KR20140016928A - Methods for mechanically forming crack initiation defects in thin glass substrates - Google Patents

Abstract

A method of mechanically forming a crack initiation defect in a thin glass substrate is described. In one embodiment, a method of separating a glass substrate into a plurality of substrates includes directing a flow of carrier fluid having an entrained abrasive material onto the surface of the glass substrate to form initiation defects in the surface of the glass substrate. . Initiation defects do not extend through the thickness of the glass substrate. Thereafter, the starting defect is heated by the laser light source and subsequently cooled by the cooling fluid so that the crack starts from the starting defect. The cracks extend through the thickness of the glass substrate and propagate across the glass substrate so that the glass substrate is separated into a plurality of substrates.

Description

METHODS FOR MECHANICALLY FORMING CRACK INITIATION DEFECTS IN THIN GLASS SUBSTRATES

Cross-reference to related application

This application claims 35 U.S.C. of US Provisional Application No. 61 / 475,409, filed April 14, 2011. Claim the benefit of priority under section 119, the contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION The present invention generally relates to laser separation of thin glass substrates, and more particularly to methods of mechanically forming crack initiation defects for use in separation of thin glass substrates using laser separation techniques.

Glass substrates, such as flat panel displays and glass substrates used in other electronic devices, are generally formed from large glass substrates that are divided into a plurality of smaller glass substrates that are incorporated into individual devices. Various separation techniques, including laser cutting techniques, are used to separate large glass substrates into a plurality of smaller glass substrates. In order to separate the glass substrate by laser cutting, starting defects or vent cracks are first formed in the glass substrate using a scoring wheel. To form an initiation defect, a scoring wheel is contacted with the glass substrate, a force orthogonal to the surface of the glass substrate is then applied to the scoring wheel, whereby the scoring wheel is crossed over the surface by a short distance. Press the scoring wheel into the surface. The force applied on the scoring wheel creates an initiation defect that extends partially through the thickness of the glass substrate. Thereafter, the starting defect is heated and rapidly cooled to propagate through vents from the starting defect and thereby separate the glass substrate.

However, when the thickness of the glass substrate is reduced, forming initiation defects in the surface of the glass substrate, as described above, is generally due to the large magnitude of vertical force required to form the defect by the scoring wheel, rather than local defects. This results in the formation of a series of cracks within the surface of. Even in situations where only one crack is formed, this one crack generally extends through the thickness of the glass substrate. Such cracks can propagate easily and uncontrollably across the width of the glass substrate, thereby often causing severe breakage of the glass substrate before laser separation.

Accordingly, there is a need for alternative methods and apparatus for creating crack initiation defects in thin glass substrates to facilitate separation of the thin glass substrates into a plurality of individual glass substrates by laser separation.

Embodiments described herein form crack initiation defects in the surface of a thin glass substrate without perforating the thin glass substrate or initiating uncontrolled crack propagation within the thin glass substrate, thereby forming the thin glass substrate into a plurality of individual substrates. A method for facilitating separation into a substrate is provided. An apparatus for performing these methods is also disclosed.

According to one embodiment, a method of separating a glass substrate into a plurality of substrates without perforating the thin glass substrate or initiating uncontrolled crack propagation within the thin glass substrate comprises providing a glass substrate and the accompanying abrasive material. Inducing a flow of carrier fluid having a surface of the glass substrate to form an initiation defect in the surface of the glass substrate. Thereafter, the starting defect can be heated by the laser light source and subsequently cooled by the cooling fluid so that the crack starts from the starting defect. The cracks extend through the thickness of the glass substrate and propagate across the glass substrate to separate the glass substrate into a plurality of substrates.

In another embodiment, a method of separating a glass substrate into a plurality of individual substrates without perforating the thin glass substrate or initiating uncontrolled crack propagation within the thin glass substrate provides a step of providing a glass substrate and polishing material. Contacting the surface of the glass substrate with the abrasive fiber comprising. Thereafter, the abrasive fiber is traversed over the surface of the glass substrate such that the abrasive material of the abrasive fiber forms an initiation defect in the surface of the glass substrate.

In another embodiment, a method of separating a glass substrate into a plurality of individual substrates without perforating the thin glass substrate or initiating uncontrolled crack propagation within the thin glass substrate provides a step of providing a glass substrate and a rotating abrasive wheel. compliantly supporting the glass substrate in proximity to the rotating abrasive wheel. The surface of the glass substrate is then contacted with the rotating polishing wheel such that the principal component of the force exerted by the rotating polishing wheel relative to the glass substrate is substantially parallel to the surface of the glass substrate, thereby minimizing the flexure of the glass substrate. Then, the polishing wheel polishes starting defects in the surface of the glass substrate.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be readily apparent to those skilled in the art from the description or the embodiments described herein, including the following description, claims and also accompanying drawings. Will be recognized by doing.

It is to be understood that both the above general description and the following detailed description are intended to provide an overview or framework that describes various embodiments and understands the nature and characteristics of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.

