Coating for ceramic substrates

Abstract

A method of metallizing a ceramic substrate includes depositing a barrier layer onto a substrate, depositing a tie layer onto the barrier layer, and depositing a metal layer onto the tie layer to metallize the substrate. The barrier layer may include an oxygen-rich material, a nitrogen-rich material, or a carbon-rich material.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Provisional Application No. 63 / 399,297, filed on August 19, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to metallized substrates and methods of making metallized substrates. More specifically, the present disclosure relates to substrates comprising ceramics (e.g., zirconium oxide), and methods and materials for metallizing zirconium oxide-based materials. Such methods are particularly useful in medical device applications. Summary of the invention

[0004] In Example 1, a method for metallizing a substrate includes depositing a barrier layer onto the substrate, depositing a connection layer onto the barrier layer, and depositing a metal layer onto the connection layer to metallize the substrate. The barrier layer includes an oxygen-rich material, a nitrogen-rich material, or a carbon-rich material.

[0005] In Example 2, the method of Example 1, wherein the substrate comprises a ceramic material.

[0006] In Example 3, the method of Example 1 or 2, wherein the dielectric substrate is selected from the group consisting of zirconia, stabilized zirconia, partially stabilized zirconia, tetragonal zirconia, magnesia stabilized zirconia, ceria stabilized zirconia, yttria stabilized zirconia, and calcia stabilized zirconia.

[0007] In Example 4, the method of any of Examples 1 to 3, wherein the oxygen-rich material is selected from the group consisting of aluminum oxide, titanium oxide, silicon dioxide, tantalum oxide, niobium oxide, tungsten oxide, and molybdenum oxide.

[0008] In Example 5, the method of any of Examples 1 to 4, wherein the oxygen-enriched material has an oxygen percentage of 5% to 80%.

[0009] In Example 6, the method of any of Examples 1 to 5, wherein the nitrogen-rich material is selected from the group consisting of titanium nitride, aluminum nitride, tantalum nitride, tungsten nitride, niobium nitride, and molybdenum nitride.

[0010] In Example 7, the method of any of Examples 1 to 6, wherein the nitrogen-rich material has a nitrogen percentage of 5% to 80%.

[0011] In Example 8, the method of any of Examples 1 to 7, wherein the carbon-rich material is selected from the group consisting of silicon carbide, tungsten carbide, aluminum carbide, tantalum carbide, and molybdenum carbide.

[0012] In Example 9, the method of any of Examples 1 to 8, wherein the carbon-rich material has a carbon percentage of 5% to 80%.

[0013] In Example 10, the method of any of Examples 1 to 9, wherein the connecting layer comprises titanium, chromium, molybdenum, niobium, tungsten, tantalum, or vanadium.

[0014] In Example 11, the method of any of Examples 1 to 10, wherein the barrier layer is deposited onto the substrate by sputtering, thermal evaporation, or flame spraying.

[0015] In Example 12, the method of any of Examples 1 to 11, wherein the metal layer allows for brazing of the substrate.

[0016] In Example 13, the method of any of Examples 1 to 12, wherein the barrier layer has a thickness of 0.0005 to 50 microns.

[0017] In Example 14, the metallized ceramic substrate includes a base ceramic substrate comprising zirconium; a barrier layer directly contacting the base substrate; a tie layer directly contacting the barrier layer; and a metal layer bonded to the tie layer.

[0018] In Example 15, the ceramic substrate of Example 14, wherein the metal layer is a brazing material.

[0019] In Example 16, a method of metallizing a dielectric substrate includes depositing a barrier layer onto the dielectric substrate, depositing a connection layer onto the barrier layer, and depositing a metal layer onto the connection layer to metallize the dielectric substrate. The barrier layer includes an oxygen-rich material, a nitrogen-rich material, or a carbon-rich material.

[0020] In Example 17, the method of Example 16, wherein the dielectric substrate comprises a ceramic material.

[0021] In Example 18, the method of Example 16, wherein the dielectric substrate is selected from the group consisting of: zirconia, stabilized zirconia, partially stabilized zirconia, tetragonal zirconia, magnesia-stabilized zirconia, cerium-stabilized zirconia, yttria-stabilized zirconia and calcium-stabilized zirconia, as well as aluminum oxide, titanium dioxide, and the like.

[0022] In Example 19, the method of Example 16, wherein the oxygen-rich material is selected from the group consisting of aluminum oxide, titanium oxide, silicon dioxide, tantalum oxide, niobium oxide, tungsten oxide, and molybdenum oxide.

[0023] In Example 20, the method of Example 16, wherein the oxygen-enriched material has an oxygen percentage of 5% to 80%.

[0024] In Example 21, the method of Example 16, wherein the nitrogen-rich material is selected from the group consisting of titanium nitride, aluminum nitride, tantalum nitride, tungsten nitride, niobium nitride, and molybdenum nitride.

[0025] In Example 22, the method of Example 16, wherein the nitrogen-rich material has a nitrogen percentage of 5% to 80%.

[0026] In Example 23, the method of Example 16, wherein the carbon-rich material is selected from the group consisting of silicon carbide, tungsten carbide, aluminum carbide, tantalum carbide, and molybdenum carbide.

[0027] In Example 24, the method of Example 16, wherein the carbon-rich material has a carbon percentage of 5% to 80%.

[0028] In Example 25, the method of Example 16, wherein the connecting layer comprises titanium, chromium, molybdenum, niobium, tungsten, tantalum, or vanadium.

