This description pertains to glass surfaces and articles having through vias with new geometries and/or improved adhesion to copper.
3D interposers with through package via (TPV) interconnects that connect the logic device on one side and memory on the other side is an important technology for high bandwidth devices. Glass and glass ceramic substrates with vias are desirable for many applications, including for use as in interposers used as an electrical interface, RF filters, and RF switches. The current substrates of choice are polymer or silicon. Polymer interposers suffer from poor dimensional stability while silicon wafers are expensive and suffer from high dielectric loss due to semiconducting properties. There is a trend, therefore, toward use of glass as a superior substrate material due to its low dielectric constant, thermal stability, and low cost. Current challenges to make glass through vias are long process times and limited aspect ratio of vias. Glass through vias can be fully or conformally filled by conducting metals such as copper to provide an electrical pathway. The chemical inertness and low intrinsic roughness of glass, however, pose a problem related to adhesion of the copper with the glass wall inside the vias. Lack of adhesion between copper and glass could lead to reliability issues such as cracking, delamination and low pull-out strength.
Accordingly, a need exists for a TGV structure with a conducting metal that has improved reliability. A need also exists for manufacturing glass substrates with through vias in an efficient manner with a higher degree of control of via geometry and aspect ratios.
Corning has developed through glass vias (TGV) processing technology to create either through or blind vias in glass substrates. This technology can produce TGV in laminate glasses composed of fast-etching clad and slow-etching core and laminate glasses composed of slow-etching clad and fast-etching core. The present disclosure provides methods of making glass through vias from laminate glass substrate in a shortened time compared to single glass compositions, wherein the glass vias have unique and improved shapes. The present disclosure provides methods of making glass through vias that have geometries that keep metal filling secure within the through vias.
In a 1st aspect, a method comprises forming a pilot hole or damage track through a laminate glass structure using a laser. The laminate glass structure comprising a first layer and a second layer adjacent to the first layer. The first layer is formed from a first glass composition. The second layer is formed from a second glass composition different from the first glass composition. After forming the pilot hole, the laminate glass structure is exposed to etching conditions that etch the first glass composition at a first etching rate and the second glass composition at a second etching rate, wherein the first etch rate is different from the second etch rate, to form an etched hole.
In a 2nd aspect, for the method of the 1st aspect, the glass laminate structure further comprises a third layer adjacent to the second layer opposite the first layer. The third layer is formed from a third glass composition different from the second glass composition. The third glass composition has a third etch rate when exposed to the etching conditions. The third etch rate is different from the second etch rate.
In a 3rd aspect, for the method of the 2nd aspect, the third glass composition is the same as the first glass composition, and the first etch rate is the same as the third etch rate.
In a 4th aspect, for the method of the 2nd aspect, the third glass composition is different from the first glass composition, and the third etch rate is different from the first etch rate.
In a 5th aspect, for the method of the 2nd aspect, the glass laminate structure further comprises a fourth layer adjacent to the third layer opposite the second layer; the fourth layer is formed from a fourth glass composition different from the third glass composition; the fourth glass composition has a fourth etch rate when exposed to the etching conditions; the fourth etch rate is different from the third etch rate.
In a 6th aspect, for the method of any of the 1st through 5th aspects, the etched hole has a first lateral dimension in the first layer and a second lateral dimension in the second layer, and wherein the first lateral dimension is different from the second lateral dimension.
In a 7th aspect, for the method of the 6th aspect, exposing the laminate glass structure to the etching conditions forms the etched hole which further has a third lateral dimension in the third layer, wherein the third lateral dimension is different from the second lateral dimension.
In an 8th aspect, for the method of the 7th aspect, the third lateral dimension is the same as the first lateral dimension.
In a 9th aspect, for the method of the 7th aspect, the third lateral dimension is different from the first lateral dimension.
In a 10th aspect, for the method of the 7th aspect, exposing the laminate glass structure to the etching conditions forms the etched hole which further has a fourth lateral dimension in the fourth layer, wherein the fourth lateral dimension is different from the third lateral dimension.
