METHOD FOR METALLIZING GLASS ARTICLE

Abstract

A method for manufacturing a glass article includes forming a first layer of a first metal on a glass substrate including silicon dioxide and aluminum oxide, performing a first heat treatment on the glass substrate with the first layer of the first metal, forming a second layer of a second metal on the first layer of the first metal, and performing a second heat treatment on the second layer of the second metal. The first and second heat treatments induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region including the first metal, the second metal, aluminum oxide, and silicon dioxide. The first metal can be silver. The second metal can be copper.

Description

Priority

[0001] This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 62 / 957,562, filed January 6, 2020, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] Semiconductor packaging technology has undergone significant evolution over the past few years. Early efforts to package more complex semiconductor circuits (and thereby achieve greater functionality and performance within a given package) focused on growing the size of the semiconductor chip in two dimensions within the package. However, practically speaking, lateral expansion in two dimensions cannot be achieved indefinitely. Eventually, designs would be hampered by power and signal routing complexity, power dissipation issues, performance issues, and manufacturing yield issues.

[0003] In response to this trend, efforts are being made to vertically extend semiconductor chips. These include so-called 2.5-dimensional (2.5D) integration and 3-dimensional (3D) integration. These packaging technologies use interposers to interconnect two or more semiconductor chips within a single package. Herein, the term "interposer" broadly refers to any structure that extends or complements the electrical connections between two or more electronic devices. The primary function of an interposer is to interconnect two or more semiconductor chips, enabling high-pitched terminal spacing and avoiding the need for vias through the semiconductor chip itself. This technology involves flipping the semiconductor chip from its normal orientation and placing it in a chip-substrate-up, chip-side-down orientation. The chip is provided with microbump terminals (high-pitched) that connect to corresponding terminals on the top surface of the interposer. The opposite, bottom surface of the interposer is connected to the package substrate (usually an organic substrate) via appropriate terminals (usually Controlled Collapse Chip Connection (C4) joints). The interposer is provided with through vias, which allow terminals of the semiconductor chip on the upper surface of the interposer to be electrically connected to terminals of the package substrate on the lower surface of the interposer.

[0004] Traditionally, interposers have typically used silicon as the base substrate. These interposers feature metallized vias that penetrate the substrate, providing pathways for electrical signals to travel between opposing sides of the interposer. However, while silicon interposers offer a promising and practical solution for vertical integration of semiconductor chips, they have also presented challenges. In particular, they have been plagued by CTE mismatch within the integration stack, such as a mismatch in the coefficient of thermal expansion (CTE) between the silicon interposer and the organic packaging substrate. This undesirable CTE mismatch can lead to poor connections between the semiconductor chip and the silicon interposer, as well as between the silicon interposer and the packaging substrate. Silicon interposers are also relatively expensive and suffer from high dielectric loss due to the semiconducting properties of silicon.

[0005] Organic interposers (e.g., FR4 (Flame Retardant 4)) have also begun to be introduced. However, organic interposers have problems with dimensional stability.

[0006] On the other hand, using glass as the base substrate for an interposer is thought to solve many of the problems that silicon and organic interposers have.Glass is a very advantageous substrate material for electrical signal transmission, as it has excellent dimensional stability, an adjustable (variable) coefficient of thermal expansion (CTE), low electrical loss at high frequencies, high thermal stability, and can be molded into large thicknesses and panel sizes.

[0007] However, metallizing vias in glass substrates to provide conductive paths has been challenging. This is due to the poor adhesion of some conductive metals (especially copper) to the glass's major surfaces and via sidewalls. Without wishing to be bound by theory, it is speculated that the weak bond between conductive metals and glass is due to the different types of bonds that bind metals to each other and those that form glass. Glass, simply put, is a network of oxide molecules (such as silicon dioxide, aluminum oxide, or boron oxide) formed by covalent bonds. Metals, on the other hand, consist of a "sea" of freely moving electrons within a lattice of stationary cationic atomic nuclei. Thus, the bonding mechanism of glass is fundamentally different from that of metals, limiting the adhesion between metals and glass. This problem can be alleviated by roughening the glass surface to which the metal is bonded, as this creates a mechanical interlock between the metal and glass. However, this approach is not ideal because roughening the glass surface can introduce additional problems. Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, new approaches are needed to solve the problem of metallizing vias in glass substrates intended for use as interposers, and the general problem of depositing metal on glass substrates. [Means for solving the problem]

[0009] The present disclosure solves the above-mentioned problems by (a) selecting a glass substrate having a composition containing aluminum oxide in addition to silicon dioxide, (b) depositing a first layer of a first metal, such as silver, on a desired surface of the glass substrate (e.g., on the sidewalls of a via), (c) heat-treating the glass substrate with the first layer, (d) depositing a second layer of a second metal, such as copper, on the first layer (e.g., filling the remaining voids in the via with the second metal to completely metallize the via), and (e) heat-treating the glass substrate with the second layer again. These heat-treating steps allow the first metal, the second metal, and the aluminum (or aluminum oxide) and silicon (or silicon dioxide) from the glass substrate to intermix to form a glass article (e.g., an interposer) having a metal region containing the first metal, the second metal, aluminum oxide, and silicon dioxide. The metal region contains aluminum oxide and silicon dioxide in addition to the first and second metals as primary components. The substantial intermixing of the first and second metals in the metal region allows the first and second metals to adhere strongly to the glass substrate. Without being bound by theory, it is believed that the intermixing of aluminum oxide and silicon dioxide throughout the metal region results in a covalent bond between the metal region and the entire glass article, including the glass substrate.

[0010] According to a first aspect of the present disclosure, a method for manufacturing a glass article includes forming a first layer of a first metal on a glass substrate including silicon dioxide and aluminum oxide, performing a first heat treatment on the glass substrate with the first layer of the first metal, forming a second layer of a second metal on the first layer of the first metal, and performing a second heat treatment on the second layer of the second metal, and the first and second heat treatments induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region including the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0011] In some embodiments, the glass substrate has a first surface, a second surface, and at least one via, the first surface and the second surface being generally opposite-facing major surfaces of the glass substrate, and the at least one via is defined by a sidewall surface extending from the first surface to the second surface through the glass substrate. In some embodiments, a first layer of a first metal is formed on the sidewall surface.

[0012] In some embodiments, the glass substrate is an alkaline earth aluminoborosilicate substrate, an alkali aluminoborosilicate glass substrate, or an alkali aluminoborosilicate glass substrate. In some embodiments, the glass substrate is an alkali-free aluminoborosilicate glass substrate. In some embodiments, the glass substrate is not subjected to a surface roughening treatment.

[0013] In some embodiments, the glass substrate has a composition comprising 6-15 mol% Al2O3 (on an oxide basis). In some embodiments, the glass substrate has a composition comprising 64.0-71.0 mol% SiO2, 9.0-12.0 mol% Al2O3, 7.0-12.0 mol% B2O3, 1.0-3.0 mol% MgO, 6.0-11.5 mol% CaO, 0-2.0 mol% SrO, 0-0.1 mol% BaO, and at least 0.01 mol% SnO2 (on an oxide basis), where [Al2O3] is the mol% of Al2O3 and Σ[RO] is the sum of the mol% of MgO, CaO, SrO, and BaO, and 1.00≦Σ[RO] / [Al2O3]≦1.25.

[0014] In some embodiments, the first metal consists essentially of silver, hi some embodiments, the first metal comprises one or more of silver, palladium, platinum, ruthenium, nickel, cobalt, and gold.

[0015] In some embodiments, forming a first layer of a first metal on the glass substrate comprises spin-coating the glass substrate with a nanoparticle suspension of the first metal, hi some embodiments, forming a first layer of a first metal on the glass substrate comprises electroless plating.

[0016] In some embodiments, the first heat treatment comprises exposing the glass substrate, having the first layer of the first metal formed thereon, to a temperature of 325°C or greater. In some embodiments, the first heat treatment comprises exposing the glass substrate, having the first layer of the first metal formed thereon, to a temperature of 325°C to 425°C. In some embodiments, the first heat treatment comprises exposing the glass substrate, having the first layer of the first metal formed thereon, to a temperature of 325°C or greater for a time period of 45 minutes or greater. In some embodiments, the first heat treatment comprises exposing the glass substrate, having the first layer of the first metal formed thereon, to a temperature of 325°C or greater for a time period of 45 minutes to 75 minutes. In some embodiments, the first heat treatment comprises exposing the glass substrate, having the first layer of the first metal formed thereon, to a temperature of 325°C to 425°C for a time period of 45 minutes to 75 minutes.

[0017] In some embodiments, the method further includes, after forming the first layer of the first metal and before forming the second layer of the second metal on the first layer, determining that the first layer has either (a) a conductivity below a predetermined conductivity or (b) a resistivity above a predetermined resistivity, and forming an intermediate layer of an intermediate metal on the first layer by electroless plating. In such embodiments, forming the second layer of the second metal on the first layer of the first metal includes forming the second layer of the second metal on the intermediate layer of the intermediate metal. In such embodiments, the first and second heat treatments induce intermixing of the first metal, the intermediate metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0018] In some embodiments, forming a second layer of a second metal on the first layer of a first metal comprises electroplating the second layer of the second metal on the first layer. In some embodiments, the second heat treatment comprises exposing the glass substrate having the second layer of the second metal formed thereon to a temperature of at least 300°C for a time period of at least 20 minutes. In some embodiments, the second heat treatment comprises exposing the glass substrate having the second layer of the second metal formed thereon to a temperature of 300°C to 400°C for a time period of at least 20 minutes.

[0019] According to a second aspect of the present disclosure, a method for manufacturing a glass interposer includes forming a first layer of a first metal on sidewall surfaces of one or more vias in a glass substrate including silicon dioxide and aluminum oxide, performing a first heat treatment on the glass substrate with the first layer of the first metal, electroplating a second layer of a second metal on the first layer of the first metal to fully metallize the one or more vias, and performing a second heat treatment on the second layer of the second metal. The first and second heat treatments then induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide in the glass substrate to form a metal region including the first metal, the second metal, aluminum oxide, and silicon dioxide. In some embodiments, the first metal consists essentially of silver, and the second metal comprises copper.

[0020] In some embodiments, the first heat treatment comprises exposing the glass substrate, having the first layer of the first metal, to a temperature of 325°C or greater for a time period of 45 minutes or greater. In some embodiments, the first heat treatment comprises exposing the glass substrate, having the first layer of the first metal, to a temperature of 325°C or greater for a time period of 45 to 75 minutes. In some embodiments, the second heat treatment comprises exposing the glass substrate, having the second layer of the second metal, to a temperature of at least 300°C for a time period of at least 20 minutes. In some embodiments, the second heat treatment comprises exposing the glass substrate, having the second layer of the second metal, to a temperature of 300°C to 400°C for a time period of at least 20 minutes.

[0021] In some embodiments, the glass substrate has a composition including (on an oxide basis) 64.0 to 71.0 mol % SiO, 9.0 to 12.0 mol % AlO, 7.0 to 12.0 mol % BO, 1.0 to 3.0 mol % MgO, 6.0 to 11.5 mol % CaO, 0 to 2.0 mol % SrO, 0 to 0.1 mol % BaO, and at least 0.01 mol % SnO, wherein 1.00≦Σ[RO] / [AlO]≦1.25, where [AlO] is the mol % of AlO and Σ[RO] is the sum of the mol % of MgO, CaO, SrO, and BaO. -7 ~50×10 -7 / °C.