[0029] In Example 26, the method of Example 16, wherein the barrier layer is deposited onto the dielectric substrate by sputtering, thermal evaporation, or flame spraying.

[0030] In Example 27, the method of Example 16, wherein the metal layer allows for brazing of the dielectric substrate.

[0031] In Example 28, the method of Example 16, wherein the barrier layer has a thickness of 0.0005 to 50 microns.

[0032] In Example 29, the metallized ceramic substrate includes a base ceramic substrate comprising zirconium; a barrier layer directly contacting the base substrate; a tie layer directly contacting the barrier layer; and a metal layer bonded to the tie layer.

[0033] In example 30, the ceramic substrate of claim 29, wherein the metal layer is a brazing material.

[0034] In Example 31, an implantable medical device having a feed-thru assembly includes a metallized ceramic substrate. The metallized ceramic substrate includes a base ceramic substrate containing zirconium; a barrier layer directly contacting the base substrate; a connection layer directly contacting the barrier layer; and a metal layer bonded to the connection layer.

[0035] In Example 32, the implantable medical device of Example 31 further includes one or more leads bonded to the metallized ceramic substrate.

[0036] In Example 33, the implantable medical device of Example 31, wherein the barrier layer comprises aluminum oxide.

[0037] In Example 34, the implantable medical device of Example 31, wherein the dielectric substrate is yttria-stabilized zirconia.

[0038] In Example 35, the implantable medical device of Example 31, wherein the connecting layer comprises titanium.

[0039] Although multiple examples are disclosed, other examples of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples of the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram depicting a patient monitoring system according to certain examples of the present disclosure.

[0041] Figure 2 Implantable medical devices according to certain examples of the present disclosure are shown.

[0042] Figure 3 According to some examples of the present disclosure Figure 2 A perspective view of an implantable medical device.

[0043] Figure 4 is a schematic diagram of an implantable system implanted in a patient that delivers electrical stimulation to the heart according to certain examples of the present disclosure.

[0044] Figure 5 is a partial cross-sectional view of a pulse generator according to some examples of the present disclosure Figure 4 Schematic diagram of the implantable system.

[0045] Fig. 6A is a perspective view of a feedthrough assembly including a base substrate according to certain examples of the present disclosure.

[0046] Figure 6B yes Fig. 6A A three-dimensional front view of the base substrate.

[0047] Figure 6C yes Fig. 6A An enlarged cross-sectional view of the base substrate surface.

[0048] Figures 7A-7H is a schematic diagram of an assembly process of an exemplary feedthrough assembly according to certain examples of the present disclosure.

[0049] Figure 8 A schematic diagram of a structure including a substrate, a barrier layer, a connecting layer, and a metal layer according to certain examples of the present disclosure is shown.

[0050] Fig. 9 is a flow chart illustrating a method of metallizing a dielectric substrate according to certain examples of the present disclosure.

[0051] Although the present disclosure may have a variety of modifications and alternative forms, specific examples have been shown by way of example in the accompanying drawings and are described in detail below. However, the purpose is not to limit the present disclosure to the specific examples described. On the contrary, the present disclosure is intended to cover all modifications, equivalents, and alternatives that fall within the scope of the present disclosure defined by the appended claims. DETAILED DESCRIPTION

[0052] Ceramic materials are used in many applications, including medical device applications, because of their biocompatibility and benefits such as straight-through signal transmission (e.g., electromagnetic signal transparency), structural integrity (e.g., corrosion resistance, structural strength), and / or sealing capabilities. Such materials are used in a variety of components in medical devices, such as therapeutic devices (e.g., pacemakers, defibrillators, neuromodulators, ablation needles, ablation catheters, rechargeable IMDs, puncture and cautery devices) and sensing devices.

[0053] Zirconia-based ceramic materials are particularly useful due to their strength and durability. However, zirconia-based ceramics have limitations when metallized using physical vapor deposition ("PVD") methods (e.g., sputtering deposition, thermal evaporation, cathodic arc deposition, electron beam physical vapor deposition, evaporative deposition, close space sublimation, pulsed laser deposition, pulsed electron deposition, and sublimation sandwich methods). In order to metallize ceramic materials such as zirconia-based materials, a tie layer can be deposited between the ceramic substrate and the metal layer. However, depositing the tie layer material onto a substrate containing a zirconia-based ceramic can result in damage and corrosion of the substrate material, particularly at and near the interface between the substrate and the tie layer. Because the substrate may contain elements such as oxygen, nitrogen, and / or carbon, and the tie layer contains a material that is "hungry" for these elements, the tie layer can essentially "eat" or consume these elements, which degrades the material and structure of the substrate. Examples of the present disclosure help address such issues.

[0054] In some examples, a barrier layer is deposited between the substrate and the tie layer to act as a buffer between the oxygen-hungry, nitrogen-hungry, and / or carbon-hungry tie layers. The barrier layer may comprise a material rich in oxygen, nitrogen, and / or carbon so that the barrier layer can withstand the loss of these elements to the desired tie layer. In this way, the substrate is less likely to degrade.

[0055] In other examples, the connecting layer itself—or at least a portion thereof closest to the substrate—can be formulated to include higher than typical amounts of oxygen, nitrogen, and / or carbon and / or to include lower than typical amounts of a metal (e.g., a metal such as titanium, chromium, tantalum, tungsten, molybdenum, niobium, or nickel). In this way, the connecting layer is less hungry for the oxygen, nitrogen, and / or carbon of the substrate.