In a 11th aspect, for the method of any of the 1st through 10th aspects, the difference between the first etch rate and the second etch rate is 5% or more of the first etch rate.
In a 12th aspect, for the method of the 11th aspect, the difference between the first etch rate and the second etch rate is 10% or more of the first etch rate.
In a 13th aspect, for the method of the 12th aspect, the difference between the first etch rate and the second etch rate is 30% or more of the first etch rate.
In a 14th aspect, for the method of any of the 1st through 13th aspects, the first etch rate is greater than the second etch rate.
In a 15th aspect, for the method of the 14th aspect, the etched hole has a morphology comprising an hourglass shape.
In a 16th aspect, for the method of any of the 1st through 13th aspects, the first etch rate is less than the second etch rate.
In a 17th aspect, for the method of the 16th aspect, the etched hole has a morphology comprising a cylindrical shape or a shape where the lateral dimension of the first and third layer are smaller than the lateral dimension of the second layer.
In an 18th aspect, for the method of the 16th aspect, the first layer has an outer surface and the third layer has an outer surface; and the first etch rate is less than the second etch rate.
In a 19th aspect, for the method of the 18th aspect, a mask is formed on the outer surface of the first layer and/or the outer surface of the third layer prior to exposing the laminate glass structure to etching conditions.
In a 20th aspect, for the method of the 19th aspect, the mask forming covers the outer surfaces with a physical masking.
In a 21st aspect, for the method of the 20th aspect, the physical masking is an acid resistant material.
In a 22nd aspect, for the method of the 21st aspect, the acid resistant material is an acid resistant laminate coating.
In a 23rd aspect, for the method of the 22nd aspect, the acid resistant laminate coating is acid resistant tape.
In a 24th aspect, for the method of the 21st aspect, the acid resistant material is an acid resistant deposited coating.
In a 25th aspect, for the method of the 24th aspect, the acid resistant deposited coating is chromium oxi-nitride.
In a 26th aspect, for the method of the 20th aspect, the physical masking has a plurality of holes.
In a 27th aspect, for the method of the 26th aspect, the mask material is printed or deposited over the outer surfaces.
In a 28th aspect, for the method of the 6th aspect, the difference between the first lateral dimension and the second lateral dimension is 5% or more of the first lateral dimension.
In a 29th aspect, for the method of the 28th aspect, the difference between the first lateral dimension and the second lateral dimension is 10% or more of the first lateral dimension.
In an 30th aspect, for the method of any of the 28th through 29th aspects, the first lateral dimension is greater than the second lateral dimension.
In a 31st aspect, for the method of any of the 28th through 29th aspects, the first lateral dimension is less than the second lateral dimension.
In a 32nd aspect, for the method of any of the 1st through 32nd aspects, the method further comprises filling the etched hole with a conductive material.
In a 33rd aspect, for the method of any of the 1st through 32nd aspects, the laminate glass structure is fusion drawn.
In a 34th aspect, for the method of any of the 1st through 33rd aspects, the method further comprises forming the damage track through the laminate glass structure using the laser.
In a 35th aspect, for the method of any of the 1st through 34th aspects, at least one layer in the laminate glass structure is formed from a glass composition that is not photo-machinable.
In a 36th aspect, for the method of the 35th aspect, each layer in the laminate glass structure is formed from a glass composition that is not photo-machinable.
In a 37th aspect, a device comprises: a laminate glass structure comprising: a first layer; a second layer adjacent to the first layer; a third layer adjacent to the second layer opposite the first layer; wherein: the first layer is formed from a first glass composition; the second layer is formed from a second glass composition different from the first glass composition; the third layer is formed from the first glass composition; and a hole through the laminate glass structure has a first lateral dimension in the first layer, a second lateral dimension in the second layer, and a third lateral dimension in the third layer.
