阅读说明：本技术 铝硅酸镁盐玻璃陶瓷 (Magnesium aluminosilicate glass-ceramics ) 是由 G·H·比尔 H·D·伯克 蔡岭 M·O·韦勒 于 2019-07-09 设计创作，主要内容包括：玻璃陶瓷包含：SiO-2的范围是40摩尔％至80摩尔％；Al-2O-3的范围是5摩尔％至20摩尔％；MgO的范围是5摩尔％至20摩尔％；以及B-2O-3、ZnO和TiO-2中的至少一种,每个的范围是0摩尔％至10摩尔％；从而使得玻璃陶瓷还包括铝硅酸镁盐晶相,其浓度是玻璃陶瓷的5重量％至80重量％。(The glass-ceramic comprises: SiO 2 2 Is in the range of 40 to 80 mole%; al (Al) 2 O 3 Is in the range of 5 to 20 mole%; MgO is in the range of 5 to 20 mole%; and B 2 O 3 ZnO and TiO 2 At least one of, each in the range of 0 mole% to 10 mole%; so that the glass-ceramic also comprises aluminiumMagnesium silicate crystal phase in a concentration of 5 to 80 wt.% of the glass-ceramic.)

1. A glass-ceramic, comprising:

SiO₂in the range of 40 to 80 mole%;

Al₂O₃in the range of 5 to 20 mole%;

MgO in the range of 5 to 20 mole%; and

B₂O₃ZnO and TiO₂At least one of, each in the range of 0 mole% to 10 mole%;

wherein the glass-ceramic further comprises a magnesium aluminosilicate crystalline phase at a concentration of 5 to 80 wt.% of the glass-ceramic.

2. The glass-ceramic of claim 1, comprising:

SiO₂in the range of 55 to 75 mole%;

Al₂O₃in the range of 9 to 15 mole%; and

MgO in the range of 7 to 15 mol%.

3. The glass-ceramic of claim 1 or 2, comprising:

B₂O₃ZnO and TiO₂In the range of from 0 mol% to 10 mol% of each.

4. The glass-ceramic of any of claims 1 or 2 wherein the magnesium aluminosilicate crystalline phase comprisesAt least one of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂。

5. The glass-ceramic of claim 4 wherein the magnesium aluminosilicate crystalline phase comprises at least two of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂。

6. The glass-ceramic of claim 4 wherein the magnesium aluminosilicate crystalline phase comprises at least three of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂。

7. The glass-ceramic of claim 4 wherein the magnesium aluminosilicate crystalline phase comprises at least MgAl₂O₄/ZnAl₂O₄And MgTiO₅。

8. The glass-ceramic of claim 7 wherein the aluminum magnesium silicate crystalline phase further comprises: ZrO (ZrO)₂；TiO₂；MgSiO₃；TiO₂And ZrO₂；TiO₂And MgSiO₃；ZrO₂And MgSiO₃；TiO₂、MgSiO₃And Mg₂Al₄Si₅O₁₈；TiO₂、MgSiO₃And Mg-filled beta-quartz; or TiO₂、MgSiO₃、Mg₂Al₄Si₅O₁₈And Mg-filled beta-quartz.

9. The glass-ceramic of any of claims 1-8, wherein the glass-ceramic is configured such that the dielectric loss is 0.001 or less for signals at frequencies of 1GHz or less.

10. The glass-ceramic of any of claims 1-9, wherein the glass-ceramic is configured such that the dielectric loss is 0.001 or less for signals at frequencies of 10GHz or less.

11. The glass-ceramic of any of claims 1-10, wherein the glass-ceramic is configured such that the dielectric loss is 0.001 or less for signals at frequencies of 10GHz or greater.

12. The glass-ceramic of claim 11 wherein the glass-ceramic is configured such that the dielectric loss is 0.001 or less for signals having a frequency of 25GHz to 60 GHz.

13. The glass-ceramic of any of claims 1-12, wherein the glass-ceramic is configured to have a dielectric constant of less than 6.0.

14. The glass-ceramic of any one of claims 1-13, wherein the glass-ceramic is configured as a two-dimensional plane having at least one smallest dimension of 1 cm.

15. An antenna, semiconductor circuit or signal transmission structure comprising the glass-ceramic of any one of claims 1-14.

16. A method of forming a glass-ceramic, comprising:

mixing a plurality of oxides to form a precursor composition;

melting the precursor composition at a temperature of at least 1500 ℃ for a time period of 1 hour to 24 hours;

annealing at a temperature of at least 500 ℃; and

ceramization is carried out at a temperature ranging from 750 ℃ to 1150 ℃ for a time ranging from 1 hour to 10 hours.

17. The method of claim 16, wherein the plurality of oxides comprises SiO₂、Al₂O₃、MgO、B₂O₃、ZnO、TiO₂Or ZrO₂At least two of them.

18. The method of claim 16 or 17, further comprising:

the melt is subjected to a shock crushing prior to the annealing step.

19. The method of claim 18, wherein mixing and melting are repeated a plurality of times.

20. The method of any one of claims 16-19, wherein ceramming is performed at a temperature in the range of 800 ℃ to 1000 ℃ for a time period of 2 hours to 6 hours.