[0056] The methods described herein have many applications. Certain medical device applications are described below, but the methods can be used in applications other than medical devices and in medical devices that are not explicitly shown in one of the figures.

[0057] In medical device applications, certain ceramic components may require metallization. Metallization can be used as a conduction path for electrical signals, a conduction path for heat, a reflector for optical applications, and / or to provide a bonding surface for adhesives, welding, soldering, and / or brazing.

[0058] Exemplary Implantable Medical Device Applications

[0059] Example 1

[0060] Figure 1 is a schematic diagram of a system 100 including an implantable medical device (IMD) 102 implanted within a patient's body 104 and configured to communicate with a receiving device 106. Components of the IMD 102, such as a housing and electrical feedthrough components, may include a zirconia-containing material, a portion of which is metallized, and a barrier layer as described further below.

[0061] In multiple instances, the IMD 102 may be implanted subcutaneously in an implantation site or pocket in the patient's chest or abdomen, and the IMD 102 may be configured to monitor (e.g., sense and / or record) physiological parameters associated with the patient's heart 108. The IMD 102 may be an implantable cardiac monitor (ICM) (e.g., an implantable diagnostic monitor (IDM), an implantable loop recorder (ILR)) configured to record physiological parameters, such as one or more cardiac activation signals, heart sounds, blood pressure measurements, oxygen saturation, etc. For example, the IMD 102 may include sensors or circuits for detecting respiratory system signals, cardiac system signals, and / or signals associated with patient activity. In an example, the IMD 102 may be configured to sense intrathoracic impedance, from which a variety of respiratory parameters may be derived, including, for example, respiratory tidal volume and minute ventilation. In multiple instances, the IMD 102 may be configured to monitor physiological parameters, which may include one or more signals indicating the patient's physical activity level and / or metabolic level, such as acceleration signals. Sensors and associated circuits may be incorporated with IMD 102 to detect one or more signals associated with body motion or body posture and / or position. For example, an accelerometer and / or GPS device may be used to detect patient activity, patient position, body orientation, and / or torso position. IMD 102 may be configured to sense and / or record at regular intervals, continuously, and / or in response to detected events.

[0062] As shown, the IMD 102 may include a housing 110 having two electrodes 112 and 114 coupled thereto. According to various examples, the IMD 102 may include any number of electrodes (and / or other types of sensors such as thermometers, barometers, pressure sensors, optical sensors, motion sensors, etc.) in any number of various types of configurations, and the housing 110 may include any number of different shapes, sizes, and / or features. In various examples, the IMD 102 may be configured to sense physiological parameters and record physiological parameters. For example, the IMD 102 may be configured to activate (e.g., periodically, continuously, upon detection of an event, etc.), record a specified amount of data (e.g., physiological parameters) in a memory, and then transmit the recorded data to the receiving device 106. In the case of an IMD, for example, the IMD 102 may be activated, record cardiac signals for a period of time, deactivate, and activate to transmit the recorded signals to the receiving device 106. In various cases, the receiving device 106 may be, for example, a programmer, a controller, a patient monitoring system, etc.

[0063] IMD 102 may include a head that may house a variety of circuit components such as an antenna therein. In multiple instances, IMD 102 and receiving device 106 may communicate via a wireless link. For example, IMD 102 and receiving device 106 may be combined via a short-range radio link (e.g., Bluetooth, IEEE 802.11, and / or a proprietary wireless protocol). The communication link may facilitate one-way and / or two-way communication between IMD 102 and receiving device 106. Data and / or control signals may be transmitted between IMD 102 and receiving device 106 to coordinate the functions of IMD 102 and / or receiving device 106. In multiple instances, patient data may be downloaded periodically or on command from one or more IMD 102 and receiving device 106. For example, a physician and / or patient may communicate with IMD 102 and receiving device 106 to obtain patient data or initiate, terminate, or modify a record and / or treatment.

[0064] In some examples, housing 110 may be a core component housing that encapsulates a controller circuit. The controller circuit is coupled to a first feedthrough component at a first end and to a second feedthrough component at a second end. The feedthrough component may be configured to provide an electrical connection path between a circuit component of the head (e.g., an electrode and an antenna) and the controller circuit. Similarly, the second feedthrough component may be configured to provide an electrical connection path between one or more batteries and / or between an electrode and the controller circuit.

[0065] As will be discussed in greater detail below, portions of the housing and / or feedthrough assembly may include a metallized dielectric substrate having a barrier layer (eg, a coating) to protect the underlying dielectric substrate.

[0066] Example 2

[0067] Figure 2 An implantable medical device (IMD) 210 in the form of a leadless cardiac pacemaker (LCP) is shown implanted in a heart 212 of a patient 214. Components of IMD 210, such as a housing and electrical feedthrough components, may include a zirconium oxide-containing material, a portion of which is metallized, and includes a barrier layer described further below.

[0068] like Figure 2 As shown, the heart 212 includes a right ventricle 216, a right atrium 218, and a tricuspid valve 220 that separates the right atrium 218 from the right ventricle 216. The inferior vena cava 222 leads to the right atrium 218. The IMD 210 can be implanted in the right ventricle 216. The IMD 210 can have a proximal end 224 and a distal end 226. The IMD 210 can be implanted so that the proximal end 224 is closest to the tricuspid valve 220 and the distal end 226 is in contact with the endocardium 228 lining the wall of the right ventricle 216. After the IMD 210 is implanted, the IMD 210 can provide electrophysiological therapy to the heart 212.