In a 38th aspect, for the device of the 37th aspect, the first lateral dimension is at least 5% or more smaller than the second lateral dimension, and the third lateral dimension is at least 5% or more smaller than the second lateral dimension.
In a 39th aspect, for the device of the 37th aspect, the second lateral dimension is at least 5% or more greater of the first lateral dimension and the second lateral dimension is at least 5% or more greater of the third lateral dimension.
In a 40th aspect, for the device of the 38th through 39th aspect, the hole has a morphology comprising a shape where the lateral dimension of the first and third layer are smaller than the lateral dimension of the second layer.
In a 41st aspect, for the device of the 37th aspect, the first lateral dimension is at least 5% or more greater than the second lateral dimension, and the third lateral dimension is at least 5% or more greater than the second lateral dimension.
In a 42nd aspect, for the device of the 37th aspect, wherein the second lateral dimension is at least 5% or more smaller of the first lateral dimension and the second lateral dimension is at least 5% or more smaller of the third lateral dimension.
In a 43rd aspect, for the device of the 41st through 42nd aspect, the hole has a morphology comprising an hourglass shape.
In a 44th aspect, for the device of the 37th aspect, the first lateral dimension is about equal to the second lateral dimension, and the third lateral dimension is about equal to the second lateral dimension.
In a 45th aspect, for the device of the 37th aspect, the second lateral dimension is about equal to the first lateral dimension and the second lateral dimension is about equal to the third lateral dimension.
In a 46th aspect, for the device of the 44th through 45th aspect, the hole has a morphology comprising a cylindrical shape.
In a 47th aspect, for the device of the 37th through 46th aspect, the hole is an etched hole.
In a 48th aspect, for the device of any of the 32nd through 47h aspects, the hole is filled with a conductive material.
In a 49th aspect, for the device of any of the 32nd through 48th aspects, at least one layer in the laminate glass structure is formed from a glass composition that is not photo-machinable.
In a 50th aspect, for the device of the 32nd through 48th aspect, the first glass composition and the second glass composition are not photo-machinable.
Vias in glass (including glass-ceramic) substrates (or glass laminate structures) typically need to be fully or conformally filled by conducting metals such as copper to provide an electrical pathway. Copper is a particularly desirable conducting metal. In some embodiments, copper is deposited using electroless deposition, or electroless deposition followed by electroplating. Electroless deposition often involves the use of a catalyst, such as Pd. For this type of electroless deposition of copper onto glass, the copper typically does not form a chemical bond to the glass, and instead relies on mechanical interlocking and/or surface roughness for adhesion. More generally, conductive metals such as copper often do not adhere well to glass due to the chemical inertness and low intrinsic roughness of glass materials.
This lack of adhesion can lead to low pull-out strength, and failure mechanisms such as copper falling out of the via hole, or copper pistoning due to differential CTE when a substrate with copper vias is thermally cycled. Described herein are approaches to mitigate some of the issues caused by this lack of adhesion.
Described herein are methods to make TGV using laminate glasses. One method combines a core material with a high etch rate and a clad material with a low etch rate. This design allows this product to have a durable skin layer which can be resistant to chemical (weathering) and mechanical attack to survive in manufacturing processes and extend product lifetime, and in the meanwhile, the less durable core materials enables a much faster etch rate and can significantly shorten process time. In addition, due to the contrasting etch rates between core and clad layers, higher aspect ratio vias can be formed in laminate glasses when compared to similar composition single component glasses.