[0022] According to a second aspect of the present disclosure, a glass article includes: (a) a glass substrate containing silicon dioxide and aluminum oxide as its main components (by weight percentage); and (b) a metal region containing a first metal, a second metal, silicon dioxide, and aluminum oxide, wherein the metal region has: (i) a partial region α containing the second metal as its main component (by weight percentage), (ii) a partial region β containing the first metal as its main component (by weight percentage), with the second metal being contained in a larger amount than silicon dioxide and the second metal being contained in a larger amount than aluminum oxide, and (iii) a partial region γ containing the first metal as its main component (by weight percentage), with the silicon dioxide being contained in a larger amount than the second metal and the aluminum oxide being contained in a larger amount than the second metal. Of partial region α, partial region β, and partial region γ, partial region γ is the region closest to the glass substrate, and partial region α is the region farthest from the glass substrate. In some embodiments, the first metal consists essentially of silver and the second metal comprises copper.

[0023] In some embodiments, a transition region containing silicon dioxide as a main component by weight and containing more of the first metal than aluminum oxide is further included between the glass substrate and the partial region γ. In some embodiments, aluminum oxide is present seamlessly from the glass substrate to the partial region α.

[0024] In some embodiments, the glass article is an interposer including a first side, a second side, a thickness between the first side and the second side, and at least one via opening at the first side and extending through at least a portion of the thickness toward the second side, each of the vias being fully metallized with a metal region disposed about its central axis.

[0025] Additional features and advantages are set forth in the detailed description that follows, and will become apparent to those skilled in the art in part from the description, or may be learned by practice of the embodiments described herein, including the following detailed description, claims, and accompanying drawings.

[0026] It is to be understood that both the foregoing general description and the following detailed description are exemplary only and are intended to provide an overview or framework for understanding the nature and features of the claimed invention. In addition, the accompanying drawings are included to provide a further understanding, and are incorporated into and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the following detailed description, serve to explain the principles and operation of various embodiments. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a perspective view of a glass substrate before it is processed into an interposer, showing a first surface separated from a second surface by a thickness, and a plurality of vias that open into the first surface, which is the main surface, and extend through the thickness of the glass substrate. [Figure 2] FIG. 2 is a cross-sectional elevation view taken along line II-II of FIG. 1, illustrating some vias extending completely through the thickness of the glass substrate and opening to both the first and second surfaces, and the sidewall surfaces defining each via. [Figure 3] 2 is a flowchart illustrating a method for manufacturing a glass article from a glass substrate such as the glass substrate of FIG. [Figure 4] 4 is an elevational view of area IV of FIG. 2 after the step of forming a first layer of a first metal on the glass substrate (particularly on the sidewall surfaces of the vias) in the method shown in FIG. 3; [Figure 5] 4, showing the state after the step of forming an intermediate layer of an intermediate metal on the first layer of the first metal by electroless plating in the method shown in FIG. [Figure 6] 5, showing the state after the step of forming a second layer of a second metal on the first layer of a first metal in the method shown in FIG. 3; [Figure 7] 5, showing the state after the step of forming a second layer of a second metal on the intermediate layer of the intermediate metal in the method shown in FIG. [Figure 8]8 is a view similar to FIGS. 6 and 7, showing the state after the step of heat treating the second layer in the method shown in FIG. 3, resulting in a glass article having a metal region including a first metal, a second metal, and, if an intermediate layer is added, an intermediate metal, aluminum oxide, and silicon dioxide. [Figure 9] 4 is a graph illustrating the relative weight percentages of individual chemical elements as a function of position within the glass article produced by the method shown in FIG. 3 , illustrating: (i) a glass substrate primarily comprising silicon dioxide and aluminum oxide; (ii) a subregion α of a metal region primarily comprising a second metal (by weight percentage); (iii) a subregion β of a metal region primarily comprising a first metal (by weight percentage), with the second metal being more abundant than silicon dioxide and the second metal being more abundant than aluminum oxide; and (iv) a subregion γ of a metal region primarily comprising a first metal (by weight percentage), with the first metal being more abundant than silicon dioxide and the second metal being more abundant than aluminum oxide. [Figure 10] 4 is a photograph showing an example of a glass article manufactured according to the method shown in FIG. 3, showing that a tape peeling test showed no peeling of the metal from the glass substrate, and that the metal region was well bonded to the glass substrate. [Figure 11] 4 is a photograph showing an example of a glass article manufactured according to the method shown in FIG. 3, showing that a tape peeling test showed no peeling of the metal from the glass substrate, and that the metal region was well bonded to the glass substrate. [Figure 12] 4 is a photograph showing an example of a glass article manufactured according to the method shown in FIG. 3, showing that a tape peeling test showed no peeling of the metal from the glass substrate, and that the metal region was well bonded to the glass substrate. [Figure 13] FIG. 4 is a photograph showing a comparative example of a glass article produced according to the method shown in FIG. 3 except that the step of heat treating the first layer of the first metal was omitted, and shows that a tape peel test revealed significant metal peeling from the glass substrate, indicating insufficient bonding of the deposited first layer of the first metal and second layer of the second metal to the glass substrate. [Figure 14]FIG. 4 is a photograph showing a comparative example of a glass article produced according to the method shown in FIG. 3 except that a glass substrate containing no aluminum oxide was used, showing that a tape peel test revealed significant metal peeling from the glass substrate, indicating poor bonding of the deposited first layer of a first metal and second layer of a second metal to the glass substrate. [Figure 15] FIG. 4 is a photograph showing a comparative example of a glass article produced according to the method shown in FIG. 3 except that the step of heat treating the first layer of the first metal was omitted, and shows that a tape peel test revealed significant metal peeling from the glass substrate, indicating insufficient bonding of the deposited first layer of the first metal and second layer of the second metal to the glass substrate. DETAILED DESCRIPTION OF THE INVENTION

[0028] Reference will now be made in detail to preferred embodiments of the present disclosure, as illustrated in the accompanying drawings, wherein, wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0029] Glass substrate 1, there is shown a glass substrate 100 in the form of an interposer. The glass substrate 100 has a first surface 102 and a second surface 104. The first surface 102 and the second surface 104 are major surfaces of the glass substrate 100. The first surface 102 and the second surface 104 are at least generally parallel and face in generally opposite directions.

[0030] For reasons discussed below, the glass substrate 100 of the present disclosure has a composition that includes a metal oxide glass network former, such as aluminum oxide (Al2O3). In some embodiments, the glass substrate 100 is an alkaline earth aluminoborosilicate substrate, an alkali aluminoborosilicate glass substrate, an alkali aluminoborosilicate glass substrate, or an alkaline earth aluminoborosilicate glass substrate. In other embodiments, the glass substrate 100 is an alkali-free glass, such as an alkali-free aluminoborosilicate glass substrate or an alkali-free aluminoborosilicate glass substrate. "Alkali-free" refers to a state in which the glass substrate 100 does not intentionally contain a significant amount of alkali metal, and even if the glass substrate 100 contains alkali metal, it is present as an impurity. In some embodiments, the glass substrate 100 has a composition that includes 6 to 15 mol % Al2O3 and 60 to 78 mol % SiO2 (on an oxide basis).

[0031] For example, in some embodiments, the glass substrate 100 comprises (on an oxide basis) 64.0-71.0 mol% SiO, 9.0-12.0 mol% AlO, 7.0-12.0 mol% BO, 1.0-3.0 mol% MgO, 6.0-11.5 mol% CaO, 0-2.0 mol% SrO, 0-0.1 mol% BaO, and at least 0.01 mol% SnO, where [AlO] is the mol% of AlO and Σ[RO] is the sum of the mol% of MgO, CaO, SrO, and BaO, and Σ[RO] satisfies 1.00≦Σ[RO] / [AlO]≦1.25. In such embodiments, the glass substrate 100 has a 20×10 -7 ~50×10 -7 / °C, e.g., 28 x 10 -7 / ℃~34×10 -7 / °C, e.g., approximately 31.7 × 10 -7 The term "CTE," "coefficient of thermal expansion," and the like refer to the change in size of an object due to a change in temperature. CTE indicates the rate of change in dimension per degree of temperature change at constant pressure, where dimension refers to, for example, volume, area, or length.

[0032] In some embodiments, the glass substrate 100 comprises (on an oxide basis) 61-75 mol % SiO, 7-15 mol % AlO, 0-12 mol % BO, 9-21 mol % NaO, 0-4 mol % KO, 0-7 mol % MgO, and 0-3 mol % CaO.

[0033] In some embodiments, the glass substrate 100 comprises (on an oxide basis) 60-70 mol% SiO, 6-14 mol% AlO, 0-15 mol% BO, 0-15 mol% LiO, 0-20 mol% NaO, 0-10 mol% KO, 0-8 mol% MgO, 0-10 mol% CaO, 0-5 mol% ZrO, 0-1 mol% SnO, 0-1 mol% CeO, less than 50 ppm AsO, and less than 50 ppm SbO, where 12 mol%≦LiO+NaO+KO≦20 mol% and 0 mol%≦MgO+CaO≦10 mol%.

[0034] In some embodiments, the glass substrate 100 comprises (on an oxide basis) 64-68 mol% SiO, 12-16 mol% NaO, 8-12 mol% AlO, 0-3 mol% BO, 2-5 mol% KO, 4-6 mol% MgO, and 0-5 mol% CaO, where 66 mol%≦SiO+BO+CaO≦69 mol%, NaO+KO+BO+MgO+CaO+SrO>10 mol%, 5 mol%≦MgO+CaO+SrO≦8 mol%, (NaO+BO)-AlO≦2 mol%, 2 mol%≦NaO-AlO≦6 mol%, and 4 mol%≦(NaO+KO)-AlO≦10 mol%.

[0035] In some embodiments, the glass substrate 100 comprises (on an oxide basis) 66-78 mol % SiO2, 4-11 mol % Al2O3, 4-11 mol % B2O3, 0-2 mol % Li2O, 4-12 mol % Na2O, 0-2 mol % K2O, 0-2 mol % ZnO, 0-5 mol % MgO, 0-2 mol % CaO, 0-5 mol % SrO, 0-2 mol % BaO, and 0-2 mol % SnO2.

[0036] In some embodiments, the glass substrate 100 comprises (on an oxide basis) 69.49 mol % SiO, 8.45% AlO, 14.01% NaO, 1.16% KO, 0.185% SnO, 0.507% CaO, 6.2% MgO, 0.01% ZrO, and 0.008% FeO.

[0037] In some embodiments, the glass substrate 100 is manufactured using a glass manufacturing system that uses a fusion process to create a glass sheet and then cut the glass substrate 100 into the desired shape. The fusion process results in a glass substrate 100 with a uniform thickness as manufactured, such as a glass substrate 100 with a total thickness variation (TTV) of less than 1.0 μm. Therefore, finishing processes such as polishing may not be required before the glass substrate 100 can be used as an interposer. If the glass substrate 100 obtained by the fusion process is too thick, the thickness of the glass substrate 100 can be reduced by any known means, such as etching or polishing. In yet other embodiments, the glass substrate 100 is manufactured using a process other than the fusion process and then polished or etched to the desired thickness. After manufacturing the glass substrate 100, the glass substrate 100 can also be annealed to reduce residual stress in the glass substrate 100.

