Hermetic thin film substrate bonding

Abstract

The present disclosure provides a sealing structure comprising a thin film layer of sputtered material, such as Nitinol, Titanium or similar. The sealing structure preferably further comprises a dissimilar material layer, such as a non-Nitinol and / or non-sputtered material, wherein an eutectic Gold-Tin intermediate layer is provided for bonding the thin film sputtered material layer to the dissimilar material layer. Examples of dissimilar materials include ceramics and glass.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 625,783, filed January 26, 2024, the disclosure of which is incorporated herein by reference. Background Technology

[0003] This disclosure relates in general to the field of material bonding, such as techniques and processes designed to join dissimilar materials (including hyperelastic materials, such as nitinol or other shape memory metals / alloys) in a manner that provides certain characteristics, such as mechanical integrity, conductivity, and / or hermetic sealing. For example, for some structures / components, successful hermetic bonding can provide / improve suitability for medical implants. Bonding techniques and materials involving fusion welding at temperatures above the transformation or melting temperatures of the bonded materials can lead to deterioration, damage, and / or other effects on the bonded materials. Summary of the Invention

[0004] This article describes methods, systems, and apparatus for facilitating the formation of stable hermetic seals between ceramic bodies or other substrates and nitinol or other hyperelastic layers, which can be used, for example, in pressure-sensing implantable devices.

[0005] In some embodiments, this disclosure relates to implantable pressure sensors comprising a sensor body mechanically and / or electrically coupled to a diaphragm structure, which may be formed of a thin-film nitinol or similar hyperelastic material. Such devices can advantageously integrate a nitinol (or similar) thin-film diaphragm formed using physical vapor deposition (PVD) or similar processes with a ceramic sensor body or other non-nitinol substrates (e.g., glass, polyimide, FR4, laminate, PTFE, aluminum, or other metals). Such integration can be achieved according to various aspects of this disclosure to maintain the mechanical properties of the nitinol layer, such as hyperelasticity.

[0006] Examples of this disclosure provide a method for hermetically bonding a thin-film nitinol separator / layer to a base substrate (e.g., ceramic) using a relatively low-temperature process to prevent interference with the superelasticity and / or other properties of nitinol. Such a process may involve the integration of one or more gold-tin (Au / Sn) layers, which may be applied directly to and / or around the periphery of a nitinol separator structure that can be used as a deflectable pressure sensor diaphragm. The Au / Sn layer advantageously enables the formation of a hermetically tight seal without compromising the superelastic properties of nitinol, and further provides a structural seal and / or electrical interface between the separator and the base / substrate.

[0007] In some embodiments, the gold-tin layer implemented in conjunction with the examples of this disclosure comprises an alloy of about 80% gold (Au) and about 20% tin (Sn). Such a composition can provide a eutectic solid with a melting point advantageously below the nitinol transition temperature and below the melting points of pure Au and pure Sn. By melting this eutectic alloy (which can occur below the nitinol transition temperature, thus preserving the physical properties of nitinol), a robust hermetic seal can be established between the base substrate / ceramic sensor body and the nitinol diaphragm. The resulting seal is not only hermetically effective but also adheres well to both bonded materials.

[0008] The gold-tin (Au / Sn) alloy layer implemented as described herein can advantageously exhibit thermal expansion characteristics intermediate between those of a base ceramic (or other non-NiTiN base) and a NiTiN diaphragm structure. This intermediate thermal expansion characteristic can advantageously reduce the risk of separation or crack formation in the sensor, a risk that might otherwise exist due to the difference in thermal expansion and contraction between the diaphragm and the base material. Therefore, aspects of this disclosure can promote the long-term integrity and reliability of pressure sensors and / or other devices, which may be particularly beneficial for biomedical implant applications.

[0009] The pressure sensors disclosed herein, configured for implantation, include a sensor body and a diaphragm. Hermetically bonding the PVD nitinol diaphragm to the ceramic sensor body requires a cryogenic process to avoid interfering with the nitinol properties. This invention integrates an Au / Sn layer onto the periphery of the diaphragm, thereby allowing for a hermetically sealed environment while maintaining the hyperelastic properties of nitinol. The 80 / 20 Au / Sn alloy forms a eutectic solid with a melting point below the nitinol transformation temperature. Welding or melting the eutectic alloy allows for a hermetically sealed environment between the ceramic and nitinol, resulting in excellent adhesion between the two materials. The Au / Sn alloy exhibits thermal expansion characteristics intermediate between ceramic and nitinol, thus preventing separation and crack formation due to thermal expansion / contraction.

[0010] In some embodiments, this disclosure relates to nitinol-substrate bonding / bonding technology, wherein one or more Au / Sn alloy layers are implemented directly between a base substrate (e.g., a ceramic material) and a nitinol separator. In some embodiments, one or more intermediate layers, such as titanium (Ti), nitinol, titanium-tungsten (TiW), titanium-tungsten gold (TiW / Au), etc.

[0011] Any of the various systems, apparatuses, devices, etc. disclosed herein can be sterilized (e.g., using heat, radiation, ethylene oxide, hydrogen peroxide, etc.) to ensure their safe use in patients, and the methods herein may include sterilizing the associated systems, apparatuses, devices, etc. (e.g., using heat, radiation, ethylene oxide, hydrogen peroxide, etc.).

[0012] The methods and structures disclosed herein for treating patients also encompass similar methods and structures for performing or placing on simulated patients, which can be used for, for example, training; demonstration; program and / or device development; and so on. Simulated patients can be physical, virtual, or a combination of physical and virtual. Simulations can include simulations of all or part of a patient, such as the whole body, parts of the body (e.g., chest), systems (e.g., cardiovascular system), organs (e.g., heart), or any combination thereof. Physical elements can be: natural, including human or animal carcasses or parts thereof; synthetic; or any combination of natural and synthetic. Virtual elements can be entirely in a computer simulation or overlaid on one or more physical elements. Virtual elements can be presented on any combination of a screen, headphones, holographic projection, speakers, headsets, pressure transducers, temperature transducers, or any combination using suitable technologies.

[0013] For the purpose of summarizing this disclosure, certain aspects, advantages, and novel features have been described. It should be understood that, depending on any particular instance, not all such advantages may be realized. Therefore, the disclosed instances may be carried out in a manner that implements or optimizes one or more advantages as taught herein, without necessarily implementing other advantages as may be taught or suggested herein. Attached Figure Description

[0014] For illustrative purposes, various examples are depicted in the accompanying drawings, and these examples should in no way be construed as limiting the scope of the invention. Furthermore, various features of different disclosed examples can be combined to form other examples that are part of this disclosure. Throughout the drawings, reference numerals may be used repeatedly to indicate correspondences between reference elements.

[0015] Figure 1 Examples of human anatomy are illustrated, showing sample sensor implantation locations based on one or more instances.

[0016] Figure 2 It is a block diagram representing a system for wirelessly monitoring one or more physiological parameters associated with a patient, based on one or more instances.

[0017] Figure 3A and Figure 3B A cross-sectional side view of a piezoresistive pressure sensor device according to one or more examples is shown.

[0018] Figure 4A and Figure 4B A cross-sectional side view of a capacitive pressure sensor device according to one or more examples is shown.

[0019] Figure 5 This is a block diagram illustrating a thin film deposition system according to one or more examples.

[0020] Figure 6 A side cross-sectional schematic diagram of a sensor device having capacitive electrodes that are structurally conformal to a thin-film hyperelastic diaphragm, according to one or more examples, is shown.

[0021] Figure 7 A side cross-sectional schematic diagram of a sensor device with a pressure transmission medium according to one or more examples is shown.

[0022] Figure 8A and Figure 8B Front and rear perspective views of a nitinol membrane structure according to one or more examples are shown.

[0023] Figure 9 A base structure for a sensor device is shown according to one or more examples.

[0024] Figure 10A and Figure 10B Perspective and cross-sectional views of a sensor device according to one or more examples are shown, the sensor device including one or more diaphragm structures physically coupled to a base structure.

[0025] Figure 11A and Figure 11B Front and rear perspective views of a sensor diaphragm structure according to one or more examples are shown.

[0026] Figure 12 The base structure for a capacitive sensor device is shown according to one or more examples.

[0027] Figure 13A and Figure 13B Perspective and cross-sectional views of a sensor device according to one or more examples are shown, the sensor device including one or more diaphragm structures physically coupled to a base structure.

[0028] Figure 14A and Figure 14B Perspective and cross-sectional views of a dual-side sensor device according to one or more examples are shown respectively.

[0029] Figure 15A and Figure 15B The images show exploded and assembled / bonded views of material stacks that provide hermetic seals and / or electrical interfaces between thin-film nitinol (or other metal) layers and dissimilar substrates (e.g., ceramics, glass) using gold-tin alloy fillers according to one or more examples.

[0030] Figure 16A and Figure 16BThe images show exploded and assembled / bonded views of material stacks capable of producing hermetically sealed seals between thin-film nitinol (or other metal) layers and dissimilar substrates (e.g., ceramics, glass) using gold-tin alloy fillers, according to one or more examples.

[0031] Figure 17A and Figure 17B The images show exploded and assembled / bonded views of material stacks capable of producing hermetically sealed seals between thin-film nitinol (or other metal) layers and dissimilar substrates (e.g., ceramics, glass) using gold-tin alloy fillers, according to one or more examples.

[0032] Figure 18 shows the temperature profiles of the process of bonding dissimilar materials using one or more gold-tin layers according to one or more examples.

[0033] Figure 19 Force curves are shown for the process of bonding dissimilar materials using one or more gold-tin layers according to one or more examples.

[0034] Figure 20A Figure 20B and Figure 20C Schematic diagrams, close-up views, and side cross-sectional views of wafers with multiple diaphragm structures formed on them, according to one or more examples, are shown respectively.

[0035] Figure 21A and Figure 21B An exploded and assembled / bonded view of a gold-tin bond including a hard stop is shown according to one or more examples.

[0036] Figure 22A A sensor base structure including embossed hard stop bumps is shown according to one or more examples.

[0037] Figure 22B and Figure 22C Exploded and assembled / bonded views of a gold-tin bond including hard stop bumps are shown according to one or more examples.

[0038] Figure 23A A sensor base structure including a hard stop extrusion section is shown according to one or more examples.

[0039] Figure 23B and Figure 23C Exploded and assembled / bonded views of the gold-tin bond, including the hard stop extrusion, are shown according to one or more examples.

[0040] Figure 24A and Figure 24B Exploded and assembled / bonded views of gold-tin bonds, including redundant bonding portions / sealing portions, are shown according to one or more examples.

[0041] Figure 25A and Figure 25B Plan view and side cross-sectional view of a diaphragm structure having one or more gold-tin seals according to one or more examples are shown respectively.

[0042] Figure 26A and Figure 26B Plan view and side cross-sectional view of a diaphragm structure having one or more gold-tin seals according to one or more examples are shown respectively.

[0043] Figure 27A and Figure 27B Plan view and side cross-sectional view of a diaphragm structure having one or more gold-tin seals according to one or more examples are shown respectively.

[0044] Figure 28A and Figure 28B Plan view and side cross-sectional view of a diaphragm structure with parallel gold-tin seals according to one or more examples are shown respectively.

[0045] Figure 29A and Figure 29B Plan view and side cross-sectional view of a diaphragm structure with parallel gold-tin seals according to one or more examples are shown respectively.

[0046] Figure 30 A plan view of a diaphragm structure with a grid pattern for a gold-tin seal, according to one or more examples, is shown.

[0047] Figure 31A , Figure 31B and Figure 31C Isolation, deconstruction, and bonding / assembly views of material stacks including multiple gold-tin bonds, according to one or more examples, are shown respectively.

[0048] Figure 32 It is a graph showing the relationship between the gold and tin concentrations in gold-tin alloys and the associated melting point according to one or more examples.

[0049] Figure 33A and Figure 33B An exploded and bonded / assembled view of a structure having a gold-tin bond that provides electrical connection, according to one or more examples, is shown.

[0050] Figure 34A and Figure 34B Plan view and side view of a sensor device with gold-tin electrical contacts according to one or more examples are shown respectively.

[0051] Figure 35 A sensor device having gold-tin electrical contacts bonded to an electrical device is shown according to one or more examples.

[0052] Figure 36 It is a cross-sectional view of the human heart and associated vascular system based on one or more examples, illustrating certain catheter entry paths used in sensor device implantation procedures. Detailed Implementation

[0053] The titles provided herein are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.

[0054] Although certain preferred examples are disclosed below, it should be understood that the subject matter of the invention extends beyond the specific examples disclosed, reaching other alternative examples and / or uses, as well as modifications and equivalents thereof. Therefore, the scope of the claims that may arise therefrom is not limited to any of the specific examples described below. For example, in any method or process disclosed herein, the actions or operations of said method or process may be performed in any suitable order and are not necessarily limited to any particular disclosed order. Various operations may be described sequentially as multiple discrete operations in a manner that may aid in understanding certain examples; however, the order of description should not be construed as implying that these operations are sequentially related. Furthermore, the structures, systems, and / or apparatuses described herein may be embodied as integrated components or separate components. For the purpose of comparison, certain aspects and advantages of these examples are described. Not all of these aspects or advantages are necessarily achieved by any particular example. Thus, for example, various examples may be performed in a manner that achieves or optimizes one or a set of advantages taught herein, without necessarily achieving other aspects or advantages also taught or suggested herein.

[0055] This document uses certain spatial relative terms, such as “external,” “internal,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” “top,” “bottom,” “distal,” “proximal,” and similar terms, to describe the spatial relationship of one device / element or anatomical structure to another device / element or anatomical structure. It should be understood that these terms are used herein for ease of description of the positional relationship between elements / structures, as illustrated in the figures. It should be understood that, in addition to the orientations depicted in the figures, spatial relative terms are intended to cover different orientations of elements / structures in use or operation. For example, an element / structure described as “above” another element / structure may indicate a position relative to the subject patient or an alternative orientation of the element / structure located below or beside such other element / structure, and vice versa. It should be understood that spatial relative terms (including those listed above) can be understood relative to the corresponding orientations shown in the reference figures.

[0056] For convenience, certain reference numerals are repeated in different figures within the group of figures disclosed herein for the purpose of identifying devices, components, systems, features, and / or modules that have similar characteristics in one or more aspects. However, with respect to any instance disclosed herein, the reuse of common reference numerals in the figures does not necessarily indicate that such features, devices, components, or modules are identical or similar. Rather, those skilled in the art can understand from the context that the use of common reference numerals may imply the degree of similarity between the referenced subjects. The use of a particular reference numeral in the context of the description of a particular figure can be understood to relate to the device, component, aspect, feature, module, or system identified in that particular figure, and not necessarily to any device, component, aspect, feature, module, or system identified by the same reference numeral in another figure. Furthermore, aspects of individual figures identified by common reference numerals can be interpreted as sharing characteristics or being completely independent of each other.