Another method combines a core material with a low etch rate and a clad material with a high etch rate. This method employs a physical patterned mask that is applied to a less durable cladding layer. The physical mask will allow protection of the cladding layer while in patterned areas diffusion through the thickness of the laminate structure can occur. A physical mask can be utilized when forming TGV in laminates having a cladding glass that is less durable than the core glass. Additionally, this method of masking allows pockets to be formed around or near the TGV. The physical masking can be an acid resistant material in the form of a laminate such as a film or tape. Acid resistant materials should be made of a material does not chemically react with acid including HCl, HNO3, dilute H2SO4, and HF, and does not physically change in response to slight temperature and environmental change. Tapes and films can suitably be an organic polymeric materialthat is resistant to acid, such as polyethylene (PE), polypropylene (PP), polystyrene, polybutylene succinate (PBS), or polytetrafluoroethylene (PTFE). Polymers containing ester (—COOC—), amide (—NH—CO—), imide (—N═CO—) bonds are reactive (decompose) in acid and may not suitable as acid resistant masks. Based on the CTE mismatch between glass and polymer (acid resistant) materials, increased temperature can introduce tension between glass and the mask and leads to the delamination of the physical mask. Laminate polymeric acid resistant materials can be employed in the form of a film, or tape. The physical masking can be an acid resistant acid resistant deposited coating. Examples of deposited coatings include chromium oxi-nitride (CrON) tantalum, nickle (alloys) and silicone. Alternatively, a deposited coating can be a polymeric coating as described above, where the coating is deposited as an ink via an ink printer or screen printer. The physical mask will undergo removal or delamination at the temperature outside of acid etching (working) temperature range and will be removed after the etching is done.
The product produced from these methods consists of laminate glass containing TGV. The TGV can consist of different morphologies, including cylinder and hourglass. The TGV can have top and bottom diameters smaller than the waist diameter. The glass product can have protective cladding remaining, or be of a single composition if all cladding is removed during etch.
As used herein, term “liquidus temperature” refers to the highest temperature at which devitrification occurs in the glass composition.
As used herein, the term “CTE” refers to the coefficient of thermal expansion of the glass composition averaged over a temperature range from about 20° C. to about 300° C.
The term “substantially free,” when used to describe the absence of a particular oxide component in a glass composition, means that the component is present in the glass composition in an amount less than 1 mol. %.
As used herein, the term “glass laminate structure” refers to a specific type of glass substrate that has multiple distinct layers fused together, for example by a fusion draw process.
Where a range of numerical values is recited herein, comprising upper and lower values, unless otherwise stated in specific circumstances, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the claims be limited to the specific values recited when defining a range. Further, when an amount, concentration, or other value or parameter is given as a range, one or more preferred ranges or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether such pairs are separately disclosed. Finally, when the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. Whether or not a numerical value or end-point of a range recites “about,” the numerical value or end-point of a range is intended to include two embodiments: one modified by “about,” and one not modified by “about.”
As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art.
The term “or,” as used herein, is inclusive; more specifically, the phrase “A or B” means “A, B, or both A and B.” Exclusive “or” is designated herein by terms such as “either A or B” and “one of A or B,” for example.
The indefinite articles “a” and “an” to describe an element or component means that one or at least one of these elements or components is present. Although these articles are conventionally employed to signify that the modified noun is a singular noun, as used herein the articles “a” and “an” also include the plural, unless otherwise stated in specific instances. Similarly, the definite article “the,” as used herein, also signifies that the modified noun may be singular or plural, again unless otherwise stated in specific instances.
For glass compositions described herein as components of glass structures, the concentration of constituent components (e.g., SiO2, Al2O3, Na2O and the like) of the glass compositions are given in mole percent (mol. %) on an oxide basis, unless otherwise specified. Glass compositions disclosed herein have a liquidus viscosity which renders them suitable for use in a fusion draw process and, in particular, for use as a glass cladding composition or a glass core composition in a fusion laminate process. As used herein, unless noted otherwise, the terms “glass” and “glass composition” encompass both glass materials and glass-ceramic materials, as both classes of materials are commonly understood. Likewise, the term “glass structure” should be understood to encompass structures containing glasses, glass ceramics, or both.
In some embodiments, the properties of a laminate glass structure are exploited to control the shape of an etched hole through the laminate glass structure. A “laminate glass structure” refers to a structure having two or more sheets of glass laminated together to form a stack. One method to fabricate a laminate glass structure is now described. Any suitable method may be used.
