include a pressure sensitive adhesive that can provide significant strength to promote a peeling process of the first substrate from the second substrate while also allowing for subsequent removal without leaving residual material on the first substrate. In one example, the adhesive material can be broken down by exposure to ultraviolet light. A specific example of flexible material with a UV sensitive adhesive material can comprise dicing tape commonly used as a backing tape during silicon wafer dicing.

[0069] As shown in FIG. 8, the leading peripheral edge 911 of the first substrate 601 can include a length "L3" defined between a first lateral edge 801a and a second lateral edge 801b of the first substrate 601. As shown in the figures, the length "L3" extends in the same direction as the width "Wl" of the vacuum plate 103. Optionally the step of bonding the flexible membrane 917 can include bonding the flexible membrane to the second major surface 601b of the first substrate 601 such that the flexible membrane 917 extends along substantially the entire length "L3" of the leading peripheral edge 911 of the first substrate 601. In further examples, the flexible membrane 917 may extend from about 70% to about 100% of the length "L3", such as from about 85% to about 100%, such as from about 90% to about 100%, such as about 95% to about 100% of the length "L3". Increasing the extent to which the flexible membrane 917 extends along the length "L3" can help evenly distribute the force across the length "L3" of the leading peripheral edge 911 to reduce stress concentrations and allow simultaneous peeling along the entire length "L3" of the flexible membrane 917.

[0070] The step 1909 of bonding the flexible membrane 917 can optionally bond the flexible membrane 917 to cover substantially the entire second major surface 601b of the first substrate 601. Indeed, as shown in FIG. 9, the flexible membrane 917 extends the entire length of the first substrate 601 from the leading peripheral edge 911 to the trailing peripheral edge 915 of the first substrate 601. Bonding the flexible membrane 917 to over substantially the entire second major surface 601b of the first substrate 601 can help protect the second major surface 601b from damage and can also help adjust the overall effective stiffness of the first substrate 601. Although not shown, in further examples, the flexible membrane 917 may be bonded across only a portion of the second major surface 601b. For example, the flexible membrane 917 may extend a distance at least about 8 cm (e.g., about 3 inches) from the leading peripheral edge 911 in a direction from the leading peripheral edge 911 to the trailing peripheral edge 915 of the first substrate 601. Extending the flexible membrane 917 over only part of the second major surface 601b can expose portions of the second major surface 601b for processing even while the flexible membrane 917 is bonded to a portion of the second major surface 601b of the first substrate 601. Extending the flexible membrane 917 over only part of the second major surface 601b can also reduce material costs and can reduce the time to subsequently remove the flexible membrane 917 from the first substrate 601. Extending the flexible membrane 917 over only part of the second major surface 601b may be useful when it is not necessary to stiffen portions of the first substrate 601 that may already have sufficient stiffness for the particular process application.

[0071] As shown in FIG. 10, the flexible membrane 917 includes a tab 1001 that extends off the leading peripheral edge 911 of the first substrate 601 by a distance "D". As the lower surface 1003 of the tab 1001 can include a pressure-sensitive adhesive, the end of the tab may be folded under itself to cover the pressure-sensitive adhesive, thereby preventing the tab 1001 from inadvertently bonding to adjacent portions of the second substrate 603 or the peeling apparatus 101. For instance, in some examples, the flexible membrane may extend about twice the distance "D" and then be folded under and adhered to itself to form a folded tab with an effective distance "D". In some examples, the distance "D" of the tab 1001 extending off the leading peripheral edge 911 of the first substrate 601 can be within a range of from about 5 cm (2 inches) to about 20 cm (8 inches) although other sized tabs may be provided in further examples. Moreover, the illustrated tab can extend the entire length "L3" of the leading peripheral edge 911.

[0072] As shown by arrow 1907 in FIG. 19, the step 1909 of bonding can be carried out after the step 1905 of processing. In further example, as indicated by arrow 1911, the method can proceed directly to the step 1909 of bonding. For instance, the method may start at step 1901 with the processing step already carried out. For example, the method may begin with the first substrate bonded to the second substrate wherein the first substrate has been processed while the first substrate was bonded on the second substrate. In such examples, the method can start at step 1901 and proceed directly to the step 1909 of bonding. In another example, as mentioned previously, the step 1905 of processing may be carried out after the step 1909 of bonding as indicated by arrow 1913. Such an order of steps can proceed, for example, when the flexible membrane 917 does not interfere with the step 1905 of processing.