1. Field of the invention

The present disclosure relates to glass ceramic compositions and articles, and more particularly, to magnesium aluminosilicate glass ceramic compositions and articles having low dielectric loss characteristics.

2. Background of the invention

As digital technology continues to expand, data connections and processing rates may experience a progression from about 1 Gbit/second to tens of Gbit/second. The corresponding electronics technologies required to achieve these data rates may result in signal transmission and reception frequencies that extend from about 1 gigahertz (GHz) to tens of GHz.

Due to the electrical and mechanical properties, the materials available at present are not sufficient to handle these bandwidth increases. For example, polymers (e.g., teflon) degrade at high temperatures and are difficult to bond to metal films in antennas, semiconductor circuits, and signal transmission structures of electronic devices. Other ones, such as ceramics (e.g., alumina) or glasses (e.g., aluminosilicates), either do not have the proper combination of loss tangent and dielectric constant characteristics or otherwise contain alkaline components that may undesirably diffuse into subsequently deposited films.

The present disclosure discloses magnesium aluminosilicate glass ceramic compositions and articles having improved dielectric loss characteristics.

Disclosure of Invention

In some embodiments, the glass-ceramic comprises: SiO 2₂Is in the range of 40 to 80 mole%; al (Al)₂O₃Is in the range of 5 to 20 mole%; MgO is in the range of 5 to 20 mole%; and B₂O₃ZnO and TiO₂At least one of, each in the range of 0 mole% to 10 mole%; wherein the glass-ceramic further comprises a crystalline phase of magnesium aluminosilicate having a concentration of from 5 to 80 weight percent of the glass-ceramic.

In one aspect that can be combined with any other aspect or embodiment, a glass-ceramic comprises: SiO 2₂Is in the range of 55 mole% to 75 mole%; al (Al)₂O₃Is in the range of 9 to 15 mole%; and MgO is in the range of 7 mol% to 15 mol%.

In one aspect that can be combined with any other aspect or embodiment, a glass-ceramic comprises: b is₂O₃ZnO and TiO₂In the range of from 0 mol% to 10 mol% of each.

In one aspect which can be combined with any other aspect or embodiment, the magnesium aluminosilicate crystalline phase comprises at least one of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂。

In one aspect that may be combined with any other aspect or embodiment, the magnesium aluminosilicate crystalline phase comprises at least two of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂。

In one aspect that can be combined with any other aspect or embodiment, the magnesium aluminosilicate crystalline phase comprises at least three of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂。

In one aspect which can be combined with any other aspect or embodiment, the magnesium aluminosilicate crystalline phase includes at least MgAl₂O₄/ZnAl₂O₄And MgTiO₅。

In one aspect which may be combined with any other aspect or embodiment, the magnesium aluminosilicate crystalline phase further comprises: ZrO (ZrO)₂；TiO₂；MgSiO₃；TiO₂And ZrO₂；TiO₂And MgSiO₃；ZrO₂And MgSiO₃；TiO₂、MgSiO₃And Mg₂Al₄Si₅O₁₈；TiO₂、MgSiO₃And Mg-filled beta-quartz; or TiO₂、MgSiO₃、Mg₂Al₄Si₅O₁₈And Mg-filled beta-quartz.

In one aspect that can be combined with any other aspect or embodiment, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals at frequencies of 1GHz or less.

In one aspect that can be combined with any other aspect or embodiment, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals at frequencies of 10GHz or less.

In one aspect which can be combined with any other aspect or embodiment, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals at frequencies of 10GHz or greater.

In one aspect that can be combined with any other aspect or embodiment, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals having a frequency of 25GHz to 60 GHz.

In one aspect that can be combined with any other aspect or embodiment, the glass-ceramic is configured to have a dielectric constant of less than 6.0.

In one aspect that can be combined with any other aspect or embodiment, the glass-ceramic is configured as a two-dimensional plane having at least one smallest dimension of 1 cm.

In one aspect that can be combined with any other aspect or embodiment, the antenna, semiconductor circuit, or signal transmission structure comprises any of the glass-ceramics disclosed herein.

In some embodiments, a method of forming a glass-ceramic comprises: mixing a plurality of oxides to form a precursor composition; melting the precursor composition at a temperature of at least 1500 ℃ for a period of 1 hour to 24 hours; annealing at a temperature of at least 500 ℃; and ceramming at a temperature range of 750 ℃ to 1150 ℃ for 1 hour to 10 hours.

In one aspect which can be combined with any other aspect or embodiment, the plurality of oxides includes at least two of: SiO 2₂、Al₂O₃、MgO、B₂O₃、ZnO、TiO₂Or ZrO₂。

In one aspect which can be combined with any other aspect or embodiment, the method further comprises: prior to the annealing step, the melt is subjected to a chopping (chopping) process.

In one aspect that can be combined with any other aspect or embodiment, the mixing and melting are repeated multiple times.

In one aspect that can be combined with any other aspect or embodiment, the ceramming is performed at a temperature in a range of 800 ℃ to 1000 ℃ for a time period in a range of 2 hours to 6 hours.

