WO2019136051A1

WO2019136051A1 - Methods of processing a substrate

Info

Publication number: WO2019136051A1
Application number: PCT/US2019/012030
Authority: WO
Inventors: Sean Matthew Garner; Ming-Huang Huang; Rajesh Vaddi; Bin Zhu
Original assignee: Corning Incorporated
Priority date: 2018-01-04
Filing date: 2019-01-02
Publication date: 2019-07-11
Also published as: TW201936524A

Abstract

A method is provided for processing a substrate comprising a target layer and a first sacrificial layer defining a first outer major surface of the substrate. The method can comprise forming a via extending through the first sacrificial layer and through at least a portion of the target layer. The via can comprise a via opening comprising a crown dimension at the first outer major surface of the substrate. The method can further comprise reducing a thickness of the first sacrificial layer while increasing the crown dimension by exposing the via and the first sacrificial layer to an etchant.

Description

METHODS OF PROCESSING A SUBSTRATE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Serial No. 62/613481 filed on January 4, 2018, the content of which is relied upon and incorporated herein by reference in its entirety.

BACKGROUND

[0002] Substrates are typically used to support electrical circuit components on a substrate. Such substrates are known to comprise through vias to facilitate electrical connections between the circuit components. It is further known to provide the substrate as a glass substrate and to form the through vias by way of laser drilling through the glass substrate.

SUMMARY

[0003] The following presents a simplified summary of the disclosure to provide a basic understanding of some exemplary aspects described in the detailed description.

[0004] The present disclosure relates generally methods of processing a substrate and, more particularly, to methods of processing a substrate comprising a sacrificial layer and a target layer.

[0005] In accordance with some embodiments, a method of processing a substrate is provided where the substrate can comprise a target layer and a first sacrificial layer defining a first outer major surface of the substrate. The method can comprise forming a via extending through the first sacrificial layer and through at least a portion of the target layer. The via can comprise a via opening comprising a crown dimension at the first outer major surface of the substrate. The method can further comprise reducing a thickness of the first sacrificial layer while increasing the crown dimension, until at least the first sacrificial layer is entirely removed from the target layer, by exposing the via and the first sacrificial layer to an etchant.

[0006] In one embodiment, the via comprises a through via.

[0007] In another embodiment, the substrate can further comprise a second sacrificial layer defining a second outer major surface of the substrate with the target layer disposed between the first sacrificial layer and the second sacrificial layer. In some embodiments, the reducing the thickness of the first sacrificial layer while increasing the crown dimension can further reduce the thickness of the second sacrificial layer, at least until the second sacrificial layer is entirely removed from the target layer, by further exposing the second sacrificial layer to the etchant.

[0008] In another embodiment, the method can further comprise reducing the thickness of the target layer by exposing the target layer to the etchant.

[0009] In another embodiment, the target layer can comprise a material selected from the group consisting of: glass, glass-ceramic, and ceramic, and a first sacrificial layer can comprise at least the material of the target layer.

[0010] In another embodiment, the etch rate of the first sacrificial layer can be less than the etch rate of the target layer.

[0011] In another embodiment, prior to reducing the thickness of the first sacrificial layer, the thickness of the first sacrificial layer can be less than a thickness of the target layer.

[0012] In another embodiment, the method can comprise separating the substrate along a separation path to provide a sheet comprising a portion of the target layer and a portion of the first sacrificial layer. An outer edge of the portion of the target layer can be defined by the separating of the substrate along the separation path, and the outer edge of the portion of the target layer can form a portion of an outermost exposed edge of the sheet.

[0013] In accordance with other embodiments, a method of processing a substrate is provided. The substrate can comprise a target layer comprising a material selected from the group consisting of: glass, glass-ceramic, and ceramic, and a first sacrificial layer can comprise at least the material of the target layer. The first sacrificial layer can define a first outer major surface of the substrate. The method can comprise forming a via extending through the first sacrificial layer and through at least a portion of the target layer. The via can comprise a via opening comprising a crown dimension at the first outer major surface of the substrate. The method can further comprise reducing a thickness of the first sacrificial layer while increasing the crown dimension by exposing the via and the first sacrificial layer to an etchant.