[0069] Figure 3 yes Figure 2 A three-dimensional image of an implantable medical device. Figure 3 In the example shown, the IMD 310 includes a housing 330, an electrode 332, an electrode insulator 334, a housing insulator 336, and a plurality of tines 338 (four are shown). The housing 330 has a generally cylindrical shape and extends from the proximal end 324 to the distal end 326. The housing 330 can house control electronics and communication electronics as well as a battery. The housing 330 can be formed of a biocompatible metal (e.g., a material containing zirconium oxide as described in more detail below). In some examples, the electrode 332 can be formed of a biocompatible metal (e.g., titanium, iridium, gold, or stainless steel). The plurality of tines 338 can be formed of a flexible, elastic, biocompatible metal (e.g., nitinol). The electrode 332 and the plurality of tines 338 are disposed at the distal end 326. The electrode insulator 334 is disposed between the electrode 332 and the plurality of tines 38 to electrically insulate the electrode 332 from the plurality of tines 338. The housing insulator 336 is disposed between the housing 330 and the tines 338 to electrically insulate the housing 330 from the tines 338 .

[0070] As will be discussed in greater detail below, housing 330, electrode insulator 334, and / or housing insulator 336 may be formed from a metallized dielectric substrate having a barrier layer (eg, coating) to protect the underlying dielectric substrate.

[0071] Example 3

[0072] Figure 4 is a schematic diagram of an implantable system in a patient that delivers electrical stimulation to the heart. Components of pulse generator 402, such as the housing and electrical feedthrough components, may include a zirconium oxide-containing material, a portion of which is metallized, and a barrier layer as described further below.

[0073] although Figure 4 The delivery of electrical stimulation to the heart is shown, but examples of the present disclosure may also be used in devices that provide electrical stimulation to other areas, such as spinal cord stimulation and subcutaneous electrode configurations. Figure 4 The example shows that the implantable system includes a pulse generator 402, which is configured to generate electrical stimulation for the heart 400.

[0074] In some instances, the pulse generator can be a pacemaker, a defibrillator, and / or a neuromodulator. The pulse generator 402 is typically implanted subcutaneously in an implantation location or pocket in the patient's chest or abdomen. The pulse generator 402 is connected to an implantable lead 406. The lead 406 is used to transmit electrical signals between the implantable pulse generator 402 and the heart 400. The lead 406 includes a flexible lead body having a proximal portion 412 and a distal portion 414. In various instances, the lead 406 enters the vascular system through a vascular access site formed in the wall of the left subclavian vein. In various other instances, other suitable vascular access sites may be used. The lead 406 may extend through the left brachiocephalic vein and the superior vena cava so that one or more electrodes 418 disposed on the distal portion 414 of the lead 406 may be implanted in the right atrium, right ventricle, left ventricle, or other locations.

[0075] Example 4

[0076] Figure 5 A schematic diagram of an implantable system 500 according to various examples is provided with a partial cross-sectional view of a pulse generator 505. Components of the pulse generator 505, such as the housing, the head, and the electrical feedthrough assembly, can include a zirconium oxide-containing material, a portion of which is metallized, and a barrier layer as described further below.

[0077] The pulse generator 505 includes a pulse generator housing 510 that includes electronic components, a battery power source, and a header 512 mounted on the exterior of the pulse generator housing 510. The pulse generator housing 510 includes a feed-through structure, such as a feed-through connector assembly 515, which, when connected, operably connects an implantable lead 520 to the electronic components within the pulse generator 505. According to some examples, the pulse generator housing 510 includes an opening 525. In some examples, the housing 510 can include a plurality of openings 525.

[0078] In various examples, the feedthrough connector assembly 515 seals the opening 525 of the pulse generator 505. In this way, the feedthrough connector assembly 515 seals the inner cavity of the pulse generator 505 from the external environment, for example, sealing the inner cavity from moisture and / or biological products.

[0079] Exemplary Feedthrough Assemblies

[0080] Fig. 6A is a perspective view of an exemplary feedthrough assembly 600 that may be used with the medical devices described above. Figure 6B is a perspective front view of the base substrate 602 of the feedthrough assembly 600; and Figure 6C 602. FIG. 600 is an enlarged cross-sectional view of a surface of a base substrate 602. As shown, a feedthrough assembly 600 may include a base substrate 602 connecting one or more wires 604 (e.g., conductors) and a housing assembly 606. The base substrate 602 may be connected to the wires 604 and the housing assembly 606 via one or more metal layers 608.

[0081] like Figure 6B As shown, the base substrate 602 may include one or more openings 610 for the lead 604 to pass through, and the base substrate 602 may be used as a dielectric insulator in the feedthrough assembly 600. The base substrate 602 may be biocompatible so that it can be included in a medical device (e.g., the different IMDs discussed in the previous figures). Suitable materials for the base substrate 602 may include zirconia-based ceramics. Zirconia-based ceramic materials include, for example, zirconia, stabilized zirconia, partially stabilized zirconia, tetragonal zirconia, magnesia-stabilized zirconia, cerium-stabilized zirconia, yttria-stabilized zirconia ("YSZ"), and calcia-stabilized zirconia, as well as alumina and titanium dioxide, among others.