Drawings

The disclosure will be better understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows a schematic cross-sectional view of a glass ceramic laminate article according to some embodiments.

Fig. 2 shows a graph of loss tangent versus frequency for examples 1-3, according to some embodiments.

FIG. 3 shows a graph of dielectric constant versus frequency for examples 1-3, according to some embodiments.

Fig. 4 shows a graph of loss tangent versus frequency for examples 4-8, according to some embodiments.

FIG. 5 shows dielectric constant versus frequency for examples 4-8, according to some embodiments.

Fig. 6 shows a plot of loss tangent versus frequency for comparative examples, according to some embodiments.

FIG. 7 shows a graph of dielectric constant versus frequency for comparative examples, according to some embodiments.

FIG. 8 shows a graph of loss tangent versus frequency for magnesium aluminosilicate glass compositions and magnesium aluminosilicate glass ceramic compositions, according to some embodiments.

FIG. 9 shows a graph of dielectric constant versus frequency for magnesium aluminosilicate glass compositions and magnesium aluminosilicate glass ceramic compositions, according to some embodiments.

Detailed Description

Reference will now be made in detail to exemplary embodiments, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the exemplary embodiments. It is to be understood that the application is not limited to the details or methodology set forth in the description or illustrated in the drawings. It is also to be understood that the terminology is for the purpose of description only and should not be regarded as limiting.

Moreover, any examples set forth in this specification are intended to be illustrative, not limiting, and merely set forth some of the many possible embodiments for the claimed invention. Other suitable modifications and adjustments will generally be apparent to those skilled in the art based on various conditions and parameters, which are within the spirit and scope of this disclosure.

As signal frequencies increase to accommodate increased data processing rates, specifications and requirements relating to absorption losses associated with insulating materials used in electronic devices become increasingly important. For example, with the use of higher frequency communication signals, the signals must pass through various physical obstructions that may cause attenuation or blockage of these signals. Examples of physical barriers are electrically insulating substrates (e.g., antennas, semiconductor circuits, signal transmission structures) used in circuit fabrication. These obstacles and substrates have an impact on the electrical performance of the electronic device because the obstacles and substrates are configured to transmit high frequency signals or are located close to the area associated with the increased signal frequency transmitted by the device. Because these physical barrier materials are not complete insulators, they are associated with dielectric losses that affect the strength of signals passing through them.

In other words, a higher loss tangent physically represents a material with a greater ability to convert electromagnetic energy into thermal energy. For electromagnetic waves (EM) propagating through the device material, its electromagnetic energy is converted into thermal energy resulting in a reduction in the intensity of the signal frequency transmitted by the device, thereby degrading electrical performance.

Dissipation losses represent radiated energy as the EM propagates,

the compositions and substrates (particularly glass ceramic compositions) presented herein are suitable for use in electronic devices, electronic device substrates, and other compatible applications that enable higher frequency communications in the devices without significant performance degradation as is related to other non-electrical device requirements. In addition, the glass-ceramic composition can be formed in lower cost manufacturing processes (e.g., a pull-up forming process, a roll-to-sheet process, a float process, and a pull-down (e.g., slot draw, fusion draw, etc.) forming process).

Definition of

The term "coupled" (in all forms: connected, and the like) generally means that two elements are joined to each other either directly or indirectly (electrically or mechanically). Such engagement may naturally be static or may naturally be movable. Such joining may be achieved through the two components and any additional intermediate elements (electrically or mechanically) that are integrally formed as a single unitary piece with each other or with the two components. Such engagement may naturally be permanent, or may naturally be removable or disengagable, unless otherwise stated.

The terms "glass article", "glass-ceramic article" and "glass-ceramic article" are used in their broadest sense to include any object made in whole or in part of glass and/or glass-ceramic. All compositions are expressed as mole percent (mol%) unless otherwise indicated.

Unless otherwise indicated, the term "Coefficient of Thermal Expansion (CTE)" means taking an average over a temperature range of 20 ℃ to 300 ℃. The CTE can be determined by using a program such as that described in ASTM E228 "Standard Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilator" or ISO 7991:1987 "Glass-Determination of coeffient of mean Thermal Expansion" or the like.

In embodiments for glass-ceramic laminate articles having a core glass layer and a clad glass-ceramic layer, the terms "lower CTE" and "low CTE" may be used interchangeably for clad layers made from glass-ceramic compositions (e.g., prior to ion exchange) having a CTE lower than the CTE of the core layer in the present disclosure. In some examples, the CTE of the cladding layer is at least about 5x10 less than the CTE of the core layer as a result of the inclusion of the glass-ceramic composition of the present disclosure^-7/℃。

With respect to the laminated glass-ceramic structures of the present disclosure, the terms "mechanically strengthened" and "mechanically strengthened" mean that the glass-ceramic or laminate is formed by laminating a high CTE core glass with a low CTE clad glass-ceramic layer(s) such that when the laminate is cooled after lamination, compressive stress is created in the cladding layers. These compressive stresses may counteract externally applied mechanical stresses (e.g., applied through manufacturing-related handling, application-related loading, and other sources), which have a net effect on the reinforcement of the laminate.