[0014] In one embodiment, the via comprises a through via.

[0015] In another embodiment, the substrate comprises a second sacrificial layer defining a second outer major surface of the substrate with the target layer disposed between the first sacrificial layer and the second sacrificial layer. In some embodiments, the reducing the thickness of the first sacrificial layer while increasing the crown dimension can further reduce the thickness of the second sacrificial layer by further exposing the second sacrificial layer to the etchant.

[0016] In another embodiment, the method can further comprise reducing the thickness of the target layer by exposing the target layer to the etchant.

[0017] In another embodiment, the etch rate of the first sacrificial layer can be less than the etch rate of the target layer.

[0018] In another embodiment, prior to reducing the thickness of the first sacrificial layer, the thickness of the first sacrificial layer can be less than a thickness of the target layer.

[0019] In another embodiment, the method can further comprise separating the substrate along a separation path to provide a sheet comprising a portion of the target layer and a portion of the first sacrificial layer. An outer edge of the portion of the target layer can be defined by the separating of the substrate along the separation path. The outer edge of the portion of the target layer can form a portion of an outermost exposed edge of the sheet.

[0020] In accordance with other embodiments, a method of processing a substrate can comprise separating the substrate along a separation path to provide a sheet comprising a target layer and a first sacrificial layer defining a first outer major surface of the sheet. The outer edge of the target layer can be defined by the separating the substrate along the separation path, and the outer edge of the target layer may form a portion of an outermost exposed edge of the sheet. The method can further comprise forming a via extending through the first sacrificial layer and through at least a portion of the target layer. The via can comprise a via opening comprising a crown dimension at the first outer major surface of the sheet. The method can further comprise reducing a thickness of the first sacrificial layer while increasing the crown dimension by exposing the via and the first sacrificial layer to an etchant.

[0021] In one embodiment, the via can comprise a through via.

[0022] In another embodiment, the sheet can comprise a second sacrificial layer defining a second outer major surface of the sheet with the target layer disposed between the first sacrificial layer and the second sacrificial layer. The method can comprise reducing the thickness of the first sacrificial layer while increasing the crown dimension further reduces the thickness of the second sacrificial layer by further exposing the second sacrificial layer to the etchant.

[0023] In another embodiment, the method can further reduce the thickness of the target layer by exposing the target layer to the etchant.

[0024] In another embodiment, the etch rate of the first sacrificial layer can be less than the etch rate of the target layer.

[0025] In another embodiment, prior to reducing the thickness of the first sacrificial layer, the thickness of the first sacrificial layer can be less than a thickness of the target layer.

[0026] It is to be understood that both the foregoing general description and the following detailed description present embodiments of the present disclosure, and are intended to provide an overview or framework for understanding the nature and character of the embodiments as they are described and claimed. The accompanying drawings are comprised to provide a further understanding of the embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the disclosure, and together with the description serve to explain the principles and operations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] These and other features, aspects and advantages of the present disclosure can be further understood when read with reference to the accompanying drawings:

[0028] FIG. 1 illustrates an exemplary method of producing a substrate comprising a target layer and at least a first sacrificial layer;

[0029] FIG. 2 illustrates another exemplary method of producing a substrate comprising a target layer and at least a first sacrificial layer;

[0030] FIG. 3 illustrates still another exemplary method of producing a substrate comprising a target layer and at least a first sacrificial layer;

[0031] FIG. 4 illustrates a top plan view of edges of a substrate being removed from a central portion of the substrate;

[0032] FIG. 5 illustrates a cross sectional view of the substrate along line 5-5 of FIG. 4 [0033] FIG. 6 illustrates forming an initial via extending through the first sacrificial layer and through at least a portion of the target layer,

[0034] FIG. 7 illustrates the substrate with the initially-formed vias being inserted into an etchant bath.

[0035] FIG. 8 illustrates a portion of the sacrificial layer being removed by the etchant while the etchant increases a diameter of the vias.

[0036] FIG. 9 illustrates the entire portion of the sacrificial layer being removed by etchant while the etchant further increases the diameter of the vias.