[0057] When using alphanumeric reference numerals that include both numerical and alphabetic parts (e.g., '10a', where '10' is the numerical part and 'a' is the alphabetic part), a written description referring only to the numerical part (e.g., '10') may refer to any feature identified in the figure using such a numerical part (e.g., '10a', '10b', '10c', etc.), even if these features are identified using reference numerals that connect their numerical part with one or more alphabetic characters (e.g., 'a', 'b', 'c', etc.). That is, by way of example, a reference to feature '10' in this written description can be understood to refer to feature '10a' identified in a particular figure of this disclosure, or to the reference '10' or '10b' in the same or another figure.

[0058] This disclosure relates to systems, apparatus, and methods for hermetically bonding thin-film nitinol or other hyperelastic materials to another material / substrate. Such bonding / adhesion techniques can be used in conjunction with the encapsulation of devices configured for sensing and / or telemetry monitoring one or more physiological parameters (e.g., blood pressure) of a patient. For example, an implantable device with a thin-film pressure sensor diaphragm can be used to implement pressure sensing / monitoring and / or other applications. Such devices can be advantageously packaged for long-term implantation in a cardiac setting and can therefore have certain associated biocompatibility characteristics. The terms “associated” and “related to” are used herein in their broad and general sense. For example, where a first feature, element, component, device, or member is described as being associated with a second feature, element, component, device, or member, such description should be understood to indicate that the first feature, element, component, device, or member is directly or indirectly physically coupled, attached, connected, integrated, at least partially embedded therein, or otherwise physically related to the second feature, element, component, device, or member.

[0059] The term "thin film" is used herein according to its broad and general meaning and can refer to any film, layer, sheet, skin, veneer, coating, covering, plating, glaze, finish, shell, or other type of film with a thickness ranging from a few nanometers (nm) to a few micrometers (µm). Thin film sheets of this disclosure can be applied to a substrate during manufacturing and can be produced using various deposition techniques, including but not limited to sputtering, electrodeposition, thermal deposition, chemical vapor deposition (CVD), and physical vapor deposition (PVD). The formation of thin film sheets according to various aspects of this disclosure may involve a phase transition from solid-state source material to gas and the recombination of the gas into a solid state during the deposition process. Thin film sheets of this disclosure may include any suitable or desired material, including: metals such as gold, silver, platinum, titanium, nickel, copper, aluminum, etc., and alloys thereof; alloys such as nickel-titanium (nickel-titanium) or other hyperelastic materials, NiTiCu (nickel-titanium-copper), AuSn (gold-tin), nickel-cobalt-iron alloys (e.g., Kovar...). ® Materials used in the production of aluminum oxides include: Ni29Co17Fe54, stainless steel, etc.; semiconductors, such as silicon, gallium arsenide (GaAs), indium phosphide (InP), cadmium telluride (CdTe), etc.; oxides, such as aluminum oxide (Al2O3), titanium dioxide (TiO2), zinc oxide (ZnO), etc.; nitrides, such as titanium nitride (TiN), silicon nitride (Si3N4), gallium nitride (GaN), etc.; polymers, such as polytetrafluoroethylene (PTFE), polyimide, polyethylene terephthalate (PET), etc.; and ceramics, such as silicon carbide (SiC), aluminum nitride (AlN), etc. For example, depending on the desired material properties, the thickness of the thin film can be as small as 1 nm or as large as 10 µm, 15 µm, 20 µm or greater. The films disclosed herein can be formed using any type of sputtering process, including any process in which atoms or molecules are ejected from a target material due to bombardment by energetic particles such as ions from a plasma, wherein the ejected particles travel through a vacuum or low-pressure gas environment and condense onto the target substrate to form a thin film. As used herein, “sputtering” can encompass any type of DC, RF, magnetron, or reactive sputtering or any other vapor deposition process.

[0060] Examples of devices disclosed herein, such as capacitive pressure sensor devices, may advantageously include a diaphragm and / or electrode structure having one or more layers formed by physical vapor deposition and / or other thin-film deposition / forming processes. Such examples may advantageously include hyperelastic (e.g., nitinol) diaphragm components / layers that are bonded / joined to counterparts or corresponding structures / bases with different material properties in a manner suitable for creating a seal suitable for implantation in the human body. In some examples, such bonding / joining portions may further provide an electrical interface between the bonded / joined components.

[0061] As described in detail below, implantable pressure sensors can be used to measure pressure levels in various catheters and chambers of the body, such as the various chambers of the heart. However, due to the accessibility and environmental conditions typically associated with cardiac catheters / chambers and / or other possible sensor implantation sites within the patient, only certain types of sensors and sensor packages may be suitable for implantation in a given application. Examples of this disclosure relate to packages of pressure sensor implantable devices that include certain electronic and telemetry features to allow for data and / or electrical wireless communication between the implantable sensor device and one or more devices or systems outside the patient's body.

[0062] Various aspects of this disclosure relate to sensor devices, such as wireless implantable pressure sensor devices and other devices including hyperelastic diaphragm components. In particular, the inventive features disclosed herein can be implemented in the context of implantable sensor devices where one or more gold-tin (AuSn) layers are used to bond / attach the diaphragm component to a base substrate component. For example, examples of this disclosure may include diaphragm structures integrated with a eutectic metal layer that creates a hermetically tight and / or electrical interface. As detailed herein, hermetically bonded thin-film nitinol (e.g., physically vapor-deposited nitinol) typically requires relatively low-temperature processes to avoid affecting the material properties of nitinol (e.g., hyperelasticity). As detailed herein, integrating one or more AuSn layers onto the periphery of a nitinol layer (e.g., a diaphragm) can allow for a hermetically tight seal while maintaining the hyperelastic properties of nitinol. Regarding sensor device examples, the AuSn integrated seal can provide biocompatible sealing and / or encapsulation of internal sensor components (such as capacitive electrodes and other circuitry) as well as other structural components of the device. In some applications, AuSn can be used to create hermetically sealed electronic packages, such as by using Kovar (nickel-cobalt-iron alloy) as the material for the metal cap to better match the coefficient of thermal expansion. Nickel-tin or other hyperelastic materials bonded to AuSn according to various aspects of this disclosure provide a novel mechanism for forming hermetically sealed electronic devices. Furthermore, forming thin-film nickel-tin structures for thin-walled pressure transducers for implantable sensors, as disclosed herein, provides additional novel sensor packaging solutions. In some embodiments, titanium (Ti) can be used in addition to or instead of nickel-tin for such applications. The sputtering process for producing diaphragms for in vivo pressure transducers (including any of the full range of biocompatible, low-permeability metals, including Ti, stainless steel, nickel-tin, etc.) and the bonding of diaphragm structures to gold-tin (AuSn) according to the examples given herein can provide numerous benefits, as detailed below.

[0063] Regarding implantable pressure sensor devices, anatomical considerations may necessitate the use of sensor devices with relatively small shape factors. For example, it may be desirable to implant sensor devices, such as pressure sensor devices, using a transcatheter procedure, where the sensor device advances to the target implantation site via one or more venous or arterial vessels and / or various tortuous access paths. Examples of this disclosure are advantageously implemented in sensor devices with sufficiently small profiles / sizes for delivery by and / or within a catheter, sheath, or other device configured for transcatheter access / use. In addition to the size design constraints associated with implantable sensor devices (e.g., pressure sensor devices), sensor sensitivity and / or dynamic range requirements or expectations can also drive sensor design. For example, with respect to example pressure sensor devices, the deflectable pressure diaphragm associated with such devices can be designed in a manner that provides sufficient sensitivity to the pressure conditions to which the device is exposed.

[0064] When fabricating diaphragms with thin-film metal layers (e.g., physical vapor deposition nitinol) for implantable pressure sensors, it may be necessary to seal the device with surrounding / peripheral structures. However, various difficulties can arise when nitinol is bonded to dissimilar materials. In particular, bonding nitinol to ceramic or other dissimilar substrates used in implantable pressure sensors can be problematic. For example, due to different coefficients of thermal expansion, separation and / or breakage of the bonds / joints (e.g., welds) between the materials may occur, thereby impairing or destroying the adhesion between the dissimilar materials and the integrity of the hermetic seal created by the bonds. This paper discloses the use of low-melting-point eutectic AuSn as a solder binder to form a stable hermetic seal between a ceramic body and a nitinol diaphragm in a pressure-sensing implantable device.

[0065] In some instances, a gold-tin (AuSn) alloy layer is directly disposed between the nitinol and non-nitinol (e.g., ceramic) structures of the device stack. Alternatively, one or more intermediate layers, such as titanium (Ti), titanium-tungsten (TiW), and / or TiW-Au, may be implemented between the AuSn layer and the nitinol and non-nitinol structures. The various AuSn stack examples disclosed herein can advantageously provide sufficiently high biocompatibility for use with implantable devices. For example, implantable sensor devices, such as pressure sensor devices equipped with nitinol diaphragms, may require biocompatibility and / or encapsulation characteristics suitable for in vivo implantation. For example, regarding implantation within certain anatomical structures, such as implantation within the chambers of the heart, or other fluid-filled anatomical containers / chambers, such environments may present certain pressure, turbulence, and corrosive conditions that may be associated with fluid / blood properties and / or cardiac circulation. The human body represents a relatively harsh environment for electrically implanted devices compared to non-implantable environments. Examples of this disclosure provide sensor implantation devices that offer hermetically sealed / sealed components to extend duration and / or lifespan, which is advantageous and / or critical for implantable sensor applications. For example, such hermetically sealed components can prevent degradation or otherwise interference by components of ambient blood. Additionally, the hermetically sealed embodiments of this disclosure can help prevent any non-biocompatible components of the sensor implantation device or any non-biocompatible components associated with the sensor implantation device from creating / causing toxic conditions in vivo.

[0066] Physiological sensor implantation site

[0067] This document discloses certain examples in the context of cardiac implantable devices. However, while some principles disclosed herein may be particularly applicable to the anatomy of the heart, it should be understood that sensor implantable devices according to this disclosure can be implanted or configured for implantation in any suitable or desired anatomical structure. Furthermore, the examples of this disclosure can also be used in non-biological environments.

[0068] The anatomy of the heart is described below to aid in understanding some of the inventive concepts disclosed herein. In humans and other vertebrates, the heart typically comprises a muscular organ with four pumping chambers, in which blood flow is at least partially controlled by individual heart valves: the aortic valve, the mitral valve (or bileaflet valve), the tricuspid valve, and the pulmonary valve. Valves can be configured to open and close in response to pressure gradients present during various phases of the cardiac cycle (e.g., relaxation and contraction) to control blood flow to various regions of the heart and / or blood vessels (e.g., the lungs, aorta, etc.). Contraction of the various myocardial muscles can be facilitated by signals generated by the heart's electrical system, which will be discussed in detail below.

[0069] Figure 1Examples of a heart 1 and associated anatomical structures having various features associated with certain instances of the present invention disclosure are illustrated. The illustrated anatomical structures show example implantation sites “s” of sensor devices according to aspects of the present disclosure. Generally, the heart 1 comprises four chambers, namely the left atrium 2, the left ventricle 3, the right ventricle 4, and the right atrium 5. In terms of blood flow, blood normally flows from the right ventricle 4 into the pulmonary artery via the pulmonary valve 9, which separates the right ventricle 4 from the pulmonary artery 11 and is configured to open during systole to allow blood to be pumped to the lungs, and to close during diastole to prevent blood from leaking back into the heart from the pulmonary artery 11.

[0070] The pulmonary artery 11 carries deoxygenated blood from the right side of the heart to the lungs. Blood is then returned from the lungs to the left atrium 2 via the pulmonary vein 23. The pulmonary artery 11 includes the pulmonary trunk and the left pulmonary artery 15 and right pulmonary artery 13, branches from the pulmonary trunk, as shown in the figure. In addition to the pulmonary valve 9, the heart 1 includes three additional valves that assist in the circulation of blood within it: the tricuspid valve 8, the aortic valve 7, and the mitral valve 6. The tricuspid valve 8 separates the right atrium 5 from the right ventricle 4. The tricuspid valve 8 typically has three tips / leaflets and is normally closed during ventricular systole (i.e., systole) and open during ventricular dilation (i.e., diastole). The mitral valve 6 typically has two tips / leaflets and separates the left atrium 2 from the left ventricle 3. The mitral valve 6 is configured to open during diastole to allow blood in the left atrium 2 to flow into the left ventricle 3, and to close during systole when functioning normally to prevent blood from flowing back into the left atrium 2. Aortic valve 7 separates the left ventricle 3 from the aorta 12. Aortic valve 7 is configured to open during cardiac systole to allow blood leaving the left ventricle 3 into the aorta 12, and to close during cardiac diastole to prevent blood from leaking back into the left ventricle 3.

[0071] Heart valves typically comprise a relatively dense fibrous ring (referred to herein as the annulus), and multiple leaflets or cusps attached to the annulus. Generally, the size of the leaflets or cusps is such that, when the heart contracts, the resulting increase in blood pressure within the corresponding heart chamber forces the leaflets to open at least partially to allow flow from the heart chamber. As the pressure within the heart chamber decreases, the pressure in the subsequent chamber or blood vessel may become dominant and compress the leaflets posteriorly. Thus, the leaflets / cusps juxtapose with each other, thereby closing the flow passage. Dysfunction of the heart valve and / or associated leaflets (e.g., pulmonary valve dysfunction) can lead to valvular leakage and / or other health complications.

[0072] Atrioventricular (i.e., mitral and tricuspid) heart valves are typically coupled to an assembly of chordae tendineae and papillary muscles (not shown) to secure the leaflets of the respective valves, facilitating and / or ensuring proper engagement of the leaflets and preventing their prolapse. For example, papillary muscles may typically include finger-like projections from the ventricular wall. Valve leaflets are connected to the papillary muscles via chordae tendineae. A muscular wall 17, referred to as the septum, separates the left atrium 2 and right atrium 5, and the left ventricle 3 and right ventricle 4.

[0073] As mentioned above, certain physiological conditions or parameters associated with cardiac anatomy can affect a patient's health. For example, congestive heart failure is a condition associated with a relatively slow movement of blood through the heart and / or body, leading to increased fluid pressure in one or more chambers of the heart. Consequently, the heart cannot pump enough oxygen to meet the body's needs. The individual chambers of the heart may respond to the increased pressure by stretching to keep more blood pumped through the body or by becoming relatively stiff and / or thickened. The walls of the heart may eventually weaken and become unable to pump effectively. In some cases, the kidneys may respond to the decline in heart function by keeping the body fluid. The accumulation of fluid in the arms, legs, ankles, feet, lungs, and / or other organs can lead to congestion in the body, a condition known as congestive heart failure. Acute decompensated congestive heart failure is a leading cause of morbidity and mortality, therefore, the treatment and / or prevention of congestive heart failure is a critical concern in medical care.