In some embodiments, the cladding layers 104a, 104b of the glass structures 100 described herein may be formed from a first glass composition having an average cladding coefficient of thermal expansion CTEd a d, and the core layer 102 may be formed from a second, different glass composition which has an average coefficient of thermal expansion CTEcore. In some embodiments, the glass compositions of the cladding layers 104a, 104b may have liquidus viscosities of at least 20 kPoise. In some embodiments, the glass compositions of the core layer 102 and the cladding layers 104a, 104b may have liquidus viscosities of less than 250 kPoise.
Specifically, the glass structure 100 according to some embodiments herein may be formed by a fusion lamination process such as the process described in U.S. Pat. No. 4,214,886, which is incorporated herein by reference. Referring to
As the molten glass core composition 208 fills the trough 212, it overflows the trough 212 and flows over the outer forming surfaces 216, 218 of the lower isopipe 204. The outer forming surfaces 216, 218 of the lower isopipe 204 converge at a root 220. Accordingly, the molten core composition 208 flowing over the outer forming surfaces 216, 218 rejoins at the root 220 of the lower isopipe 204, thereby forming a core layer 102 of a laminated glass structure.
Simultaneously, the molten composition 206 overflows the trough 210 formed in the upper isopipe 202 and flows over outer forming surfaces 222, 224 of the upper isopipe 202. The molten composition 206 has a lower liquidus viscosity requirement to be run on the upper isopipe 202, and will have a CTE either equal to or less than the glass core composition 208 when present as a glass. The molten cladding composition 206 is outwardly deflected by the upper isopipe 202 such that the molten cladding composition 206 flows around the lower isopipe 204 and contacts the molten core composition 208 flowing over the outer forming surfaces 216, 218 of the lower isopipe, fusing to the molten core composition and forming cladding layers 104a, 104b around the core layer 102.
In the laminated sheet so formed, the clad thickness may be significantly thinner than the core thickness so that the clad goes into compression and the core into tension. But because the CTE difference is low, the magnitude of the tensile stress in the core will be very low (for example, on the order of 10 MPa or lower) which will allow for the production of a laminated sheet that will be relatively easy to cut off the draw due to its low levels of core tension. Sheets can thus be cut from the laminate structure that is drawn from the fusion draw apparatus. After the sheets are cut, the cut product can then be subjected to a suitable UV light treatment(s), as will be described below in the context of methods for machining the glass structure 100.
As illustrative embodiments, the processes for forming glass structures by fusion lamination described herein with reference to
The different layers of a laminate glass structure may be formed of different glass compositions having different etch rates. The compositions shown in Table 1 are all suitable for use in the fusion drawing process described herein. Further, the compositions shown in Table 1 can be used as the clad layer or the core layer. For example, they have Tg and viscosity profiles suitable for fusion draw processes.
None of the compositions shown in Table 1 are photo-machinable. So, processes that rely on a glass being photo-machinable to form complex shapes will be inapplicable to these glass compositions.
The glass compositions of Table 1 may be mixed and matched in a wide variety of combinations of layers, to form a glass laminate structure with desired differential etch rates in various layers.
In some embodiments, complex via shapes may be formed using a simple process involving a single laser damage (or drill) and etch process.
In some embodiments, a high energy laser pulse or pulses may be applied to create damage regions through the substrate. Damage regions allows etchant to flow therein during downstream etching processes. In some embodiments, damage regions may be a line of laser-induced damage formed by a pulsed laser. The pulsed laser may form the damage line by non-linear multi-photon absorption, for example. When subsequently etched, the damage region allows etchant to penetrate the substrate. And, the rate of material removal within such a damage region 120 is faster than the rate of material removal outside damage region. Exemplary ways for performing the laser damage creation and subsequent etching are disclosed in U.S. Pat. No. 9,278,886, US Pub. No. 2015/0166393, U.S. Pub. No. 2015/0166395, and U.S. Application 62/633,835, “Alkali-Free Borosilicate Glasses with Low Post-HF Etch Roughness,” filed Feb. 22, 2018, each of which is hereby incorporated by reference in its entirety. In some embodiments, a laser may be used to form an ablated hole instead of damage regions, and the ablated hole may be widened by etching. Any suitable method of forming a pilot hole or damage region through the laminate glass structure may be used.