DETAILED DESCRIPTION

[0037] Apparatus and methods will now be described more fully hereinafter with reference to the accompanying drawings in which exemplary embodiments are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0038] Methods are provided for processing a substrate are disclosed. FIG. 5 illustrates an embodiment of a substrate 501 that can include a target layer 503. The substrate 501 can further include at least a first sacrificial layer 505 defining a first outer major surface 507 of the substrate 501. In some embodiments, only a single sacrificial layer may be provided although a plurality of sacrificial layers may be provided in further embodiments. For instance, as shown in FIG. 5, the substrate 501 can include a second sacrificial layer 509 defining a second outer major surface 511 of the substrate 501 with the target layer 503 disposed between the first sacrificial layer 505 and the second sacrificial layer 509. In some embodiments, the first sacrificial layer 505 and the second sacrificial layer 509 may comprise the same material although the first sacrificial layer 505 and the second sacrificial layer 509 may comprise different materials in further embodiments. As shown, the first outer major surface 507 and second outer major surface 511 may comprise planar surfaces and/or may face opposite directions. As shown, in some embodiments, the first sacrificial layer 505 and the second sacrificial layer 509 may include a single layer of material. In further embodiments, the first sacrificial layer 505 and/or the second sacrificial layer 509 may comprise multiple layers of materials that can comprise different compositions and/or properties. [0039] The first sacrificial layer 505 and/or the second sacrificial layer 509 can comprise at least a material of the target layer 503. In this case, the sacrificial layer(s) 505, 509 and the target layer 503 may comprise material from the same material family but different in composition and/or etch rates. For example, in some embodiments, the target layer 503 can comprise a material selected from the group consisting of: glass, glass-ceramic, and ceramic. In some embodiments, the target layer 503 can comprise glass such as, without limitation, borosilicate glass, aluminosilicate glass, aluminoborosilicate glass, and soda lime glass. Furthermore, the glass target layer 503 may be strengthened (e.g., by an ion exchange process) or nonstrengthened. Embodiments of target glass layers 503 can include glass that may be alkali free to avoid shorting electrical components supported and electrically connected with one another using the target layer 503. Furthermore, the first sacrificial layer 505 and/or second sacrificial layer 509 can comprise at least the material (e.g., glass, glass-ceramic and/or ceramic) of the target layer 503.

[0040] Substrates 501 can be separated from a sheet or ribbon of material. For instance, a substrate including a target layer and one or more sacrificial layers may be formed with a wide range of techniques such as slot draw, down-draw, fusion down- draw, or up-draw. Of course, glass ribbons may also be formed using other forming processes such as a float process. By way of example, FIG. 1 illustrates a pair of forming wedges wherein a lower forming wedge 101 can fusion down draw a target layer 503 in a draw direction 103 from a root 105 of the lower forming wedge 101. An upper forming wedge 107 can further draw molten material 109 that flows over the outer surfaces of the molten material being drawn off the lower forming wedge 101 to form the first and second sacrificial layers 505, 509 disposed as the outermost layers of the substrate. As illustrated, some embodiments of the upper forming wedge 107 can be provided with a sharp root at the lowermost point of the upper forming wedge 107. In further embodiments, the lowermost point of the upper forming wedge may comprise a flat root. In some embodiments with a flat root, molten material may overflow from the trough of the upper forming wedge, down opposite sidewalls of the upper forming wedge and then straight down off the flat root to meet the molten glass associated with the lower forming wedge 101. As such, once drawn off the root 105 of the lower forming wedge 101, the target layer 503 can be disposed between the first and second sacrificial layers 505, 509. [0041] In another embodiment, FIG. 2 discloses a forming wedge 201 where outer major surfaces 207a, 207b of a sheet 205 of molten material drawn from a root 203 of the forming wedge 201 can be treated to form the first and second sacrificial layers 505, 509. For example, as shown in FIG. 2, devices 209 may apply different reactive species introduced in gaseous stream to the glass sheet that may still be hot from the draw to pyrolytically decompose and react with the glass surfaces to produce chemically adherent first and second sacrificial layers 505, 509 with the target layer 503 disposed between the sacrificial layers 505, 509.