1 schematically illustrates a method of forming a crack initiation defect in a thin glass substrate by an abrasive material entrained in a carrier fluid according to one or more embodiments illustrated and described herein.
FIG. 2 schematically illustrates a plurality of crack initiation defects formed in the surface of a glass substrate using the method shown in FIG. 1.
FIG. 3 schematically illustrates an enlarged view of a plurality of crack initiation defects of FIG. 2.
4 schematically illustrates a polishing apparatus used to form one or more crack initiation defects within the surface of a thin glass substrate according to another embodiment illustrated and described herein.
5 schematically illustrates a polishing apparatus used to form one or more crack initiation defects in the surface of a thin glass substrate, according to another embodiment illustrated and described herein.
6A and 6B schematically illustrate crack initiation defects formed in the surface of a thin glass substrate by a polishing apparatus in accordance with one or more embodiments illustrated and described herein.
7 schematically illustrates an embodiment of a polishing apparatus for forming a crack initiation defect in a thin glass substrate.
FIG. 8 schematically illustrates a plurality of crack initiation defects formed in the surface of a thin glass substrate by the polishing apparatus of FIG. 7.
9 schematically illustrates another embodiment of a method of forming crack initiation defects with abrasive fibers.
10 schematically illustrates a method of forming a crack initiation defect in a thin glass substrate by a rotating abrasive wheel in accordance with one or more embodiments illustrated and described herein.
11 schematically illustrates a method of forming a crack initiation defect in a thin glass substrate by a rotating abrasive wheel in accordance with one or more embodiments illustrated and described herein.
FIG. 12 schematically illustrates crack initiation defects formed in the surface of a thin glass substrate using the method shown in FIG. 11.
13A and 13B schematically illustrate a method of laser separating a glass substrate from a crack initiation defect in accordance with one or more embodiments illustrated and described herein.

Embodiments of a method of mechanically forming crack initiation defects in thin glass substrates will now be described in detail, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. One embodiment of a method of forming a crack initiation defect in a surface of a glass substrate is schematically illustrated in FIG. 1. The method generally includes inducing an abrasive material entrained in the flow of carrier fluid onto the surface of the glass substrate to form a plurality of local crack initiation defects. Various embodiments of methods and apparatus for forming crack initiation defects in a glass substrate will be described herein with particular reference to the accompanying drawings.

Cover glass used in electronic devices such as flat panel displays and smart phones may be formed from thin glass substrates having a thickness of 0.2 mm or less. These thin glass substrates are generally formed as large sheets or ribbons of glass and are subsequently divided into a plurality of individual glass substrates by laser separation techniques. Conventional techniques for forming crack initiation defects in thin glass substrates to facilitate laser separation can be achieved by uncontrolled separation of thin glass substrates, perforation of thin glass substrates or, in the worst case, high vertical forces used to form crack initiation defects. It has now been found that it can lead to severe breakage of the resulting thin glass substrate. As such, forming crack initiation defects in a thin glass substrate can be a source of loss and high cost. Described herein are methods and apparatus for forming crack initiation defects in glass substrates to mitigate the aforementioned disadvantages.

Referring now to FIG. 1, one method of schematically forming a crack initiation defect in the surface 102 of a thin glass substrate 100 (ie, a glass substrate having a thickness T of about 0.2 mm or less) is schematically illustrated. Crack initiation defects are formed in the surface of the glass substrate by, for example, abrasive material 114 entrained in the flow of carrier fluid 112 such as compressed air or similar carrier gas. In alternative embodiments, the flow of carrier fluid 112 may be a liquid, such as water, accompanied by abrasive material 114. In the embodiment described herein, the abrasive material 114 is entrained in the flow of compressed air discharged from the nozzle 110. The flow of carrier fluid 112 with entrained abrasive material 114 is directed onto the surface 102 of the glass substrate 100 to polish the area of the surface and thereby create local crack initiation defects.

In the embodiment described herein, the abrasive material 114 has a mesh size of about 400 mesh to about 600 mesh to form a crack initiation defect having a size suitable for propagating the crack from the crack initiation defect. However, it is understood that these figures for the mesh size of the abrasive material are exemplary and that abrasive materials having larger or smaller mesh sizes can also be used to form crack initiation defects in the surface of the glass substrate using this method. Should be.

Various kinds of abrasive materials may be used in the flow of the carrier fluid 112 to form crack initiation defects. For example, in one embodiment, the abrasive material 114 entrained in the flow of carrier fluid 112 is aluminum oxide. However, it should be understood that other suitable abrasive materials may also be used including, without limitation, silicon carbide, boron nitride, diamond and similar abrasive materials.

The flow of carrier fluid 112 with entrained abrasive material 114 does not cause excessive damage to the glass substrate (ie, does not create holes through the thickness of the glass substrate 100). Induced onto the surface of the glass substrate 100 by a pressure appropriate to cause local erosion of the surface 102 of 100. In one embodiment, the flow of carrier fluid 112 with entrained abrasive material 114 is directed onto the surface of the glass substrate at a pressure that is about 60 psi or less. For example, the flow of carrier fluid 112 with entrained abrasive material 114 may be directed onto surface 102 of glass substrate 100 by pressures of about 30 psi or more and about 60 psi or less. Maintaining the pressure of the flow of the carrier fluid 112 below 60 psi helps to mitigate excessive damage and erosion of the glass substrate 100 which may lead to the formation of through holes or, in the alternative, uncontrolled crack propagation. While it is desirable to maintain the pressure of the flow of carrier fluid 112 below 60 psi to mitigate excessive damage, pressures below about 30 psi or above about 60 psi may also be used to form crack initiation defects in the glass substrate. It should be understood that it can.