[0038] The glass substrate 100 has a thickness 106 extending from the first surface 102 to the second surface 104. In some embodiments, the thickness 106 is in the range of 25 μm to about 1 mm. However, thicknesses 106 less than or greater than this range are also contemplated. For example, in embodiments described herein, the thickness 106 of the glass substrate 100 is about 50 μm, about 100 μm, about 200 μm, about 300 μm, about 400 μm, about 500 μm, about 600 μm, about 700 μm, about 800 μm, about 900 μm, about 1 mm, or any range therebetween, such as between 50 μm and 300 μm. In some embodiments, the thickness 106 is in the range of 50 μm to 100 μm. The glass substrate 100 can have any desired shape. In some embodiments, the glass substrate 100 has a circular shape. In such an embodiment, the diameter of the glass substrate 100 may be in the range of 200 mm to 300 mm. In other embodiments, the glass substrate 100 has a square or rectangular shape.

[0039] Referring now also to FIG. 2 , the glass substrate 100 further includes one or more vias 108. In some embodiments, the glass substrate 100 includes a plurality of vias 108. In some embodiments, some or all of the one or more vias 108 extend entirely through the thickness 106 of the glass substrate 100 from the first surface 102 to the second surface 104. Such vias 108 may be referred to herein as “through vias.” In other embodiments, some or all of the one or more vias 108 open at the first surface 102 but extend only partially through the thickness 106 rather than extending completely through the thickness 106 to the second surface 104. Such vias 108 may be referred to herein as “blind vias.” In some embodiments, the glass substrate 100 includes a plurality of both through and blind vias. Each via 108 in the glass substrate 100 is defined by a sidewall surface 110.

[0040] Each via 108 has a diameter 112. While the diagram illustrates the vias 108 as having the same diameter 112, this is not necessarily the case. That is, the diameters 112 of the vias 108 within a single glass substrate 100 may vary. In some embodiments, the diameters 112 are in the range of 5 μm to 150 μm. In some embodiments, such as the illustrated embodiment, the vias 108 have an hourglass shape with a waist 114. The diameter 112 of the via 108 at the waist 114 is smaller than the diameters 112 of the via 108 at the first surface 102 and the second surface 104 of the glass substrate 100. This hourglass shape may be suitable for electroplating, as described below. In other embodiments, the vias 108 have a substantially cylindrical or substantially conical shape.

[0041] Each via 108 has a central axis 116. The central axis 116 of one via 108 is separated from the central axis 116 of an adjacent via 108 by a distance referred to as the pitch 118. The pitch 118 can be any value depending on the desired application, such as, but not limited to, about 10 μm, about 25 μm, about 50 μm, about 100 μm, about 250 μm, about 500 μm, about 1000 μm, about 2000 μm, or any value or range between any two of these values ​​(inclusive). For example, the pitch 118 can be within the ranges of 10 μm to 100 μm, 25 μm to 500 μm, 10 μm to 1000 μm, or 250 μm to 2000 μm. The pitch 118 may vary or may be constant on one glass substrate 100. The pitch 118 may be set, for example, so that the number of vias 108 per square millimeter is 1 to 20. The number of vias per unit area varies depending on the design and application of the interposer. In some embodiments, the vias 108 are patterned across the entire glass substrate 100. In other embodiments, no pattern of vias 108 is formed.

[0042] The via 108 is formed in the glass substrate 100 using one of a variety of via 108 formation techniques. For example, the via 108 can be formed by any suitable formation technique, such as drilling, etching, laser ablation, laser-assisted processing, laser damage formation and etching, abrasive blasting, abrasive water jet machining, or high-density electrothermal energy machining. In the laser damage formation and etching process, a laser is used to first form a damage path in the glass substrate 100. This allows the glass substrate 100 to be processed along the damage path. Next, an etching solution is applied to the glass substrate 100. The etching solution reduces the thickness of the glass substrate 100. At this time, the etching rate of the glass substrate 100 is increased at the damage path, so the damage path is selectively etched, opening a via 108 through the glass substrate 100.

[0043] Metallization method 200 for glass substrate 100 3-8, one or more vias 108 in a glass substrate 100 are metallized according to a novel method 200 described herein. While method 200 is described herein as a method for metallizing vias 108 in the context of a glass substrate 100 used as an interposer, it is understood that method 200 relates to depositing metal on the glass substrate 100 for any purpose, and also relates to metallizing surfaces other than the sidewall surfaces 110 of the vias 108, such as the first surface 102, the second surface 104, and / or other openings through or disposed in the glass substrate 100. When applied to a glass substrate 100 used as an interposer, as discussed in the Background section, metallizing the vias 108 provides a conductive path through the interposer, which transmits electrical signals from the first surface 102 to the second surface 104.

[0044] Forming a first layer 120 of a first metal In step 202, method 200 includes forming a first layer 120 of a first metal on a glass substrate 100 (see particularly FIG. 4). In some embodiments, first layer 120 of a first metal can cover all or substantially all of glass substrate 100. In some embodiments, first layer 120 of a first metal is a nanolayer having a thickness 124 in the range of 5 nm to about 10,000 nm.

[0045] Alternatively, the first layer 120 of the first metal can be patterned to cover a portion of the glass substrate 100, such as a portion of the first surface 102, a portion of the second surface 104, a portion or all of the sidewall surface 110 of the via 108, or a combination thereof. In some embodiments, the first metal includes one or more of silver, palladium, platinum, ruthenium, nickel, cobalt, and gold. In some embodiments, the first metal is silver or consists essentially of silver. In some embodiments, the first layer 120 of the first metal is formed on the sidewall surface 110 of the via 108. In some embodiments, the first layer 120 of the first metal is silver or consists essentially of silver, and step 202 of method 200 includes forming the first layer 120 of the first metal (e.g., silver) on the sidewall surface 110 of the via 108 of the glass substrate 100. The patterning can be performed by selectively masking some areas of the glass substrate 100 with blocking tape, photoresist, or the like when depositing the first layer 120 of the first metal on the glass substrate 100.

[0046] In some embodiments, forming the first layer 120 of the first metal on the glass substrate 100 includes contacting the glass substrate 100 with a nanoparticle suspension of the first metal. The nanoparticle suspension is prepared by dispersing nanoparticles in a liquid carrier. The liquid carrier can be water or a liquid solvent. The liquid solvent carrier can be a single solvent, a mixed solvent, or a solvent containing a non-solvent component (single solvent or mixed solvent). Exemplary solvents that can be used include, but are not limited to, hydrocarbons, halogenated hydrocarbons, alcohols, ethers, ketones, or mixtures thereof, such as 2-propanol (also known as isopropanol, IPA, or isopropyl alcohol), tetrahydrofuran (THF), ethanol, chloroform, acetone, butanol, octanol, pentane, hexane, heptane, cyclohexane, and mixtures thereof.

[0047] The term "nanoparticle" refers to a particle (component) having an average diameter (or cross-sectional dimension) along its shortest axis of about 1 nm to about 10,000 nm. Of course, the size of a nanoparticle can be expressed as a size distribution. Furthermore, in some embodiments, nanoparticles may have different sizes or particle distributions, i.e., one or more sizes or particle distributions. Thus, a particular particle size may refer to the average particle size for a size distribution of individual particles. In some embodiments, the average particle size of the nanoparticles is about 5 nm to about 10,000 nm, about 5 nm to about 7,500 nm, about 5 nm to about 5,000 nm, about 5 nm to about 2,500 nm, about 5 nm to about 2,000 nm, about 5 nm to about 1,500 nm, about 5 nm to about 1,250 nm, about 5 nm to about 1,000 nm, about 5 nm to about 750 nm, about 5 nm to about 500 nm, about 5 nm to about 250 nm, about 5 nm to about 200 nm, about 5 nm to about 150 nm, about 5 nm to about 125 nm, about 5 nm to about 100 nm, about 5 nm to about 75 The particle size of nanoparticles can be measured by a variety of methods, including dynamic light scattering and transmission electron microscopy (TEM). For example, particle size distributions are typically determined by TEM image analysis of a sample of several hundred different nanoparticles.

[0048] Nanoparticles can have any shape and surface configuration. Nanoparticle structures and geometries are widely varied, and the present disclosure is not intended to be limited to any particular geometric shape and / or configuration. Some embodiments described herein include a plurality of nanoparticles, where an individual nanoparticle or a group of nanoparticles can have the same structure and / or geometry as other nanoparticles or a different structure and / or geometry from other nanoparticles. For example, in some embodiments, nanoparticles can be spherical, ellipsoidal, polyhedral, flake-like, or crystalline in structure. In some embodiments, the nanoparticle surface can be smooth, rough, ordered, disordered, or patterned.

[0049] In some embodiments, the nanoparticles of the first metal are silver nanoparticles. In some embodiments, the silver nanoparticles have an average particle size of 10 nm to 13 nm and are dispersed in cyclohexane at a concentration of 20 wt % (commercially available from Cerion, LLC, Rochester, NY, USA). Copper nanoparticles were also used, but were found to provide insufficient bonding to the glass substrate 100.

[0050] Prior to contacting the glass substrate 100 with the nanoparticle suspension, the nanoparticle suspension is optionally sonicated to promote dispersion of the nanoparticles throughout the liquid carrier. For example, the nanoparticle suspension may be sonicated for a period of time ranging from 15 to 45 minutes, such as about 30 minutes.

[0051] By contacting the glass substrate 100 with a suspension of nanoparticles of the first metal, the first layer 120 of the first metal can be composed of a submonolayer, a monolayer, or a multilayer of nanoparticles of the first metal.

[0052] In some embodiments, contacting the glass substrate 100 with the nanoparticle suspension of the first metal comprises spin-coating the glass substrate 100 with the nanoparticle suspension. Spin-coating can be performed at any speed and for any time determined to be suitable for forming the desired first layer 120 of the first metal on the glass substrate 100. For example, the nanoparticle suspension of the first metal can be deposited on the glass substrate 100 while the glass substrate 100 is spun at 1000-5000 rpm (e.g., 1000, 2000, 3000, 4000, or 5000 rpm) for about 30 seconds, or for less than 30 seconds, or for more than 30 seconds.

[0053] In some embodiments, the step of contacting the glass substrate 100 with the nanoparticle suspension of the first metal includes dip-coating the glass substrate 100 with the nanoparticle suspension of the first metal or spray-coating the glass substrate 100 with the nanoparticle suspension of the first metal. The dip-coating can be performed at a pulling rate (sometimes referred to as a pull rate) suitable for forming the first layer 120 of the first metal on the glass substrate 100 (e.g., a rate of 30-35 mm per minute).