[0042] In still another embodiment, FIG. 3 discloses the forming wedge 201 drawing a ribbon 301 from the root 203. Spray devices 303 can apply a spray coating to the major surfaces 305a, 305b of the ribbon 301 to form the first and second sacrificial layers 505, 509. Other techniques producing the sacrificial layers 505, 509 on the target layer 503 can include chemical vapor deposition, physical vapor deposition, slot die coatings, slip coatings or other layer formation techniques.

[0043] Substrates formed with the exemplary techniques of FIGS. 1-3 can provide sacrificial layers that are integrally formed with the target layer 503 to provide a very strong interface between the target layer 503 and the sacrificial layers 505, 509. In each of the exemplary techniques of FIGS. 1-3, a substrate 501 may be separated by a separation device 111. For example, a scoring device can score the ribbon along a score line. The substrate may be separated upon rotating the substrate about the score line to separate the substrate from the ribbon. In further embodiments, a laser or other technique can be used to separate the substrate 501 from the ribbon along a separation path. Upon separation, as shown in FIG. 1, the substrate can include opposed separated end edges 113a, 113b.

[0044] Furthermore, as shown in FIG. 4, lower quality edge portions 401a, 401b can be removed to provide a high-quality substrate 501 defined between the separated end edges 113a, 113b and the separated side edges 403a, 403b. As shown in FIG. 4, the major surfaces of the substrate 501 can optionally comprise a rectangular area defined by the separated end edges 113a, 113b that are parallel to one another and the separated side edges 403a, 403b that are parallel to one another and perpendicular to the separated end edges 113a, 113b. In some embodiments, the width and/or length of the rectangular area of the substrate 501 shown in FIG. 4 can be from about 100 millimeters (mm) to about 1 meter (m) although the rectangular area can include other dimensions in further embodiments.

[0045] Thus, referring to FIG. 5, separating the substrate 501 along separation paths 525 can provide the target layer 503 with end portions 517, the first sacrificial layer 505 with end portions 513, and the second sacrificial layer 509 with end portions 515 at each separated end edge 113a, 113b, 403a, 403b. Outer edges 519 of the end portions 517 of the target layer 503 at each separated end edge 113a, 113b, 403a, 403b can be defined by the separating of the substrate along the separation path 525. Indeed, as shown, the outer edges 519 of the end portions 517 of the target layer 503 can form an exposed outermost edge of the target layer 503. Furthermore, outer edges 521 of the end portions 513 of the first sacrificial layer 505 at each separated end edge 113a, 113b, 403a, 403b can be defined by the separating of the substrate along the separation path 525. Indeed, as shown, the outer edges 521 of the end portions 513 of the first sacrificial layer 505 can form an exposed outermost edge of the first sacrificial layer 505. Still further, outer edges 523 of the end portions 515 of the second sacrificial layer 509 at each separated end edge 113a, 113b, 403a, 403b can be defined by the separating of the substrate along the separation path 525. Indeed, as shown, the outer edges 523 of the end portions 515 of the second sacrificial layer 509 can form an exposed outermost edge of the second sacrificial layer 509.

[0046] In some embodiments, once separated, the outer edges 519, 521, 523 can comprise substantially planar edges extending between the first outer major surface 507 and the second outer major surface 511 of the substrate 501. For example, each separated end edge 113a, 113b, 403a, 403b can include corresponding coplanar outer edges 519, 521, 523 extending along a separation path 525.

[0047] The substrate 501 can then be further processed to provide the target layer 503 with vias 601 (e.g., blind vias or through vias) and can further provide optional recessed areas or patterns 905 (See FIG. 9) in a major surface of the target layer 503 in further embodiments. For purposes of this disclosure, a“through via” means a hole in the substrate that extends entirely through the entire thickness of the substrate. Furthermore, for purposes of this disclosure, a“blind via” means an opening in the substrate that extends from a major surface of the substrate through a portion of a thickness of the substrate to a depth, but that does not extend all the way through the thickness of the substrate. Blind vias and/or through vias may be useful to allow the target layer 503 to act as a mounting base for electrical circuits and allow electrical circuit connections. For example, the target layer 503 can provide support for electrical components and electrical connection between supported electrical components in a desired electrical circuit configuration. The target layer 503 can be used as a material in multiple electronic applications such as micro-electro- mechanical systems (MEMS), interposers, sensors and displays.