[0082] In some examples, the base substrate 602 may include 0% to about 99.9% aluminum oxide, or about 0.1% to about 95% aluminum oxide, or about 0.2% to about 90% aluminum oxide, or about 0.3% to about 85% aluminum oxide, or about 0.5% to about 80% aluminum oxide, or about 10% to about 75% aluminum oxide, or about 20% to about 70% aluminum oxide, or percentages of aluminum oxide included in these ranges. In some examples, the base substrate 602 may include 5% to about 99.9% zirconium oxide, or about 5% to about 95% zirconium oxide, or about 10% to about 93% zirconium oxide, or about 15% to about 85% zirconium oxide, or about 20% to about 80% zirconium oxide, or about 25% to about 75% zirconium oxide, or percentages of zirconium oxide included in these ranges. The base substrate 602 may also be a mixture of aluminum oxide and zirconium oxide, containing about 90% aluminum oxide and about 10% zirconium oxide, or about 75% aluminum oxide and about 25% zirconium oxide, or about 20% aluminum oxide and about 80% zirconium oxide, or about 0.3% aluminum oxide and about 93% zirconium oxide. In the exemplary embodiment, the base substrate 602 includes YSZ.

[0083] The base substrate 602 may have a fracture toughness of up to about 15 MPa, or about 1 to about 13 MPa, or about 2 to about 10 MPa, or about 3 to about 8 MPa, or about 4 to about 7 MPa, or about 4.5 to about 6 MPa, or a fracture toughness included in these ranges. In an exemplary embodiment, the base substrate may have a fracture toughness of about 4.5 MPa or about 6 MPa. In some examples, the base substrate 602 has an average grain size of about 0.1 to about 5 μm, an elastic modulus of about 200 to about 400 GPa, a hardness of about 10 to about 20 GPa, a thermal conductivity of about 2 to about 30 W / mK at 20° C., a dielectric constant of about 9 to about 34 at 25° C. at 1 MHz, a DC volume resistivity of about 1.00E+12 to about 5.1E+14 at 25° C., and / or a CTE of about 7E(-6) to about 10E(-6) / ° C.

[0084] As mentioned above, one challenge with using ceramics (e.g., zirconium oxide-based ceramics) is the ability to metallize such ceramics, because the tie layer used to bond the metal to the ceramic consumes oxygen from the underlying ceramic material. Over time, this degrades the structural integrity of the ceramic material.

[0085] To form a sealed enclosure, a base substrate 602 (e.g., a ceramic containing zirconium oxide) can have an interface for bonding (e.g., brazing) to an enclosure component 606 (e.g., a titanium flange), which is then connected to the rest of the enclosure. One or more layers can be deposited onto the substrate 602 to help prepare the substrate prior to depositing the metal layer 608. For ceramic substrates, a tie layer (e.g., a layer containing titanium, chromium, or vanadium) can be deposited directly onto the ceramic substrate to facilitate metallization of the ceramic substrate.

[0086] However, depositing the tie layer directly onto the base substrate surface may damage or degrade the underlying base substrate 602 (e.g., a ceramic substrate including zirconium oxide) over time, making it brittle and susceptible to cracking. In some instances, the degradation of the zirconium oxide is due to the deposited tie layer penetrating the surface of the ceramic substrate 602 and disturbing the grain structure of the base substrate 602. Zirconia (e.g., zirconium dioxide or ZrO2) has a ZrO2-containing 4+ and O 2- Ion-stabilized grain structure. In some examples, the stability of the cubic crystal structure of zirconia can be enhanced at room temperature by adding yttria (Y2O3) to form yttria-stabilized zirconia ("YSZ"). When the tie layer is deposited directly onto the surface of the zirconia, the metal from the tie layer (e.g., titanium, chromium, or vanadium) can penetrate the surface and degrade the zirconia (e.g., reduce Zr 4+ The oxidation state of the ions and the O 2- ion bonding), thereby changing and weakening the originally stable cubic grain structure.

[0087] Examples of the present disclosure utilize a method of applying a barrier layer 618 prior to depositing the tie layer 620 to help mitigate degradation of the substrate. A variety of materials may be selected to deposit the barrier layer 618. For example, a material rich in certain elements (e.g., oxygen, nitrogen, or carbon) may be used. In an exemplary embodiment, an oxygen-rich material may be used such that the metal from the tie layer 620 will react with the oxygen in the barrier layer 618 before reaching the underlying zirconia, thereby protecting the underlying zirconia substrate. Similarly, in an example where a nitrogen-rich material is used in the barrier layer 618, the nitrogen may react with particles from the tie layer 620. In some examples, the material selected for the barrier layer 618 may need to withstand high temperatures (e.g., welding or brazing temperatures greater than 200 degrees Celsius).

[0088] like Figure 6CAs shown, the base substrate 602 may be made of a dielectric substrate 616 (e.g., a zirconium oxide-based ceramic), a barrier layer 618 directly contacting the base substrate 602, and a connection layer 620 deposited on top of the barrier layer 618 and directly contacting the barrier layer 618. The barrier layer 618 may include a material containing oxygen (e.g., aluminum oxide, titanium oxide, silicon dioxide, tantalum oxide, niobium oxide, tungsten oxide, and molybdenum oxide), or a material containing nitrogen (e.g., titanium nitride, aluminum nitride, tantalum nitride, tungsten nitride, niobium nitride, and molybdenum nitride), or a material containing carbon (e.g., silicon carbide, tungsten carbide, aluminum carbide, tantalum carbide, and molybdenum carbide). In some examples, the oxygen-rich material has an oxygen percentage of about 5% to 80%, or about 5% to 70%, or about 10% to 60%, or about 15% to 50%, or about 20% to 40%, or about 25% to 30%. In some examples, the nitrogen-rich material has a nitrogen percentage of about 5% to 80%, or about 5% to 70%, or about 10% to 60%, or about 15% to 50%, or about 20% to 40%, or about 25% to 30%. In some examples, the carbon-rich material has a carbon percentage of about 5% to 80%, or about 5% to 70%, or about 10% to 60%, or about 15% to 50%, or about 20% to 40%, or about 25% to 30%.