[0054] In another embodiment, forming the first layer 120 of the first metal on the glass substrate 100 includes electrolessly plating the first layer 120 of the first metal on the glass substrate 100. Electroless plating involves reducing an ionic compound of anions and cations of the first metal to the elemental form of the first metal using a chemical reducing agent. A typical electroless plating process uses (a) a plating solution of an ionic compound containing cations of the first metal, (b) a reducing agent, (c) a pH adjuster, (d) a complexing agent to solubilize the ionic compound, and (e) special additives to control the stability and plating rate of the plating solution. These solutions are then deposited on the glass substrate 100, which has a catalytically active surface. The catalytically active surface catalyzes the reduction of the ionic compound, thereby depositing the elemental form of the first metal on the contact surfaces of the glass substrate 100 (i.e., the first surface 102, the second surface 104, and / or the sidewall surfaces 110 of the vias 108). Additionally, the first metal deposited on the surface(s) of the glass substrate 100 is autocatalytic, and therefore the deposited first metal further catalyzes the reaction and deposition of the first metal, which continues until a first layer 120 of the first metal of the desired thickness 124 is obtained.

[0055] As described above, electroless plating uses a plating solution containing an ionic compound of a cation of a first metal and a solvent. Suitable ionic compounds include, for example, silver nitrate, silver sulfate, palladium chloride, palladium acetate, platinum chloride, and gold cyanide. Typically, the ionic compound is present in the plating solution at a concentration ranging from about 0.001 to about 10% by weight based on the weight of the plating solution. The solvent may be either an aqueous solvent or an organic liquid solvent, as long as it is suitable for the ionic compound. Examples of such organic liquid solvents include alcohols, ethers, ketones, and alkanes.

[0056] As described above, electroless plating uses a reducing agent, a pH adjuster, and a complexing agent. The reducing agent reduces the cations of the first metal present on the glass substrate 100. Specific examples of reducing agents include NaBH4, KBH4, NaH2PO2, hydrazine, formalin, and polysaccharides (e.g., glucose). The pH adjuster adjusts the pH of the plating solution and may be an acidic or basic compound. The complexing agent prevents hydroxide precipitation in alkaline solutions and controls the concentration of free metal cations, thereby preventing decomposition of ionic compounds and adjusting the plating rate. Specific examples of complexing agents include ammonia solution, acetic acid, guanylic acid, tartaric acid, chelating agents (e.g., ethylenediaminetetraacetic acid (EDTA)), and organic amine compounds.

[0057] In some embodiments, the temperature of the plating solution is 30°C to 50°C, for example, about 40°C. In some embodiments, the electroless plating process on the glass substrate 100 is performed for a time period of 20 seconds to 5 minutes, for example, about 30 seconds. In some embodiments, the thickness 124 of the first layer 120 of the first metal, formed by electroless plating or the like, is 10 nm to 100 nm, for example, about 50 nm.

[0058] In yet other embodiments, forming the first layer 120 of the first metal on the glass substrate 100 includes Langmuir-Blodgett deposition, electrospray ionization, direct nanoparticle deposition, evaporation, chemical vapor deposition, vacuum filtration, flame spraying, electrospray, spray deposition, electrodeposition, screen printing, proximity sublimation, nanoimprint lithography, in situ growth, microwave-assisted chemical vapor deposition, laser ablation, arc discharge, or chemical etching.

[0059] 1. subjecting the first layer 120 of the first metal to a first heat treatment; In step 204, the method 200 further includes subjecting the glass substrate 100 having the first metal first layer 120 thereon to a first heat treatment. The first heat treatment step 204 may be referred to herein as "sintering" the first metal first layer 120 deposited on the glass substrate 100. As described in more detail below, it is believed that step 204 results in intermixing of the first metal from the first layer 120 with at least one of aluminum, aluminum oxide, silicon, and silicon dioxide from the glass substrate 100, resulting in no distinct boundary between the first metal first layer 120 and the glass substrate 100.

[0060] If the first metal is a metal that is easily oxidized, step 204 can be performed in an inert atmosphere (e.g., a nitrogen gas atmosphere), or if step 204 is not performed in an inert atmosphere, a subsequent heat treatment in a reducing atmosphere (e.g., a hydrogen gas atmosphere) can be performed to convert the oxidized first metal back to its elemental form. Oxidation of the first metal can interfere with the deposition of metal(s) later in method 200 (described below). If the first metal is silver, it is not easily oxidized.

[0061] In some embodiments, the first heat treatment step 204 comprises exposing the glass substrate 100 having the first metal first layer 120 formed thereon to a temperature of 325°C or greater. In some embodiments, the first heat treatment step 204 comprises exposing the glass substrate 100 having the first metal first layer 120 formed thereon to a temperature of 325°C or greater for a time period of 45 minutes or greater. In some embodiments, the first heat treatment step 204 comprises exposing the glass substrate 100 having the first metal first layer 120 formed thereon to a temperature of 325°C or greater for a time period of 45 minutes to 75 minutes. In some embodiments, the first heat treatment step 204 comprises exposing the glass substrate 100 having the first metal first layer 120 formed thereon to a temperature of 325°C to 425°C. In some embodiments, the first heat treatment step 204 involves exposing the glass substrate 100 having the first metal layer 120 thereon to a temperature between 325°C and 425°C for a time period between 45 and 75 minutes. In some embodiments, the glass substrate 100 is initially exposed to a temperature below 325°C (e.g., room temperature) and then exposed to a temperature ramp rate (e.g., between 0.5°C per minute and 10°C per minute) to a desired temperature of 325°C or higher. In other embodiments, the glass substrate 100 having the first metal layer 120 thereon is directly placed in a preheating furnace set to a predetermined temperature within a range suitable for carrying out the first heat treatment step 204. This step 204 can be carried out by placing the glass substrate 100 having the first metal layer 120 thereon in a vertical furnace, a tube furnace, a rapid thermal annealer (RTA), or by placing it on a hot plate.

[0062] In some embodiments, the first heat treatment step 204 includes exposing the glass substrate 100 having the first metal first layer 120 thereon to a first temperature of 325°C to 375°C for a first time period, followed by a second temperature of 375°C to 425°C for a second time period longer than the first time period. The first time period can be between 1 minute and 5 minutes. The second time period can be set so that the sum of the first and second times is between 45 minutes and 75 minutes. For example, the glass substrate 100 having the first metal first layer 120 thereon can be first exposed to a first temperature of 350°C for 2 minutes, followed by a second temperature of 400°C for 60 minutes. In addition, when the glass substrate 100 provided with the first layer 120 of the first metal is exposed to a first temperature for a first time period within a range of 1 minute to 5 minutes, but the glass substrate 100 is not subsequently exposed to a second temperature for a second time period, the adhesion of the first layer 120 of the first metal to the glass substrate 100 becomes insufficient.

[0063] Determining whether the first layer has sufficient conductivity In step 206, method 200 optionally includes determining whether first layer 120 of a first metal has (a) a conductivity below a predetermined conductivity or (b) a resistivity above a predetermined resistivity. The purpose of step 206 is to determine whether second layer 128 of a second metal can be electroplated on first layer 120 (e.g., to fully metallize vias 108 in glass substrate 100 for an interposer). Resistivity can be measured using a multimeter such as a Fluke 87V (Fluke Corporation, Everett, Washington, USA) or a non-contact surface resistance meter such as that manufactured by NAGY Messsysteme GmbH (Gaufelden, Germany). Note that conductivity is the reciprocal of resistivity. The first heat treatment step 204 may result in a decrease in the electrical conductivity of the first layer 120 relative to the electrical conductivity of the first metal due to the intermixing of the first metal with silicon (or silicon dioxide) and / or aluminum (or aluminum oxide). The predetermined electrical conductivity is a conductivity that allows for the formation of a second layer 128 of a second metal by electroplating in a subsequent step of the method 200, as described below. Therefore, the predetermined electrical conductivity varies depending on the metal selected for the second metal of the second layer 128. For a typical metal(s) used as the second metal of the second layer 128, the predetermined electrical conductivity (resistivity) correlates to a sheet resistance of 100 Ω / □.

[0064] If it is determined that the first layer 120 has either (a) a conductivity below the predetermined conductivity or (b) a resistivity above the predetermined resistivity, the method 200 further includes, in step 208, electrolessly forming an intermediate layer 126 of an intermediate metal on the first layer 120 of the first metal (see particularly FIG. 5 ). In some embodiments, the intermediate metal of the intermediate layer 126 is copper or consists essentially of copper. In some embodiments, the intermediate metal includes one or more of silver, gold, cobalt, cobalt-phosphorus, copper, nickel, and nickel-phosphorus. Electroless plating is as described in detail above. Coating the first layer 120 with the intermediate layer 126 of the intermediate metal allows the subsequent electrolytic formation of a second layer 128 of a second metal on the intermediate layer 126, even if the first layer 120 does not have sufficient conductivity (its resistivity is too high). In some embodiments, intermediate layer 126 has a thickness 127 in the range of 10 nm to 100 nm. In some embodiments, step 206 is omitted, i.e., step 208 is performed to add intermediate layer 126 regardless of the conductivity or resistivity of first layer 120.

[0065] forming a second layer 128 of a second metal on the first layer 120; In step 210, method 200 further includes forming a second layer 128 of a second metal on first layer 120 (see particularly FIG. 6 ). Step 210 may be performed after step 206 or after step 208 if it is determined that the conductivity of first layer 120 is insufficient to form second layer 128 of the second metal by electroplating. In some embodiments of fabricating glass substrate 100 for interposer applications, second layer 128 of the second metal fills the remaining open portion of via 108. Thus, via 108 is now fully metallized (i.e., completely filled) with metal. In some embodiments, the second metal is one or more of copper, silver, aluminum, titanium, gold, platinum, nickel, tungsten, lead, manganese, and magnesium. In some embodiments, the second metal is an alloy of copper and manganese. In some embodiments, the second metal is copper and the first metal (of the first layer 120) is silver. In some embodiments, the second metal is a copper-manganese alloy and the first metal is silver. In some embodiments, step 210 of method 200 includes electroplating a second layer 128 of copper as the second metal on the silver first layer 120 to fully metallize one or more vias 108.

[0066] In some embodiments, forming the second layer 128 of the second metal on the first layer 120 includes electroplating the second layer 128 of the second metal on the first layer 120. If it is determined in step 206 that the first layer 120 has sufficient conductivity (or that its resistivity is not too high), then in step 210, the second layer 128 of the second metal is electroplated directly on the first layer 120. If it is determined in step 206 that the first layer 120 has insufficient conductivity or too high resistivity and an intermediate layer 126 of an intermediate metal is provided on the first layer 120 of the first metal, then in step 210, the second layer 128 of the second metal is electroplated on the intermediate layer 126 of the intermediate metal (see particularly FIG. 7 ), thereby electroplating the second layer 128 of the second metal on the first layer 120. In this case, however, an intermediate layer 126 of an intermediate metal is interposed between the first layer 120 and a second layer 128 of a second metal formed by electroplating.

[0067] In the electroplating process, a glass article 122 is placed in a plating solution containing an ionic compound having anions and cations of a second metal desired to form a second layer 128, and an electric current is applied. This deposits the elemental second metal onto the first layer 120 of the first metal, or optionally onto the intermediate layer 126 of the intermediate metal, forming a second layer 128 of the second metal. Examples of anions contained in the ionic compound containing the cation of the second metal to be deposited include sulfate, nitrate, and chloride. An example of an ionic compound is copper sulfate. An example of a plating solution is a solution of copper sulfate pentahydrate (CuSO4·5H2O), potassium pyrophosphate (K4P2O7), and citric acid dissolved in distilled water. Another example of a plating solution is a solution containing copper sulfate pentahydrate (CuSO4·5H2O), manganese sulfate monohydrate (MnSO4·H2O), sodium potassium tartrate tetrahydrate (Rochelle salt), and formaldehyde. In some embodiments, the concentration of the ionic compound in the plating solution is 0.001 M (mol / L) or more. In addition to the glass article 122, electrodes made of any conductive material may also be placed in the plating solution. In some embodiments, the temperature of the plating solution is 10°C to 50°C, for example, room temperature or 40°C.