[0048] Methods of processing the substrate 501 can include forming an initial via (e.g., through via, blind via) extending through the first sacrificial layer 505 and through at least a portion of the target layer 503. For instance, FIG. 6 illustrates an initial through via 601 extending entirely through the entire thickness 603 of the substrate 501 from the first outer major surface 507 of the first sacrificial layer 505 to the second outer major surface 511 of the second sacrificial layer 509. The via can be formed with a wide range of techniques. For example, as shown in FIG. 6, a laser device 606 can emit a laser beam 607 to laser drill a via. As shown in FIG. 6, the laser drilling can begin at the first outer major surface 507 of the first sacrificial layer 505. In addition or alternatively, the laser drilling can begin at the second outer major surface 511 of the second sacrificial layer 509. As shown in FIG. 6, the laser drilling can extend through the first sacrificial layer 505 and through at least a portion of the target layer 503. If stopped at the point 608 shown in FIG. 6, the laser drilling can produce a blind via. However, the laser drilling can further proceed to form the through via 601 shown in FIG. 7.

[0049] Various types of lasers may be used to drill vias into the substrate. In one embodiment, a solid state ultraviolet laser (e.g., Nd: YAG laser) emitting a pulsed laser beam having a wavelength of 355 nm may be used although other laser devices may be used in further embodiments. In some embodiments, vias may be formed by mechanical drilling, etching, abrasive blasting, abrasive water jet machining, focused electro -thermal energy or other technique. However, laser drilling techniques may be used to accurately produce very small width vias having a crown dimension 605 (see FIG. 6) of from about 0.1 micrometers (microns) to about 10 microns although other dimensioned vias may be formed in further embodiments.

[0050] FIG. 6 illustrates a plurality of vias 601 being periodically spaced along a row of vias. In further embodiments, the plurality of vias 601 may be arranged in other patterns, such as a matrix of vias 601 across the major surface(s) of the substrate. During drilling, all the vias may be formed simultaneously. Alternatively, a single or a plurality of drilling devices may be moved relative to the substrate in further embodiments. For instance, as shown in FIG. 6 a single laser drilling device 606 may be moved relative to a stationary substrate 501. In further embodiments, the substrate 501 may move while the laser drilling device 606 may remain stationary. In still further embodiments, both the substrate 501 and the laser drilling device 606 may move to provide appropriate drilling of the vias.

[0051] Once formed, the via 601 includes a crown dimension 605 at the first outer major surface 507 of the substrate 501. The crown dimension 605 of the initial via shown in FIG. 6 can be from about 0.1 micrometers (microns) to about 10 microns. In some embodiments, the thickness 609 of the target layer 503 can be from about 0.1 millimeter (mm) to about 1 mm such as from about 0.3 mm to about 0.7 mm although other thicknesses may be provided in further embodiments. Furthermore, the thickness 608a, 608b of each sacrificial layer 505, 509 can be from about 5% to about 50%, such as from about 10% to about 40%, such as from about 15% to about 35%, such as from about 20% to about 30% of the thickness 609 of the target layer 503. In some embodiments, the thickness 608a, 608b can be from about 10 microns to about 100 microns.

[0052] Once the desired number and placement of vias 601 are provided, the method can further include reducing the thickness 608a of the first sacrificial layer 505 and can even further reducing the thickness 608b of the second sacrificial layer 509. For example, as shown in FIG. 7, the substrate 501 may be submerged into a bath of etching solution 701 that can be contained within a containment area of a container 703. In some embodiments, the etching solution 701 can comprise an aqueous solution including deionized water, a primary acid, and a secondary acid. The primary acid may be hydrofluoric acid and the secondary acid may be nitric acid, hydrochloric acid, or sulfuric acid. In some embodiments, the etching solution 701 may include a primary acid other than hydrofluoric acid and/or a secondary acid other than nitric acid, hydrochloric acid, or sulfuric acid. Furthermore, in some embodiments, the etching solution 701 may include a primary acid. In some embodiments, the etching solution 701 may include 5% by volume of a primary acid (e.g., hydrofluoric acid), 10% by volume of a secondary acid (e.g., nitric acid), and 85% by volume of deionized water. In other embodiments, the etching solution 701 may include different proportions of the primary acid, the secondary acid, and deionized water. In some embodiments, the etching solution 701 may further include a surfactant.