[0074] Various methods for identifying and / or treating congestive heart failure include observing worsening symptoms and / or weight changes. However, such signs may appear relatively late and / or be relatively unreliable. For example, daily weight measurements can vary considerably (e.g., up to 9% or more) and may be unreliable in signaling cardiac-related complications. Furthermore, treatment guided by monitoring signs, symptoms, weight, and / or other biomarkers has not shown significant improvements in clinical outcomes. Therefore, using implanted devices to directly or indirectly measure / monitor pressure and / or other parameters can provide better results than purely observation-based solutions. For example, without direct or indirect monitoring of cardiac pressure, it may be difficult to infer, determine, or predict the presence or occurrence of congestive heart failure or other pathologies. Treatments or methods that do not involve direct or indirect pressure monitoring may include measuring or observing other current physiological conditions of the patient, such as measuring weight, chest impedance, right heart catheterization, etc.

[0075] Cardiac stress monitoring

[0076] Cardiac pressure monitoring according to examples of this disclosure can provide an active intervention mechanism for the prevention or treatment of congestive heart failure. Generally, an increase in ventricular filling pressure associated with diastolic and / or systolic heart failure may occur before the onset of symptoms leading to hospitalization. For example, in some patients, cardiac pressure parameters may be present several weeks prior to hospitalization. Therefore, a pressure monitoring system according to examples of this disclosure can be advantageously implemented to reduce hospitalization by guiding appropriate or desired drug dosing and / or administration before the onset of heart failure.

[0077] Cardiac pressure monitoring (such as left atrial pressure monitoring) can provide an apparatus to guide medication administration for the treatment and / or prevention of congestive heart failure. Such treatment can advantageously reduce readmissions and morbidity, as well as provide other benefits. Implantable pressure sensors according to examples of this disclosure can be used to predict heart failure up to two weeks or longer before the onset of symptoms or markers of heart failure (e.g., dyspnea). When using examples of cardiac pressure sensors according to this disclosure to identify predictors of heart failure, certain preventative measures, including pharmacological interventions such as modifying a patient's medication regimen, can be implemented, which can help prevent or reduce the effects of cardiac dysfunction. Direct pressure measurement within the left atrium can advantageously provide an accurate indication of pressure buildup that may lead to heart failure or other complications. For example, trends in elevated atrial pressure can be analyzed or used to identify or predict the onset of cardiac dysfunction, where medications or other treatments can be increased to induce a decrease in pressure and prevent or reduce further complications.

[0078] Figure 2 This is a block diagram representing a system 200 for wirelessly monitoring one or more physiological parameters associated with a patient, based on one or more instances. Figure 2 An implantable device 30 is shown, including a sensor device 37, which may have a specific anchoring structure 31 associated therewith. For example, the anchoring structure 31 may be configured to anchor in and / or to one or more biological tissue walls. While various examples of implantable sensor devices have been shown and described in this disclosure without a separate anchoring structure, it should be understood that such omissions are for clarity only, and any example disclosed herein may have a specific anchoring structure associated therewith for anchoring the device to a biological tissue / anatomical structure at the implantation site.

[0079] Sensor device 37 may be a pressure sensor according to any of the examples disclosed herein. In some examples, sensor 37 includes a transducer 32 and certain control circuitry 34, which may be implemented in, for example, an application-specific integrated circuit (ASIC) and / or one or more passive devices (e.g., resistors, capacitors, inductors, etc.). Sensor device 37 also includes a diaphragm 33 formed of a hyperelastic material, on which one or more electrode layers or other electronic devices representing portions of the transducer circuitry are layered / integrated. Diaphragm 33 may be at least partially integrated with the outer layer of sensor housing 36. In some examples, sensor housing 36 includes an RF transparent structure housing at least a portion of antenna 38.

[0080] The control circuitry 34 of the sensor device 37 may be configured to process signals received from the transducer 32 and / or wirelessly transmit associated signals through biological tissue using the antenna 38. The antenna 38 may include coils or loops of one or more conductive materials, such as copper wire, or piezoelectric resonators, or other wireless signal transmission components. In some instances, at least a portion of the transducer 32, control circuitry 34, and / or antenna 38 is at least partially housed or contained within a sensor housing / encapsulation structure 36, which may include any type of material and may advantageously be at least partially hermetically sealed. The housing 36 and the diaphragm 33 may be at least partially formed using vapor deposition, as described in more detail below.

[0081] The term "control circuitry" is used herein in its broad and general sense and can refer to any collection of processors, processing circuitry, processing modules / units, chips, dies (e.g., semiconductor dies comprising one or more active and / or passive devices and / or connection circuitry), microprocessors, microcontrollers, digital signal processors, microcomputers, central processing units, field-programmable gate arrays, programmable logic devices, state machines (e.g., hardware state machines), logic circuits, analog circuits, digital circuits, and / or any means of manipulating signals (analog and / or digital) based on hard-coded circuit and / or operating instructions. Control circuitry as referenced herein can also include one or more storage devices, which can be embodied in a single memory device, multiple memory devices, and / or embedded circuitry. Such data storage devices can include read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, data storage registers, and / or any means of storing digital information. It should be noted that in instances where the control circuitry includes hardware and / or software state machines, analog circuits, digital circuits, and / or logic circuits, the data storage device / register storing any associated operation instructions may be embedded within or outside the circuitry containing the state machine, analog circuitry, digital circuitry, and / or logic circuitry.

[0082] For example, in some instances, the housing / package 36 may include one or more tubes, cans, substrates / plates, or other structures comprising glass, epoxy resin, ceramics, metals, and / or other rigid materials, which may provide mechanical stability and / or protection for the components housed therein. In some instances, the housing / package 36 is at least partially flexible. For example, the housing / package may include polymers or other flexible structures / materials that may advantageously allow aspects of the sensor 37 to fold, bend, or retract to allow it to pass through a channel via a conduit or other introduction device. However, embodiments of this disclosure may be advantageously implemented in a manner that provides long-term hermetic protection, wherein a thin-film flexible diaphragm for pressure transmission and associated circuitry are integrated into a single part, component, and / or device.

[0083] Transducer 32 may include any type of sensor component or mechanism. For example, transducer 32 may be a force harvester type pressure sensor. Transducer 32 is shown and described as including one or more diaphragms. However, it should be understood that the pressure sensor device disclosed herein may utilize any type of deflectable strain or deflection measuring component configured to measure strain or deflection applied above its region / surface, such as one or more pistons, Bourdon tubes, bellows, etc. Transducer 32 may be associated with housing / package 36 such that at least a portion thereof is contained within or attached to housing / package 36. In some instances, electrode-integrated diaphragm 33 may serve as a component of a piezoresistive MEMS pressure sensor configured to detect strain due to applied pressure using bonded or shaped conductors, wherein resistance increases as pressure deforms the component / material. That is, the integrated electrode 33 of transducer 32 may be a component of a piezoresistive resistor. In such embodiments, conductors may be applied to a thin-film nitinol diaphragm layer; piezoresistive pressure sensors are referred to below. Figure 3A and 3B The following description is provided. Alternatively, the diaphragm 33 may be a component of a capacitive pressure sensor, wherein a capacitive plate / electrode layer is applied to the nitinol diaphragm layer, as described in detail throughout this disclosure; the capacitive pressure sensor is generally referred to below in conjunction with... Figure 4A and Figure 4B Describe it.

[0084] In some instances, transducer 32 includes an electromagnetic pressure sensor or components thereof, which can be configured to measure diaphragm displacement by means of capacitance change, linear variable displacement transducer (LVDT) functionality, Hall effect, or eddy current sensing. In some instances, transducer 32 includes a piezoelectric strain sensor or components thereof. For example, such a sensor can determine strain (such as pressure) on the sensing mechanism based on the piezoelectric effect in certain materials such as quartz. In some instances, transducer 32 includes a strain gauge or components thereof. In any such embodiment, the associated sensor electrodes / conductors can be applied to the thin-film nitinol diaphragm component, as described in detail herein.

[0085] Transducer 32 may be integrated with one or more layers of vapor-deposited biocompatible material, or may comprise one or more layers of vapor-deposited biocompatible material, as described in detail below. In some instances, transducer 32 is electrically and / or communicatively coupled to control circuitry 34, which may include one or more application-specific integrated circuit (ASIC) microcontrollers or chips. Control circuitry 34 may also include one or more discrete electronic components, such as tuning capacitors, resistors, diodes, inductors, etc.

[0086] exist Figure 2 In system 200, an implantable device 30 is implanted in patient 44 to monitor one or more physiological parameters (e.g., left atrial pressure). Patient 44 may have a medical implantable device 30 implanted in, for example, his / her heart (not shown) or associated physiology. For example, the implantable device 30 may be implanted at least partially in the left atrium of the patient's heart.

[0087] In some instances, the monitoring system 200 may include at least two subsystems, including an implantable internal subsystem or device 30 comprising a sensor transducer 32, and control circuitry 34 comprising one or more microcontrollers, discrete electronic components, and one or more power and / or data transmitters 38 (e.g., antenna coils). The monitoring system 200 may also include an external (e.g., non-implantable) subsystem comprising an external reader 42 (e.g., a coil), which may include a wireless transceiver electrically and / or communicatively coupled to some control circuitry 41. In some instances, both the internal and external subsystems include corresponding coil antennas for wireless communication and / or power delivery through patient tissue positioned between the internal and external subsystems. The sensor implantation device 30 may be any type of implantation device. For example, in some instances, the implantation device 30 includes a pressure sensor integrated with another functional implantation structure, such as a prosthetic shunt or stent device / structure, valve, clip, etc.

[0088] The implantable device 30 may include a specific anchoring structure 31 as described above. For example, the anchoring structure 31 may include a percutaneously deliverable shunt device configured to be secured to and / or within a tissue wall. Although some components are... Figure 2 The sensor implantation device 30 is shown as part of the implantation device 30, but it should be understood that the sensor implantation device 30 may include only a subset of the components / modules shown, and may include additional components / modules not shown. The implantation device 30 may represent an instance of any implantation device shown in Figures 8 through 18, and vice versa.

[0089] In some instances, sensor transducer 32 may be configured to generate electrical signals that can be wirelessly transmitted to a device outside the patient's body, such as the local external monitoring system 42 shown. Control circuitry 34 may include any type of transceiver circuitry configured to transmit electromagnetic signals, which may be radiated by antenna 38, which may include one or more wires, coils, plates, etc. Control circuitry 34 of implantable device 30 may include, for example, one or more chips or dies configured to perform a certain amount of processing on signals generated and / or transmitted using device 30. However, due to size, cost, and / or other constraints, implantable device 30 may not include independent processing capabilities in some instances.

[0090] The wireless signals generated by the implanted device 30 can be received by a local external monitoring device or subsystem 42, which may include a reader / antenna interface circuit module 43 configured to receive wireless signal transmissions from the implanted device 30, which is at least partially placed in the patient 44. For example, module 43 may include a transceiver device / circuit.

[0091] The external local monitor 42 can use an external antenna 48, such as a rod device, to receive wireless signal transmissions and / or provide wireless power. The reader / antenna interface circuit module 43 may include radio frequency (RF) (or other frequency band) front-end circuitry configured to receive and amplify signals from the implanted device 30. Such circuitry may include one or more filters (e.g., bandpass filters), amplifiers (e.g., low-noise amplifiers), analog-to-digital converters (ADCs) and / or digital control interface circuitry, phase-locked loop (PLL) circuitry, signal mixers, etc. The reader / antenna interface circuit 43 may also be configured to transmit signals to a remote monitoring subsystem or device 46 via a network 49. The RF circuitry of the reader / antenna interface circuit module 43 may also include one or more of the following: digital-to-analog converter (DAC) circuitry, power amplifier, low-pass filter, antenna switch module, antenna, etc., for processing / manipulating signals transmitted via the network 49 and / or for receiving signals from the implanted device 30. In some instances, the local monitor 42 includes control circuitry 41 for performing processing of signals received from the implanted device 30. Local monitor 42 may be configured to communicate with network 49 according to known network protocols such as Ethernet, Wi-Fi, etc. In some instances, local monitor 42 includes a smartphone, laptop computer, or other mobile computing device, or any other type of computing device.

[0092] In some instances, the implantable device 30 includes a quantity of volatile and / or non-volatile data storage. For example, such data storage may include solid-state memory utilizing a floating-gate transistor array, etc. Control circuitry 34 may utilize the data storage to store sensing data collected over a period of time, wherein the stored data may be periodically transmitted to a local monitor 42 or another external subsystem. In some instances, the implantable device 30 does not include any data storage. Control circuitry 34 may be configured to facilitate the wireless transmission of data generated by the sensor transducer 32 or other data associated therewith. Control circuitry 34 may also be configured to receive input from one or more external subsystems (e.g., from the local monitor 42 or from a remote monitor 46) via, for example, a network 49. For example, implantable device 30 may be configured to receive signals that at least partially control the operation of implantable device 30, such as by activating / deactivating one or more components or sensors, or otherwise affecting the operation or performance of implantable device 30.

[0093] One or more components of the implantable device 30 may be powered by one or more power sources 35 (e.g., batteries). Due to considerations of size, cost, and / or electrical complexity, it may be desirable for the power source 35 to be substantially minimal. For example, high-power drive voltages and / or currents in the implantable device 30 could adversely affect or interfere with the operation of the heart or other body parts associated with the implantable device. In some instances, the power source 35 is substantially at least partially passive, allowing power to be wirelessly received from an external source via passive circuitry of the implantable device 30, such as through the use of short-range or near-field wireless power transmission or other electromagnetic coupling mechanisms.

[0094] In some instances, the local monitor device 42 may act as an intermediate communication device between the implanted device 30 and the remote monitor 46. The local monitor device 42 may be a dedicated external unit designed to communicate with the implanted device 30. For example, the local monitor device 42 may be a wearable communication device or another device that can be easily placed near the patient 44 and the sensor implanted device 30. The local monitor device 42 may be configured to continuously, periodically, or intermittently query the implanted device 30 to extract or request sensor-based information. In some instances, the local monitor 42 includes a user interface through which a user can view sensor data, request sensor data, or otherwise interact with the local monitor system 42 and / or the implanted device 30.

[0095] System 40 may include a secondary local monitor 47, which may be, for example, a desktop computer or other computing device configured to provide a monitoring station or interface for viewing and / or interacting with monitored cardiac pressure data. Troubleshooting may be performed using / utilizing the local monitor 47, the monitoring performed thereunder, and / or the monitored data. In one example, local monitor 42 may be a wearable device or other device or system configured to be physically located close to the patient and / or implanted device 30, wherein local monitor 42 is primarily designed to receive signals from and / or transmit signals to the implanted device 30, and to provide these signals to the secondary local monitor 47 for viewing, processing, and / or manipulation. External local monitor system 42 may be configured to receive and / or process certain metadata from or associated with the implanted device 30, such as a device ID, which may also be provided through data coupling from the implanted device 30.