[0068] Then, a current, a voltage, or a combination thereof is applied between the glass substrate 100 provided with the first layer 120 (and the intermediate layer 126, if present) and the electrode to provide a negative constant current to the glass substrate 100 provided with the first layer 120 (and the intermediate layer 126, if present). In some embodiments, a current of about 0.001 mA / cm 2 ~About 1A / cm 2The plating solution is applied at a current density range of about −0.001 V to about −20 V. This reduces the cations of the second metal that will become the second layer 128 to their elemental form on the first layer 120 (and, in some cases, on the intermediate layer 126). The current density controls the rate of this reduction reaction. Therefore, the deposition rate can be increased or decreased by increasing or decreasing the applied current. However, it should be noted that if the applied current is too high, the deposited layer will be porous and have many voids, while if the applied current is too low, the process may take an unpractically long time. Once the desired second layer 128 of the second metal is deposited on the first layer 120 (or the intermediate layer 126, if present), the current is stopped, the glass substrate 100 is removed from the plating solution, and the glass substrate 100 with the second layer 128 deposited thereon can be rinsed with deionized water. Optionally, the glass substrate 100 having the second layer 128 formed thereon can be dried, such as by passing a stream of nitrogen over the glass substrate 100 having the second layer 128 formed thereon.

[0069] In other embodiments, forming the second layer 128 of the second metal on the first layer 120 includes electroless plating, chemical vapor deposition (CVD), or physical vapor deposition (PVD), such as sputtering, thermal evaporation, and electron beam evaporation. CVD processes are suitable for relatively small vias 108 (diameters 112 of 3-5 μm) with aspect ratios up to 20, but may not be suitable for larger or deeper vias 108. Alternatively, atomic layer deposition (ALD) is a method capable of filling high aspect ratio vias 108.

[0070] In some embodiments of fabricating an interposer from the glass substrate 100, a second layer 128 of a second metal fills the remaining open portion of the via 108. If the second layer 128 is deposited by electroplating, the glass substrate 100 is placed in a plating solution to fill all of the vias 108. The second layer 128 of the second metal is then deposited on the first layer 120 (or intermediate layer 126, if present), and the deposition is continued until the via 108 is sealed, resulting in a fully metallized via 108. In some embodiments of the via 108 having an hourglass shape, the constricted neck 114 creates a metal "bridge," and the conductive second metal is first deposited on the "bridge." The second metal is then deposited on both sides of the bridge until the second layer 128 is formed and the via 108 is filled. The "bridge" serves to prevent the second metal from depositing near the first surface 102 or the second surface 104 before the via 108 is filled with the second metal, which could block and isolate the interior of the via 108. Such isolation within the via 108 would result in the formation of a void within the via 108. Once the second layer 128 of the second metal has filled the via 108 in the glass substrate 100, the current is stopped and the glass substrate 100 is removed from the plating solution.

[0071] A second heat treatment is performed on the glass article 122 having the second layer 128. In step 212, method 200 further includes subjecting glass substrate 100 provided with second layer 128 of the second metal to a second heat treatment. First heat treatment step 204 and second heat treatment step 212 induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of glass substrate 100 to form glass article 122 having metal region 132 (see FIG. 8 ) including the first metal, the second metal, aluminum oxide, and silicon dioxide. Metal region 132 includes the first metal from first layer 120, the second metal from second layer 128, the intermediate metal from intermediate layer 126 (if used), and additional components from glass substrate 100, such as aluminum (or aluminum oxide) and silicon (or silicon dioxide). In other words, in step 204, the first metal from the first layer 120 is believed to intermix with the aluminum (or aluminum oxide) and silicon (or silicon dioxide) from the glass substrate 100. Furthermore, in step 212, the second metal from the second layer 128, the first metal from the first layer 120, the intermediate metal (if present) from the intermediate layer 126, and the aluminum (or aluminum oxide) and silicon (or silicon dioxide) from the glass substrate 100 are believed to intermix. Thus, the metal region 132 includes the first metal from the first layer 120, the second metal from the second layer 128, and the intermediate metal (if present) from the intermediate layer 126, as well as aluminum, silicon, and oxygen. At least a portion of the aluminum and silicon form an oxide phase in the metal region 132. The oxide phase includes aluminum oxide and silicon dioxide. Oxygen in the oxide phase can diffuse (migrate) from the glass substrate 100 or can enter the metal region 132 from the surrounding environment (e.g., air) during steps 204 and 212. Regardless of the source of the oxygen, the result is the formation of a metal region 132 that includes aluminum oxide and silicon dioxide.Without wishing to be bound by theory, it is believed that the presence of aluminum oxide and / or silicon dioxide in metal region 132 improves adhesion of the deposited first metal, second metal, and intermediate metal (if used) to glass substrate 100.

[0072] In some embodiments, the second heat treatment includes exposing the glass substrate 100 provided with the second metal second layer 128 to a temperature of at least 300°C for a time period of at least 20 minutes. In some embodiments, the second heat treatment includes exposing the glass substrate 100 provided with the second metal second layer 128 to a temperature of 300°C to 400°C for a time period of at least 20 minutes. In some embodiments, the second heat treatment includes exposing the glass substrate 100 provided with the second metal second layer 128 to a temperature of 300°C to a strain point temperature of the glass substrate 100, such as 300°C to 400°C, e.g., 325°C to 375°C, for a time period of at least 20 minutes, e.g., 20 minutes to 8 hours. In some embodiments where the glass substrate 100 is an interposer, step 212 includes exposing the glass interposer to a temperature between 300°C and the strain point of the glass substrate 100, such as between 300°C and 400°C, for example between 325°C and 375°C, for a period of at least 20 minutes.

[0073] One purpose of step 212 is to intermix the first metal, the second metal, the intermediate metal (if present), and the silicon (or silicon dioxide) and aluminum (or aluminum oxide) from the glass substrate 100, as described above. While temperatures below 300°C may achieve this purpose, such temperatures are likely to take too long for commercial purposes. While performing step 212 at temperatures below 300°C may achieve the intermixing described above, it would likely take too long for commercial purposes. Furthermore, temperatures of 400°C or less for step 212 are suitable for most glass substrates 100. Another purpose of step 212 is to remove stresses generated within the glass substrate 100. For example, forming vias 108 by laser machining in a glass substrate 100 intended for use as an interposer can generate thermal stresses within the glass substrate 100. However, annealing the glass substrate 100 after metallizing the vias 108 can remove any residual stresses that may exist.

[0074] In some embodiments, the glass substrate 100 with the second layer 128 is placed in a heating apparatus at room temperature, and the temperature in the heating apparatus is then increased at a predetermined rate to 300°C to 400°C (or a higher or lower temperature that is compatible with the glass substrate 100 and the time available for this process). For example, the predetermined rate can be in the range of 1°C per minute to 11°C per minute. The temperature in the heating apparatus is then maintained for the above-mentioned period. After the above-mentioned period has elapsed, the temperature in the heating apparatus is lowered to room temperature at any rate that does not cause thermal cracking of the glass substrate 100, for example, in the range of 0.6°C per minute to 2.0°C per minute. Suitable heating devices for step 212 include, for example, an annealing furnace, an annealing oven (e.g., Blue M brand products available from Thermal Product Solutions, Inc., New Columbia, Pennsylvania, USA), or a forced-draft furnace (e.g., Fisher Isotemp Programmable Forced-Draft furnace, manufactured by Fisher Scientific, Inc., Waltham, Massachusetts, USA). Note that the glass substrate 100 having the second layer 128 formed thereon can be annealed in nitrogen.

[0075] Glass article 122 having the bulk composition of glass substrate 100 and metal region 132 Referring now to FIG. 9 , as described above, in step 212, the glass substrate 100 having the first and second metals deposited thereon is subjected to elevated temperatures for the time period described above, thereby substantially intermixing the first metal, the second metal, the intermediate metal (if used), and the constituent elements of the glass substrate 100, such as silicon (or silicon dioxide) and aluminum (or aluminum oxide). This is particularly illustrated in FIG. 9 , which shows how the composition of an example glass article 122 made according to method 200 varies as a function of position within the glass article 122. As described above, the glass substrate 100 primarily comprises silicon dioxide and aluminum oxide by weight. Note, however, that the weight percentages of both silicon dioxide and aluminum oxide decrease as the position within the glass substrate 100 approaches the metal region 132. Time 0 on the x-axis of FIG. 9 can be interpreted as representing the major surface of the planar glass article 122, where the metal region 132 is exposed to the external environment. Time 0 on the x-axis of FIG. 9 can also be interpreted as representing the central axis 116 of the metallized via 108, with increasing time along the x-axis representing lateral separation from the central axis 116. Note that, because the deposition is by sputtering, the x-axis also represents the time unit of sputtering time. The longer the sputtering time, the greater the depth of the compositional measurements made on the sample. Therefore, the time shown on the graph also represents the depth within the glass article 122. However, because sputtering rates vary depending on the material, time values ​​cannot be simply converted to depth.

[0076] Metal region 132 includes a first metal (Ag in this example) and a second metal (Cu and Mn in this example). Metal region 132 also includes silicon dioxide and aluminum oxide. In some embodiments, the aluminum oxide is continuous throughout metal region 132. Within metal region 132, there is a subregion α that includes the second metal as a primary component (by weight percentage). That is, (i) the weight percentage of the second metal in subregion α is higher than that of the first metal, (ii) the weight percentage of the second metal in subregion α is higher than that of silicon dioxide, and (iii) the weight percentage of the second metal in subregion α is higher than that of aluminum oxide.

[0077] Furthermore, within metal region 132, there is a subregion β that contains a first metal as a major component (by weight percentage), a second metal in greater proportion than silicon dioxide, and a second metal in greater proportion than aluminum oxide. In subregion β, (i) the weight percentage of the first metal is higher than the second metal, (ii) the weight percentage of the first metal is higher than silicon dioxide, and (iii) the weight percentage of the first metal is higher than aluminum oxide. Also, the weight percentage of the second metal is higher than the weight percentage of silicon dioxide. The weight percentage of the second metal is higher than the weight percentage of aluminum oxide.

[0078] Furthermore, within metal region 132, there is a subregion γ that contains a first metal as a major component by weight percentage, silicon dioxide in a greater amount than the second metal, and aluminum oxide in a greater amount than the second metal. In subregion γ, (i) the weight percentage of the first metal is higher than the second metal, (ii) the weight percentage of the first metal is higher than the silicon dioxide, and (iii) the weight percentage of the first metal is higher than the aluminum oxide. Also, the weight percentage of silicon dioxide is higher than the weight percentage of the second metal. The weight percentage of aluminum oxide is higher than the weight percentage of the second metal.