[0053] FIG. 7 illustrates the substrate 501 of FIG. 6 being submerged in the bath of etching solution 701 prior to the etchant solution reducing the thickness of the sacrificial layers. As shown in FIGS. 6 and 7, prior to reducing the thickness 608a, 608b of the sacrificial layers 505, 509, the thickness 608a, 608b may be less than the thickness 609 of the target layer 503. Furthermore, the etch rate of the first sacrificial layer 505 and the etch rate of the second sacrificial layer 509 can each be less than the etch rate of the target layer 503. In some embodiments, the etch rate of the sacrificial layers 505, 509 can be from about 5% to about 50%, such as from about 10% to about 40%, such as from about 15% to about 35%, such as from about 20% to about 30% of the etch rate of the target layer 503. As such, in embodiments where the sacrificial layers are to be completely removed, a reduced amount of sacrificial layer material may be required to be etched away to completely remove the sacrificial layers 505, 509 from the target layer 503. Furthermore, the reduced thickness of the sacrificial layers 505, 509 can reduce the level of difficulty of forming the initial vias (e.g., by laser processing as shown in FIG. 6).

[0054] As shown in FIG. 8, after the substrate 501 has been submerged in the bath of etching solution 701 for a period of time, the thickness 608a of the first sacrificial layer and the thickness 608b of the second sacrificial layer 509 can be reduced while increasing the crown dimension 605. In some embodiments, as shown in FIG. 9, the thickness of the first and second sacrificial layer can be further reduced until each sacrificial layer is entirely removed from the target layer although a thickness or portions of the sacrificial layer may remain in further embodiments. At the same time, the process can be designed so that the crown dimension 605 may be further enlarged until it reaches the target enlarged final crown dimension 605 (e.g., shown in FIG. 9) at the time or shortly after the first and second sacrificial layers 505, 509 are removed. In some embodiments, the final crown dimension 605 of the via 601 can be from about 10 micrometers (microns) to about 100 microns although the final via can be provided with other dimensions in further embodiments.

[0055] The etchant time can be reduced in some embodiments by agitating the etchant, applying ultrasonic energy to the etchant bath, and/or controlling the temperature of the etchant bath. As such, in some embodiments, the same result can be achieved in a shorter period of time, thereby increasing processing efficiency.

[0056] The sacrificial layers can provide a wide range of benefits. For instance, in some embodiments, providing the initial vias shown in FIG. 6 (e.g., by laser processing) may provide nonplanar abnormalities (e.g., protrusions, cracks, or other crown defects etc.) at the location where the via opens to the first outer major surface 507 of the first sacrificial layer 505 and/or the second outer major surface 511 of the second sacrificial layer 509. Such undesired surface features around the initial via can be from about 0.5 micrometers (microns) to about 1 micron and may interfere with the planarity and/or geometry of features incorporated into the target layer 503 during subsequent processing of the target layer 503. Furthermore, inner surfaces of the holes themselves may have surface imperfections resulting from the initial formation of the vias. However, as shown in FIGS. 8 and 9, the process of etching the substrate 501 with the etchant bath can remove imperfections formed at the outer major surfaces 507, 511 and/or within the bores of the initially formed vias since inner surfaces of the vias and the outer surface portions of the sacrificial layers are removed during the process of etching the substrate 501. Furthermore, material from the target layer 503 due to etching while the vias are enlarged are not redeposited on the target layer 503 since the sacrificial layer acts as a shield to prevent redepositing. As such, redeposited material is avoided that may otherwise interrupt the planarity of the target layer 503 once processing of the vias is complete.