[0096] The remote monitoring subsystem 46 may be any type of computing device or collection of computing devices configured to receive, process, and / or present monitoring data received via network 49 from local monitoring device 42, secondary local monitoring device 47, and / or implanted device 30. For example, the remote monitoring subsystem 46 may advantageously be operated and / or controlled by a healthcare entity, such as a hospital, physician, or other care entity associated with patient 44. Although some examples disclosed herein describe communication between the implanted device and the remote monitoring subsystem 46 indirectly via local monitoring device 42, in some instances, the implanted device 30 may include a transmitter capable of communicating with the remote monitoring subsystem 46 via network 49 without relaying information via local monitoring device 42.

[0097] In some instances, the antenna 48 of the external monitor system 42 includes an external coil antenna that is matched and / or tuned to inductively pair with the antenna 38 of the internal implant 30. In some instances, the implant 30 is configured to receive wireless ultrasonic power charging and / or data communication between the external monitor system 42 and the external monitor system 42. As described above, the local external monitor 42 may include a stick or other handheld reader. In some instances, the antenna 48 includes a piezoelectric crystal.

[0098] In some instances, the relay transceiver implantable device 45 is implanted or otherwise positioned on the patient 44, where device 45 acts as an intermediary between sensor 30 and external monitor 42. For example, device 45 may include one or more antennas configured to receive wirelessly transmitted signals from sensor 30 and relay the signals (with or without intermediate signal processing) to external monitor 42. Relay device 45 may be configured to transmit / broadcast signals at a higher power level than sensor device 30. Relay device 45 may further receive signals from external monitor 42 and relay such signals to sensor 30.

[0099] Implantable pressure sensor device with deflectable diaphragm

[0100] Pressure sensors that can be used in medical implant applications include sensors utilizing microelectromechanical systems (MEMS) technology. Such devices can incorporate relatively small mechanical and electrical components on a substrate such as silicon or other semiconductor substrates, and can incorporate a deformable diaphragm for measuring its pressure-induced deflection, wherein the degree of deflection of the diaphragm indicates the pressure conditions exposed to the sensor diaphragm at the implantation site. Examples of this disclosure improve certain MEMS technologies by applying a conductive layer and / or other conductive features to a deflectable diaphragm stack formed on a diaphragm substrate comprising a thin-film nitinol or similar material. The thin-film diaphragm of the sensor devices disclosed herein can be configured as components of any type of deflection-based sensor device, such as piezoresistive pressure sensors and capacitive pressure sensors. Such sensors advantageously include a flexible diaphragm layer that acts as a deformable diaphragm deflected under pressure, wherein integrated conductive features of the diaphragm stack generate a mechanism for measuring the displacement of the diaphragm. This structure can advantageously provide both transducer structure / function and protection against hostile external environments.

[0101] Regarding resistive (e.g., piezoresistive) pressure sensors, certain conductive sensing elements can be fabricated directly on the diaphragm of the device (or on an insulating layer formed on the diaphragm) using sputtering, vapor deposition, or other application processes. Changes in the resistance of such conductors can be determined to indicate a measured value of the pressure applied to the diaphragm. Generally, the change in resistance can be proportional to the strain on the conductor, where the change in conductor resistance is related to a change in conductor length caused by the deflection of the diaphragm on which the conductor is placed.

[0102] Figure 3A This is a side view of a resistive pressure sensor device 320 implemented on a substrate 328 according to one or more examples. Figure 3B It is based on one or more instances Figure 3A A side view of a piezoresistive pressure sensor 320, wherein the sensor's diaphragm 325 is deflected. The deflection of the diaphragm 325 can be caused by pressure conditions to which the diaphragm 325 is exposed. The diaphragm 325 can be formed from a substrate material (such as thin-film nitinol), or other materials that can be formed using physical vapor deposition or other processes. In some instances, the thin diaphragm 325 can be formed by etching a substrate 326 to produce a relatively thin diaphragm for sealing a cavity 329.

[0103] The diaphragm 325 may have one or more conductive traces or elements 322 disposed thereon and / or applied thereon. For example, the conductive element 322 may include a trace of metal or other electrical conductor, wherein one or more length portions of the conductor extend over the diaphragm 325, such that deflection of the diaphragm 325 causes one or more portions of the conductor 322 to elongate / stretch, thereby changing its resistance / impedance. Figure 3BAs shown, when the diaphragm 325 deflects, the current and / or voltage through the conductive element 322 can be measured to determine its corresponding resistance / impedance, thereby providing a measurement result indicating the degree of deflection of the diaphragm 325; this deflection indicates the environmental pressure experienced by the diaphragm 325.

[0104] Figure 4A This is a side view of a capacitive pressure sensor device 420 according to one or more examples. Figure 4B It is based on one or more instances Figure 4A A side view of a capacitive pressure sensor 420, wherein the diaphragm 425 of the sensor is deflected. For a capacitive pressure sensor with an electrode-integrated diaphragm structure according to the present disclosure, one or more conductive layers 422 may be deposited / applied onto / to the thin-film nitinol diaphragm 425 to create a capacitive electrode (e.g., an anode). Corresponding electrodes / plates 421 may be formed on opposing substrates 428 such that a cavity or other dielectric 429 exists between the electrodes / plates 422, 421. In some embodiments, the electrodes 421 provide a stationary / static electrode, while the diaphragm electrode 422 provides a flexible, dynamically deflectable diaphragm electrode 422. With a fixed area for such electrodes 422, 421, the capacitance between the electrodes may be proportional to the distance between the electrodes.

[0105] like Figure 4B As shown, inward / downward deflection / deformation of the diaphragm 425 can alter the spacing between conductors 421, 422 above at least a portion of the diaphragm 425, thereby changing the capacitance of the capacitor formed between the diaphragm electrode 422 and the base electrode 422. Such changes in capacitance can be measured by coupling the sensor device 420 to, for example, a tuning circuit that may have a fundamental frequency proportional to the degree of deflection of the diaphragm 425 and the electrode 422.

[0106] Figure 3A / 3B and Figure 4A Any of the devices shown in / 4B may have certain oxide and / or other insulating layers (e.g., high-k dielectric) formed on the electrode components to provide increased capacitance, reduced leakage current, improved breakdown voltage, and / or allow for reduced electrode / device size.

[0107] Thin film deposition of superelastic metallic alloy (e.g., nitinol) layers

[0108] Examples of this disclosure advantageously provide solutions for hermetically and / or electrobonded to vapor-deposited thin-film nitinol (or similar) structures (e.g., sensor diaphragm structures). Such thin-film metal alloy structures can advantageously facilitate the design of relatively small-sized devices while providing sufficient and / or improved hyperelasticity, diaphragm sensitivity, and / or sealing properties. Furthermore, the use of thin-film nitinol diaphragms in conjunction with examples of this disclosure can facilitate the integration of sensor electrodes with such diaphragm structures / stacks. In some cases, suitable and / or improved biocompatibility properties and / or relatively simplified fabrication processes can be provided through thin-film nitinol layer / diaphragm deposition.

[0109] In some instances, the sensor devices disclosed herein include plate structures in which one or more deflectable diaphragms are formed, along with surrounding mechanical structures, wherein the plate is formed by thin-film vapor deposition. Such integration of the diaphragm of the device with at least some of the other mechanical structures can reduce the number of manufacturing steps / processes required to fabricate the device and, moreover, can provide superior mechanical properties relative to certain non-integrated diaphragm solutions. Furthermore, the integration of the diaphragm of the device with other mechanical structures can reduce the number of parts and process steps required to produce the resulting sensor package. With fewer parts and areas requiring hermetic sealing, a more robust protective housing with a reduced risk of failure / leakage can be produced.

[0110] Certain examples of this disclosure provide alternatives to forged metal processing, stamping, grinding, etc., for sensor diaphragms or other structures, in order to provide structures with reduced thickness, improved sensitivity, and suitability for conformal deposition / formation thereon. For example, processes for forming metal alloy layers for thin film deposition, as described herein, can provide micron-level precision and tolerances that may be difficult or impossible to produce using certain cutting and mechanical processes. In some embodiments, physical vapor deposition processes for metal alloy structures, as disclosed herein, can produce nanometer-level precision and tolerances. Such structures can advantageously be formed using ionization deposition processes rather than by stamping, welding, or other more complex and / or inconsistent / error-prone processes.

[0111] Figure 5This is a block diagram illustrating a thin film vapor deposition system 700 according to one or more examples. Physical vapor deposition (PVD) and other vacuum deposition processes can be used to produce relatively thin films and coatings. In system 500, a source material 530 (e.g., a metal, nitinol) is transformed from a condensed phase to a gas phase 570 and then returned to a thin film condensed phase 540 applied to / applied to a target substrate 520. Sputtering or evaporation can be performed to generate an evaporative / plasma gas 570. The plasma gas 570 is deposited on the substrate 520 to form a layer 540 of the deposited source material. The vacuum chamber 510 can advantageously be free of air and particles that would otherwise interfere with directional deposition on the substrate 520.

[0112] The conversion from solid 530 to gas 570 can be achieved by applying energy from energy source 550. Energy source 550 can be any type of energy, including heat / thermocurrent, current, and / or voltage potential relative to the potential 560 associated with substrate 520. The energy can excite source material 530 to generate plasma 570. The potential 560 relative to source material 530 can be used to generate a deposition flow 570 directed toward substrate 520. In some cases, source material 530 can be positively charged, while the potential 560 of substrate 520 can be negatively charged.

[0113] With respect to the various processes and apparatuses disclosed herein, any type of deposition process can be implemented to produce any metal stack of the present invention, including physical vapor deposition or alternatives to physical vapor deposition. Examples may include cathodic arc deposition, in which a high-power arc discharges at the target (source) material to ablate some of the material into highly ionized vapor for deposition onto the workpiece. For electron beam physical vapor deposition embodiments, the material to be deposited is heated to a relatively high vapor pressure in a vacuum by electron bombardment and transported by diffusion to be deposited onto a relatively cool workpiece by condensation. For evaporation deposition, the material to be deposited can be heated to a relatively high vapor pressure by resistance heating in a vacuum. As another example, confined space sublimation may involve placing the source material and substrate relatively close to each other and radiatively heating them. Pulsed laser deposition can be implemented by ablating the source material into vapor using a high-power laser. Pulsed electron deposition can be implemented by ablating the source material using a high-energy pulsed electron beam to generate plasma under non-equilibrium conditions.

[0114] In some examples, sputtering deposition can be performed where a luminescent plasma discharge, positioned around a target substrate by a magnet, bombards the source material, thereby sputtering off some of the source material as vapor for subsequent deposition. For sputtering applications, magnetrons can be used, which utilize strong electric and magnetic fields to confine charged plasma particles close to the surface of the sputtering target. Other sputtering techniques that can be implemented include ion beam sputtering, reactive sputtering, ion-assisted deposition, high-power pulsed magnetron sputtering, gas flow sputtering, or similar techniques.

[0115] Changes in bonded sensor packaging

[0116] As described above, implantable pressure sensor devices may include a deflectable diaphragm cap comprising a thin-film nitinol and / or other hyperelastic metallic alloy bonded to a base substrate (e.g., ceramic, glass, or any other type of inorganic nonmetallic material), wherein the bonding provides a hermetically tight coupling between the nitinol and the nitinol structure and / or electrical interface. In such examples, deflection of the diaphragm portion of the cap can generate an electrical change within the device that is readable and indicates pressure conditions outside the device. For example, conductive resistor / strain gauge traces and / or capacitor electrodes may be formed on the diaphragm portion such that deflection of the diaphragm produces a change in the electrical properties of the conductor (e.g., capacitance, resistance). While capacitor plate electrodes are disclosed in some contexts herein, it should be understood that any examples disclosed herein are also applicable to resistive or piezoresistive conductor elements integrated with a diaphragm stack. For example, any capacitive sensor instance disclosed herein, described as including a flexible nitinol diaphragm with a conformal capacitive plate / electrode associated therewith, may alternatively or additionally have a resistive or piezoresistive sensor element integrated / associated with the deflectable nitinol diaphragm.

[0117] Various electronic / conductive layers, components, and / or elements can be added to a membrane structure comprising a thin nitinol layer (e.g., stacked) to achieve the integration of passive and / or active electrical components with a relatively thin membrane structure. Applying electrical and / or insulating elements (such as conductive layers configured to act as capacitive plates / electrodes in a circuit, and associated dielectrics) to a nitinol or other thin-film membrane can be performed via chemical or physical vapor deposition, sputtering, masking / etching, photolithography, screen / inkjet printing, electroplating, epitaxy, thermal oxidation, atomic layer deposition, anodizing, etc.

[0118] Figure 6A side cross-sectional schematic diagram of a sensor device 620 is shown, which has a capacitive electrode 622 that is structurally conformal to a hyperelastic diaphragm 625 with a thin film (e.g., less than 20 μm thick, such as between 5 μm and 10 μm). As with any deflectable diaphragm layer disclosed herein, the diaphragm layer 625 may comprise any type of deposited thin film hyperelastic metallic material. While deflectable diaphragm layers are described herein in certain contexts as including nitinol, it should be understood that such diaphragm layers may comprise any type of deposited (e.g., physical vapor deposition) thin film (e.g., less than 15 µm), hyperelastic metal, including alloys such as nitinol (NiTi), NiTiCu, etc. As described in detail above, the use of physical vapor deposition of nitinol, titanium, gold, and / or other materials provides a basis for producing sensor diaphragm / electrode stacks / structures suitable for implantation in the human body, as disclosed herein.

[0119] Converting internal pressure into capacitance may require relatively high biocompatibility and stability of the diaphragm electrode. To achieve the flexibility required for minimally invasive implantation devices, limiting the thickness of the deflectable diaphragm stack / structure to micrometer-scale dimensions can produce suitable products. Furthermore, a relatively large diaphragm surface area may be necessary or desirable to achieve relatively large capacitance values ​​measurable using passive or active circuitry. However, such parameters may conflict with the goal of achieving minimally invasive implantation due to the lateral dimension limitations typically associated with such devices. The use of nitinol and similar materials for the flexible diaphragm substrate on which capacitive electrodes can be placed can provide a biocompatible layer that meets the above requirements and allows for the production of low-profile, highly flexible / capacitive sensor elements.