[0089] The metal of the barrier layer 618 can be any metal that can form an oxide or a nitride or a carbide. In some examples, the barrier layer 618 can have a material including a metal that can bond with the underlying zirconium oxide substrate and the connecting layer 620. In some examples, the metal included in the barrier layer 618 can have a coefficient of thermal expansion ("CTE") that is the same or relatively similar to the underlying substrate 616 and the connecting layer 620. For example, when the connecting layer 620 includes titanium, the barrier layer 618 can include titanium oxide, titanium nitride, or aluminum oxide. In the exemplary example, the connecting layer 620 includes titanium and the barrier layer 618 includes aluminum oxide.

[0090] In some examples, the barrier layer 618 can have a thickness (d) of about 0.0005 to about 50 microns, or about 0.001 to about 40 microns, or about 0.05 to about 35 microns, or about 0.1 to about 30 microns, or about 0.5 to about 20 microns, or about 0.6 to about 10 microns, or about 0.7 to about 5 microns, or about 0.8 to about 4 microns, or about 0.9 to about 3 microns, or about 1 to about 2 microns. The barrier layer 618 can have a maximum thickness (d) of about 50 microns. The thickness (d) can be optimized to avoid any negative impact on the adhesion of the subsequent tie layer 620 to the ceramic 616. In some examples, the thickness (d) of the barrier layer 618 can be set to maintain structural integrity and reduce stress on the tie layer 620 and / or any additional layers that may be deposited on top of the tie layer 620.

[0091] In some instances, the desired thickness of the barrier layer 618 depends on the thickness of the subsequently deposited tie layer 620. For example, a thicker tie layer may require that a thicker barrier layer should be used so that the barrier layer has sufficient oxygen / nitrogen / carbon to be consumed by the tie layer. Additionally or alternatively, a thicker tie layer may require that the barrier layer should have an increased amount of oxygen / nitrogen / carbon.

[0092] In some instances, the properties of the barrier layer can be set based on the materials and the specific application. The selection of the barrier layer may involve factors such as the type of zirconium oxide-based ceramic, the barrier layer type, the barrier layer thickness, the barrier layer composition, the tie layer type, the tie layer composition, and the tie layer thickness. One or more of the above factors can be optimized to prevent the tie layer from contacting the ceramic and causing reduction of the ceramic substrate. As an example, the ratio of the thickness of the barrier layer to the thickness of the tie layer can be a stoichiometric ratio of the amount of oxygen / nitrogen / carbon contributed by each molecule of the barrier layer material to the amount of oxygen / nitrogen / carbon included in each molecule of the tie layer material.

[0093] In some examples, where the surface of the ceramic 616 is relatively smooth, a thinner barrier layer 618 can be used. In a number of examples, where the surface of the ceramic 616 is relatively rough, a thicker barrier layer 618 can be used to accommodate the surface. Depending on the roughness of the surface, the barrier layer 618 can be about 5 nm to about 75 nm thick, or about 6 nm to about 60 nm thick, or about 7 nm to about 50 nm thick, or about 8 nm to about 40 nm thick, or about 9 nm to about 30 nm thick, or about 10 nm to about 20 nm thick. In some examples, where the surface is relatively smooth, the barrier layer 618 can be less than 10 nm thick, or about 5 nm thick. In some examples, to address relatively rough surfaces, the barrier layer 618 can be about 75 nm thick.

[0094] After the barrier layer 618 is applied, additional top layers for metallization (e.g., tie layer 620 and metal layers) can be applied, which reduces the risk of ceramic degradation. The top layers will then allow for the braze layers, bonding layers, conductive layers, optical layers, and protective layers required in the device design of ceramic-based components for IMD or ablation devices.

[0095] Methods for depositing barrier layer 618 include sputtering, flame spraying, thermal evaporation, or any suitable physical vapor deposition method. In some examples, thermal evaporation can be used to deposit barrier layer 618 containing titanium nitride. In some examples, barrier layer 618 containing aluminum oxide can be deposited by sputtering.

[0096] Now back to Fig. 6A , the feed-through assembly 600 may include a conductor at least partially disposed within the opening 610. Fig. 6AAs shown, for example, the conductor may be a lead 604 disposed within an opening 610. In some instances, other examples of suitable conductor types include ribbons, filaments, and any rod having a polygonal cross-section (eg, a triangular or hexagonal cross-section).

[0097] Lead 604 can be positioned within opening 610. In some examples, lead 604 is positioned such that a portion of lead 604 is positioned outside of the IMD housing and a portion of lead 604 is positioned inside of the IMD housing. For example, lead 604 can be oriented such that a proximal end 612 of lead 604 extends outward from opening 610 and a distal end 614 extends into an inner cavity of the IMD housing. Feedthrough assembly 600 allows an implantable lead (e.g., implantable lead 520) to be coupled to electronic components and a source battery (e.g., a power supply) within the IMD via lead 604. Figure 5 Pulse generator 505 shown in ).