[0079] Silicon (or silicon dioxide) and aluminum (or aluminum oxide) migrate from the glass substrate 100 to the metal region 132 during the heat treatment steps 204, 212 that bond the first metal and the second metal. A portion of the first metal from the first layer 120 migrates to bond with a portion of the second metal from the second layer 128 during the second heat treatment step 212, forming sub-region α. ​​A portion of the second metal from the second layer 128 migrates to bond with a portion of the first metal from the first layer 120 during the second heat treatment step 212, forming sub-region β and sub-region γ.

[0080] In some embodiments where the method 200 includes a step 208 of adding an intermediate layer 126 of an intermediate metal, the metal region 132 may further include an intermediate metal.

[0081] Of the partial region α, the partial region β, and the partial region γ, the partial region γ is the region closest to the glass substrate 100, and the partial region α is the region farthest from the glass substrate 100.

[0082] In some embodiments, the glass article 122 further includes a transition region 134 disposed between the glass substrate 100 and the metal region 132. The transition region 134 includes silicon dioxide as a primary component by weight percentage, but includes more of the first metal than aluminum oxide. In some embodiments, the transition region 134 is disposed between the bulk of the glass substrate 100 and the subregion γ of the metal region 132.

[0083] In some embodiments in which the glass article 122 is an interposer, the vias 108 are fully metallized, such that the vias 108 have metal regions 132. A subregion α containing the second metal as a primary component extends about the central axis 116 of each via 108. Once the vias 108 are filled with the metal regions 132 and fully metallized, the vias 108 can electrically connect the electrical wiring of each electrical component disposed on the first surface 102 and second surface 104 of the glass article 122.

[0084] Thus, substantial intermixing of the first metal, the second metal, the intermediate metal (if present), and the constituents of the glass substrate 100, such as silicon (or silicon dioxide) and aluminum (or aluminum oxide), (forming metal regions 132) results in a strong bond between the second metal and the glass substrate 100. Considering that method 200 does not require any "roughening," whether additive or subtractive, of the surface of the glass substrate 100 to which the second metal is to be applied, the resulting bond strength is surprising. Typically, such a roughening step is used to increase the surface roughness of the target surface of the glass substrate 100, which provides structural properties to the surface that allow the metal to physically bond. However, method 200 eliminates the need for such a roughening step, making it more cost-effective. In some embodiments, the surface roughness (R a ) is 1 to 3 nm. [Example]

[0085] Example 1 In Example 1, first, a glass substrate 100 was selected. The selected glass substrate 100 was Eagle XG (registered trademark) available from Corning Incorporated (Corning, New York, USA). This glass substrate 100 was an alkali-free aluminoborosilicate glass substrate, and its main components were silicon dioxide, aluminum oxide, calcium oxide, magnesium oxide, etc. More specifically, the glass substrate 100 contained 64.0 to 71.0 mol% SiO, 9.0 to 12.0 mol% AlO, 7.0 to 12.0 mol% BO, 1.0 to 3.0 mol% MgO, 6.0 to 11.5 mol% CaO, 0 to 2.0 mol% SrO, 0 to 0.1 mol% BaO, and at least 0.01 mol% SnO (on an oxide basis). When the mol% of AlO is [AlO] and the sum of the mol% of MgO, CaO, SrO, and BaO is Σ[RO], the relationship Σ[RO] / [AlO] was 1.00≦Σ[RO] / [AlO]≦1.25. The glass substrate 100 also had a first surface 102 and a second surface 104 that were substantially parallel and flat. The glass substrate 100 did not have vias 108.

[0086] A silver nanoparticle suspension was obtained and a first layer 120 of silver as the first metal was formed. This suspension consisted of silver nanoparticles with an average particle size of 10 nm to 13 nm dispersed in cyclohexane at a concentration of 20 wt %. This silver nanoparticle suspension was then subjected to ultrasonic treatment for 30 minutes. The ultrasonic treatment deflocculated the silver nanoparticles, improving their dispersion throughout the liquid carrier.

[0087] Next, step 202 of method 200 was performed to form a first layer 120 of silver as a first metal on the first surface 102 of the glass substrate 100. More specifically, the glass substrate 100 was contacted with a silver nanoparticle suspension. Specifically, the glass substrate 100 was spin-coated with the nanoparticle suspension to form the first layer 120 of silver as a first metal on the glass substrate 100. The rotation speed of the glass substrate 100 was 1000 rpm.

[0088] Next, the first heat treatment, which is step 204 of method 200, was performed. More specifically, the glass substrate 100 provided with the first layer 120 of silver as the first metal was placed on a heating plate having a temperature of 350°C for 2 minutes. Then, the glass substrate 100 provided with the first layer 120 of silver as the first metal was placed in a furnace having an air temperature of 350°C. The air temperature of the furnace was then increased to 400°C at a rate of 1°C per minute. The glass substrate 100 provided with the first layer 120 of silver as the first metal was left in the furnace for 1 hour.

[0089] Next, step 206 of method 200 was performed. More specifically, the sheet resistance of first layer 120 was measured using a Fluke 87A multimeter. The sheet resistance was 0.7 Ω / □. From this value, it was determined that the resistivity of first layer 120 was not so high that a second layer 128 of a second metal could be formed by electroplating in accordance with subsequent step 210 (i.e., first layer 120 has sufficient conductivity).

[0090] Next, step 210 of method 200 was performed to form a second layer 128 of copper-manganese alloy as a second metal on the first layer 120 of silver as a first metal. More specifically, a plating solution was prepared by dissolving copper sulfate and manganese sulfate (concentration: 1 M (mol / L)) in deionized water. Then, the glass substrate 100 provided with the first layer 120 of silver as a first metal was placed in the plating solution, and electroplating was performed using a copper plate as an electrode. A current of 50 mA was applied for one hour. As a result, a second layer 128 of copper alloy as a second metal with a thickness of 2.5 μm was formed on the first layer 120 by electroplating.

[0091] Next, the second heat treatment, step 212 of method 200, was performed. More specifically, the glass substrate 100 provided with the first layer 120 of silver as the first metal and the second layer 128 of copper-manganese alloy as the second metal was annealed in a vacuum oven. First, the glass substrate 100 was placed in a vacuum oven with a room temperature environment. Next, the temperature inside the vacuum oven, to which the glass substrate 100 was exposed, was increased from room temperature to 350°C at a rate of 5°C per minute. Next, the glass substrate 100 was exposed to a temperature of 350°C for 30 minutes. Next, the glass substrate 100 was cooled to room temperature at a rate of 5°C per minute.

[0092] A second heat treatment (step 212) of the glass substrate 100 provided with the first layer 120 of silver as the first metal and the second layer 128 of a copper-manganese alloy as the second metal resulted in a glass article 122, as described above in connection with FIG. 9 . In the resulting glass article 122, the first metal, silver, the second metals, copper and manganese, and silicon and aluminum, both present in the form of oxides, originating from the glass substrate 100, were dispersed throughout the entire metal region 132 in a substantially mixed state. Specifically, the glass substrate 100 was primarily composed of silicon dioxide and aluminum oxide, but the relative amounts of both silicon dioxide and aluminum oxide decreased with increasing distance from the glass substrate 100 to the metal region 132. The primary component of the subregions β and γ of the metal region 132 was silver originating from the first layer 120. Between the glass substrate 100 and the metal region 132 was a transition region 134 that was primarily silicon dioxide but contained more silver from the first layer 120 than aluminum oxide.

[0093] Subregions β and γ of metal region 132 were primarily composed of silver derived from first layer 120, but also contained copper and manganese migrated from second layer 128 throughout the region. Furthermore, in subregions β and γ, the relative amounts of silicon dioxide and aluminum oxide generally decreased toward subregion α. ​​In subregion γ, the weight percentages of silicon dioxide and aluminum oxide both exceeded the weight percentages of copper and manganese derived from second layer 128.

[0094] Subregion α of metal region 132 contained primarily copper and manganese from second layer 128. In subregion α of metal region 132, the weight percentages of copper and manganese from second layer 128 were higher than the weight percentage of silicon dioxide and higher than the weight percentage of aluminum oxide. The presence of aluminum oxide in subregion α is surprising because it indicates that aluminum or aluminum oxide migrated from glass substrate 100 to subregion α during first heat treatment step 204 and second heat treatment step 212. Furthermore, subregion α also contained silver from first layer 120.

[0095] The generation of a transition region 134 where silver from the first layer 120 appears to have entered the glass network structure, and the migration of aluminum or aluminum oxide throughout the metal region 132 resulted in a strong bond between the metal region 132 and the glass substrate 100, enabling the metal region 132 containing copper and manganese as the second metal to be strongly bonded to the silver deposited as the first layer 120 and to the glass substrate 100.

[0096] Referring to FIG. 10 , the resulting glass article 122 was subjected to a crosshatch tape test in accordance with ASTM standard D3359-09, "Standard Test Methods for Measuring Adhesion by Tape Test," to test the bondability (adhesion) of the metal region 132 to the glass substrate 100. The tape test was performed as follows: First, 11 vertical and 11 horizontal cuts were made in the metal region 132 to create a grid pattern. Next, pressure-sensitive adhesive tape was applied over this grid pattern. The tape was then peeled off. The amount and type of peeled material were compared with the descriptions and diagrams in the ASTM standard document. Upon tape peeling, 0% of the metal region 132 peeled off from the glass article 122. This test result corresponds to "5B" in the ASTM standard. This indicates a high level of bonding between the silver (the metal deposited as the first layer 120) and the copper and manganese (the metals deposited as the second layer 128) to the glass substrate 100.

[0097] Example 2 In Example 2, a glass substrate 100 was first selected. The glass substrate 100 selected in Example 2 was "Eagle XG" available from Corning Incorporated (Corning, New York, USA). Otherwise, the glass substrate 100 of Example 2 was similar to the glass substrate 100 of Example 1. The glass substrate 100 of Example 2 was then processed by a method 200 similar to that of the glass substrate 100 of Example 1, except for step 210. In step 210 of Example 2, a non-acidic plating solution was prepared by dissolving copper sulfate (concentration: 1 M (mol / L)) in deionized water. The copper plating solution may further contain sulfuric acid, but it has been found that this is unnecessary for step 210. The glass substrate 100 provided with a first layer 120 of silver as the first metal was then placed in the plating solution, and electroplating was performed using a copper plate as an electrode. A current of 50 mA was applied for one hour. As a result, a second layer 128 of copper as a second metal having a thickness of 2.5 μm was formed on the first layer 120 of silver by electroplating.

[0098] 11, the resulting glass article 122 was subjected to a similar crosshatch tape test in accordance with ASTM standard D3359-09, "Standard Test Method for Measuring Adhesion by Tape Test." Upon tape removal, 0% of the metal area 132 was removed from the glass article 122. This test result corresponds to a "5B" rating in the ASTM standard. This indicates that the silver (the metal deposited as the first layer 120) and the copper (the metal deposited as the second layer 128) were bonded to the glass substrate 100 at a high level.

[0099] Example 3 In Example 3, Lotus NXT manufactured by Corning Incorporated (Corning, New York, USA) was used as the glass substrate 100. This glass substrate 100 was an alkaline earth aluminoborosilicate glass substrate 100 containing aluminum oxide as a network former. Otherwise, the glass substrate 100 of Example 3 was processed in the same manner 200 as the glass substrate 100 of Example 2.