[0073] As indicated by arrows 1915, 1917, the method can eventually proceed to a step 1919 of peeling the leading peripheral edge 911 of the first substrate 601 from the second substrate 603 by applying a force "F" to the tab 1001. As shown in FIG. 5, to prepare for the step 119 of peeling, the arm 119 together with the vacuum attachment member 117 attached to a distal end of the arm can be pivoted in direction 501 about the float hinge 127 to an open orientation.

[0074] Next, as shown in FIG. 6, after the second substrate 603 is positioned over the vacuum plate 103. The vacuum source 104 can apply vacuum and consequent suction through the plurality of vacuum ports 301. The second major surface 603b of the second substrate 603 is thereafter vacuum attached to the surface 303 of the vacuum plate 103. Once vacuum attached, the second substrate 603 has a fixed shape. In the illustrated example, the second substrate 603 can be fixed in a substantially flat planar shape although other shapes may be desired in further examples. Fixing the shape can help secure the second substrate 603 firmly in place to facilitate the peeling process.

[0075] Before, during or after vacuum attaching the second substrate 603 to the vacuum plate 103, the arm 119 together with the vacuum attachment member 117 can be pivoted in direction 605 about the float hinge 127 to a closed orientation shown in FIG. 7. In the closed orientation shown in FIG. 7, the arm 119 extends across the first substrate 601 in a direction from the trailing peripheral edge 915 to the leading peripheral edge 911 of the first substrate 601. As further shown in FIG. 7, the hinge pin 129 may travel up the slot 131 of the float hinge 127 in response to the arm being closed over the overall thickness of the first and second substrate.

[0076] As shown in FIG. 7, the step 1919 of peeling can include the step of vacuum attaching the tab 1001 to the vacuum attachment member 117. Indeed, the vacuum source 118 can apply vacuum and consequent suction through the plurality of vacuum ports 401 such that the tab 1001 is vacuum attached to the surface 403 of the vacuum attachment member 117. The step 1919 of peeling can then apply the force "F" to the tab 1001 with the vacuum attachment member 117. Indeed, with reference to FIG. 2, the actuator 133 can apply the force "F" in the upward direction that causes tensile forces "Fl" and "F2" to be applied to the pins 201a, 201b of the vacuum attachment member 117.

[0077] As shown by the force distribution represented schematically by a row of parallel arrows in FIG. 8, the method can uniformly apply the force "F" to the tab 1001 along the length "L3" of the leading peripheral edge 911 of the first substrate 601. As such, stress can be distributed evenly across the leading peripheral edge 911 to avoid unnecessarily high stress concentrations along the leading peripheral edge. As shown in FIG. 10, since the force is being applied a distance "D" from the leading peripheral edge 911, the force can be concentrated at the interface between the leading peripheral edge 911 and the second substrate 603. Eventually, the stress at the leading peripheral edge 911 results in an initial separation 1005 between the leading peripheral edge 911 and the second substrate 603. Initial separation may begin at one end of the leading peripheral edge. Alternatively, in some examples, the step of peeling can peel the leading peripheral edge 911 of the first substrate 601 from the second substrate 603 substantially simultaneously along the entire length "L3" of the leading peripheral edge 911. Simultaneous peeling along the entire length "L3" of the leading peripheral edge 911 can be achieved with uniform application of force along the entire length of the leading peripheral edge and can help reduce unnecessary stress spikes along the length that may otherwise damage the first substrate.

[0078] Sometime after the step 1919 of peeling the leading peripheral edge 911 of the first substrate 601, the method can optionally include the step 1921 of determining a bond strength between the leading peripheral edge 1919 of the first substrate 601 and the second substrate 603 based on information obtained during the step 1919 of peeling. For instance, information (e.g., a force measurement) from the load sensor 141 can be transmitted by the

communication line 141a to the control device 143. The control device 143 can be configured to monitor the information from the load sensor 141 and may be further configured to identify when the initial separation 1005 occurs due to a spike in the information, such as a force measurement, that occurs at the time of the initial separation 1005. The information provided by the load sensor 141 at the time of the initial separation 1005 can be used to determine (e.g., calculate) the bond strength between the leading peripheral edge 1919 of the first substrate 601 and the second substrate 603. The bond strength can be used in a wide variety of ways. For instance, determining the bond strength can be used to help determine the specifications of the first substrate bonded to the second substrate. This information can be provided to vendors that may like this information for appropriate further processing of the first substrate. The bond strength can also be provided as feedback to the control device 143 for modifying a subsequent process of separating a subsequent first substrate from a subsequent second substrate. Indeed, a series of separation procedures may be assumed to involve substrates with similar bonding strength. As such, feedback of the bonding strength can be used to help fine tune the process to increase efficiency and effectiveness of separation (e.g., reducing time to initial separation, maintaining a minimum bend radius while separating, etc.).