The nozzle 110 and substrate 100 have a flow of carrier fluid 112 with entrained abrasive material 114 that is less than 25.4 mm (1 inch) and preferably 19 mm where local crack initiation defects 116 are formed. Are positioned relative to each other to have contact areas 118 (shown in FIG. 3) having a diameter D of no greater than (0.75 inches). Maintaining contact area 118 below 25.4 mm (1 inch) minimizes the formation of crack initiation defects in undesirable areas that can lead to the onset of uncontrolled separation and should remain intact. It mitigates damage to the glass substrate within the so-called "quality area" of the glass substrate. In one embodiment described herein, the contact region 118 has a diameter D of at least about 6.35 mm (0.25 inch) and up to about 19 mm (0.75 inch).

The glass substrate 100 may be positioned such that, for example, when the glass substrate 100 is cantilevered under the carrier fluid 112, an area of the glass substrate opposite the contact area 118 of the carrier fluid is elastically supported. have. An arrangement is shown in FIG. 1 where the glass substrate 100 is positioned on the support 109 such that at least a portion of the glass substrate 100 is cantilevered from the end of the support 109. In this arrangement, the glass substrate 100 is curved when the flow of the carrier fluid 112 and the abrasive material 114 impinges on the surface 102 of the glass substrate 100 and is bent by the abrasive material. It is elastically supported to minimize the depth of initiating defects caused. Thus, it should be understood that the phrase “compliantly supported” means that at least a portion of the glass substrate freely curves or reacts away from the crack initiation mechanism when a crack initiation defect is formed.

In the alternative, the glass substrate 100 is elastically supported on the elastic surface when the flow of carrier fluid 112 with the entrained abrasive material 114 is directed onto the surface 102 of the glass substrate 100. Can be. For example, the elastic surface may be a foam pad or similar cushion on which the glass substrate 100 is positioned when the flow of carrier fluid 112 is directed onto the surface 102 of the glass substrate 100. have. In another embodiment, the elastic surface is a Bernoulli chuck in which the glass substrate 100 is positioned to buffer the glass substrate 100 when a flow of carrier fluid is directed onto the surface 102 of the glass substrate 100. Or an air bearing such as a similar air flotation device. The elastic surface is glass substrate 100 when the flow of carrier fluid 112 and abrasive material 114 collides with surface 102 of glass substrate 100 such that the depth of local initiation defects caused by the abrasive material is minimized. Elastically support and cushion and allow the glass substrate 100 to react slightly. An exemplary embodiment of an elastic surface, specifically an air bearing, is shown schematically in FIGS. 4 and 5 and described in more detail herein.

Referring now to FIGS. 2 and 3, the flow of carrier fluid 112 with entrained abrasive material 114 corresponds to the location of the glass substrate 100 corresponding to the location of the contact region 118 of the flow of carrier fluid 112. It can be used to form at least one crack initiation defect 116 in a localized region on the surface 102 of the. More specifically, the abrasive material 114 entrained in the flow of carrier fluid 112 forms a plurality of crack initiation defects 116 in the contact region 118 of the flow of carrier fluid 112. The surface density of crack initiation defects 116 (ie, the number of crack initiation defects per unit area) can be controlled by the residence time of the flow of carrier fluid 112 at a particular location on surface 102 of glass substrate 100. Can be. Thus, longer residence times result in higher crack initiation defect surface densities. For a given contact region 118, any of the crack initiation defects 116 of the plurality of crack initiation defects located within the contact region 118 may be separated vents or by using laser separation techniques as described in more detail herein. It can be used to initiate a crack.

Referring now to FIG. 4, another embodiment of a method of mechanically forming an initiation defect within a surface 102 of a glass substrate 100 is schematically illustrated. As described above, the glass substrate has a thickness T that is 0.2 mm or less. In this embodiment, crack initiation defects are formed using the polishing apparatus 140. Polishing device 140 generally includes a drum member 141 and one or more abrasive fibers 142. The drum member 141 is generally cylindrical in shape and has a central axis of rotation 143 generally corresponding to the long axis of the drum member 141. The one or more abrasive fibers 142 (four are shown in FIG. 4) may be used as the abrasive fibers 142 rotate relative to the rotation axis 143 when the drum member 141 is rotated about the rotation axis 143. Extends from surface 146 of drum member 141 to rotate with 141.

In the embodiment described herein, the abrasive fibers 142 are secured in respective respective ports 148 formed in the surface 146 of the drum member 141, and may be secured by epoxy or another suitable material. It is fixed in its respective receiving port. The abrasive fiber 142 includes a filament 144 on which the abrasive material 114 is coated. In the embodiment described herein, the filament 144 has a diameter of about 0.15 mm to about 0.22 mm and is formed from steel wire. However, it is to be understood that the filaments may be formed from other materials including, without limitation, polymeric materials, carbon fibers or other metallic materials. Moreover, it should also be understood that the filaments may be formed with a diameter greater than about 0.22 mm or less than 0.15 mm.

In the embodiment described herein, the angle α between the glass substrate 100 and the abrasive fiber 142 when the abrasive fiber 142 initiates contact with the glass substrate 100 is such that they are in contact with the glass substrate 100. Small enough to prevent the fibers from raising the glass substrate when in contact. For example, in one embodiment, the angle α between the abrasive fiber 142 and the glass substrate 100 is about 45 degrees or less. In order to facilitate the required angle α between the abrasive fiber 142 and the glass substrate 100 at initial contact, the filament 144 forming the abrasive fiber 142 may be curved as shown in FIG. 4. have. In an alternative or additional example, abrasive fibers 142 may be located in drum member 141 such that the abrasive fibers are tangential to the surface of the wheel as shown in FIG. 4.