[0100] 12, the resulting glass article 122 was subjected to a similar crosshatch tape test in accordance with ASTM standard D3359-09, "Standard Test Method for Measuring Adhesion by Tape Test." Upon tape removal, 0% of the metal area 132 was removed from the glass article 122. This test result corresponds to a "5B" rating in the ASTM standard. This indicates that the silver (the metal deposited as the first layer 120) and the copper (the metal deposited as the second layer 128) were bonded to the glass substrate 100 at a high level.

[0101] Comparative Example 1 In Comparative Example 1, the glass substrate 100 used was "Eagle XG" available from Corning Incorporated (Corning, New York, USA), similar to that used in Example 2. The glass substrate 100 of Comparative Example 1 was processed in the same steps as in the method 200 of Example 2, except that the first heat treatment step 204 was omitted for the glass substrate 100 provided with the first layer 120 of silver as the first metal.

[0102] 13, a similar crosshatch tape test was performed on the glass article 122 obtained by performing the other steps, according to ASTM standard D3359-09, "Standard Test Method for Measuring Adhesion by Tape Test." Tape removal revealed that a significant percentage of the metal area 132 had delaminated from the glass substrate 100, indicating poor bonding of the copper and silver to the glass substrate 100. The poor bonding (adhesion) indicates that the first heat treatment step 204 for the glass substrate 100 having the first layer of the first metal 120 thereon is a critical step in the method 200 for achieving strong bonding of the second layer of the second metal 128 to the glass substrate 100.

[0103] Comparative Example 2 In Comparative Example 2, high-purity fused silica was used as the glass substrate 100. High-purity fused silica does not contain aluminum oxide as a network former. As a result, the softening temperature of high-purity fused silica is relatively high. The glass substrate 100 of Comparative Example 2 was processed using the same steps as in Method 200 of Example 2. The only difference was that high-purity fused silica was used as the glass substrate 100 instead of "Eagle XG" (which contains aluminum oxide).

[0104] 14, a similar crosshatch tape test was performed on the metal layer deposited on the glass substrate 100 following other steps, in accordance with ASTM Standard D3359-09, "Standard Test Method for Measuring Adhesion by Tape Test." Tape removal revealed that a significant percentage of the deposited metal had peeled off from the glass substrate 100, indicating poor bonding of the metal to the glass substrate 100. The poor bonding (adhesion) indicated that the presence of aluminum oxide in the composition of the glass substrate 100 is important for strong bonding of the second layer 128 of the second metal to the glass substrate 100.

[0105] Comparative Example 3 In Comparative Example 3, Lotus NXT available from Corning Incorporated (Corning, New York, USA) was used as the glass substrate 100, similar to that used in Example 3. The glass substrate 100 of Comparative Example 3 was processed in the same steps as in the method 200 of Examples 2 and 3, except that the first heat treatment step 204 was omitted for the glass substrate 100 provided with the first layer 120 of the first metal.

[0106] 15, a similar crosshatch tape test was performed on the metal layer deposited on the glass substrate 100 following other steps, in accordance with ASTM standard D3359-09, "Standard Test Method for Measuring Adhesion by Tape Test." Tape removal revealed that a significant percentage of the deposited metal had delaminated from the glass substrate 100, indicating poor bonding of the metal to the glass substrate 100. The poor bonding (adhesion) indicates that the first heat treatment step 204 for the glass substrate 100 having the first layer of the first metal 120 thereon is a critical step in the method 200 for achieving strong bonding of the second layer of the second metal 128 to the glass substrate 100.

[0107] Aspect 1 of the present description is forming a first layer of a first metal on a glass substrate comprising silicon dioxide and aluminum oxide; performing a first heat treatment on the glass substrate having the first layer of the first metal provided thereon; forming a second layer of a second metal on the first layer of the first metal; and performing a second heat treatment on the second layer of the second metal, The method includes a first heat treatment and a second heat treatment to induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0108] Aspect 2 of this description is a glass substrate having a first surface, a second surface, and at least one via, the first surface and the second surface being major surfaces of the glass substrate facing in generally opposite directions, the at least one via extending through the glass substrate and defined by a sidewall surface extending from the first surface to the second surface; 2. The method of embodiment 1, wherein a first layer of a first metal is formed on the sidewall surface.

[0109] Aspect 3 of the present description is The method of embodiment 1 or 2, wherein the glass substrate is an alkaline earth aluminoborosilicate substrate, an alkali aluminoborosilicate glass substrate, or an alkali aluminoborosilicate glass substrate.

[0110] Aspect 4 of the present description is 3. The method of claim 1 or 2, wherein the glass substrate is an alkali-free aluminoborosilicate glass substrate.

[0111] Aspect 5 of the present description is In the method according to any one of Aspects 1 to 4, the glass substrate has not been subjected to a treatment for roughening the surface.

[0112] Aspect 6 of the present description is Aspect 6. The method of any one of aspects 1 to 5, wherein the glass substrate has a composition comprising 6 to 15 mol % Al2O3 (on an oxide basis).

[0113] Aspect 7 of the present description is the glass substrate has a composition including (on an oxide basis) 64.0 to 71.0 mol % SiO2, 9.0 to 12.0 mol % Al2O3, 7.0 to 12.0 mol % B2O3, 1.0 to 3.0 mol % MgO, 6.0 to 11.5 mol % CaO, 0 to 2.0 mol % SrO, 0 to 0.1 mol % BaO, and at least 0.01 mol % SnO2; The method of any one of Aspects 1 to 5, wherein 1.00≦Σ[RO] / [Al2O3]≦1.25, where [Al2O3] is the molar percentage of Al2O3 and Σ[RO] is the sum of the molar percentages of MgO, CaO, SrO, and BaO.

[0114] Aspect 8 of the present description is Aspect 8. The method of any one of aspects 1-7, wherein the first metal consists essentially of silver.

[0115] Aspect 9 of the present description is Aspect 8. The method of any one of aspects 1-7, wherein the first metal comprises one or more of silver, palladium, platinum, ruthenium, nickel, cobalt, and gold.

[0116] Aspect 10 of the present description is Aspect 10. The method of any one of aspects 1-9, wherein forming a first layer of the first metal on the glass substrate comprises spin-coating the glass substrate with a nanoparticle suspension of the first metal.

[0117] Aspect 11 of the present description is Aspect 10. The method of any one of Aspects 1 to 9, wherein forming a first layer of a first metal on the glass substrate comprises electroless plating.

[0118] Aspect 12 of the present description is Aspect 12. The method of any one of Aspects 1 to 11, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. or greater.

[0119] Aspect 13 of the present description is Aspect 12. The method of any one of Aspects 1 to 11, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325°C to 425°C.

[0120] Aspect 14 of the present description is Aspect 12. The method of any one of aspects 1-11, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. or greater for a time period of 45 minutes or greater.

[0121] Aspect 15 of the present description is 12. The method of any one of Aspects 1 to 11, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. or higher for a time period of 45 minutes to 75 minutes.

[0122] Aspect 16 of the present description is 12. The method of any one of Aspects 1 to 11, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325°C to 425°C for a time period of 45 minutes to 75 minutes.

[0123] Aspect 17 of the present description is The method according to any one of aspects 1 to 16, After forming a first layer of a first metal and before forming a second layer of a second metal on the first layer of the first metal, determining that the first layer has either (a) a conductivity below a predetermined conductivity or (b) a resistivity above a predetermined resistivity; forming an intermediate layer of an intermediate metal on the first layer of the first metal by electroless plating; forming a second layer of a second metal on the first layer of a first metal includes forming a second layer of a second metal on an intermediate layer of an intermediate metal; The first and second heat treatments induce intermixing of the first metal, the intermediate metal, the second metal with at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0124] Aspect 18 of the present description is The method of any one of Aspects 1 to 17, wherein forming a second layer of a second metal on the first layer of a first metal includes forming the second layer of a second metal on the first layer by electroplating.

[0125] Aspect 19 of the present description is Aspect 19. The method of any one of aspects 1-18, wherein the second heat treatment comprises exposing the glass substrate having the second layer of the second metal thereon to a temperature of at least 300° C. for a time period of at least 20 minutes.

[0126] Aspect 20 of the present description is The method of any one of Aspects 1 to 18, wherein the second heat treatment comprises exposing the glass substrate having the second layer of the second metal thereon to a temperature of 300°C to 400°C for a time period of at least 20 minutes.

[0127] Aspect 21 of the present description is forming a first layer of a first metal on sidewall surfaces of one or more vias in a glass substrate comprising silicon dioxide and aluminum oxide; performing a first heat treatment on the glass substrate having the first layer of the first metal provided thereon; electroplating a second layer of a second metal over the first layer of the first metal to fully metallize the one or more vias; and performing a second heat treatment on the second layer of the second metal, The method includes a first heat treatment and a second heat treatment to induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0128] Aspect 22 of the present description is the first metal consists essentially of silver; 22. The method of embodiment 21, wherein the second metal comprises copper.

[0129] Aspect 23 of the present description is 23. The method of embodiment 21 or 22, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. or greater for a time period of 45 minutes or greater.

[0130] Aspect 24 of the present description is 23. The method of embodiment 21 or 22, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. or higher for a time period of 45 to 75 minutes.

[0131] Aspect 25 of the present description is 23. The method of claim 21 or 22, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. to 425° C. for a time period of 45 minutes to 75 minutes.

[0132] Aspect 26 of the present description is Aspects 26. The method of any one of Aspects 21-25, wherein the second heat treatment comprises exposing the glass substrate having the second layer of the second metal thereon to a temperature of at least 300° C. for a time period of at least 20 minutes.

[0133] Aspect 27 of the present description is Aspects 21-25, wherein the second heat treatment comprises exposing the glass substrate having the second layer of the second metal thereon to a temperature of 300°C to 400°C for a time period of at least 20 minutes.

[0134] Aspect 28 of the present description is the glass substrate has a composition including (on an oxide basis) 64.0 to 71.0 mol % SiO2, 9.0 to 12.0 mol % Al2O3, 7.0 to 12.0 mol % B2O3, 1.0 to 3.0 mol % MgO, 6.0 to 11.5 mol % CaO, 0 to 2.0 mol % SrO, 0 to 0.1 mol % BaO, and at least 0.01 mol % SnO2; If the mole percentage of Al2O3 is [Al2O3] and the sum of the mole percentages of MgO, CaO, SrO, and BaO is Σ[RO], then 1.00≦Σ[RO] / [Al2O3]≦1.25; The glass substrate is 20 x 10 -7 ~50×10 -7 28. The method of any one of Aspects 21 to 27, wherein the thermal expansion coefficient (CTE) is 1 / °C.

[0135] Aspect 29 of the present description is a glass substrate containing silicon dioxide and aluminum oxide as its main components (by weight percentage); 1. A glass article comprising: a first metal; a second metal; and a metal region comprising silicon dioxide and aluminum oxide; The metal area is a subregion α containing the second metal as a major component (by weight percentage); a partial region β containing the first metal as a main component (by weight percentage), containing the second metal in greater amounts than silicon dioxide, and containing the second metal in greater amounts than aluminum oxide; a subregion γ containing a first metal as a main component (by weight percentage), containing more silicon dioxide than the second metal, and containing more aluminum oxide than the second metal; It has Of the partial region α, the partial region β, and the partial region γ, the partial region γ is the region closest to the glass substrate, and the partial region α is the region farthest from the glass substrate.