In the present disclosure, the terms "loss tangent", "dielectric loss tangent" and "dielectric loss"used interchangeably, refers to the inherent dissipation of electromagnetic energy (e.g., heat) imparted by a particular glass-ceramic composition, layer, or laminate structure in connection with embodiments of the present disclosure. The loss tangent can be parameterized by the loss angle (δ) or the corresponding loss tangent (tan δ). The complex permittivity (permitvity) is the ability of a substance (e.g., the glass-ceramic of the present disclosure) to store electrical energy in the presence of an external electric field. Furthermore, the terms "complex dielectric constant" and "average dielectric constant (D)_k) "may be used interchangeably in this disclosure. The complex dielectric constant is complex in that it describes the phase and magnitude of the polarization associated with the oscillating field. In the present disclosure, the term "average dielectric constant (D)_k) "and" relative complex dielectric constant (. epsilon.)_r) "is used interchangeably and is defined as the ratio of the real part of the complex permittivity to the permittivity of free space.

"loss tangent" is expressed as the ratio of the imaginary part to the real part of the complex dielectric constant. Generally, the average dielectric constant and loss tangent of a material depend on the frequency of the external field. Thus, dielectric properties measured in the kHz range may not be representative of dielectric properties of microwave frequencies. Furthermore, unless otherwise specified, the "loss tangent" and "average dielectric constant (D) of the glass-ceramics of the present disclosure_k) "Properties can be measured at 1GHz or higher frequencies, in an open cavity resonator configuration, according to Split Post Dielectric Resonator (SPDR), or according to techniques understood by those skilled in the art of this disclosure. The particular method selected may be selected based on the thickness of the sample and its lateral dimensions.

The present disclosure generally relates to glass-ceramic compositions having varying levels of crystalline phases and articles having magnesium aluminosilicate glass compositions. These glass-ceramics (including in the layers used to laminate the glass-ceramic articles) typically have low dielectric loss characteristics. The glass-ceramic is preferably alkali-free and, after ceramization, the mineral crystallizes during the heat treatment. As a result, the remaining glass component is relatively silica-rich, making the remainder closer to pure SiO₂This is very goodDielectric properties. Minerals can also have very good dielectric properties, and thus the combination of glass and minerals contributes to the overall electrical properties of the material. For example, some aspects of the present disclosure relate to glass-ceramic compositions comprising a loss tangent of 0.001 or less for signals having a frequency greater than 1GHZ or less than 1 GHZ. In addition, these glass-ceramic compositions are generally characterized as having relatively low CTE values, e.g., less than 70x10^-7This would make them well suited for use as core glass layers with higher CTE values (i.e., the CTE value of the core layer is at least as good as the cladding layer, or at least 70x10^-7/° c) of a laminate (e.g., a mechanically reinforced laminate).

The magnesium aluminosilicate glass ceramic contains a network former SiO₂、Al₂O₃And MgO. In some instances, SiO is present₂The following ranges are possible: from 40 mol% to 80 mol%, alternatively from 45 mol% to 75 mol%, alternatively from 50 mol% to 70 mol% (e.g., 58 mol%), alternatively from 55 mol% to 65 mol%, alternatively from 60 mol% to 70 mol%. In some instances, Al is present₂O₃The following ranges are possible: 5 to 20 mole%, or 8 to 17 mole%, or 10 to 15 mole% (e.g., 14 mole%), or 9 to 12 mole%. In some examples, MgO present may be in the following ranges: 5 to 20 mol%, alternatively 8 to 17 mol%, alternatively 7 to 12 mol%, alternatively 10 to 15 mol% (e.g., 14 mol%).

In some instances, SiO is present₂Can be from 40 mol% to 80 mol%, Al present₂O₃May be 5 to 20 mol% and MgO present may be 5 to 20 mol%. In some instances, SiO is present₂Can be 55 mol% to 75 mol%, Al present₂O₃May be 9 to 15 mol% and MgO present may be 7 to 15 mol%. In some instances, SiO is present₂Can be 60 mol% to 70 mol%, Al present₂O₃Can be10 to 15 mol% and MgO present may be 10 to 15 mol%. In some instances, SiO is present₂Can be 60 mol% to 70 mol%, Al present₂O₃May be 9 to 12 mol% and MgO present may be 7 to 12 mol%. In some instances, SiO is present₂Can be 55 to 65 mol%, Al present₂O₃May be 10 to 15 mol% and MgO present may be 10 to 15 mol%.

In some examples, the magnesium aluminosilicate glass-ceramic comprises B₂O₃ZnO and TiO₂At least one of (1). In some examples, the magnesium aluminosilicate glass-ceramic comprises B₂O₃ZnO and TiO₂At least two of them.

In some examples, B is present₂O₃The following ranges are possible: 0 to 10 mol%, alternatively 1 to 8 mol%, alternatively 2 to 5 mol%, alternatively 2 to 3 mol%. In some examples, the ZnO present may be in the following range: 0 to 10 mol%, alternatively 1 to 8 mol%, alternatively 3 to 6 mol%, alternatively 4 to 5 mol%. In some instances, TiO is present₂The following ranges are possible: 0 to 10 mol%, alternatively 1 to 9 mol%, alternatively 3 to 7 mol%, alternatively 5 to 6 mol%.