[0120] Device 620 includes an integrated capacitive electrode 622 (or a resistive conductor for resistor applications) on a hyperelastic diaphragm 625. Electrode 622 can be part of a flexible stack 627 used as a capacitive electrode, eliminating the need to additionally transfer pressure from the diaphragm 625 to a separate sensor element. Figure 6 In this example, as with other examples disclosed herein, since there is no pressure-transmitting fluid, sensor 620 can be considered a dry capacitive sensor (see [link to other examples]). Figure 7 The sensor 620's package (e.g., an external nitinol housing / layer) itself forms a component of the pressure transducer element, i.e., a plate / electrode of the capacitor element. In other words, the external nitinol layer / housing 625 provides biocompatible / hermetic packaging and, due to its integration with the capacitor electrode 622, transmits pressure to the sensor's electrical signal.

[0121] The diaphragm electrode 622 is combined with the corresponding electrode 621 to form a capacitor electrically coupled to the circuit 634 of the sensor 620. The capacitor plates 621, 622 can be electrically coupled to the resonant circuit of the circuit 634 via certain electrical leads / connectors 624a, 624b, which can be integrated with the structure of the base substrate / structure 605 in any suitable or desired manner (e.g., through various traces, vias, etc.). A nitinol diaphragm 625, which may have associated peripheral sidewalls / protrusions 628, can be physically sealed to the base structure / substrate 605 and the connection / joint 623 to provide a hermetically sealed volume / space 629 between the capacitor plates 621, 622. The base substrate / structure 605 may include ceramic, glass, nitinol, or other metals or materials. The volume 629 may include a vacuum volume.

[0122] The nitinol layer 625 provides a thin, flexible, ultra-elastic, biocompatible, externally facing housing for device 620. Furthermore, the thin-film diaphragm 625 provides relatively large deflection and correspondingly large variations in capacitance and signal amplitude while remaining resilient. The conductor layer 622 can advantageously insulate the memory metal structure diaphragm 625, thereby electrically isolating the nitinol layer 625 from the circuitry of capacitors 622 / 821. In other words, the nitinol layer 625 can serve as a substrate for depositing / applying the conductor layer 622, wherein the conductor 622 is electrically isolated from the diaphragm 625 by an insulating layer 626a (e.g., oxide).

[0123] Compared to sensors that include deflectable capacitive sensor diaphragms formed of glass layers, using thin-film nitinol or other hyperelastic metals as described herein offers a variety of advantages. For example, when comparing the elasticity of nitinol and glass in the context of deflectable diaphragms, nitinol can be considered to offer superior hyperelastic properties. Generally, nitinol can withstand significant elastic deformation and return to its original shape upon stress removal, which can be beneficial for applications requiring a considerable degree and amount of deflection. Conversely, glass, as a relatively brittle material, typically exhibits relatively low elasticity, making it unable to effectively withstand large strains and capable of fracturing under high stress. Furthermore, the strength of a glass substrate can depend on the surface finish of the glass, where cracks or fissures on the surface can act as stress concentrators, potentially compromising its structural strength. In contrast, a nitinol diaphragm 625 can advantageously withstand high stress and strain without yielding to permanent deformation, while glass, due to its brittleness, may be prone to catastrophic failure under stress.

[0124] Compared to glass diaphragms, the thin-film nitinol diaphragm 625 offers additional benefits, including the ability to form shaped surfaces (such as corrugations or extrusions) within the diaphragm layer, which can increase the effective surface area of ​​the diaphragm 625. Furthermore, forming corrugations, extrusions, and / or other surface topological features in the diaphragm layer (e.g., diaphragm layer 625) of the examples of this disclosure can increase the linear deflection state / sensitivity of the diaphragm. On the other hand, forming shaped surfaces in glass presents certain challenges due to its structural brittleness / fragility and the lack of available processes for precisely generating surface features in glass surfaces. Nitinol can be mechanically tuned in ways that glass and other diaphragms cannot, and when implemented with a conformal electrode layer covering a large portion of the nitinol diaphragm as described herein, it provides greater deflection to produce larger capacitance changes. For corrugations in the diaphragm layer, such three-dimensional features can be formed by depositing a thin film of metal on a surface / mold / mandrel having such surface features. Regarding fractal and / or porous surface features, their formation may involve masking, electroplating, etc.

[0125] One or more of the dielectric layers 626a and 626b may comprise a high-k dielectric material. In addition to electrically isolating the plates 622 and 621 from the physically proximate substrates 625 and 605 to prevent damage to the sensor signals, the presence of dielectric 626 also serves to protect the circuitry associated with the electrodes 621 and 622 from circuit breakdown caused by capacitance between the plates 622 and the substrates 625 and 605, which may be at least partially conductive, as in the case of nitinol. Using a high-dielectric material prevents the formation of capacitance between the nitinol layer 625 and the electrode layer 622, thereby reducing unwanted stray capacitance that could negatively impact the circuitry.

[0126] Capacitor electrodes 621, 622 are electrically coupled to a circuit 634, which may include an antenna configured to facilitate the wireless transmission of sensor signals and / or signals derived therefrom. In some embodiments, circuit 634 includes active circuitry, including amplifiers configured to convert the capacitance of plates 621, 622 into readable signals. Generally, the capacitors formed by plates 621, 622 can be electrically coupled to the antenna in such a way that changes in the capacitance of the capacitors cause changes in the resonance of the antenna, wherein such resonance of the antenna can be decoded to determine the stress level causing the resulting capacitance.

[0127] The bonding portion 623 advantageously provides an electrical interface through which the conductive wire 632 can pass to the base structure. That is, the bonding portion 623 can serve as both a hermetically sealed element and an electrical interface. The bonding portion 623 can take any of the bonding / joining forms described herein and can advantageously include one or more gold-tin (AuSn) layers that can facilitate bonding / melting at temperatures below the transition temperature of the nitinol layer (e.g., diaphragm 625).

[0128] Pressure sensor using pressure transmission medium

[0129] Some pressure sensor solutions may include sensors encapsulated in a diaphragm integrated housing / enclosure, with the transmission fluid disposed between an external flexible diaphragm and an internal capacitive sensor device. Figure 7 A side cross-sectional schematic diagram of a sensor device 720 having a pressure transmission medium 752 according to one or more examples is shown.

[0130] The pressure transmission medium 752 contained within the housing of device 720 may include an incompressible fluid, such as oil or gel. Figure 6 Unlike other examples, device 7 includes a separate pressure sensor device / element 710, which includes its own deflectable diaphragm separate from the diaphragm 725 of the housing.

[0131] The region surrounded by a housing 733, including a deflectable diaphragm 725, contains a sensor 710 (e.g., a MEMS sensor). A pressure-transmitting fluid or other medium (e.g., oil, gel, epoxy resin) 752 is disposed around the sensor element 710 such that external pressure causing inward deflection of the diaphragm 725 is transmitted to the pressure sensor 710 for its sensing. Pressure conditions outside the housing 733 can cause inward deflection of the diaphragm 725 in a manner similar to applying pressure to the surface of the sensor element / diaphragm. In some instances, the pressure-transmitting medium 752 may comprise an incompressible fluid or medium. Alternatively, the medium 752 may be compressible, wherein deflection of the diaphragm 725 can cause a reduction in the volume of the internal chamber of the housing 733, thereby compressing the fluid / medium and resulting in an increase in pressure within the housing 733, which is then transferred to the sensor element 710.

[0132] The pressure transmission medium 752 is sealed within a housing 733 via a bonding portion 723, which seals the diaphragm structure 770 to the base structure 780 and provides an hermetically sealed housing 733 for the sensor element 710. The diaphragm structure 770 may include a thin-film diaphragm 725 and a peripheral stack 728, which may also include nitinol and / or other materials / layers for bonding to the corresponding structure 738 associated with the base 780. The sensor element 710 may be electrically coupled to a circuit 734, which may include an antenna configured to facilitate the wireless transmission of sensor signals and / or signals derived therefrom. In some embodiments, the circuit 734 includes active circuitry, including amplifiers configured to convert the capacitance of plates 621, 622 into readable signals.

[0133] The bonding portion 723 advantageously provides an electrical interface through which the conductive wire 732 can pass to the base structure. That is, the bonding portion 723 can serve as both a hermetically sealed element and an electrical interface, allowing conductors or other electrical components to be integrated with the diaphragm structure 770. The bonding portion 723 can take any of the bonding / joining forms described herein and can advantageously include one or more gold-tin (AuSn) layers that can facilitate bonding / melting at temperatures below the transition temperature of the nitinol layer (e.g., diaphragm 725).

[0134] Using a gold-tin layer with airtight bonding to nickel-titanium

[0135] Nickel-titanium is a shape memory alloy composed of approximately equal parts nickel and titanium, possessing certain beneficial properties due to its crystal structure and the phase transformations it undergoes. These properties include superelasticity and the shape memory effect. However, exposure to high temperatures can affect the unique properties of nickel-titanium because it causes changes in the material's crystal structure. For example, nickel-titanium can undergo a thermal transformation when exposed to temperatures exceeding its austenite completion temperature. Repeated exposure to high temperatures can lead to a gradual change in the alloy's crystal structure. Even prolonged exposure to relatively low temperatures can induce this change. Heating nickel-titanium above its transformation temperature, such as when melting bonding materials to bond to nickel-titanium, can result in a loss or reduction in superelasticity, changes in the transformation temperature, and / or microstructural changes. Recrystallization and / or grain growth occurring in the material's microstructure can affect its mechanical properties, such as strength and hardness. Furthermore, the shape memory effect of nickel-titanium depends on the generation of recovery stress during the phase transformation. High-temperature exposure reduces the alloy's ability to generate this stress, thus affecting its shape recovery capability.

[0136] Given the temperature limitations of nitinol, traditional joining techniques such as welding and brazing can present challenges when used with nitinol. This is exacerbated when a hermetic seal is required at the joint. While welding nitinol is possible, it typically requires precise process refinement to accommodate the specific design, usually handled by subject matter experts. Furthermore, welding can limit the choice of materials used for welding to nitinol to other metals similar to nitinol.

[0137] Examples of this disclosure advantageously implement gold-tin (AuSn) alloys to form hermetically sealed and / or electrical connections between thin films (e.g., physically vapor-deposited) nitinol and dissimilar materials (e.g., ceramics, glass, printed circuit boards). Gold-tin provides a desirable binder due to its relatively low melting temperature, high thermal / electrical conductivity, and fatigue, corrosion, and creep resistance. The low melting temperature advantage provided by AuSn is advantageous for certain sensor applications disclosed herein, as it preserves the unique properties of nitinol while hermetically bonding it to a dissimilar material on a functional substrate. By avoiding elevated temperatures, the gold-tin alloy effectively protects the integrity of the hyperelastic and shape memory properties of nitinol.

[0138] In addition to preserving the mechanical properties of nitinol, the gold-tin hermetic bonding method proposed herein offers advantages in facilitating electrical connections between nitinol and other circuit elements. Such features can be particularly beneficial in applications where mechanical and electrical integration is important or necessary, such as medical implants, sensors, actuators, and various other electronic devices. The gold-tin layer used in the example bonding / bonding configurations disclosed herein can further provide relatively low reactivity, thus offering corrosion and degradation resistance upon exposure to bodily fluids, promoting the long-term integrity of the implant. Furthermore, since both gold and tin are biocompatible materials capable of being deposited using physical vapor deposition (PVD) techniques or other similar processes (e.g., sputtering / electron beam evaporation / electrodeposition), the thin-film gold-tin bonding layers of the examples disclosed herein can be deposited using such processes, which produce stoichiometric alloys of gold and tin metals without impurities. Finally, some types of gold-tin bonding / bonding features as disclosed herein can be implemented using semiconductor industry-standard flip-chip bonding processes / mechanisms. For example, gold-tin features can be flip-chip bonded by melting gold-tin molded parts without using flux or corrosive additives that could ultimately cause biocompatibility issues in long-term implanted devices.

[0139] Figure 8A and Figure 8B A front and rear perspective view of a diaphragm cover / structure 870 of a sensor device according to one or more examples are shown, the cover / structure comprising nitinol and / or other hyperelastic materials. Figure 9A base structure 980 for a sensor device is shown according to one or more embodiments. Figure 10A and Figure 10B Perspective and cross-sectional views are shown respectively of a combined sensor device 1000, including a diaphragm cover / structure 870 physically coupled to a base structure 980, according to one or more embodiments. (The remaining text appears to be incomplete and possibly contains errors.) Figure 8A , Figure 8B , Figure 9 Figure 10A and Figure 10B Use any of the options to interpret the following description.

[0140] Structure / plate 870 can provide a structure for one side / plate of the pressure sensing capacitor, wherein certain contacts / connections 871 of plate 870 can facilitate electrical connection between electrode 822 and paired electrode base structures (see...). Figure 9 The plate 870 is joined / bonded to the corresponding sensor structure using a gold-tin (AuSn) alloy layer to provide its hermetic seal. References herein to components 'bonded' to each other are to be understood as being joined in any manner (e.g., welding, adhesive bonding, etc.). Contacts 871, which may be at least partially formed of AuSn, can be connected to electrodes 822 via direct physical contact or wiring connections through traces on the nitinol substrate / layer 821. While the diaphragm plate 870 and certain similar devices / structures disclosed herein are shown and described as having an elliptical shape, it should be understood that such devices / structures can have any suitable or desired shape, such as rectangular, circular, or similar shapes. As with any other instance disclosed herein, an active capacitive sensor may occupy the entire surface or most of the surface of the plate 870, or the capacitive sensor may occupy multiple smaller diaphragm regions 825a, 825b, 825c (collectively or individually referred to as "825"), such as... Figure 8A and Figure 8B As shown, the diaphragm plate 870 and / or associated sensor device / component can have an elliptical shape, similar to the union of two semicircles on opposite sides of a rectangle (in some cases referred to as an "oblong"), thus providing a shape reminiscent of a speed skating rink or athletic track. In some contexts, the shape of the plate / sensor 870 can be described as a "stadium" shape, a "disc" shape, or an elongated ellipse.

[0141] The diaphragm plate 870 includes a sheet / layer of superelastic thin film nitinol 821, wherein the nitinol can be deflected in one or more regions in a dimension perpendicular to the surface of layer 821, such as at least in regions 825 corresponding to capacitor electrodes 822a, 822b, 822c (collectively or individually referred to as "825"). In terms of processing, the nitinol layer 821 (including the diaphragm portion 825 and the region 829 outside the diaphragm 825) can be deposited on the substrate using physical vapor deposition or other deposition processes. The cap structure 870 may include a peripheral sealing flange 872 above the nitinol sheet / layer 821 (relative to...). Figure 8A The peripheral sealing flange 872 may include a trim, lip, edge, or similar structure configured to physically bond to the base to provide a space between the nitinol layer 821 and the base. The flange 872 may be formed at least partially from nitinol formed / deposited on layer 821 to create the raised structure, as shown. In some instances, one or more gold-tin (AuSn) layers are disposed on or near the nitinol flange 872 to provide an adhesive for bonding the cap 870 to the base 980 (see [reference]). Figure 9 The peripheral bonded / sealed portions of the thin-film nitinol diaphragm structure can typically be non-deflectable portions / regions of the nitinol layer because such portions / regions are bonded to at least partially rigid structures and cannot be freely bent inward in response to pressure changes, unlike diaphragm portions / regions 822.