[0079] After the step 1919 of peeling the leading peripheral edge 911, the method can further include the step 1923 of completely removing the first substrate 601 from the second substrate 603. In still another example, as shown in FIGS. 11 and 12 the step 1923 of completely removing the first substrate 601 from the second substrate 603 comprises completely peeling the first substrate from the second substrate. Indeed, the vacuum attachment member 117 can be lifted wherein the arm 119 pivots in direction 135 about the float hinge 127 to such that the peel apparatus 101 achieves the open orientation. In the open orientation shown in FIG. 12, the first substrate 601 is completely peeled from the second substrate 603 even though the figure illustrates an outer corner of the first substrate 601 resting (without adhesion) on an outer portion of the second substrate 603.

[0080] In some examples, during the step of peeling (e.g., initially peeling, partially peeling, completely peeling) the first substrate from the second substrate, the method can further include the step 1925 of controlling a bend radius "R" (see FIG. 11) of the first substrate 601. For example, there may be desire to ensure that the first substrate 601 is not peeled in such a way that the bend radius is smaller than a predetermined minimum bend radius. The predetermined minimum bend radius may be a radius that the first substrate 601 may be safely bent without a significant probability of breaking or otherwise being damaged. In one example, the control device 143 may control the actuator 133 to provide a predetermined varying force "F" over time after initial separation 1005. Varying the force "F" in a controlled manner over time can be designed to ensure that the bend radius "R" does not fall below a predetermined minimum bend radius. In further examples, although not shown, a proximity sensor may be provided that senses the actual bend radius of the first substrate wherein the control device 143 can appropriately modify the force "F" applied by the actuator based on feedback from the proximity sensor.

[0081] In further examples, in addition to preselecting a minimum bend radius, the step 1925 of controlling the bend radius "R" can further include selecting a flexible membrane 917 to increase the effective stiffness of the first substrate 601 to maintain the bend radius "R" of the first substrate 601 above the minimum bend radius during a step of peeling (e.g., initially peeling, partially peeling, completely peeling) the first substrate from the second substrate. For instance, a dicing tape can be selected for the flexible membrane 917 that has a sufficient rigidity to adjust the effective rigidity of the first substrate 601 when applied across the entire second major surface 601b of the first substrate 601. The rigidity of the first substrate 601 may be adjusted by choosing the material and/or thickness of the dicing tape (including the backing and/or the adhesive), for example. Increasing the rigidity of the first substrate 601 can help the first substrate resist bending, and therefore help maintain a bend radius "R" above the predetermined minimum bend radius while peeling (e.g., initially peeling, partially peeling, completely peeling) the first substrate 601 from the second substrate 603.

[0082] Once the step 1923 of completely removing the first substrate 601 from the second substrate 603 is complete, the method can end at any point of the process as indicated by arrows 1927, 1929, 1931 and 1933. Before ending the method, in one example, the method can further continue with the optional step 1935 of processing the first substrate 601 as indicated by arrow 1937. Indeed, further processing steps, may be carried out wherein the flexible membrane 917 may provide protection to the second major surface 601b of the first substrate 601. In further examples, the tab 1001 may be used to help process the first substrate (e.g., handle the first substrate) without gripping the first substrate that may otherwise damage the first substrate.

[0083] Before ending, the method can also include the step 1939 of removing the flexible membrane 917 from the first substrate 601. Various removal techniques may be used depending on the characteristics of the adhesive used to bond the flexible membrane 917 to the first substrate 601. In one example, the step 1939 of removing the flexible membrane 917 from the first substrate 601 can include exposing the flexible membrane to ultraviolet light to release the flexible membrane 917 from the second major surface 601b of the first substrate 601, as when the adhesive of the flexible membrane is UV sensitive.

[0084] The method described with respect to FIG. 19 and FIGS. 1-12 can be carried out with a wide range of substrates. FIGS. 13-15 illustrate another example that, unless otherwise noted, can include identical steps and/or equivalent steps discussed with respect to FIG. 19 and FIGS. 1-12 above. However, in the illustrated example of FIGS. 13-15, a first substrate 1301 comprises a carrier substrate and a second substrate 1302 (e.g., glass substrate or silicon wafer) can be vacuum attached to the vacuum plate 103. Similarly as discussed above, the first substrate 1301 can be peeled (e.g., completely peeled) from the second substrate 1302 as shown in FIGS. 13 and 15.