[0136] Aspect 30 of the present description is 30. The glass article of claim 29, further comprising a transition region between the glass substrate and the partial region γ, the transition region containing silicon dioxide as a primary component (by weight percentage) and containing more of the first metal than aluminum oxide.

[0137] Aspect 31 of the present description is Aspect 31. The glass article according to aspect 29 or 30, wherein aluminum oxide is present seamlessly from the glass substrate to the partial region α.

[0138] Aspect 32 of the present description is the glass article is an interposer including a first surface, a second surface, a thickness between the first surface and the second surface, and at least one via opening at the first surface and extending through at least a portion of the thickness toward the second surface; Aspect 32. The glass article of any one of aspects 29 to 31, wherein each of the vias is fully metallized with a metal region disposed about a central axis of the via.

[0139] Aspect 33 of the present description is the first metal consists essentially of silver; Aspect 33. The glass article of any one of aspects 29 to 32, wherein the second metal comprises copper.

[0140] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the claims.

[0141] Preferred embodiments of the present invention will be described below in detail.

[0142] Embodiment 1 forming a first layer of a first metal on a glass substrate comprising silicon dioxide and aluminum oxide; performing a first heat treatment on the glass substrate provided with the first layer of the first metal; forming a second layer of a second metal on the first layer of the first metal; and performing a second heat treatment on the second layer of the second metal, wherein the first heat treatment and the second heat treatment induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0143] Embodiment 2 the glass substrate having a first surface, a second surface, and at least one via, the first surface and the second surface being major surfaces of the glass substrate facing in generally opposite directions, the at least one via being defined by a sidewall surface extending from the first surface to the second surface and penetrating the glass substrate; 2. The method of embodiment 1, wherein the first layer of the first metal is formed on the sidewall surfaces.

[0144] Embodiment 3 3. The method of claim 1 or 2, wherein the glass substrate is an alkaline earth aluminoborosilicate substrate, an alkali aluminoborosilicate glass substrate, or an alkali aluminoborosilicate glass substrate.

[0145] Embodiment 4 3. The method of claim 1 or 2, wherein the glass substrate is an alkali-free aluminoborosilicate glass substrate.

[0146] Embodiment 5 5. The method according to any one of embodiments 1 to 4, wherein the glass substrate has not been subjected to a treatment for roughening the surface.

[0147] Embodiment 6 6. The method of any one of embodiments 1 to 5, wherein the glass substrate has a composition comprising 6 to 15 mol % Al2O3 (on an oxide basis).

[0148] Embodiment 7 the glass substrate has a composition including (on an oxide basis) 64.0 to 71.0 mol % SiO2, 9.0 to 12.0 mol % Al2O3, 7.0 to 12.0 mol % B2O3, 1.0 to 3.0 mol % MgO, 6.0 to 11.5 mol % CaO, 0 to 2.0 mol % SrO, 0 to 0.1 mol % BaO, and at least 0.01 mol % SnO2; 6. The method of any one of claims 1 to 5, wherein 1.00≦Σ[RO] / [Al2O3]≦1.25, where [Al2O3] is the mole % of Al2O3 and Σ[RO] is the sum of the mole % of MgO, CaO, SrO, and BaO.

[0149] Embodiment 8 8. The method of any one of embodiments 1 to 7, wherein the first metal consists essentially of silver.

[0150] Embodiment 9 8. The method of any one of the preceding claims, wherein the first metal comprises one or more of silver, palladium, platinum, ruthenium, nickel, cobalt, and gold.

[0151] Embodiment 10 10. The method of any one of claims 1 to 9, wherein forming a first layer of a first metal on the glass substrate comprises spin-coating the glass substrate with a nanoparticle suspension of the first metal.

[0152] Embodiment 11 10. The method of any one of embodiments 1 to 9, wherein forming a first layer of a first metal on the glass substrate comprises electroless plating.

[0153] Embodiment 12 12. The method of any one of claims 1 to 11, wherein the first heat treatment comprises exposing the glass substrate provided with the first layer of the first metal to a temperature of 325°C or higher.

[0154] Embodiment 13 12. The method of any one of claims 1 to 11, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325°C or greater for a time period of 45 minutes or greater.

[0155] Embodiment 14 12. The method of any one of claims 1 to 11, wherein the first heat treatment comprises exposing the glass substrate provided with the first layer of the first metal to a temperature of 325°C or higher for a time period of 45 minutes to 75 minutes.

[0156] Embodiment 15 The method comprises: determining, after forming the first layer of the first metal and prior to forming the second layer of the second metal on the first layer of the first metal, that the first layer has either (a) a conductivity below a predetermined conductivity or (b) a resistivity above a predetermined resistivity; forming an intermediate layer of an intermediate metal on the first layer of the first metal by electroless plating; forming a second layer of a second metal on the first layer of the first metal includes forming the second layer of the second metal on the intermediate layer of the intermediate metal; 15. The method of any one of claims 1 to 14, wherein the first heat treatment and the second heat treatment induce intermixing of the first metal, the intermediate metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0157] Embodiment 16 15. The method of any one of claims 1 to 14, wherein forming a second layer of a second metal on the first layer of the first metal comprises forming the second layer of the second metal on the first layer by electroplating.

[0158] Embodiment 17 17. The method of any one of claims 1 to 16, wherein the second heat treatment comprises exposing the glass substrate provided with the second layer of the second metal to a temperature of at least 300°C for a time of at least 20 minutes.

[0159] Embodiment 18 forming a first layer of a first metal on sidewall surfaces of one or more vias in a glass substrate comprising silicon dioxide and aluminum oxide; performing a first heat treatment on the glass substrate provided with the first layer of the first metal; electroplating a second layer of a second metal over the first layer of the first metal to fully metallize the one or more vias; and performing a second heat treatment on the second layer of the second metal, wherein the first heat treatment and the second heat treatment induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

[0160] Embodiment 19 the first metal consists essentially of silver; 19. The method of embodiment 18, wherein the second metal comprises copper.

[0161] Embodiment 20 20. The method of claim 18 or 19, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. or greater for a time period of 45 minutes or greater.

[0162] Embodiment 21 21. The method of any one of claims 18 to 20, wherein the second heat treatment comprises exposing the glass substrate provided with the second layer of the second metal to a temperature of at least 300°C for a time of at least 20 minutes.

[0163] Embodiment 22 the glass substrate has a composition including (on an oxide basis) 64.0 to 71.0 mol % SiO2, 9.0 to 12.0 mol % Al2O3, 7.0 to 12.0 mol % B2O3, 1.0 to 3.0 mol % MgO, 6.0 to 11.5 mol % CaO, 0 to 2.0 mol % SrO, 0 to 0.1 mol % BaO, and at least 0.01 mol % SnO2; If the mole percentage of Al2O3 is [Al2O3] and the sum of the mole percentages of MgO, CaO, SrO, and BaO is Σ[RO], then 1.00≦Σ[RO] / [Al2O3]≦1.25; The glass substrate is 20×10 -7 ~50×10 -7 22. The method of any one of embodiments 18 to 21, wherein the thermal expansion coefficient (CTE) is 1 / °C.

[0164] Embodiment 23 a glass substrate containing silicon dioxide and aluminum oxide as its main components (by weight percentage); 1. A glass article comprising: a first metal; a second metal; and a metal region comprising silicon dioxide and aluminum oxide; The metal region is a subregion α containing the second metal as a main component (by weight percentage); a partial region β containing the first metal as a main component (by weight percentage), containing the second metal in a greater amount than silicon dioxide, and containing the second metal in a greater amount than aluminum oxide; a subregion γ containing the first metal as a main component (by weight percentage), containing more silicon dioxide than the second metal, and containing more aluminum oxide than the second metal; It has Of the partial region α, the partial region β, and the partial region γ, the partial region γ is the region closest to the glass substrate, and the partial region α is the region farthest from the glass substrate. A glass article.

[0165] Embodiment 24 24. The glass article of claim 23, further comprising a transition region between the glass substrate and the partial region γ, the transition region comprising silicon dioxide as a major component (by weight percentage) and containing more of the first metal than aluminum oxide.

[0166] Embodiment 25 25. The glass article according to claim 23 or 24, wherein aluminum oxide is present seamlessly from the glass substrate to the partial region α.

[0167] Embodiment 26 the glass article is an interposer including a first surface, a second surface, a thickness between the first surface and the second surface, and at least one via opening at the first surface and extending through at least a portion of the thickness toward the second surface; 26. The glass article of any one of claims 23-25, wherein each of the vias is fully metallized with the metal region disposed about a central axis of the via.

[0168] Embodiment 27 the first metal consists essentially of silver; 27. The glass article of any one of embodiments 23 to 26, wherein the second metal comprises copper. [Explanation of symbols]

[0169] 100 Glass substrate 102 First Side 104 Second Side 108 Beer 110 Side wall 114 Waist 120 First Layer 122 Glass articles 126 Middle Class 128 Second Layer 132 Metal area 134 Transient region

Claims

1. forming a first layer of a first metal on a glass substrate comprising silicon dioxide and aluminum oxide, the first metal comprising one or more of silver, palladium, platinum, ruthenium, nickel, cobalt, and gold; performing a first heat treatment on the glass substrate provided with the first layer of the first metal; forming a second layer of a second metal on the first layer of the first metal, the second metal comprising copper; and performing a second heat treatment on the second layer of the second metal, the first heat treatment and the second heat treatment induce intermixing of the first metal, the second metal, and at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide; The method, wherein the first heat treatment comprises exposing the glass substrate having the first layer of the first metal thereon to a temperature of 325° C. to 425° C. for a time period of 45 minutes or more.

2. the glass substrate having a first surface, a second surface, and at least one via, the first surface and the second surface being major surfaces of the glass substrate facing in generally opposite directions, the at least one via being defined by a sidewall surface extending from the first surface to the second surface and penetrating the glass substrate; The method of claim 1 , wherein the first layer of the first metal is formed on the sidewall surfaces.

3. The method according to claim 1 or 2, wherein the glass substrate is an alkaline earth aluminoborosilicate substrate, an alkali aluminoborosilicate glass substrate, or an alkali aluminoborosilicate glass substrate.

4. The method comprises: determining, after forming the first layer of the first metal and prior to forming the second layer of the second metal on the first layer of the first metal, that the first layer has either (a) a conductivity below a predetermined conductivity or (b) a resistivity above a predetermined resistivity; and forming an intermediate layer of an intermediate metal on the first layer of the first metal by electroless plating when the first layer is determined to have either (a) a conductivity below a predetermined conductivity or (b) a resistivity above a predetermined resistivity; forming a second layer of a second metal on the first layer of the first metal includes forming the second layer of the second metal on the intermediate layer of the intermediate metal; 4. The method of claim 1, wherein the first heat treatment and the second heat treatment induce intermixing of the first metal, the intermediate metal, the second metal with at least one of aluminum, aluminum oxide, silicon, and silicon dioxide of the glass substrate to form a metal region comprising the first metal, the second metal, aluminum oxide, and silicon dioxide.

Images