[0142] The insulating / oxide layer 826 can be formed or deposited on the nitinol 821 in any suitable or desired manner. For example, the insulating layer 826 can be formed only in the region of the diaphragm 825. The nitinol layer 821 can have a thickness d1 of, for example, about 5 μm, or any other value less than 10 μm. In some embodiments, although described as a 'thin film' diaphragm layer, it should be understood that the thickness of the flexible diaphragm layer disclosed herein can be up to 20 µm or greater. Electrode metal 822 can be applied to the oxide layer 826 and can also be confined within the region of the diaphragm 825. Although three circular diaphragms 825 are shown, it should be understood that the diaphragm plate / structure disclosed herein can have any number, configuration, or shape of diaphragms.

[0143] In some embodiments, the nitinol layer 821 in the diaphragm region 825 differs substantially from the region 829 outside the diaphragm in one or more aspects. For example, the diaphragm portion 825 may be thinner than the region 829 outside the diaphragm. Additionally or alternatively, certain shape or surface features of the diaphragm region 825 may distinguish the diaphragm from the rest of the nitinol sheet / layer. For example, corrugations, protrusions, notches, indentations, or other features may define the outer periphery of the diaphragm region 825 and / or other regions or features of the diaphragm 825.

[0144] The peripheral flange 872 may have a gold-tin alloy (AuSn) layer 878 disposed thereon, which provides a sealing contact surface 879. Additionally, the electrical contact 871 may include AuSn. The conductivity of the nitinol layer 821 and the side support structure / flange 871 can be significantly lower than that of the electrode conductor 822 and the AuSn layers 871, 878, which allows electrical shunt through the electrical interface of the AuSn molding without through adjacent nitinol layers. At the top of the contact flange 872 (relative to...) Figure 8A The use of AuSn (in its orientation) advantageously allows for electrical contact with electrical contacts implemented on / in the vapor-deposited nitinol 821, while also providing a hermetically tight seal. Furthermore, since nitinol typically cannot withstand high temperatures, AuSn is suitable for positioning and melting near nitinol, as AuSn melts at temperatures below the nitinol transition temperature.

[0145] In some embodiments, an electrically conductive contact 871, including AuSn, may be applied / formed on the electrode layer 822 such that the molded part 871 is in electrical contact / communication with it. For example, the electrical contact 871 may be in physical contact with the electrode layer 822. When the diaphragm plate 870 is joined (e.g., bonded) to the capacitor plate 822, the contact 871 may be in contact with the cathode structure physically coupled to the capacitor plate (see [link to relevant documentation]). Figure 9 Figure 10A Figure 10B An electrical connection is provided between the diaphragm electrode 822 and the associated capacitive resonant circuit of the sensor device. The electrical contact 871 may have the form of a raised flange, edge, lip, margin, or similar structure, and typically provides a corresponding surface 991 for interaction with the base structure (see [reference]). Figure 9 The physical contact surface of an electrical connection.

[0146] In some embodiments, electrical contacts 991 and / or 871 may comprise conductive AnSn solder, or other types of material formed as flanges projecting in a dimension perpendicular to the plane of plate 870, substrate 980, and / or device 1000. Contact 871 may be formed in any suitable or desired manner, such as by vapor deposition, sputtering, or other application processes.

[0147] In some embodiments, a peripheral gap 877 separates adjacent portions / lengths of conductor 871 that may extend substantially along the periphery of electrode 822. The gap 877 can provide a path for removing gas from the space within contact 871, allowing for a vacuum seal of chamber 1009. In some instances, contact 871 forms a continuous periphery around electrode 822 without a circumferential gap, which may allow for the implementation of independent and / or isolated capacitors.

[0148] A peripheral sealing structure 872 may be applied to and / or around the periphery of the plate 870, such as by direct application to a thin-film metal (e.g., nitinol) layer 821. The peripheral structure 872 may take the form of a raised flange, edge, lip, or similar structure, and typically provides a sealing contact surface 879 for sealing against a corresponding surface of the base structure 980. The peripheral structure 872 may project in a direction perpendicular to the surface of the nitinol layer 821 to provide a structure that offsets the capacitor electrode 822 from the base 980. For example, a gold-tin top surface 879 may be configured to bond to a corresponding surface or feature 992 of the base structure 980 of the sensor device 1000.

[0149] A sensor base 980 may have a capacitive electrode 981 formed thereon, which may each be paired with a corresponding capacitive electrode of the capacitive electrodes 822 of the diaphragm plate 870, such that when the plate 870 is coupled to the base 980, a variable capacitance, at least partially based on the deflection state of the diaphragm 825, exists between and is measurable on the plates 822 and 981. Electrodes 981, which may have fixed non-deflection attachments / structures, may be combined with deflectable electrodes 822 to form one or more variable capacitors having capacitance that varies according to the deflection state of the electrode 822. The static properties of the base electrode (e.g., cathode) 981 may be provided by its coupling and / or integration with a rigid or semi-rigid substrate structure 901. Either electrode 822 or 981 may have an elliptical (e.g., circular) shape, as shown.

[0150] The base 980 may also include electrical contacts 991 configured to contact / bond to corresponding electrical contacts 871 of the diaphragm plate 870. That is, the contacts 991 of the base 980 may be electrically isolated from the capacitor plate 981, but electrically coupled to the electrode 822 via the contacts 871. When the diaphragm plate 870 is bonded to the base structure 980, these contacts may be bonded together at the coupling interface 1007, as shown in Figure 10. Although the contacts 991 may be configured such that they do not directly contact the capacitor plate 981, both the capacitor plate 981 and the electrical contacts 991 can ultimately be connected in the same capacitance-residing circuit through various electrical interconnections to allow measurement of the capacitance between plates 822, 981. When the workpieces 870, 980 are bonded / coupled together, the static / fixed capacitor electrode 981 may be axially aligned and / or centered with the dynamic capacitor electrode 822. Electrical contact 991 may have the form of a raised flange, edge, lip, rim or similar structure, and typically provides a contact surface for electrical connection with the corresponding surface 871 of diaphragm plate 870.

[0151] The area of ​​physical contact and sealing between the diaphragm plate 870 and the substrate 980 can be via peripheral protrusions 992. The dimensions of the electrical contact flanges 991 and 872 can be designed and set at known distances to offset the capacitor electrodes 822 and 981 by a desired distance. For example, opposing flange contacts 991 and 871 can physically contact to create an electrical connection between plates 870 and 980, and define the accuracy of the offset of electrodes 981 and 822. Contact flanges 992 and 972 can provide peripheral seals for a hermetically sealed device 1000. The peripheral structure 992 of the base 980 can advantageously span the entire periphery of the base substrate 901, such that the interface between such peripheral structures provides a hermetically sealed protection for the internal cavity 1009 from external environmental influences when in close bonded contact with the peripheral structure 872 of the diaphragm plate 870. The internal cavity 1009 can be filled with air or other inert gases, or it can be vacuum-sealed. In instances where cavity 1009 includes a vacuum, the sensor can provide an absolute pressure sensor. Alternatively, some instances include the presence of gas within cavity / volume 1009, which can be used as a relative pressure sensor implementation. Furthermore, cavity 1009 can provide a ventilation path to a large volume. Such a large exhaust volume can advantageously reduce air compression resistance while allowing the cathode and anode to be placed very close to each other, with minimal / very small volume between the electrodes.

[0152] The substrate 901 of the base structure 980 (e.g., a cathode structure) may comprise ceramic, glass, or any other suitable material, whether rigid or flexible. For example, the substrate 901 may include and / or have an associated printed circuit board and / or application-specific integrated circuit (ASIC) containing specific circuitry configured to process the capacitive signal of the capacitor 1095. The base substrate 901 may include certain electrical connections configured to facilitate proper electrical coupling of the respective capacitor plates 822, 981. For example, certain vias or other connections may be made through at least a portion of the thickness of the substrate 901.

[0153] In some implementations, the deflection of diaphragm 825 is measured independently to provide individual sensor signals, thereby providing additional levels of sensitivity. For example, different capacitors 1095 can be tuned to have different mmHg / fF curves (or curves based on other units, such as variations in electrode displacement (Δz) per mmHg), allowing consideration (e.g., zeroing) of tissue growth that may accumulate disproportionately on one capacitor diaphragm 825 relative to another. In the examples of Figures 8 through 10, the three capacitors 1095 can operate uniformly as a single capacitor sensor, or they can be separated by certain electrical contacts / connections to form three separate capacitors. In some instances, capacitor electrode 822 and / or capacitor electrode 981 may comprise gold.

[0154] The junction / bonding 1005 between the cap structure 870 and the base structure 980 can be implemented using one or more gold-tin (AuSn) and / or gold (Au) layers to create a relatively hard / good junction / bonding that provides a hermetically sealed and electrical interface between the nitinol material of the cap 870 and the non-nitinol material of the base 980. Bonding with nitinol (e.g., thin-film nitinol) and similar materials is often challenging due to molecular structure and temperature response; therefore, the use of the eutectic metal alloy AuSn allows for efficient bonding while protecting the molecular integrity of the substrate. The exemplary AuSn junction / bonding techniques of this disclosure are particularly useful for sensor applications where sensing mechanisms involving transduction and / or electrical coupling between nitinol and non-nitinol components are implemented, as AuSn junction / bonding can provide biocompatibility and electrical pathways between components.

[0155] Generally, when nitinol is exposed to high or even low temperatures for extended periods, the material can become amorphous instead of remaining hyperelastic. Gold-tin alloys (AuSn) can advantageously become eutectic in certain compositions, allowing the alloy to melt at relatively low temperatures (e.g., as low as 280°C), thus enabling the formation of junctions / bonds at temperatures that do not interfere with the nitinol crystal structure. Therefore, AuSn-nitinol bonding, as described in detail below, can be used to bond to nitinol structures, such as bond 1005 described above with respect to Figures 8 through 10, as well as other examples disclosed herein, to produce hermetically and electrically bonded junctions with nitinol structures.

[0156] Figure 11A and Figure 11BFront and rear perspective views of a sensor cap / diaphragm structure 1170 according to one or more examples are shown. The cap / structure 1170 can be used in alternative sensor designs where capacitor electrodes are not conformally deposited on the nitinol layer, but rather the cap 1170 contains one or more internal sensor device chambers, in which one or more sensor devices and a pressure-transmitting medium (e.g., oil, gel) are disposed, configured to transmit the deflection of the nitinol diaphragm to the internal sensor devices; examples relating to such pressure-transmitting fluid sensor devices have been described in detail above.

[0157] The cap 1170 includes a thin nitinol layer covering the diaphragm region. In some instances, the cap structure 1170 may include an accumulation of NiTi material 1164 surrounding the diaphragm 1125, wherein at least a portion of a cylindrical or other shaped volume / space is provided within the raised can structure 1164, wherein such a space can be filled with pressure-transmitting fluid when the cap structure 1170 is assembled with the base structure to form a sensor device. In some embodiments, no raised diaphragm outer structure is formed around the diaphragm (as) 1125. For example, any cylinder or other volume / space where the pressure of the transmission fluid is disposed may be exclusively associated with the base structure 1280.

[0158] The cover structure 1170 may include a peripheral sealing flange 1172 that is above the nitinol sheet / layer 1121 and / or a thicker nitinol structure (if implemented) 1164 surrounding the diaphragms 1125a, 1125b, 1125c (relative to) Figure 11A The peripheral sealing flange 1172 may include edges, lips, margins, or similar structures, as described above in conjunction with other examples, which are configured to physically engage with the base to provide a space between the nitinol layers 1121, 1164 and the base. The flange 1172 may be formed at least partially from nitinol formed / deposited on layer 1121 to create the raised structure, as shown. In some embodiments, the peripheral flange 872 is flush with the raised structure 1164 around the diaphragm. For example, the cap may include a thin-film diaphragm layer 1121 and the raised outer structure 1164 without an additional raised nitinol structure. Instead, an adhesive (e.g., AuSn) may be applied to such an integrated structure 1164, such as in the form of a pre-formed structure placed against the structure 1164 / 1172.

[0159] In some instances, one or more gold-tin (AuSn) layers are disposed on or near the nitinol flange 1172 to provide an adhesive for bonding the cap 870 to the base 980 (see [link to documentation]). Figure 9The AuSn layer can be deposited using sputtering, vapor deposition, or other processes, or it can be a solid preform structure with, for example, a stadium shape or other shape as shown in the figure, physically placed on the Nitinol structure, with or without an intermediate oxide between the two materials.

[0160] Figure 12 A base structure 1280 for a capacitive sensor device 1300 according to one or more embodiments is shown. Figure 13A and Figure 13B Perspective and cross-sectional views of a sensor device 1300, including a diaphragm cover / structure 1170 physically coupled to a base structure 1280, are shown respectively.

[0161] The sensor base 1280 may have one or more cylinders or other volumes / spaces 1209 in which the sensor device 1210 may be placed / located, such that when the cover 1170 is coupled to the base 1280, a fluid medium 1252 (e.g., an incompressible fluid, such as oil or gel) may be placed in the tank space 1209 surrounding the sensor 1210. In such a configuration, the pressure condition / reading associated with the sensor device 1210 may be affected by and indicate the deflection state of the corresponding diaphragm 1125. The tank 1209 may have a raised flange 1391 surrounding the tank, which may abut against a corresponding structural seal of the cover 1170 to provide a fluid-sealed chamber for pressure sensing. Although an auxiliary seal 1391 is shown, it should be understood that the device 1300 may not include such a seal, and instead an external hermetically sealed seal 1305 may be used to contain the pressure-transmitting fluid medium. For example, in some instances, the chamber 1309 may be absent.

[0162] The area of ​​physical contact and sealing between the diaphragm plate 1170 and the substrate 1280 can be via the peripheral protrusion 1392. When the base contact 1392 is in tight bonded contact with the diaphragm plate 1170, the connection interface 1305 can provide an airtight seal to protect the internal structure / components from the influence of the external environment.

[0163] The substrate 1201 of the base structure 1280 may comprise ceramic, glass, or any other suitable material, whether rigid or flexible. For example, the substrate 1201 may include and / or have an associated printed circuit board and / or application-specific integrated circuit (ASIC) containing specific circuitry configured to process capacitive signals from a capacitor. The junction / bonding portion 1305 between the cap structure 1170 and the base structure 1280 may be implemented using one or more gold-tin (AuSn) layers and / or gold (Au) layers 1178 to create a relatively hard / good junction / bonding portion that provides an hermetically sealed seal and possible electrical interface between the nitinol material of the cap 1170 and the non-nitinol material of the base 1280.