In some examples, B is present₂O₃Can be 0 mol% to 10 mol% (e.g., 0 mol%), the ZnO can be present 3 mol% to 6 mol% (e.g., 5 mol%), and the TiO can be present₂Can be 3 to 7 mole% (e.g., 6 mole%). In some examples, B is present₂O₃May be 2 mol% to 5 mol% (e.g., 2.8 mol% or 3 mol%), ZnO may be present 3 mol% to 6 mol% (e.g., 4.4 mol% or 5 mol%), and TiO may be present₂Can be 3 to 7 mole% (e.g., 5.3 or 6 mole%).

In some examples, the magnesium aluminosilicate glass-ceramic comprises a crystalline phase at a concentration of 5 wt.% to 80 wt.% of the glass-ceramic. In some examples, the crystalline phases are in the following ranges: 10 to 75 mole%, alternatively 20 to 65 weight%, alternatively 25 to 50 weight%, alternatively 35 to 50 weight%. In some examples, the crystalline phases are in the following ranges: 5 to 75 wt%, or 5 to 50 wt%, or 5 to 40 wt%, or 5 to 30 wt%, or 5 to 25 wt%, or 5 to 15 wt%, or 5 to 10 wt%.

In some examples, the magnesium aluminosilicate crystalline phase comprises at least one of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂. In some examples, the magnesium aluminosilicate crystalline phase comprises at least two of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂. In some examples, the magnesium aluminosilicate crystalline phase comprises at least three of: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, or SiO₂. In some examples, the magnesium aluminosilicate crystalline phase comprises at least MgAl₂O₄/ZnAl₂O₄And MgTiO₅. In some examples, the magnesium aluminosilicate crystalline phase may further comprise: ZrO (ZrO)₂；TiO₂；SiO₂；MgSiO₃；TiO₂And ZrO₂；TiO₂And MgSiO₃；ZrO₂And MgSiO₃；TiO₂、MgSiO₃And Mg₂Al₄Si₅O₁₈；TiO₂、MgSiO₃And Mg-filled beta-quartz; or TiO₂、MgSiO₃、Mg₂Al₄Si₅O₁₈And Mg-filled beta-quartz. In some examples, the Mg-filled beta-quartz comprises MgO and Al₂O₃And SiO₂The ratio of (A) to (B) is in the range of 1:1:2 to 1:1: 8.

In some embodiments, the glass-ceramic may be formed by a pull-up process. In some embodiments, the glass-ceramic may be formed by a downdraw process (e.g., slot draw and fusion draw forming processes). The fusion draw process is an industrial technique that can be used to mass produce thin glass sheets. The fusion draw process results in thin glass sheets with superior flatness and surface quality compared to other flat glass manufacturing techniques. As a result, fusion draw can be used to make thin glass substrates for cover glass for liquid crystal displays as well as various personal electronic devices.

The fusion draw process involves flowing molten glass from a trough known as an "isopipe," which is typically made of zircon or other refractory material. The molten glass overflows the top of the isopipe from both sides and merges at the bottom of the isopipe to form a single sheet, wherein the isopipe is brought into direct contact with only the interior of the final sheet. Since neither exposed surface of the final glass sheet is in contact with the isopipe material during the drawing process, both external surfaces of the glass are of a perfect quality without subsequent finishing.

To enable fusion drawing, it is desirable that the glass-ceramic composition have a sufficiently high liquidus viscosity (i.e., the viscosity of the molten glass at the liquidus temperature). In some implementations of the present disclosure, the glass ceramic composition has a liquidus viscosity of greater than 5 kpoise, greater than 10 kpoise, greater than 50 kpoise, or even greater than 100 kpoise.

A single isopipe was used to complete the conventional fusion draw process to obtain a uniform glass product. In some instances, more complex fusion draw processes may be used to form the laminated glass-ceramic article. In the laminate fusion draw process, two isopipes are used to form a laminate sheet comprising a core glass composition (higher CTE) surrounded on one or both sides by an outer cladding layer comprising a glass ceramic composition. One advantage of the laminate fusion process is that when the CTE of the clad glass-ceramic is less than that of the core glass layer, the CTE difference (i.e., CTE mismatch) between the two elements results in a compressive stress being built up in the outer cladding layer. Such compressive stress increases the strength of the final laminate glass-ceramic product without the need for additional strengthening (e.g., by ion exchange treatment).

In some examples, two pieces of the downdraw glass ceramic composition of the present disclosure may be laminated by a roll-to-roll process. Such compositions preferably have a liquidus viscosity of about 5 kpoise to about 10 kpoise. The sheets are rolled together and then subjected to a "cake cutting" step to form the resulting laminate into sheet form.