[0057] Furthermore, in some embodiments, achieving the desired final crown dimension 605 (see FIG. 9) during the process of etching can also achieve complete removal of the sacrificial layers 505, 509 at the same time to expose the pristine major surfaces 901, 903 of the target layer 503 shown in FIG. 9. The average surface roughness along the pristine major surfaces 901, 903, even around the via openings, can be from about 0.2 nanometers (nm) to 1 nm, such as from about 0.5 nm to 1 nm. The average surface roughness may be determined over an area and can be measured with an AFM scanner. As such, once enlarging the final crown dimension is complete, additional processing steps are not required to remove the sacrificial layers since the sacrificial layers are removed when the final crown dimension is achieved. Furthermore, in some embodiments, undercutting between the sacrificial layers and the target layers can be reduced since the sacrificial layers can be formed integrally with the target layer 503 due to the processing techniques (e.g., shown in FIGS. 1-3) and/or since the sacrificial layers can at least a material of the target layer such as a material selected from the group consisting of glass, glass-ceramic, and ceramic. Still further, the sacrificial layers allow maintenance of a significant portion (95%-l00%) of the thickness 609 of the target layer 503 while the vias 601 are enlarged due to etching as shown in FIGS. 8-9.

[0058] In still further embodiments, the thickness of the target layer 503 may be reduced by exposing the target layer to the etchant. For instance, in some embodiments the thickness of the target layer 503 may be reduced (e.g., less than 5%) to allow further widening of the via while also ensuring that the sacrificial layers are entirely removed. Furthermore, features or patterns may be etched into one or both of the major surface 901, 903 of the target layer 503. For instance, as shown in FIG. 6, a pattern 611 may be machined (e.g., with the laser or other device) into the major surface of the sacrificial layer. As shown in FIG. 8, eventually the pattern exposes a portion of the major surface corresponding to the pattern to the etchant before the sacrificial layers have been removed. As such, the pattern 905 can be etched into the major surface of the target layer 503 after the sacrificial layers are removed. The pattern 905 can provide for electrical traces between components, reception areas for portions of components, or other functionality to the target layer 503.

[0059] It will be appreciated that the various disclosed embodiments may involve particular features, elements or steps that are described in connection with that particular embodiment. It will also be appreciated that a particular feature, element or step, although described in relation to one particular embodiment, may be interchanged or combined with alternate embodiments in various non-illustrated combinations or permutations.

[0060] It is also to be understood that, as used herein the terms“the,”“a,” or “an,” mean“at least one,” and should not be limited to“only one” unless explicitly indicated to the contrary. Likewise, a“plurality” is intended to denote“more than one.”

[0061] Ranges can be expressed herein as from“about” one particular value, and/or to“about” another particular value. When such a range is expressed, examples comprise from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent“about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0062] The terms“substantial,”“substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description.

[0063] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

[0064] While various features, elements or steps of particular embodiments may be disclosed using the transitional phrase“comprising,” it is to be understood that alternative embodiments, comprising those that may be described using the transitional phrases“consisting” or“consisting essentially of,” are implied. Thus, for example, implied alternative embodiments to an apparatus that comprises A+B+C comprise embodiments where an apparatus consists of A+B+C and embodiments where an apparatus consists essentially of A+B+C.

[0065] It will be apparent to those skilled in the art that various modifications and variations can be made to the present disclosure without departing from the spirit and scope of the appended claims. Thus, it is intended that the present disclosure cover the modifications and variations of the embodiments herein provided they come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A method of processing a substrate comprising a target layer and a first sacrificial layer defining a first outer major surface of the substrate, the method comprising:

forming a via extending through the first sacrificial layer and through at least a portion of the target layer, the via comprising a via opening comprising a crown dimension at the first outer major surface of the substrate; and

reducing a thickness of the first sacrificial layer while increasing the crown dimension, until at least the first sacrificial layer is entirely removed from the target layer, by exposing the via and the first sacrificial layer to an etchant.