[0098] Leads 604 may also be described as feedthroughs, pins, or conductors. In some instances, leads 604 may be straight (i.e., the distal and proximal ends of lead 604 may be axially aligned). Leads 604 may be directly or indirectly operably connected to electronic components (e.g., a printed circuit board or other electronic assembly) within the IMD housing. Leads 604 may be directly secured to a printed circuit board or other electronic assembly. In some instances, leads 604 may be soldered, wire bonded, or welded to a printed circuit board or other electronic assembly.

[0099] In various examples, the wire 604 is made of a metallic material. For example, in some examples, the wire 604 is made of titanium. The wire 604 can be formed of any suitable material, for example, titanium, tantalum, tungsten, platinum, palladium, stainless steel (e.g., SS316), nickel-cobalt-chromium-molybdenum alloy (e.g., MP35N, MP35N / silver drawn copper bonding wire, MP35N / silver drawn filling tube), nitinol, cobalt-chromium-nickel alloy (e.g., elgiloy), cobalt-chromium-nickel-molybdenum-iron alloy, or a combination thereof. Other exemplary materials for the lead 604 include, but are not limited to, platinum-iridium (PtIr), palladium-iridium (PdIr), silver (Ag), gold (Au), or a combination thereof.

[0100] Housing assembly 606 can be made of the same material as the housing. In some examples, housing assembly 606 is made of titanium, titanium alloy, MP35N, stainless steel, or a combination thereof. In an exemplary example, housing assembly 606 can be a titanium flange for connecting to an IMD housing. As shown, metal layer 608 is bonded to connection layer 620. In some examples, metal layer 608 can be a brazing material (e.g., copper, nickel, silver, aluminum, gold).

[0101] Figures 7A-7His a schematic diagram of an assembly process of an exemplary feedthrough assembly according to an example of the present disclosure. Figures 7A-7H The assembly process shown in the figure is an example of various features of a method of metallizing a substrate to manufacture a feedthrough assembly. Although the combination of those shown features is clearly within the scope of the present invention, this example and its description are not meant to indicate that the inventive concepts provided herein are limited to fewer features, additional features, or alternative features. Figures 7A-7H One or more of those features shown in .

[0102] In addition, one or more steps of the following process may be optional and / or may be modified by one or more steps of other examples described herein. In addition, one or more steps of other examples described herein may be added to the process.

[0103] As shown, a base substrate 702 is placed in a sputtering chamber 704. The base substrate 702 can be a dielectric insulator for a medical device component, such as a housing or feedthrough assembly through which an electrical conductor passes. The substrate 702 can be a dielectric ceramic substrate selected from the group consisting of zirconium oxide, stabilized zirconium oxide, partially stabilized zirconium oxide, tetragonal zirconium oxide, magnesium oxide stabilized zirconium oxide, cerium oxide stabilized zirconium oxide, yttria stabilized zirconium oxide, and calcium oxide stabilized zirconium oxide, as well as aluminum oxide, titanium dioxide, and the like. The sputtering chamber can include a sputtering target 706, a gas inlet 708, and a gas outlet 710.

[0104] A barrier layer (e.g., such as Figure 7B The barrier layer 618 may include a material containing oxygen (e.g., aluminum oxide, titanium oxide, silicon dioxide, tantalum oxide, niobium oxide, tungsten oxide, and molybdenum oxide), or a material containing nitrogen (e.g., titanium nitride, aluminum nitride, tantalum nitride, tungsten nitride, niobium nitride, and molybdenum nitride), or a material containing carbon (e.g., silicon carbide, tungsten carbide, aluminum carbide, tantalum carbide, and molybdenum carbide). In some examples, the oxygen-rich material has an oxygen percentage of about 5% to 80%, or about 5% to 70%, or about 10% to 60%, or about 15% to 50%, or about 20% to 40%, or about 25% to 30%. In some examples, the nitrogen-rich material has a nitrogen percentage of about 5% to 80%, or about 5% to 70%, or about 10% to 60%, or about 15% to 50%, or about 20% to 40%, or about 25% to 30%. In some examples, the carbon-rich material has a carbon percentage of about 5% to 80%, or about 5% to 70%, or about 10% to 60%, or about 15% to 50%, or about 20% to 40%, or about 25% to 30%. The connecting layer may include titanium, chromium, molybdenum, niobium, tungsten, tantalum, or vanadium.

[0105] After the substrate 702 is coated with these layers, as Figure 7CAs shown, the coated substrate 702c can then be removed from the sputtering chamber 704 and placed within a housing assembly 712. The housing assembly 712 can be shaped and configured to be later attached to the housing of the IMD. A first top metallization layer 714d can then be deposited onto the connection layer and in the space between the coated substrate 702c and the housing assembly 712 (see FIG. Fig.7D ). The top metallization layer 714d may allow the dielectric substrate 702 to be brazed or bonded to the housing assembly 712.

[0106] In some examples, the substrate 702 may include one or more openings 716. A second top metallization layer 714e may be deposited onto the connection layer of the substrate 702 within the one or more openings 716 (see Fig. 7E ). In some examples, the metallization layer 714 may include a noble metal (e.g., gold) to braze the leads 718 to the substrate 702, which may be a dielectric insulator. In some examples, the substrate 702 may also be brazed to a titanium or niobium ferrule with a noble metal. One or more electrical conductors or leads 718 may then be inserted through each opening 716 of the substrate 702 (see FIG. Figure 7F ).