In the embodiment described herein, the abrasive material applied to the filament is diamond having a mesh size of about 600 or more and about 1000 or less. However, it should be understood that other abrasive materials including, without limitation, aluminum oxide, silicon carbide, or boron nitride may be used to coat the filaments. It should also be understood that other mesh sizes may also be used.

Polishing device 140 may be coupled to a motor (not shown), such as a variable speed electric motor, to facilitate rotating drum member 141 and abrasive fiber 142 about axis of rotation 143 of drum member. have. In the embodiment described herein, the rotation speed suitable for forming the crack initiation defect in the glass substrate by the polishing apparatus 140 includes a range of about 60 rpm to about 2000 rpm. However, it should be understood that rotational speeds outside the range of about 60 rpm to about 2000 rpm may also be used.

Referring also to FIG. 4, in one embodiment, the glass substrate 100 is positioned on the elastic surface 130 when crack initiation defects are formed in the glass substrate by the polishing apparatus 140. The elastic surface 130 may comprise a foam material as described above, or in the alternative, the elastic surface 130 may be an air bearing as shown in FIG. 4. In this embodiment, the elastic surface 130 (ie, air bearing) supports the glass substrate 100 on the air cushion 132 when the polishing apparatus 140 is in contact with the glass substrate 100. The air cushion 132 elastically supports the glass substrate 100 when the abrasive fiber 142 is in contact with the surface 102 of the glass substrate 100, thereby buffering the glass substrate 100 and Absorbs excessive force applied to the 100 and thereby prevents serious damage to the glass substrate 100.

4 shows one arrangement for elastically supporting a glass substrate, it should be understood that other arrangements are possible. For example, in an alternative embodiment, the glass substrate 100 positions the glass substrate on the support such that the end of the glass substrate 100 in contact with the abrasive fibers as shown in FIG. 1 is cantilevered from the end of the support. Can be elastically supported. In this arrangement, the glass substrate 100 has a depth of initiation defects caused by the abrasive fibers being curved by the abrasive substrate 142 when the abrasive fibers 142 collide with the surface 102 of the glass substrate 100. Is elastically supported so that is minimized.

In order to form a crack initiation defect in the surface 102 of the glass substrate 100, the abrasive fiber 142 is one in which the abrasive fiber 142 is rotated about the rotation axis 143 of the drum member 141 and thus the abrasive fiber. The glass substrate 100 has a surface 102 by rotating the polishing apparatus 140 such that 142 is rotated about an axis of rotation that is substantially perpendicular to the long axis of each abrasive fiber (ie, 90 ° +/- 10 °). Contact with and traversed over the surface. In one embodiment, the polishing apparatus 140 has the rotation axis 143 of the drum member 141 as the abrasive fiber is rotated (when the polishing fiber 142 forms point contact with the surface 102). Surface 102 of glass substrate 100 spaced from surface 102 of substrate 100 and such that only tip portion 145 of each abrasive fiber 142 contacts surface 102 of glass substrate 100. Is located close to. The abrasive material located on the tip portion 145 of each abrasive fiber 142 polishes crack initiation defects in the surface 102 of the glass substrate 100 as the polishing apparatus is rotated. Positioning the polishing device 140 such that only the tip portion 145 of each abrasive fiber 142 forms point contact with the surface 102 of the glass substrate 100 is the surface 102 of the glass substrate 100. Minimize the length of crack initiation defects polished into, and also ensure that the resulting crack initiation defects do not extend through the thickness of the glass substrate 100. One embodiment of the crack initiation defect 116 formed by the polishing apparatus using the technique described above is schematically illustrated in FIG. 6A. In this embodiment, the crack initiation defect 116 is caused by positioning the polishing apparatus 140 relative to the glass substrate such that the tip of the abrasive fiber is in contact with the surface 102 of the glass substrate without first contacting the edge of the glass substrate. Offset from the edge of the substrate. However, it should be understood that in other embodiments, the crack initiation defect 116 may extend from the edge of the glass substrate 100 as described in more detail herein.

Referring to FIG. 5, in another embodiment, the rotary polishing apparatus 140, in particular the rotation axis 143 of the polishing apparatus 140, is such that the abrasive fibers 142 first contact the edges of the substrate and then the glass substrate. Spaced from the surface 102 of the glass substrate 100 to form more than one point contact (ie, line contact) with the surface 102 of the 100. More specifically, in this embodiment, the rotary polishing apparatus 140 has the abrasive fibers 142 curved against the surface 102 of the glass substrate 100 and the abrasive fibers 142 when the abrasive fibers 142 are rotated. Some length of the abrasive fiber proximate the tip portion 145 of the form a line contact with the surface 102 of the glass substrate 100 and thereby within the surface 102 of the glass substrate 100 by the abrasive fiber 142. It is positioned relative to the glass substrate 100 to increase the length of the resulting crack initiation defects formed. In some embodiments described herein, the portion of the abrasive fiber 142 that makes line contact with the glass substrate 100 may be about 6.35 mm (0.25 inch) or less. 6B schematically illustrates a crack initiation defect 116 formed in the surface 102 of the glass substrate 100 using the technique described above. In this embodiment, the crack initiation defect 116 causes the glass substrate 100 to form initial contact with the edges of the glass substrate 100 before the abrasive fibers are moved across the surface 102 of the glass substrate 100. Extends from the edge of).