Damage regions or holes can be etched to form vias. Etching processes may include submerging the glass article in an etchant bath. Additionally, or alternatively, etchant may be sprayed onto the glass article. The etchant may remove material of the substrate to enlarge damage regions or holes. Any suitable etchants and etching methods may be utilized. Non-limiting examples of etchants include strong mineral acids such as nitric acid, hydrochloric acid, acylic acid or phosphoric acid; fluorine containing etchants such as hydrofluoric acid, ammonium bifluoride, sodium fluoride, and the like; and mixtures thereof. In some embodiments, the etchant is hydrofluoric acid.
A glass surface that has been etched has distinctive structural characteristics, and one of skill in the art can tell from inspecting a glass surface whether that surface has been etched. Etching often changes the surface roughness of the glass. So, if one knows the source of the glass and the roughness of that source, a measurement of surface roughness can be used to determine whether the glass has been etched. In addition, etching generally results in differential removal of different materials in the glass. This differential removal can be detected by techniques such as electron probe microanalysis (EPMA).
In some embodiments, the diameter of the hole changes as a function of axial position. For example, the diameter of hole 522 in
In some embodiments, the minimum diameter as a percentage of the maximum diameter may be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 90%, 99% or any range having any two of these values as endpoints, including endpoints. In some embodiments, the minimum diameter is 50% to 100% of the maximum diameter.
The hole may have any suitable axial length. The axial length of a hole corresponds to the thickness of the substrate near the hole. As non-limiting examples, the thicknesses of the substrate (and axial hole length) may be 10 μm, 60 μm, 120 μm, 180 μm, 240 μm, 300 μm, 360 μm, 420 μm, 480 μm, 540 μm, 600 μm, 720 μm, 840 μm, 960 μm, 1080 μm, 1500 μm, 2000 μm, or any range having any two of these values as endpoints, including endpoints. In some embodiments, the thickness of the substrate and the axial hole length is 10 μm to 2000 μm, or 240 μm to 360 μm, or 600 μm to 1500 μm.
The layers of glass within the substrate may have any suitable thickness. Each layer within a substrate may have the same thickness. Or, some layers may have a thickness different from the others. As non-limiting examples, the thicknesses of individual layers may be 0.1 μm, 1 μm, 5 μm, 10 μm, 60 μm, 120 μm, 180 μm, 240 μm, 300 μm, 360 μm, 420 μm, 480 μm, 540 μm, 600 μm, 720 μm, 840 μm, 960 μm, 1080 μm, or 1500 μm, or any range having any two of these values as endpoints, including endpoints. In some embodiments, the outermost layers each have a thickness of 10 μm to 120 μm, and a single inner or core layer has a thickness of 480 μm to 840 μm.
Via 110 may have any suitable minimum diameter and maximum diameter. As non-limiting examples, these diameters may be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, or any range having any two of these values as endpoints, including endpoints. In some embodiments, the maximum via diameter may be 10 μm to 200 μm, or 40 μm to 60 μm. In some embodiments, the maximum via diameter may be 10 μm to 200 μm, or 40 μm to 60 μm.
High aspect ratio vias with a via length of 240 μm to 360 μm and a maximum via diameter of 40 μm to 60 μm are particularly desirable for certain applications at the present time. “Aspect ratio” as used herein refers to the ratio of the via length to the maximum via diameter.
Via 110 may have any suitable aspect ratio. As non-limiting examples, the aspect ratio may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 40 or any range having any two of these values as endpoints, including endpoints. In some embodiments, the aspect ratio may be 4 to 8, 12 to 20, or 14 to 18.