2. The method of claim 1, wherein the via comprises a through via.

3. The method of any one of claims 1 and 2, wherein the substrate comprises a second sacrificial layer defining a second outer major surface of the substrate with the target layer disposed between the first sacrificial layer and the second sacrificial layer, wherein the reducing the thickness of the first sacrificial layer while increasing the crown dimension further reduces the thickness of the second sacrificial layer, at least until the second sacrificial layer is entirely removed from the target layer, by further exposing the second sacrificial layer to the etchant.

4. The method of any one of claims 1-3, further comprising reducing the thickness of the target layer by exposing the target layer to the etchant.

5. The method of any one of claims 1-4, wherein the target layer comprises a material selected from the group consisting of: glass, glass-ceramic, and ceramic, and a first sacrificial layer comprises at least the material of the target layer.

6. The method of any one of claims 1-5, wherein the etch rate of the first sacrificial layer is less than the etch rate of the target layer.

7. The method of any one of claims 1-6, wherein prior to reducing the thickness of the first sacrificial layer, the thickness of the first sacrificial layer is less than a thickness of the target layer.

8. The method of any one of claims 1-7, further comprising separating the substrate along a separation path to provide a sheet comprising a portion of the target layer and a portion of the first sacrificial layer, wherein an outer edge of the portion of the target layer is defined by the separating of the substrate along the separation path, and the outer edge of the portion of the target layer forms a portion of an outermost exposed edge of the sheet.

9. A method of processing a substrate comprising a target layer comprising a material selected from the group consisting of: glass, glass-ceramic, and ceramic, and a first sacrificial layer comprising at least the material of the target layer and the first sacrificial layer defining a first outer major surface of the substrate, the method comprising:

reducing a thickness of the first sacrificial layer while increasing the crown dimension by exposing the via and the first sacrificial layer to an etchant.

10. The method of claim 9, wherein the via comprises a through via.

11. The method of any one of claims 9 and 10, wherein the substrate comprises a second sacrificial layer defining a second outer major surface of the substrate with the target layer disposed between the first sacrificial layer and the second sacrificial layer, wherein the reducing the thickness of the first sacrificial layer while increasing the crown dimension further reduces the thickness of the second sacrificial layer by further exposing the second sacrificial layer to the etchant.

12. The method of any one of claims 9-11, further comprising reducing the thickness of the target layer by exposing the target layer to the etchant.

13. The method of any one of claims 9-12, wherein the etch rate of the first sacrificial layer is less than the etch rate of the target layer.

14. The method of any one of claims 9-13, wherein prior to reducing the thickness of the first sacrificial layer, the thickness of the first sacrificial layer is less than a thickness of the target layer.

15. The method of any one of claims 9-14, further comprising separating the substrate along a separation path to provide a sheet comprising a portion of the target layer and a portion of the first sacrificial layer, wherein an outer edge of the portion of the target layer is defined by the separating of the substrate along the separation path, and the outer edge of the portion of the target layer forms a portion of an outermost exposed edge of the sheet.

16. A method of processing a substrate comprising:

separating the substrate along a separation path to provide a sheet comprising a target layer and a first sacrificial layer defining a first outer major surface of the sheet, wherein an outer edge of the target layer is defined by the separating the substrate along the separation path, and the outer edge of the target layer forms a portion of an outermost exposed edge of the sheet;

forming a via extending through the first sacrificial layer and through at least a portion of the target layer, the via comprising a via opening comprising a crown dimension at the first outer major surface of the sheet; and

17. The method of claim 16, wherein the via comprises a through via.

18. The method of any one of claims 16 and 17, wherein the sheet comprises a second sacrificial layer defining a second outer major surface of the sheet with the target layer disposed between the first sacrificial layer and the second sacrificial layer, wherein the reducing the thickness of the first sacrificial layer while increasing the crown dimension further reduces the thickness of the second sacrificial layer by further exposing the second sacrificial layer to the etchant.

19. The method of any one of claims 16-18, further comprising reducing the thickness of the target layer by exposing the target layer to the etchant.

20. The method of any one of claims 16-19, wherein the etch rate of the first sacrificial layer is less than the etch rate of the target layer.

21. The method of any one of claims 16-20, wherein prior to reducing the thickness of the first sacrificial layer, the thickness of the first sacrificial layer is less than a thickness of the target layer.