[0164] Although Figure 10B and Figure 13B A diaphragm cap structure and sensor implemented on one side of the base substrate are shown; however, it should be understood that any of the sensors and bonding features disclosed herein can be implemented in a sensor device with dual-sided sensor features. Figure 14A and Figure 14B Perspective and cross-sectional views of a bifacial sensor device 1400 according to one or more embodiments are shown, respectively. Figure 14A and Figure 14B The various illustrations and references can be found above. Figure 8A , Figure 8B , Figure 9 Figure 10A and Figure 10B This can be understood from the description. Although the dual-sided sensor device 1400 is shown as a sensor device having conformal capacitor electrodes formed on a nitinol diaphragm, it should be understood that the dual-sided sensor device can also be implemented in conjunction with a pressure-transmitting fluid tank / chamber embodiment.

[0165] Figure 15A and Figure 15BExploded and assembled / bonded views of material stack bonding / joints 150, according to one or more examples, are shown, which can create a hermetically sealed bond between a thin-film nitinol (or other metal) layer 152 and a dissimilar substrate (e.g., ceramic, glass) using a gold-tin alloy filler. The bonding / joint 150 can be used to bond nitinol (or other similar hyperelastic materials) to a dissimilar (e.g., non-nitinol) substrate of any example disclosed herein. Various examples of this disclosure are described in the context of gold-tin bonding with nitinol. However, it should be understood that the examples of gold-tin bonding disclosed herein can be implemented to bond to any sputtered material, and references herein to nitinol layers / substrates can be understood to refer to embodiments using other sputtered materials. Such materials can include any thin-film metal, such as titanium, tantalum, etc. The example sputtered materials can be deposited using vapor deposition, electrodeposition, thermal deposition, or any method in which a solid substrate is converted into a gaseous form and re-cured and applied to the substrate. Alternatively, gold-tin bonding can be used to bond alloys other than nitinol that can provide the desired hermetic seal, such as kovar (nickel-cobalt-iron alloy). Such bonded layers / substrates can be associated with / integrated with thin-walled pressure transducer structures.

[0166] 2) Ti is a reasonable alternative material (biocompatibility), with some advantages and disadvantages. If protection can be claimed for a broader range of sputtering processes, creating diaphragms (a full range of biocompatible, low-permeability metals, including titanium, stainless steel, and nitinol), for in vivo pressure conduction (both fluidic and dry-cap configurations), and bonded to AuSn, then the intended protection would be covered.

[0167] Stack 150 comprises one or more layers 155 bonded to a nitinol layer / formed part 152 (or similar hyperelastic material) of a non-nitinol material 158 (e.g., ceramic, glass, PCB) using a eutectic gold-tin (AuSn) alloy or other eutectic metal. In some instances, the AuSn layer 155 may contain approximately (e.g., within 5%) 80% gold (Au) and 20% tin by weight. This composition can provide a eutectic alloy in which the material melts or solidifies at a single temperature like a pure metal, rather than melting or solidifying over a temperature range like many alloys. The eutectic temperature of the AuSn layer 155 can advantageously be relatively low, such as approximately 280°C (536°F), which is significantly lower than the melting point of pure gold (1064°C or 1947°F). The AuSn layer (which may be a preformed layer) may have a thickness of approximately 25 μm or other thicknesses.

[0168] An intermediate gold-tin (AuSn) layer 155 is sandwiched between the nitinol 151 and the base structure 159, and can provide the desired thermal and electrical conductivity, wettability, and corrosion resistance for use in chronic implantable devices. Furthermore, the AuSn composition as disclosed herein can be bonded using a heat / welding technique, where the material's high thermal conductivity facilitates heat dissipation, and its high electrical conductivity promotes reliable electrical connections. The relatively low eutectic point of AuSn 155 also minimizes thermal stress during bonding / welding, which protects sensitive sensor components and prevents molecular deformation of adjacent nitinol 152.

[0169] As described above, the bonding wires of the sensor implant housing can have a similar Figure 15B The diagram illustrates the layers combined to create hermetic and / or conductive seals. In some instances, a gold-tin (AuSn) layer 155 is deposited (e.g., vapor deposition or as a preform structure) on a thin-film nitinol 152 and / or a base substrate 158, with or without intermediate seed layers 154, 156 of gold and / or other metals. Intermediate gold 154, 156 may be included to enhance the bonding, compatibility, and / or functionality between the nitinol 152 and the glass / ceramic (or other substrate) 158, which may not adhere directly or interact sufficiently well with each other for bonding purposes.

[0170] A gold-tin (AuSn) layer 155 hermetically bonds a nickel-titanium 151 and a ceramic / glass 159 stack, each stack potentially having seed layers 154, 156, such as gold seed layers. The gold layers 154, 156 may have a thickness of less than 1 μm. The gold seed layer 156 may be photolithographically patterned / sputtered onto a substrate 158. In some embodiments, the AuSn layer 155 may be applied to the substrate 158 without an intermediate gold layer 156. The glass and / or ceramic structures and materials disclosed herein are described as such to provide exemplary embodiments, and it should be understood that any such reference structures / materials may include any type of non-metallic (e.g., inorganic) material, such as woven glass fiber fabrics, epoxy adhesives, plastics, polymers, or even metallic structures (such as stainless steel).

[0171] The seed layer materials 153, 157 to the gold layer 156 can be selected based on the material to which they are applied. For example, seed layer 153 can be titanium suitable for bonding with nitinol layer 150. For seed layer 157, the material can be nickel or titanium, suitable for bonding with ceramic or similar materials. Layers 157 and 156 can be collectively considered as seed layers of substrate 158, and layers 153 and 154 can be collectively considered as seed layers of thin-film nitinol 152.

[0172] The thin film nitinol 152, formed using physical vapor deposition (PVD) or a similar process, can be metallized with a gold layer 154, exhibiting acceptable adhesion between layers. This provides the desired interface for applying a gold-tin interlayer 155 between the nitinol 152 and the non-nitinol substrate 158. For example, the PVD nitinol 152 can be conformally metallized with pure gold using sputtering or other processes. Seed layers 153 and 157 can provide the necessary intermediates for the application of gold layers 154 and 156, respectively.

[0173] Gold (Au) layers 154 and 156 can advantageously promote adhesion because gold adheres well to nitinol, glass, ceramics, and other substrates, while also forming good bonds with AuSn alloys. Furthermore, gold layers 154 and 156 can provide a desired barrier layer to prevent potentially undesirable interactions between nitinol 152, glass / ceramic 158, and AuSn 155, such as diffusion or chemical reactions that could weaken bonds or alter material properties. Additionally, since gold is a good electrical and thermal conductor, gold layers 154 and 156 can advantageously impart these properties to the overall structure 150. Gold layers 154 and 156 can also be used to prepare the surfaces of nitinol 152 and ceramic / glass 158 to better deposit the AuSn layer 155, thereby ensuring a more uniform and consistent layer. Although described as gold, other metals can be used for layers 154 and 156, such as nickel, palladium, titanium, titanium alloys, aluminum, platinum, etc. In some embodiments, the nitinol stack 151 comprises a nitinol layer of about 1 μm to 3 μm thickness having a sputtered titanium-tungsten (TiW) barrier metal 153 to which an AuSn layer 155 is bonded. The transition TiW (or other materials described herein) barrier layer can advantageously allow the AuSn to remain molten for a period of time to adhere to the base gold layer 154.

[0174] Intermediate seed layers 153 and 157 may comprise any suitable or desired gold or gold-tin intermediate interface, such as titanium, chromium, nickel, copper alloys, silver, platinum alloys, palladium alloys, titanium alloys, etc. In some instances, layers 153 and 157 comprise oxides. Layers 153 and 157 may improve the adhesion of the gold layer to nitinol 152 and / or glass / ceramic 158, and / or may modify the surface properties (such as their electrical properties) of the glass / ceramic in a desired manner. Layers 153 and 157 may comprise any suitable or desired oxide, such as titanium or chromium. In some embodiments, layer 153 may comprise titanium dioxide, which is naturally formed on the nitinol surface and may be enhanced by various treatments. Other options include silicon dioxide, which may provide an insulating layer and / or have surface properties modified to improve adhesion or functionalize, niobium pentoxide, and other oxides. Substrate seed layer 157 may comprise silicon dioxide, titanium dioxide, alumina, zirconium dioxide, yttrium oxide, or other similar oxides.

[0175] In some embodiments, a gold-tin (AuSn) layer 155 is introduced into the stack 150 as a preformed structure sandwiched / placed between gold seed layers. For example, the preform may comprise an AuSn layer cut to specific tracks, with a thickness less than 100 μm, such as about 50 μm or less, or as low as 25 μm or less. The preform 155 may be sandwiched between two layers 151, 159. In some embodiments, the AuSn preform 155 is stamped / machined from sheet, or laser-cut or die-cut. In some embodiments, the gold-tin (AuSn) layer 155 is grown on a thin film of nitinol 155. As described herein, an AuSn “preform” may comprise a piece of material that has been preformed or formed into a specific configuration (such as an external track) prior to reflow. Such preforms may be shaped into a specific form resembling the final desired shape of the AuSn seal / bond. The use of AuSn preforms can help reduce the amount of processing or machining required to achieve the final shape and size of hermetically and / or electrically sealed components. It also helps ensure consistency and uniformity during the manufacturing process. AuSn preforms, as described herein, can be manufactured using a variety of techniques, such as casting, extrusion, powder metallurgy, etc.

[0176] like Figure 15B As shown, standard semiconductor packaging tools, such as flip-chip bonding, can be used to form the bonded stack 150 for precise alignment and to apply controlled forces and heat to create a hermetic seal. For some applications, creating a biocompatible interface may require additives or fluxes, which could potentially make the device harmful to the body. Conversely, bonding using a gold-tin (AuSn) alloy, as disclosed herein, allows bonding to be performed without the need for fluxes or other chemicals to create the bond. Alternatively, in examples of this disclosure, the bonding process may involve presenting an inert gas during bonding, sufficient to create a hermetic seal. This disclosure provides various combinations of using AuSn in medical implants. As with other examples presented herein, Figure 15A and Figure 15B The combination allows for the cryogenic mechanical bonding of nickel-titanium to dissimilar materials such as glass and ceramics.

[0177] Figure 16A and Figure 16B Exploded and assembled / bonded views of another configuration of a material stack 160, according to one or more examples, capable of producing an hermetically sealed seal between a thin-film nitinol (or other metal) layer 162 and a dissimilar substrate 168 (e.g., ceramic, glass), using gold-tin alloy filler 165. Figure 16A and Figure 16B The bond wire stacking 160 is similar to Figure 15A and Figure 15BThe configuration differs in that the thin-film nitinol 162 has a gold-tin (AuSn) 164 applied to it without an intermediate gold layer. AuSn (e.g., Au80Sn20) 164 can be directly sputtered onto nitinol 152.

[0178] In some instances, an additional pre-fabricated AuSn layer 165 may be sandwiched / placed between the AuSn-seeded nitinol stack 161 and the non-nitinol substrate stack 169. Although shown as including a gold seed layer 166, it should be understood that in any disclosed instance, ceramic, glass, or similar substrates may be seeded with AuSn 164 in the manner of the nitinol stack 161. The AuSn seed layer 164 may be conformally sputtered directly onto the thin film nitinol 162, or may be applied in any other suitable manner. The AuSn seed layer 164 may include an intermediate layer 163 sandwiched between the AuSn layer 164 and the nitinol layer 162. The base structure 168 may be seeded with gold 166 formed on the intermediate layer 167 (e.g., titanium, chromium, nickel, etc.).

[0179] Figure 17A and Figure 17B Exploded and assembled / bonded views of another material stack 170, according to one or more examples, are shown, capable of creating a hermetically tight seal between a thin-film nitinol (or other metal) layer 172 and a dissimilar substrate 178 (e.g., ceramic, glass). In the example configuration 170, a relatively thick gold-tin (AuSn) layer 175 (e.g., stoichiometric Au80Sn20) is directly sputtered onto the thin-film nitinol 172 (possibly with an intermediate seed layer 173). For example, the thickness of the AuSn layer 175 can be greater than 20 μm.

[0180] The substrate 178 can be seeded with gold 176 or a similar metal, and gold or similar metals (such as chromium, titanium, nickel, etc.) can be formed on the intermediate layer 177. The seeded base substrate 179 can be bonded to the nitinol stack 171 by reflowing / melting the AuSn layer 175.

[0181] By implementing a thicker AuSn layer 175, it may be unnecessary or undesirable to include additional AuSn preform layers (e.g., as described above, in combination with...). Figure 15A / 15B and Figure 16A / 16B describes the preformed layers 155, 165). That is, the use of the AuSn preformed structure can be completely omitted, and instead, a thicker sputtered AuSn 175 layer can be applied directly onto the thin film 172. This configuration is preferred because it reduces the number of components in the bonding wire stack 170 and provides a relatively more original material composition due to the controlled sputtering application.

[0182] Any bond line stack disclosed above in conjunction with Figures 15 through 17 or any other part of this disclosure may include a gold-tin (AuSn) layer for bonding nitinol and non-nitinol structures together by heating and / or applying pressure to the AuSn layer and / or other components according to a suitable temperature and force distribution. Figure 18 illustrates the temperature distribution of a process for bonding dissimilar materials (such as nitinol bonding / joining to non-nitinol materials such as ceramics, glass, or printed circuit boards) using one or more AuSn layers according to some examples.

[0183] Figure 18 illustrates a process in which AuSn bonding wires can be heated from the baseline (BL) temperature to the melting temperature of AuSn 181 (e.g., about 280°C / 536°F) in a gradually increasing manner, for a period of time sufficient for AuSn to adhere to both nitinol and non-nitinol structures, after which the temperature can be lowered back to the baseline temperature. Figure 19 Force curves are shown for the process of bonding dissimilar materials using one or more gold-tin layers, according to one or more examples. For example... Figure 19 As shown, near the start of heating for AuSn bonding, the structures to be bonded can be pressed into pressure contacts to promote adhesion to AuSn, thereby promoting bonding between the materials. Bonding force 191 can be maintained for a time period t, spanning the time the AuSn (and / or other components) are subjected to heating temperature 181 (see Figure 18). As shown, the holding force can be applied for a period before and after maximum heating. That is, the bonded components can be forcibly held together during at least a portion of the temperature ramp-up and / or ramp-down.