Referring now to fig. 1, in some embodiments, a glass ceramic laminate 100 may be formed using a glass ceramic composition according to the present disclosure. As described above, the glass ceramic laminate 100 is exemplary; thus, the glass-ceramic compositions of the present disclosure can be used in other articles, forms, and structures (e.g., non-laminate substrates for electronic devices, non-laminate device covers, etc.). The glass-ceramic laminate 100 includes a core glass layer 110 surrounded by a pair of cladding layers 120, the cladding layers 120 each comprising a glass-ceramic composition according to the present disclosure. For example, the cladding layer may comprise: SiO 2₂Is in the range of 40 to 80 mole%; al (Al)₂O₃Is in the range of 5 to 20 mole%; MgO is in the range of 5 to 20 mole%; b is₂O₃ZnO and TiO₂At least one of, each in the range of 0 mole% to 10 mole%; and all values in between these concentrations.

As shown in fig. 1, a pair of clad layers 120 are laminated to the core glass layer 110 at its main surfaces 6, 8. Further, the CTE of the core glass layer 110 of the glass-ceramic laminate 100 is greater than or equal to the CTE of the glass-ceramic composition used for the cladding layer 120. In some examples, the glass-ceramic is configured as a two-dimensional plane having at least one smallest dimension of 1 cm.

In some implementations, exemplary glass-ceramic compositions that can be used for cladding layer 120 (examples 1-8) are provided in table 1 below, and: table 2 shows their crystal phase compositions, FIGS. 2 and 4 show loss tangents, and FIGS. 3 and 5 show dielectric constants (D) at frequencies of less than 10GHz_k) Values (examples 1 to 8) and dielectric constant (D) at frequencies greater than 10GHz_k) Values (examples 4-8).

Examples

The embodiments described herein are further illustrated by the following examples. Table 1 below describes the chemical composition of examples 1-8.

For the glass-ceramic compositions presented herein (including the exemplary compositions of table 1), each oxide component has functionality. Pure SiO₂Has a low CTE and is incompatible with the fusion draw process due to its high melting temperature. Thus, SiO in the glass-ceramic₂The amount of (A) is 40 to 80 mol%, and all SiO between these levels₂Amount of the compound (A). Comprising greater than about 50 mol% SiO₂The composition of (a) may result in a lower loss tangent at greater than or equal to 10 GHz.

Alumina (Al)₂O₃) May serve to increase the stiffness of the resulting glass-ceramic of the present disclosure. However, Al should be carefully controlled₂O₃Since it may also inhibit the formation of sufficient crystalline phase levels, which may negatively affect the loss tangent properties of the resulting glass-ceramic. Therefore, Al in the glass-ceramic₂O₃The amount of (C) is 5 to 20 mol%, and all Al between these levels₂O₃Amount of the compound (A). In addition, alkaline earth oxides (e.g., MgO) may function to improve the melting behavior of the glass-ceramic compositions of the present disclosure. Thus, the amount of MgO in the glass-ceramic is 5 mol% to 20 mol%, and all MgO amounts between these levels.

In these compositions, Al is included as a network former₂O₃And MgO to ensure formation of a stable glass (prior to crystal establishment), minimize CTE, and facilitate fusionAnd (4) forming and shaping. By reacting these network formers with SiO₂Mixing at the appropriate concentration can achieve a stable bulk glass while minimizing the need for additional network modifiers (e.g., alkali metal oxides).

For B₂O₃This metal oxide can reduce the viscosity of the glass and aid in the forming process, including the fusion draw forming process. Thus, B in the glass-ceramic₂O₃The amount of (B) is 0 to 10 mol%, and all B between these levels₂O₃Amount of the compound (A). For ZnO, this metal oxide may promote melting. Thus, the amount of ZnO in the glass-ceramic is 0 mol% to 10 mol%, and all ZnO amounts between these levels. For TiO₂This metal oxide functions as a nucleating agent for crystallization. Thus, TiO in the glass-ceramic₂In an amount of 0 to 10 mole%, and all TiO between these levels₂Amount of the compound (A).

TABLE 1

The following table 2 describes the crystalline phase compositions of examples 1-8. The differences between examples 4 and 5 and examples 6-8 may be due to differences in the blending, amount and size of the mineral phases.

TABLE 2

Fig. 2 and 4 show graphs of loss tangent versus frequency for examples 1-3 (fig. 2) and examples 4-8 (fig. 4), according to some embodiments. Figures 3 and 5 show graphs of dielectric constant versus frequency for examples 1-3 (figure 3) and examples 4-8 (figure 5), according to some embodiments.

Loss tangent is the ability of a substance to dissipate electromagnetic energy (e.g.,heat) and can be parameterized by the loss angle δ or the loss tangent tan δ. Complex permittivity is the ability of a substance to store electrical energy in the presence of an external electric field. The complex dielectric constant is complex in that it describes the phase and magnitude of the polarization associated with the oscillating field. The loss tangent is expressed as the ratio of the imaginary part to the real part of the dielectric constant as a complex number. Dielectric constant (or relative complex dielectric constant,. epsilon.)_r) Is defined as the ratio of the real part of the complex permittivity as a complex number to the complex permittivity of free space. Generally, both the dielectric constant and the loss tangent of a material depend on the frequency of the external field.