In some embodiments, such as those described in the examples of
It is expected that the desirable dimensions will change in the future, and that the concepts described herein may be used to provide appropriate holes and vias for those dimensions.
Unless otherwise specified, dimensions described herein are measured using: (1) optical microscopy for external features such as substrate thickness and via diameter at the surface of the substrate; and (2) fluorescent confocal microscopy images for internal features, such as via diameter inside the substrate.
After vias are formed, they may optionally coated and/or filled with a conductive material, for example through metallization. The metal or conductive material can be, for example copper, aluminum, gold, silver, lead, tin, indium tin oxide, or a combination or alloy thereof. The process used to metalize the interior of the holes can be, for example, electro-plating, electroless plating, physical vapor deposition, or other evaporative coating methods. The holes may also be coated with catalytic materials, such as platinum, palladium, titanium dioxide, or other materials that facilitate chemical reactions within the holes.
Corning has developed through glass vias (TGV) processing technology to create either through vias in glass substrates. This technology can produce TGV in laminate glasses composed of fast-etching clad and slow-etching core and laminate glasses composed of slow-etching clad and fast-etching core. The present disclosure provides methods of making glass through vias from laminate glass substrate in a shortened time compared to single glass compositions, wherein the glass vias have unique and improved shapes. The TGV forming methods according embodiments discussed herein are capable of forming TGV in laminate glass have the added complexity of having layers of differing etch rates between the core glass and the exterior cladding glass. The method used to create the TGV depends on the chemistries of the two combined glasses used to form the laminate.
The invention to be described is a process by which a TGV is made in a laminate glass structure.
Referring to
Referring to
In some embodiments, the mask 1915 comprises one or more open regions at which the glass substrate 100 remains uncovered. The open regions of the mask 1915 can have a pattern corresponding to the desired pattern of the cavities or wells 1925 to be formed in the glass substrate 100. For example, the pattern of the mask 1915 can be an array of regularly repeating rectangular shapes (e.g., to receive microprocessors/electronic components as described herein). In such embodiments, the shapes patterned by the mask 1915 can correspond closely to the shape of the microprocessors/electronic components. Other shapes also can be used, and the shapes can correspond closely to the shape of the electronic components or be capable of securely holding the electronic components in position on the glass substrate 100. Thus, the mask 1915 can be configured as an etch mask to enable selective etching of the upper glass cladding layer 1905 and/or the lower glass cladding layer 1907 and form the cavities or wells 1925 in the glass substrate 100 as described herein.
In some embodiments, the glass substrate 100 with the mask 1915 disposed thereon is exposed to the etchant 1920. For example, the upper glass cladding layer 1905 and/or the lower glass cladding layer 1907 is contacted with the etchant 1920 as shown in
In some embodiments, the upper glass cladding layer 1905 and/or the lower glass cladding layer 1907 etch at least 1.5 times faster, at least 2 times faster, at least 5 times faster, at least 10 times faster, at least 20 times faster, or at least 100 times faster than the glass central core 110. Additionally, or alternatively, a ratio of the etch rate of the upper glass cladding layer 1905 and/or the lower glass cladding layer 1907 to the etch rate of the glass central core 1910 is about 5, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 95, about 100, or any ranges defined by any combination of the stated values.
This invention takes advantage of the differing chemical compositions between the core material and the cladding material. In one instance the cladding acts as a built in masking/protective layer for the interior core. In another instance (
Specific advantages for making TGV for a laminate glass containing fast-etching core and slow-etching clad include:
1. A durable skin layer allows the glass surface to be more resistant to chemical and mechanical attack during manufacturing processes and improves product yield. In addition, a durable skin layer can extend the resulting product lifetime by preventing it from being attacked by humidity and the chemicals from manufacturing processes.