[0085] FIGS. 16-18 illustrate yet another example that, unless otherwise noted, can include identical steps and/or equivalent steps discussed with respect to FIG. 19 and FIGS. 1-15 above. However, in the illustrated example of FIGS. 16-18, a first substrate 1601a comprises a first carrier substrate and a second substrate 1601b comprises a second carrier substrate that can be vacuum attached to the vacuum plate 103. An intermediate substrate 1603 can be sandwiched between and removably bonded to the first carrier substrate 1601a and the second carrier substrate 1601b. Similarly as discussed above, the first substrate 1601a can be peeled (e.g., completely peeled) from the second substrate 1601b by being peeled (e.g., completely peeled) from the intermediate substrate 1603. Once completely peeled, the intermediate substrate 1603 may be peeled from the second carrier substrate 1601b by one of the methods shown in FIGS. 5-12 or FIGS. 13-15. The intermediate substrate may be made of one or more layers. For example, the intermediate substrate may be a display panel including a backplane substrate, a cover substrate, and display elements disposed therebetween.

[0086] These are just a few examples of variations that can be made to the apparatus and method described above. Other various modifications and variations can be made without departing from the spirit and scope of the claims.

Claims

What is claimed is:

1. A method of processing a first substrate with a first major surface of the first substrate removably bonded to a first major surface of a second substrate, the method comprising the steps of:

(I) bonding a flexible membrane to a second major surface of the first substrate, wherein the flexible membrane includes a tab that extends off a leading peripheral edge of the first substrate; and

(II) peeling the leading peripheral edge of the first substrate from the second substrate by applying a force to the tab.

2. The method of claim 1 , wherein the first substrate comprises a substrate selected from the group consisting of: a glass substrate and a silicon wafer.

3. The method of claim 1 , wherein the first substrate includes a thickness of from about 100 microns to about 300 microns.

4. The method of claim 1 , wherein the second substrate comprises a carrier substrate including a thickness of from about 300 microns to about 700 microns.

5. The method of claim 1 , wherein the second substrate comprises a carrier substrate including a footprint that is larger than a footprint of the first substrate.

6. The method of any one of claims 1-5, wherein prior to step (II), further comprising the step of processing the first substrate while the first substrate is bonded to the second substrate.

7. The method of claim 6, wherein the step of processing the first substrate occurs prior to step (I).

8. The method of any one of claims 1-5, wherein the leading peripheral edge includes a length defined between a first lateral edge and a second lateral edge of the first substrate, and step (I) includes bonding the flexible membrane to the second major surface of the first substrate such that the flexible membrane extends along substantially the entire length of the leading peripheral edge.

9. The method of claim 8, wherein step (II) uniformly applies the force to the tab along the length of the leading peripheral edge.

10. The method of claim 8, wherein step (II) peels the leading peripheral edge of the first substrate from the second substrate substantially simultaneously along the entire length of the leading peripheral edge.

1 1. The method of any one of claims 1-5, wherein after step (II), further comprising the step of completely removing the first substrate from the second substrate.

12. The method of claim 1 1, wherein the step of completely removing the first substrate from the second substrate comprises completely peeling the first substrate from the second substrate.

13. The method of any one of claims 1-5, further comprising the steps of preselecting a minimum bend radius of the first substrate and selecting a flexible membrane to increase the effective stiffness of the first substrate to maintain a bend radius of the first substrate above the minimum bend radius while peeling the first substrate from the second substrate.

14. The method of any one of claims 1-5, further comprising the step of controlling a bend radius of the first substrate while peeling the first substrate from the second substrate.

15. The method of any one of claims 1-5, wherein step (I) bonds the flexible membrane to cover substantially the entire second major surface of the first substrate.

16. The method of any one of claims 1-5, wherein step (I) bonds the flexible membrane to the second major surface of the first substrate such that the tab extends a distance of from about 5 cm to about 20 cm off the leading peripheral edge of the first substrate.

17. The method of any one of claims 1-5, wherein after step (II), further comprising the step of removing the flexible membrane from the first substrate.

18. The method of claim 17, wherein the step of removing the flexible membrane from the first substrate includes exposing the flexible membrane to ultraviolet light to release the flexible membrane from the second major surface of the first substrate.

19. The method of any one of claims 1-5, wherein step (II) includes vacuum attaching the tab to a vacuum attachment member and then applying the force to the tab with the vacuum attachment member.

20. The method of any one of claims 1 -5, further comprising the step of determining a bond strength between the leading peripheral edge of the first substrate and the second substrate based on information obtained during step (II).