[0107] Figure 7G-7H yes Figure 7F 7. When the assembly 700 is heated to a brazing temperature, the metallization layer 714 bonds the leads 718 to the substrate 702 and the substrate 702 to the housing assembly 712, thereby locking these components to form a hermetic seal.

[0108] Figure 8 A schematic diagram of a four-layer structure 800 is shown. The bottom layer is a substrate 802 (e.g., the multiple substrate examples discussed above). For example, in some instances, the substrate 802 includes a ceramic material including zirconium oxide. A barrier layer 804 is directly located above the substrate 802 and is in direct contact with the substrate 802 (e.g., the multiple barrier layer examples discussed above). For example, the barrier layer 804 may include a material including oxygen, nitrogen, and / or carbon to protect the substrate 802 from the effects of the oxygen-poor, nitrogen-poor, and / or carbon-poor connecting layer material. A connecting layer 806 is directly located above the barrier layer 804 and is in direct contact with the barrier layer 804 (e.g., the multiple connecting layer examples discussed above). For example, the connecting layer 806 may include a material that is capable of bonding to a metal layer. A metal layer 808 is directly located above the connecting layer 806 and is in direct contact with the connecting layer 806 (e.g., the multiple metal layer examples discussed above). For example, the metal layer 808 may include a metal. Using the structure 800, the ceramic substrate 802 may be metallized. Structure 800 may be incorporated into many different applications including, but not limited to, the medical device applications described above.

[0109] Fig. 9900 is a flow chart showing a method of metallizing a ceramic substrate (e.g., zirconia-based materials such as zirconia, stabilized zirconia, partially stabilized zirconia, tetragonal zirconia, magnesia-stabilized zirconia, ceria-stabilized zirconia, yttria-stabilized zirconia, and calcia-stabilized zirconia, as well as alumina and titania, etc.).

[0110] In step 902, method 900 includes depositing a barrier layer onto a substrate. In step 904, method 900 includes depositing a connection layer onto the barrier layer. The connection layer may include titanium, chromium, or vanadium. These layers may be deposited using a physical vapor deposition method such as sputtering, thermal evaporation, or flame spraying.

[0111] In step 906, method 900 includes depositing a top metallization layer onto the connection layer. The top metallization layer allows for brazing or bonding to the dielectric substrate.

[0112] Various modifications and additions may be made to the exemplary examples discussed without departing from the scope of the present disclosure. For example, while the examples described above relate to specific features, the scope of the present disclosure also includes examples with different combinations of features and examples that do not include all of the described features. Therefore, the scope of the present disclosure is intended to include all such substitutions, modifications, and variations that fall within the scope of the claims, as well as all equivalents thereof.

Claims

1. A method for metallizing a substrate, the method comprising: depositing a barrier layer onto the substrate; depositing a tie layer onto the barrier layer; as well as depositing a metal layer onto the connection layer to metallize the substrate, The barrier layer comprises an oxygen-rich material, a nitrogen-rich material or a carbon-rich material. The method of claim 1 , wherein the substrate comprises a ceramic material.

3. The method according to claim 1 or 2, wherein the substrate is selected from the group consisting of zirconia, stabilized zirconia, partially stabilized zirconia, tetragonal zirconia, magnesia stabilized zirconia, ceria stabilized zirconia, yttria stabilized zirconia and calcia stabilized zirconia.

4. The method according to any one of claims 1 to 3, wherein the oxygen-rich material is selected from the group consisting of aluminum oxide, titanium oxide, silicon dioxide, tantalum oxide, niobium oxide, tungsten oxide and molybdenum oxide.

5. The method according to any one of claims 1 to 4, wherein the oxygen-rich material has an oxygen percentage of 5% to 80%.

6. The method of any one of claims 1 to 5, wherein the nitrogen-rich material is selected from the group consisting of titanium nitride, aluminum nitride, tantalum nitride, tungsten nitride, niobium nitride, and molybdenum nitride.

7. The method according to any one of claims 1 to 6, wherein the nitrogen-rich material has a nitrogen percentage of 5% to 80%.

8. The method of any one of claims 1 to 7, wherein the carbon-rich material is selected from the group consisting of silicon carbide, tungsten carbide, aluminum carbide, tantalum carbide, and molybdenum carbide.

9. The method according to any one of claims 1 to 8, wherein the carbon-rich material has a carbon percentage of 5% to 80%. 10 . The method according to claim 1 , wherein the connecting layer comprises titanium, chromium, molybdenum, niobium, tungsten, tantalum or vanadium.

11. The method of any one of claims 1 to 10, wherein the barrier layer is deposited onto the dielectric substrate by sputtering, thermal evaporation or flame spraying.

12. The method of any one of claims 1 to 11, wherein the substrate comprises zirconium oxide.

13. The method according to any one of claims 1 to 12, wherein the barrier layer has a thickness of 0.0005 to 50 microns.

14. A metallized ceramic substrate, comprising: a base ceramic substrate comprising zirconium; a barrier layer in direct contact with the base substrate; a tie layer directly contacting the barrier layer; as well as A metal layer is bonded to the connection layer.

15. The metallized ceramic substrate of claim 14, wherein the metal layer is a brazing material.

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