2. A fast-etching core layer allows TGV to be made much faster and or with less thickness removal in a laminate glass than a single composition glass. Current lamanent glass can achieve a core-to-clad thickness ratio of 9:1. Given we use Iris-like glass composition as the clad and Odin-like glass composition as the core, the etch rate of Iris is ˜70 times higher than Odin glass. This could allow a TGV to form in laminate glass ˜70× faster than in a similar thickness single composition glass. (See
3. A high aspect ratio can be achieved using a laminate glass because the skin layer is more durable to chemical attack.
Alternately,
Sample 1 was prepared using laminated glass with a 600 μm core having the composition of Example 1, and 50 μm clad layers with the composition of Example 11 on both sides. The structure was similar to that of
Sample 1 was drilled using a laser technique described in previous Corning patent publications: US 2013-0247615, “Methods of Forming High-Density Arrays of Holes in Glass”, filed Nov. 30, 2011 and US 2014-0147623, “Sacrificial Cover Layers for Laser Drilling Substrates and Methods Thereof”, filed Nov. 27, 2013, which are incorporated by reference in their entireties. In the laser drilling technique used, a pulsed ultra-violet (UV) laser is focused to an approximately 6 um diameter (1/e2) spot on the surface of a sample. The laser is a frequency tripled neodymium doped yttrium orthovanadate (Nd:YVO4) laser with a wavelength of about 355 nm. The pulse width is about 30 nsec. The average removal rate of material from the substrate was about 0.5 μm to 2 μm per pulse. So, the depth an individual drilled hole is controllable by the number of laser pulses applied. The repetition rate of the pulse train during the process is between 1 kHz and 150 kHz, with 1 kHz to 30 kHz being the most commonly used. The pilot holes formed with this method typically have a 12-16 um entry (top) diameter and a 4-8 um exit (bottom) diameter.
This laser drilling technique was used on Sample 1 with 1100 pulses at 5K repetition rate. Sample 1 was then etched in a solution containing 3M of HF and 2.4M HNO3, with an etching time targeting a top diameter of 28 μm.
Laminate glass has advantages of making precise glass structure compared to single glass compositions. Laminate glasses can be potentially used in microelectronics industry for electronics packaging given an etching stop layer can be developed at core-clad interface. Fabrication of TGV on these laminated glasses enables connections between the silicon chips mounted in the glass structures. However, since the exterior cladding glass is less durable than the interior core glass (E1>E2), a physical masking on the surface can be employed. As shown in
In the case of a laminate glass where the exterior cladding layer is more durable than the core (E1<E2), the cladding itself can act as a surface masking layer allowing acid to penetrate and create a TGV through the central thickness of the fast etching core material. In this case, a picosecond pulse laser using Bessel beam optics, to form a focal line, is used to create a damage track through the thickness of the glass. This damage track is preferentially etched using the same 2.9M HF 0.1 vol % polyelectrolyte surfactant solution to form a TGV.
Those skilled in the relevant art will recognize and appreciate that many changes can be made to the various embodiments described herein, while still obtaining the beneficial results. It will also be apparent that some of the desired benefits of the present embodiments can be obtained by selecting some of the features without utilizing other features. Accordingly, those who work in the art will recognize that many modifications and adaptations are possible and can even be desirable in certain circumstances and are a part of the present disclosure. Therefore, it is to be understood that this disclosure is not limited to the specific compositions, articles, devices, and methods disclosed unless otherwise specified. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Features shown in the drawing are illustrative of selected embodiments of the present description and are not necessarily depicted in proper scale. These drawing features are exemplary, and are not intended to be limiting.
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 description that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.
Unless otherwise expressly stated, percentages of glass components described herein are in mol % on an oxide basis.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the illustrated embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments that incorporate the spirit and substance of the illustrated embodiments may occur to persons skilled in the art, the description should be construed to include everything within the scope of the appended claims and their equivalents.
This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Ser. No. 63/114,122 filed on Nov. 16, 2020, the content of which is relied upon and incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/058613 | 11/9/2021 | WO |
Number | Date | Country | |
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63114122 | Nov 2020 | US |