Referring now to FIG. 7, one embodiment of a polishing apparatus 140 is schematically illustrated. In this embodiment, the abrasive fiber 142 is positioned on the drum member 141 to obtain a predetermined pattern of initiation defects on the surface 102 of the glass substrate 100. Specifically, FIG. 7 illustrates an embodiment of a polishing apparatus 140 in which a plurality of abrasive fibers 142 are arranged in rows 170 extending axially on the surface 146 of the drum member 141. . The abrasive fibers 142 in each row 170 are equidistantly spaced by a distance s in the axial direction. A plurality of rows of abrasive fibers 142 are spaced equidistantly on the surface 146 of the drum member 141 in the circumferential direction.

Referring now to FIG. 8, there is shown a glass substrate 100 in which a pattern of crack initiation defects 116 is formed using the polishing apparatus of FIG. 7. Each crack initiation defect 116 is spaced apart by a distance S corresponding to the spacing of the abrasive fibers 142 on the polishing apparatus 140 of FIG. 7. Thus, it should be understood that the polishing apparatus 140 may be composed of a plurality of abrasive fibers arranged to produce a plurality of crack initiation defects 116 in the surface 102 of the glass substrate by only one pass of the polishing apparatus. do. Furthermore, the abrasive fibers 142 may be arranged on the drum member 141 of the polishing apparatus 140 to achieve the desired pattern of crack initiation defects 116 on the surface 102 of the glass substrate 100, Crack initiation defects in the desired pattern can be used to divide the glass substrate into a plurality of individual glass substrates having the required dimensions. In these embodiments, the plurality of abrasive fibers preferably form a wide area 117 of crack initiation defects 116 as shown in FIG. The region 117 of the plurality of initiating defects 116 facilitates faster alignment of the laser with at least one of the defects in the region during subsequent laser separation processes.

While the embodiment described above uses rotating abrasive fibers to form crack initiation defects in the surface of the glass substrate, the abrasive fibers are used to form crack initiation defects in the surface of the glass substrate by moving the glass substrate relative to the abrasive fiber. It should be understood that it can be. For example, referring to FIG. 9, another embodiment of a technique for creating a crack initiation defect in the surface 102 of the glass substrate 100 by abrasive fibers 142 is shown. In this embodiment, the abrasive fiber is held in a fixed position. The abrasive fiber 142 may be formed by moving the glass substrate 100 in the direction indicated by arrow 200 such that the abrasive fiber 142 contacts the surface 102 of the glass substrate 100 when the glass substrate is moved. Traversed above surface 102. As mentioned above, the abrasive fibers 142 minimize the contact angle α between the abrasive fibers 142 and the surface of the glass substrate 100 (ie, by 45 ° or less) whereby the abrasive fibers 142 are made of glass. It is positioned to prevent raising the substrate 100.

Based on the above, the abrasive fibers can be traversed over the surface of the glass substrate by rotating the abrasive fiber relative to the glass substrate or by moving the glass substrate relative to the fixed abrasive fiber.

Referring now to FIG. 10, another embodiment of a method of forming a crack initiation defect in a surface of a glass substrate is schematically illustrated. In this embodiment, a rotating abrasive wheel 150 is used to form crack initiation defects within the surface of the glass substrate 100. The abrasive wheel 150 generally includes abrasive materials such as silicon carbide, aluminum oxide, diamond, etc. having a mesh of less than about 1000. For example, in some embodiments, the abrasive material may have a mesh of at least about 300 or at most about 1000. In other embodiments, the abrasive material may have a mesh of at least about 400 and at most about 600. In yet another embodiment, the abrasive material may have a mesh of about 300 to about 400.

In one embodiment, the glass substrate 100 is positioned on the elastic surface 130 when crack initiation defects are formed in the glass substrate by the polishing wheel 150. The elastic surface 130 may comprise foam material as described above, or in the alternative, the elastic surface 130 may be an air bearing as shown in FIG. 10. The air cushion 132 elastically supports the glass substrate 100 when the polishing wheel 150 is in contact with the surface 102 of the glass substrate 100, thereby buffering the glass substrate 100 and Absorbs excessive force applied to the 100 and thereby prevents damage to the glass substrate 100.

10 shows one arrangement for elastically supporting a glass substrate, it should be understood that other arrangements are possible. For example, in an alternative embodiment, the glass substrate 100 positions the glass substrate on the support such that the end of the glass substrate 100 in contact with the polishing wheel is cantilevered from the end of the support, as shown in FIG. 1. Can be elastically supported. In this arrangement, the glass substrate 100 is designed so that when the polishing wheel is in contact with the surface 102 of the glass substrate 100, the glass substrate 100 is curved, thereby minimizing the depth of initiation defects caused by the polishing wheel. Elastically supported.

The rotary polishing wheel 150 is in contact with the glass substrate 100 to polish the crack initiation defects into the surface 102 of the glass substrate 100 in a manner that reduces the curvature of the glass substrate 100. For example, referring specifically to FIG. 10, in one embodiment, the polishing wheel 150 is rotated about an axis of rotation 154 parallel to the surface 102 of the glass substrate 100. The rotary polishing wheel 150 is then in contact with the surface 102 of the glass substrate 100. Since the polishing wheel 150 is rotated, the main component of the force exerted on the glass substrate 100 by the polishing wheel 150 is in the tangential direction with respect to the polishing wheel, and thus the planar direction of the glass substrate 100 ( Ie, in a direction parallel to the plane of the glass substrate), which reduces curvature in the glass substrate. An auxiliary component of the force exerted on the glass substrate 100 by the polishing wheel 150 is in a direction perpendicular to the glass substrate 100. However, since the glass substrate is elastically supported on the elastic surface 130, the auxiliary component of the force results in the displacement of the glass substrate 100 on the elastic surface, thereby minimizing damage to the glass substrate and grinding wheel Prevent 150 from puncturing the glass substrate.