As seen from fig. 2 and 3, examples 1-3 all exhibited a loss tangent of less than 0.001 and a dielectric constant of less than 5.6 for frequency signals below 1GHz, thus being suitable for existing wireless operating frequencies (which are typically below 10 GHz). However, as described above, the data rates expected to be achieved by next generation devices may result in signal transmission and reception frequencies extending to tens of GHz. Figures 4 and 5 illustrate next generation materials that are capable of achieving electrical properties comparable to those observed in examples 1-3 at low frequencies below 10GHz and higher frequencies above 25 GHz. All embodiments in the frequency range of 25GHz and 50GHz, except for embodiment 4 at 50GHz, have a loss tangent of less than 0.001 and a dielectric constant of less than 5.5 (and in some embodiments, less than 5.0).

According to some embodiments, the loss tangent (fig. 6) and the dielectric constant (fig. 7) of the comparative examples were measured. As seen from fig. 6, pure glass samples (e.g., alkali-containing and alkali-free borosilicate glasses and soda lime glasses) not only had a loss tangent in excess of 0.001 at 10GHz, but also steadily increased when exposed to higher frequencies up to 60 GHz. Specifically, for alkali-free borosilicate glasses and soda-lime glasses, the loss tangent approaches or even exceeds 0.01, or is 10 times higher than that measured in examples 4-8. While alkali-containing boroaluminosilicate glasses have somewhat lower loss tangents (but still measurably above 0.001), the alkali component exhibits undesirable diffusion into subsequently deposited films, negatively impacting device performance.

The alumina ceramic did exhibit a loss tangent below or slightly above 0.0001 for the entire frequency range, but did not have a suitably low dielectric constant (which is about 10 between 10GHz and 60 GHz) (in contrast to examples 4-8 being below 5.5). High dielectric constant materials are generally not suitable for the continued scaling of microelectronic devices. For example, signal reflection may be controlled by the dielectric constant. In laminates (e.g., those described herein), it is possible to obtain structures that produce low reflection through the combination of a low dielectric glass-ceramic cladding and a high dielectric glass core. Thus, the desired function of the high dielectric alumina and cladding is directly contradictory. Teflon exhibits a low loss tangent of less than 0.001 with a dielectric constant of about 2 for the entire frequency range. However, as explained above, wireless devices are discarding polymer-based materials that degrade at high temperatures and are difficult to bond with metal films in antennas, semiconductor circuits, and signal transmission structures of electronic devices.

FIGS. 8 and 9 show graphs of loss tangent and dielectric constant versus frequency for magnesium aluminosilicate glass compositions and magnesium aluminosilicate glass ceramic compositions, respectively, according to some embodiments. While both have relatively similar compositions, in some instances, the ceramming process from which the crystalline phases of the glass-ceramic composition originate involves heating the glass-ceramic at a nucleation temperature of 750 ℃ to 1150 ℃ for 1 hour to 10 hours. In some examples, the first step involves mixing multiple oxides (e.g., SiO)₂、Al₂O₃、MgO、B₂O₃ZnO or TiO₂) To form a precursor composition.

Thereafter, the precursor composition is melted at a temperature of at least 1500 ℃ for a time period of 1 hour to 24 hours. In some examples, the melting is performed at a temperature of at least 1600 ℃ (e.g., 1650 ℃). In some examples, the melting is performed for a duration of 4 hours to 20 hours (e.g., 16 hours) or 8 hours to 12 hours.

After melting, the melt is shattered in the process, thereby reducing the time and energy required to shatter the glass into finely divided particles, and the melt (i.e., molten glass) is poured from the furnace in a fine stream into a water bath to rapidly quench the glass. As a result, the molten glass stream can be broken into small fragments, which can then be ground to the desired particle size. In some examples, a stream of molten glass may be passed between metal rollers to form a thin glass ribbon, which is then ground and ground to a desired particle size. In some instances, mixing and melting are repeated multiple times prior to the breaking.

In some examples, after the comminution, annealing is optionally performed at a temperature of at least 500 ℃, at least 600 ℃, at least 700 ℃ (e.g., 750 ℃), or at least 800 ℃. In some instances, the sample may be quenched immediately in water. The glass particles are then remelted under the same or similar conditions as for melting (as described above), poured and annealed.

Finally, ceramming may be performed at a nucleation temperature range of 750 ℃ to 1150 ℃ for 1 hour to 10 hours. In some examples, ceramming can be performed at nucleation temperature ranges of 800 ℃ to 1100 ℃, or 850 ℃ to 1050 ℃, or 900 ℃ to 1000 ℃ (e.g., 950 ℃), and all values in between these temperatures. In some examples, ceramization may be performed at a nucleation temperature of 800 ℃, or 850 ℃, or 900 ℃, or 950 ℃, or 1000 ℃. In some examples, ceramming may include multiple heat treatments at different temperatures and durations between about 750 ℃ to about 1150 ℃ for between about 1 to about 10 hours.

In some examples, ceramming may be performed for a time period ranging from 2 hours to 12 hours, or from 3 hours to 9 hours (e.g., 4 hours), or from 4 hours to 8 hours, and all values in between these times. In some examples, ceramming may be performed for a period of 2 hours, or 3 hours, or 4 hours, or 5 hours, or 6 hours. In some examples, ceramming may be performed at a nucleation temperature range of 800 ℃ to 1000 ℃ for a time period of 2 hours to 6 hours.