Referring now to FIG. 11, in another embodiment, the polishing wheel 150 applies a vertical force applied on the glass substrate 100 by the polishing wheel 150 when the polishing wheel 150 is in contact with the glass substrate. Rotated about an axis of rotation 154 that is not parallel to the surface 102 of the glass substrate 100 to minimize it. For example, in one embodiment, the internal angle (ie, the minimum angle) between the axis of rotation 154 of the polishing wheel 150 and the surface 102 of the glass substrate is the glass substrate 100 by the polishing wheel 150. The force exerted on the phase is usually greater than 45 ° and less than 90 ° so that it is parallel to the plane of the glass substrate 100 rather than orthogonal to the plane of the glass substrate 100. More specifically, arrow 160 in FIG. 11 indicates the magnitude of the component of the force exerted on the glass substrate by the polishing wheel 150 in a direction parallel to the plane of the glass substrate 100, while arrow 162 indicates the glass. The magnitude of the component of the force applied on the glass substrate in the direction orthogonal to the plane of the substrate 100 is indicated.

As indicated, rotating the polishing wheel 150 about a rotation axis 154 that is not parallel to the surface 102 of the glass substrate 100, in particular at angles greater than about 45 ° and less than 90 °, results in a glass substrate 100. The main component of the force applied to the phase (i.e., the component having the maximum magnitude) is in the plane of the glass substrate 100 (i.e., the glass substrate) rather than orthogonal to the surface 102 of the glass substrate 100. Parallel to the plane). This minimizes the amount of curvature in the glass substrate 100 due to contact with the rotating polishing wheel 150 when the polishing wheel 150 and the glass substrate 100 are contacted to form a crack initiation defect by polishing. .

In either of the above embodiments, the normal force (ie, the force indicated by arrow 162) exerted by the polishing wheel 150 against the surface 102 of the glass substrate 100 is generally about 0.1 N or greater. And about 24 N or less. In one embodiment, the normal force exerted by the abrasive wheel is at least about 1 N and at most about 10 N.

In some embodiments, the normal force exerted by the polishing wheel 150 on the surface 102 of the glass substrate 100 depends on the mesh of the polishing dimensions of the polishing wheel 150. For example, about 1000 meshes can be used in conjunction with a vertical force of about 0.1 N to about 10 N. However, when the mesh is in the range of at least 400 and at most 600, the normal force exerted by the polishing wheel 150 against the surface 102 of the glass substrate 100 is about 1 N to about 24 N.

The abrasive wheel 150 can be rotated at various rotational speeds to form crack initiation defects. In general, the rotational speed of the polishing wheel 150 may be in the range of about 200 rpm to about 40,000 rpm.

In yet another embodiment, the polishing wheel 150 has a rotation axis 154 that is not parallel to the surface 102 of the glass substrate 100 from an orientation in which the rotation axis 154 is parallel to the surface 102 of the glass substrate. In orientation, the rotation axis 154 is not parallel to the surface 102 of the glass substrate, or the rotation axis 154 is in an orientation parallel to the surface 102 of the glass substrate 100 or the rotation axis 154 is From an orientation that is not parallel to the surface 102 of the glass substrate, the rotation axis 154 is rotated about the rotation axis 154 that changes from an orientation that is not parallel to the surface 102 of the glass substrate 100. The axis of rotation 154 can be changed repeatedly, and the axis of rotation 154 performs the repeated change. By the effect of this change, the contact orientation of the plane of the polishing wheel 150 with respect to the glass substrate 100 and thus the contact position between the polishing wheel and the glass substrate in a direction perpendicular to the rotation axis 154 is changed, and more A wide defect area is created on the surface of the glass substrate. In other words, the direction perpendicular to the plane of the polishing wheel is changed. The abrasive wheel 150 is said to be vibrated.

This vibration can be accomplished in other ways. For example, in alternative embodiments, the polishing wheel 150 may be mounted on the axis in an orientation such that the plane of the polishing wheel 150 is not perpendicular to the axis. As such, without changing the rotation axis 154, the orientation of the plane of the polishing wheel 150 is changed relative to the glass substrate 100, and the contact position between the polishing wheel 150 and the glass substrate 100 is changed. In a direction perpendicular to the axis of rotation (eg, perpendicular to the axis), thereby again creating a wider defect area. In other words, the direction perpendicular to the plane of the polishing wheel is changed. Thus, the vibration is a change in the plane of the polishing wheel 150 relative to the glass substrate 100 when the polishing wheel is rotated.

Referring to FIG. 12, a crack initiation defect 116 formed by the polishing wheel 150 is schematically illustrated. The crack initiation defect 116 does not extend through the thickness of the glass substrate 100. However, the depth of crack initiation defect 116 may depend on the thickness of the glass substrate. For example, in some embodiments, the thickness of the crack initiation defect is 0.1 × T and T is the thickness of the glass substrate 100. The crack initiation defect 116 may have a length of 8 mm or less. For example, in some embodiments, the length of crack initiation defects is at least about 2 mm and at most about 8 mm. In another embodiment, the crack initiation defect has a nominal length of about 5 mm.

Referring now to FIGS. 13A and 13B, crack initiation defects formed using the method described herein may be characterized by penetrating vents in the glass substrate along the separation line requiring the thin glass substrate to separate the plurality of substrates using laser separation techniques. That is, to form and propagate cracks). For example, after a crack initiation defect is formed in the surface 102 of the glass substrate 100 using one of the methods described herein, the laser light source 180 is lasered onto the substrate 102 of the glass substrate 100. It is used to heat the crack initiation defect 116 and the volume of glass surrounding the crack initiation defect 116 by guiding the beam 182 of the light source 180. In the embodiment shown in FIGS. 13A and 13B, the beam 182 of the laser light source 180 beams on the surface 102 of the glass substrate 100 having dimensions large enough to encompass the crack initiation defect 116. Has an area 190. Beam region 190 is located on crack initiation defect 116 to heat the defect.

When the glass substrate 100 has reached the required temperature by laser heating, a cooling jet 186 of cooling fluid, such as water, air or another suitable cooling fluid, is placed on the crack initiation defect 116 by the cooling nozzle 184. Sprayed into. Cooling jet 186 generally forms a cooling region 192 on surface 102 of glass substrate 100 having a size sufficient to encompass crack initiation defect 116. Rapid cooling of the glass surrounding the crack initiation defect 116 causes the crack to originate from the crack initiation defect and propagate through the thickness T of the glass substrate 100. In order to propagate the crack above the required separation line 196 in the crack propagation direction 194, the glass substrate may be moved relative to the beam 182 of the cooling jet 186 and the laser light source 180 in the direction indicated by arrow 188. Alternatively, or alternatively, the cooling jet 186 and the beam region may cause the crack to propagate along the required separation line 196, thereby ultimately separating the thin glass substrate 100 into a plurality of smaller glass substrates. 196 may be traversed over the surface 102 of the glass substrate.

It should now be understood that the methods and apparatus described herein can be used to mechanically form crack initiation defects in thin glass substrates to facilitate laser separation of the glass substrates into a plurality of individual glass substrates. The technique of forming crack initiation defects described herein facilitates the formation of crack initiation defects by a relatively small vertical force applied to the glass substrate so that such techniques in particular have a thickness of less than about 0.2 mm. Uncontrolled cracking or perforation of a glass substrate is prevented when it has. However, it should also be understood that the techniques described herein can also be effectively used to form crack initiation defects in substrates having thicknesses greater than about 0.2 mm.

Thus, non-limiting examples of examples include the following embodiments:

C1. CLAIMS 1. A method of forming a starting defect in a glass substrate to facilitate separating the glass substrate into a plurality of substrates, the method comprising: providing a glass substrate; Directing a flow of carrier fluid with the entrained abrasive material onto the surface of the glass substrate to form an initiation defect in the surface of the glass substrate; Heating an initiation defect by a laser light source; Cooling the initiation defect with a cooling fluid such that cracks are initiated from the initiation defect and extend through the thickness of the glass substrate and propagate across the glass substrate to separate the glass substrate into a plurality of substrates.

C2. The method of C1, wherein the flow of carrier fluid comprises compressed air and the abrasive material has a mesh size of 400 to 600.

C3. For C1 or C2, the starting defect comprises a plurality of starting defects; And a plurality of starting defects are located within the diameter of the contact region of the flow of carrier fluid on the surface of the glass substrate.

C4. The method of C3, wherein the diameter of the contact area is less than about 19 mm (0.75 inch) on the surface of the glass substrate.

C5. CLAIMS 1. A method of forming a starting defect in a glass substrate to facilitate separating the glass substrate into a plurality of substrates, the method comprising: providing a glass substrate; Contacting the surface of the glass substrate with the abrasive fiber comprising the abrasive material; Traversing the abrasive fiber over the surface of the glass substrate such that the abrasive material of the abrasive fiber forms an initiation defect in the surface of the glass substrate.

C6. The method of C5, wherein the abrasive fiber makes point contact with the surface of the glass substrate.

C7. The method of C5, wherein the abrasive fiber makes a linear contact with the surface of the glass substrate.

C8. The method according to any one of C5 to C7, wherein the contact angle between the abrasive fiber and the surface of the glass substrate is 45 degrees or less.

C9. The method of C5, wherein the abrasive fibers are traversed over the surface of the glass substrate by moving the glass substrate relative to the abrasive fiber when the abrasive fiber is in contact with the surface of the glass substrate.

C10. The method of C5, wherein the abrasive fibers are traversed over the surface of the glass fibers by rotating the abrasive fibers about an axis of rotation substantially perpendicular to the long axis of the abrasive fibers.

C11. The method of any of C5 through C10, further comprising elastically supporting the glass substrate when the abrasive fiber is in contact with the surface of the glass substrate.

C12. The method of any of C5 through C11, wherein the glass substrate is elastically supported on the air bearing.

C13. CLAIMS 1. A method of forming a starting defect in a glass substrate to facilitate separating the glass substrate into a plurality of substrates, the method comprising: providing a glass substrate; Elastically supporting the glass substrate in proximity to the rotating polishing wheel; The surface of the glass substrate is brought into contact with the surface of the glass substrate so that the main component of the force applied by the rotating polishing wheel with respect to the glass substrate is parallel to the surface of the glass substrate, thereby minimizing curvature of the glass substrate, Polishing the starting defect in the surface.