In some examples, ceramming may be followed by a crystal growth process (i.e., formation of a crystalline phase) at 1000 ℃ to 1100 ℃ for about 2 hours. In some examples, ceramization may be performed at 850 ℃ for 2 hours, followed by a heat treatment at 900 ℃ for 4 hours or 950 ℃ for 4 hours. In some examples, the temperature range in which the crystal growth process is performed may be: 750 ℃ to 1350 ℃, or 800 ℃ to 1300 ℃, or 850 ℃ to 1250 ℃, or 900 ℃ to 1200 ℃, or 950 ℃ to 1150 ℃, or 1000 ℃ to 1100 ℃, and all values in between these temperatures.

X-ray diffraction (XRD) measurements were performed to identify crystalline phases. Dielectric properties of glass-ceramics subjected to a ceramization condition at 950 ℃ for 4 hours were measured on polished samples (which were 3 inches by 3 inches or 5 inches by 5 inches and less than 1mm in thickness). As shown in table 2, at least the following minerals were observed: MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃Or ZrO₂。

Returning to fig. 8 and 9, the magnesium aluminosilicate glass has a comparable but slightly higher dielectric constant than the associated glass-ceramic that has been subjected to the treatment described above. Similar to the loss tangent observed for the borosilicate glass of fig. 6, the loss tangent of the aluminosilicate glass steadily increases and approaches 0.01 (about 0.006 at 10GHz and about 0.009 at 60 GHz) over the frequency range of 10GHz to 60 GHz. Thus, at higher frequencies (where the electronic device will operate to handle data connections and processing rates of tens of Gbits/sec), the loss tangent of magnesium aluminosilicate glass is almost 10 times as high as that measured for magnesium aluminosilicate glass ceramics. Such as MgAl₂O₄/ZnAl₂O₄、MgTiO₅、TiO₂、MgSiO₃、ZrO₂、Mg₂Al₄Si₅O₁₈Mg-filled beta-quartz, SiO₂The presence of such crystalline minerals serves to reduce the loss tangent of the magnesium aluminosilicate glass.

In some examples, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals at frequencies of 1GHz or less. In some examples, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals at frequencies of 10GHz or less. In some examples, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals at frequencies of 10GHz or higher. In some examples, the glass-ceramic is configured to have a dielectric loss of 0.001 or less for signals in the frequency range of 25GHz to 50 GHz. In some examples, the glass-ceramic is configured to have a dielectric constant of less than 6.0.

In some examples, the glass-ceramics of the present disclosure may contain a low concentration of at least one fining agent, such as SnO₂、CeO₂、As₂O₃、Sb₂O₅、Cl^-Or F^-Etc. to help reduce or in any other way eliminate gaseous inclusions during the melting process. In some examples, the glass-ceramic comprises SnO₂The fining agent may range from 0.005 mol% to 0.7 mol%, alternatively from 0.005 mol% to 0.5 mol%, alternatively from 0.005 mol% to 0.2 mol%.

Thus, as presented herein, the disclosed glass-ceramic compositions and glass-ceramic articles are suitable for use in electronic devices, electronic device substrates, and other compatible applications that enable higher frequency communications in the devices without significant performance degradation as is related to other non-electrical device requirements. For example, as higher frequency communication signals are used in these devices, the signals must pass through various physical obstructions that otherwise cause the signals to be attenuated or blocked. Thus, the glass-ceramic compositions and articles of the present disclosure may be well suited for use as such barriers. Examples of such physical obstacles are: electrically insulating substrates used in the manufacture of electrical circuits (e.g., antennas, semiconductor circuits, and signal transmission structures); and device covers and other related structures that can be used to house circuitry and other electronic device components used in electronic devices that operate with high frequency signals.

One advantage of the composition and method of forming the same is that improved signal reflection properties are observed. For example, because signal reflection is governed by the dielectric constant, the stacks formed using the pulldown method described herein may be used to produce structures with low reflection through the combination of a low dielectric cladding and a high dielectric core. Furthermore, compressive stress may be used to increase the mechanical strength of the laminate relative to conventional techniques (e.g., tempered soda lime glass). The glass-ceramics disclosed herein also provide scaling advantages because the structures formed can have sheet sizes on the order of meters, rather than being limited to centimeters as with conventional materials (e.g., ceramics). Thus, the glass-ceramics of the present application can be free standing substrates (e.g., translucent, opaque, or with colorants added).

As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have a broad meaning as commonly understood and accepted by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Those skilled in the art who review this disclosure will appreciate that these terms are intended to describe certain features described and claimed without limiting these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or variations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

As used herein, "optional" or "optionally" and the like are intended to mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. As used herein, the indefinite articles "a" or "an" and their corresponding definite articles "the" mean at least one, or one or more, unless otherwise indicated.

The positions of elements referred to herein (e.g., "top," "bottom," "above," "below," etc.) are used merely to describe the orientation of the various elements in the drawings. It should be noted that the orientation of the various elements may be different according to other exemplary embodiments, and such variations are intended to be included in the present disclosure.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. Various singular/plural permutations may be expressly set forth herein for the sake of clarity.

It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the claimed subject matter. Accordingly, the claimed subject matter is not limited, except as by the appended claims and their equivalents.