C14. The method of C13, wherein the rotation axis of the rotary polishing wheel is parallel to the surface of the glass substrate.

C15. The method of C13, wherein the rotation axis of the rotary polishing wheel is not parallel to the surface of the glass substrate.

C16. The method of C15, wherein the angle between the axis of rotation of the rotating abrasive wheel and the surface of the glass substrate is greater than 45 degrees and less than 90 degrees.

C17. The method according to any one of C13 to C16, wherein the depth of the starting defect is 0.1xT and T is the thickness of the glass substrate.

C18. The method of any one of C13-C17, wherein the force exerted by the rotating polishing wheel on the glass substrate is at least about 0.1 N and at most about 10 N, and the rotating polishing wheel is coated with a material having a mesh of about 1000.

C19. The method of any one of C13-C17, wherein the force exerted by the rotating polishing wheel on the glass substrate is at least about 1 N and at most about 24 N, and the rotating polishing wheel has a material having at least about 400 and at most about 600 meshes. How to be coated.

C20. The method of C13 to C19, wherein the glass substrate is elastically supported on the air bearing.

C21. The method of any of C13-C20, wherein the rotating abrasive wheel is vibrated.

C22. The method of C21, wherein the axis of rotation of the rotary polishing wheel is changed.

C23. The method of C21, wherein the axis of rotation of the rotary polishing wheel does not change.

It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. As such, if the modifications and variations of the various embodiments described herein are within the scope of the appended claims and their equivalents, the present invention is intended to embrace such modifications and variations.

Claims (20)

A method of forming a starting defect in a glass substrate to facilitate separating the glass substrate into a plurality of substrates, the method comprising:
Providing a glass substrate;
Directing a flow of carrier fluid with the entrained abrasive material onto the surface of the glass substrate to form an initiation defect in the surface of the glass substrate;
Heating an initiation defect by a laser light source;
Cooling the initiation defect with a cooling fluid such that cracks are initiated from the initiation defect and extend through the thickness of the glass substrate and propagate across the glass substrate to separate the glass substrate into a plurality of substrates. The method of claim 1, wherein the flow of carrier fluid comprises compressed air and the abrasive material has a mesh size of 400 to 600. 6. The method of claim 1, wherein the initiating defect comprises a plurality of initiating defects;
And a plurality of starting defects are located within the diameter of the contact region of the flow of carrier fluid on the surface of the glass substrate. The method of claim 3, wherein the diameter of the contact area is less than about 19 mm (0.75 inch) on the surface of the glass substrate. A method of forming a starting defect in a glass substrate to facilitate separating the glass substrate into a plurality of substrates, the method comprising:
Providing a glass substrate;
Contacting the surface of the glass substrate with the abrasive fiber comprising the abrasive material;
Traversing the abrasive fiber over the surface of the glass substrate such that the abrasive material of the abrasive fiber forms an initiation defect in the surface of the glass substrate. The method of claim 5, wherein the abrasive fiber makes point contact with the surface of the glass substrate. The method of claim 5, wherein the abrasive fiber makes a linear contact with the surface of the glass substrate. The method of claim 5, wherein the contact angle between the abrasive fiber and the surface of the glass substrate is 45 ° or less. The method of claim 5, wherein the abrasive fibers are traversed over the surface of the glass substrate by moving the glass substrate relative to the abrasive fiber when the abrasive fiber is in contact with the surface of the glass substrate. The method of claim 5, wherein the abrasive fiber is traversed over the surface of the glass fiber by rotating the abrasive fiber about an axis of rotation substantially perpendicular to the long axis of the abrasive fiber. 6. The method of claim 5, further comprising compliantly supporting the glass substrate when the abrasive fiber is in contact with the surface of the glass substrate. The method of claim 5, wherein the glass substrate is elastically supported on the air bearing. A method of forming a starting defect in a glass substrate to facilitate separating the glass substrate into a plurality of substrates, the method comprising:
Providing a glass substrate;
Elastically supporting the glass substrate in proximity to the rotating polishing wheel;
The surface of the glass substrate is brought into contact with the surface of the glass substrate so that the main component of the force applied by the rotating polishing wheel with respect to the glass substrate is parallel to the surface of the glass substrate, thereby minimizing curvature of the glass substrate, Polishing the starting defect in the surface. The method of claim 13, wherein the axis of rotation of the rotary polishing wheel is parallel to the surface of the glass substrate. The method of claim 13, wherein the axis of rotation of the rotary polishing wheel is not parallel to the surface of the glass substrate. The method of claim 15, wherein the angle between the axis of rotation of the rotating abrasive wheel and the surface of the glass substrate is greater than 45 degrees and less than 90 degrees. The method of claim 13, wherein the depth of the starting defect is 0.1 × T and T is the thickness of the glass substrate. The method of claim 13, wherein the force exerted by the rotating polishing wheel on the glass substrate is at least about 0.1 N and at most about 10 N, wherein the rotating polishing wheel is coated with a material having a mesh of about 1000. 14. The method of claim 13, wherein the force exerted by the rotating abrasive wheel on the glass substrate is at least about 1 N and at most about 24 N, wherein the rotating polishing wheel is coated with a material having a mesh of at least about 400 and up to about 600 mesh. . The method of claim 13, wherein the glass substrate is elastically supported on the air bearing.

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