[0184] Figure 20A Figure 20B and Figure 20C Schematic, close-up, and side cross-sectional views of a wafer 2000 having multiple structures 2070 according to one or more embodiments are shown, each having a gold-tin bonding surface 2075 formed thereon. Multiple molds / substrates can be formed on the wafer 2000 for depositing thin-film nitinol structures, such as sensor device cover structures, enabling the production of a relatively large number of diaphragm plates / stacks for pressure sensor devices according to various aspects of this disclosure using a single wafer. The reference numeral "2070" in the following description may refer to a single shaped substrate of the wafer 2000 on which a thin-film nitinol layer is deposited, or may refer to a thin-film nitinol layer / plate structure deposited on a substrate.

[0185] Wafer 2000 includes multiple diaphragm structures / shapes 2070, each of which may include or be used to create an individual sensor diaphragm plate. Each of the illustrated plates 2070 can serve as a substrate / mandrel / mold, on which a thin-film diaphragm layer of nitinol metal alloy or similar material can be deposited to form a thin-film diaphragm plate, comprising, for example, nitinol or other hyperelastic materials with a thickness of less than 10 μm (e.g., 4 μm to 6 μm; about 5 μm). The nitinol layer may have a uniform thickness in the diaphragm region 2025 and the surrounding peripheral structure 2029.

[0186] The molded part / plate 2070 may be configured with spacing 2001 around one or more portions of the periphery 2029 of the respective diaphragm plate molded part 2070. This facilitates the deposition of nitinol and / or other layers of the diaphragm plate in a relatively precise area and / or shape, and / or facilitates the separation of the individual diaphragm plates 2070 after their formation to mechanically separate the individual plates from the wafer structure 2000. A physical connector 2002 may be used to connect the diaphragm plate substrate 2070 to an external structure 2005 of the wafer 2000, which may serve as a gate / tab structure for anchoring individual substrates 2003 to the external sample / structure 2005. An internal portion 2003 of the structure 2000 (e.g., the substrate 2070 for nitinol deposition) may be separable from the wafer 2000, or deposited material layers (e.g., nitinol, insulators, electrodes) may be removed from the substrate without separating the substrate 2003.

[0187] The wafer 2000 can be formed from any suitable or desired material, such as silicone, stainless steel, titanium, nickel, alumina, sapphire, glass, ceramics, etc. Once the nitinol base separator layer 2025 has been deposited on the plate structure 2003, additional layers can be applied to the separator plate using a mask and / or other suitable processes. A thin-film nitinol (e.g., 5 μm) separator layer 2025 can be deposited on the substrate 2003, and additional peripheral flange structures 2029 can be formed / accumulated in the peripheral region and / or other regions of the substrate 2003 using vapor deposition or other processes. Gold-tin (AuSn) 2075 can be applied to the periphery 2029 of the nitinol structure 2070 (e.g., by direct sputtering). The total thickness of the nitinol structure 2070 in the peripheral region 2029, together with the AuSn bonding layer 2075, can advantageously be between 3 μm and 6 μm.

[0188] Figure 21A and Figure 21BExploded and assembled / bonded views of a gold-tin bonded stack 210 according to one or more examples are shown, comprising a nitinol stack 211 bonded to a base substrate stack 219, the base substrate stack including a hard stop molding 201. The hard stop 201 can be used to provide a defined bond line gap distance / height d1 between the thin-film nitinol layer / structure 211 and the base structure 219 comprising a dissimilar material. As shown, the hard stop 201 can be laterally positioned outside at least a portion of the gold-tin bond 215 (i.e., positioned between the gold-tin 215 and the exterior of the device including the stack 210). As with other examples disclosed herein, the thin-film nitinol structure 211 can be gold seeded with a gold 214 (or similar metal) layer and / or an intermediate seed layer 213 (e.g., titanium, chromium, platinum, nickel, etc.). Similarly, the base substrate 219 may include a layer 218 of ceramic, glass, etc., and may be seeded with gold (or similar metal) layer 216 and / or intermediate seed layer 217 (e.g., chromium, titanium, silicon dioxide, tungsten, etc.). The gold seed layer may be photolithographically patterned onto the corresponding material, or applied in another manner. The hard stop profiles disclosed herein may include metals and / or be formed using metal manufacturing processes. However, it should be understood that any hard stop profile disclosed herein may include non-metallic profiles, such as non-metallic profiles / substrates extruded from ceramic, glass, or other rigid materials.

[0189] Hard stops 201, which can help make the bonding between the NiTiNo 211 and non-NiTiNo 219 structures more repeatable / reliable, can be formed and / or constructed in various ways. For example, the use of hard stop moldings can provide alignment mechanisms that can facilitate the repeatable placement of the gold-tin preform. Hard stop 201 may include gold or similar metals and may be extruded or formed in some other way to provide a set distance d1 between the two layers. As described throughout this disclosure, when forming the gold-tin (AuSn) bonding between structures 211, 219, the AuSn layer 215 (e.g., the preform structure) can melt like solder. That is, when AuSn 215 becomes eutectic, it becomes molten, thus exhibiting the liquid form of AuSn, which does not maintain its rigid layer thickness when force is applied to it, but rather when in the vertical dimension (relative to) Figure 21A and Figure 21B When compressed / pressed on the orientation of the AuSn layer 215, it can flow outward to a certain extent. In order to prevent the thickness of the AuSn layer 215 from decreasing below dimension d1, the hard stop 201 prevents structures 211, 219 from getting closer than allowed by the interference thickness dimension d1 of the hard stop 201, thereby allowing the ability to set the separation distance to a very specific dimension / height d1 when the AuSn layer 215 is compressed.

[0190] Physical vapor deposition processes offer a variety of tools for producing extruded portions, such as hard-stop extruded portions 201. For example, electron beam deposition, focused ion beam milling or deposition, laser microfabrication, etc., can be used to sputter / vapor deposition, electroplating, patterning, or applying extruded portions 201.

[0191] Figure 22A A sensor base structure 229 including an embossed hard stop bump 203 is shown according to one or more examples. Figure 22B and Figure 22C An exploded and assembled / bonded view of an apparatus 220 including a gold-tin bonding portion 225 between NiTiNo 221 and non-NiTiNo 228 structures is shown, wherein the gap d2 between the bonded structures is set / determined by a hard stop bump 203. The hard stop 203 can be implemented as an imprinted gold bump to provide a precise distance d2 between mating components, wherein direct reflow using AuSn 225 as the eutectic solder can be implemented to bond the structures together. In some instances, the bump 203 is a gold-mounted bump that is ultrasonically placed on a ceramic (or glass, PCB, etc.) substrate 228. Such processes can be implemented using standard semiconductor packaging techniques using a gold ball wire bonder. For example, instead of removing the thin gold wire after placing the first ball joint, as is done in some wire-bonded integrated circuit chip applications, the wire can be immediately cut, leaving a hard stop extruded portion. To flatten this extrusion, the ball joint can be “imprinted”. Since gold is generally malleable, this can be accomplished by pressing down on the spherical joint, flattening the extruded portion, and transforming the spherical joint into a more cylindrical molded part. The base structure 229 may include a recess 202 having a bottom layer 204 configured to provide a volume for placing a sensor device, wherein the volume 202 may be filled with a pressure-transmitting fluid, as described in detail herein.

[0192] The hard stop 203 can be formed by masking and electroplating, or alternatively by using gold studs having a structure similar to that of a microchip wire bond. In some embodiments, the hard stop bump 203 is not extruded, but rather flattened to create a dicing line for the coin-forming part. That is, instead of forming a complete wire bond, the gold wire can be cut, leaving the bump, where an ultrasonic mechanism is used to perform the bonding to create a solid metal-to-metal bond. The bump 203 can be imprinted to a thickness of less than 20 μm (e.g., 10 μm to 20 μm). Since the gold material constituting the bump 203 is malleable, these bumps can be imprinted by physically pushing them. A machine configured to apply ultrasonic pulses during the extrusion of the gold wire to create the metal-to-metal bond can be used to perform the imprinting.

[0193] The gold hard stop bump 203 is advantageously non-eutectic and has a melting point higher than that of gold-tin 225, such that during the reflow process used to melt the gold-tin (AuSn) binder 225 to produce a hermetically sealed layer, the bump 203 remains solid and retains its size d2. In other words, during the heating process used to melt the AuSn layer 225, AuSn is the only layer / material that melts due to its eutectic nature.

[0194] Figure 23A A sensor base structure 239 including a hard stop extrusion portion 206 is shown according to one or more embodiments. Figure 23B and Figure 23C Exploded and assembled / bonded views of the gold-tin (AuSn) bond, including the hard stop extrusion 206, are shown. The hard stop extrusion 206 may have the form of a continuous flange surrounding the central region of structure 239 on the inner radius of the AuSn bond track 235. The base structure 239 may include a recess 205 having a bottom layer 207 configured to provide a volume for housing a sensor device, wherein the volume 205 may be filled with a pressure-transmitting fluid, as described in detail herein.

[0195] The hard stop 206 may include an electrodeposited gold (Au) extrusion that can be formed in a continuous eutectic liquid flow receiving flange / lip providing a hard stop dimension d3. For example, the gold seed layer of the base structure 238 may be patterned to form tracks rather than a continuous plane. In some embodiments, a ceramic (or other material) substrate 238 may be patterned to produce a flange 206 with or without a gold layer. For example, the hard stop flange may be formed in a ceramic or glass substrate 238, and a thin gold layer may be applied over the flange. The hard stop flange 206 can advantageously prevent molten gold-tin (AuSn) layer 235 (e.g., a preformed structure) from flowing into the internal sensor space 205.

[0196] When molten, the AuSn layer 235 can be pushed outward as it is compressed / planarized to a thickness of dimension d3, and pushed outward away from flange 206 and fill the edge of the bonding assembly. The dimensions of the hard stop 206 can be designed such that there is no large volume of outwardly pushed AuSn when cap 231 and base 238 are engaged.

[0197] Figure 24A and Figure 24BExploded and assembled / bonded views of a gold-tin (AuSn) bond stack 240 including redundant bond portions / seales 302a, 302b according to one or more examples are shown. Structure 240 includes a nitinol stack 241 comprising a nitinol thin-film substrate 242 having a plurality of orbitals 245 with AuSn bond configurations, which may have an intermediate seed layer 243 having any separable material as described herein. The nitinol stack 241 is bonded to a non-nitinol base stack 249 comprising a non-nitinol base 248 seeded with gold 246, and optionally an intermediate layer 247.

[0198] The bonding wires of stack 240 include multiple segments 245a, 245b of gold-tin (AuSn) to form multiple bonding wire seals. For example, the AuSn 245a, 245b can be patterned in a manner that produces laterally spaced AuSn moldings 245a, 245b, which in some embodiments can be at least partially thermally and / or electrically isolated from each other. Segmented AuSn bonding moldings can be formed using physical vapor deposition or other processes. For example, photolithography can be performed for this purpose, which enables the ability to pattern arbitrary patterns. The space 301 between the AuSn moldings can be air-filled, vacuum-filled, or filled with another material selected to provide desired insulation or other properties. By implementing redundant AuSn seals, failure or ineffectiveness of one AuSn seal may not lead to failure of the hermetic seal of stack 240, as the remaining seals can advantageously and independently provide a hermetic seal. Therefore, redundant AuSn seals as disclosed herein can provide a fail-safe mechanism for implantable devices and other applications. Furthermore, using redundant seals can provide improved structural and / or electrical properties for implant bonding wires. Some of the examples below provide variations of redundant AuSn seals according to various aspects of this disclosure.

[0199] Individual bonding tracks 302a, 302b can be patterned into continuous tracks, where one or both tracks provide a hermetically tight interface / seal and / or an electrical interface / seal. Redundant bonding portions, as disclosed herein, can address potential problems associated with mismatches in the coefficients of thermal expansion between the bonding materials. Additional bonding portions can provide thermal strain adaptation and bond failure randomness. For example, redundant tracks / bond portions 302a / 302b can provide mechanical benefits for hermetically tight sealing, such as preventing the propagation of cracks / defects from damaged bonding portions throughout the seal. For example, defects in bonding portion 302a can be confined to that bonding portion because spatial separation 301 prevents structural defects from affecting adjacent bonding portions 302b. Furthermore, since thermal expansion is a volumetric process, the relatively smaller volume of segmented bonding portions can result in smaller differences in volumetric expansion.

[0200] Figure 25A and Figure 25B Plan view and side cross-sectional view of a diaphragm structure 250 according to one or more examples are shown, the diaphragm structure having one or more gold-tin (AuSn) seals 255 disposed on a nitinol bonding wire structure. Figure 25A and Figure 25B In one example, the AuSn seal 255 provides an orbital seal around the periphery 259 of the structure 250, wherein the periphery 259 includes a nitinol buildup surrounding the exterior of the structure 250 to provide an hermetically tight seal around the inner diaphragm 252. Although shown as having a peripheral buildup / protrusion 259, it should be understood that in some embodiments, the nitinol regions 252, 259 have a uniform thickness such that the periphery 259 of the nitinol layer is flush with the surface of the diaphragm 252. According to any of the examples disclosed herein, the diaphragm structure 250 can be bonded to a corresponding base structure (not shown for visual clarity). Figure 25A and Figure 25B (As shown in the image).

[0201] Figure 26A and Figure 26B Plan view and side cross-sectional view of a diaphragm structure 260 according to one or more examples are shown, the diaphragm structure having one or more gold-tin (AuSn) seals 265 disposed on a nitinol bonding wire structure. Figure 26A and Figure 26B In one example, the AuSn seal 265 provides an orbital seal around the periphery 269 of the structure 260, wherein the periphery 269 includes an outer nitinol buildup around the structure 260 to provide an hermetically tight seal around the inner diaphragm 262. The structure 250 also includes an inner nitinol buildup 267 around the multi-row diaphragm 262, which may have an elliptical shape / boundary, as shown. Although shown as having peripheral and inner buildups / protrusions 269, 267, it should be understood that in some embodiments, the nitinol regions 262, 267, 269 have a uniform thickness such that the peripheral 269 and inner 267 of the nitinol layer are flush with the surfaces of the nitinol diaphragm 262. According to any of the examples disclosed herein, the diaphragm structure 260 may be bonded to a corresponding base structure (not shown for visual clarity). Figure 26A and Figure 26B (As shown in the image).

[0202] Figure 27A and Figure 27B Plan view and side cross-sectional view of a diaphragm structure 270 according to one or more examples are shown, the diaphragm structure having one or more gold-tin (AuSn) seals 275 disposed on a nitinol bonding wire structure. Figure 27A and Figure 27B In this example, the AuSn seal 275 provides an orbital seal around a periphery 279 of the structure 270, wherein the periphery 279 includes an outer Nitino deposit surrounding the structure 270 to provide an hermetically tight seal around the inner diaphragm region 272. Figure 25A / 25B and Figure 26A Compared to the example of / 26B, the diaphragm structure 270 does not include multiple elliptical thin-film diaphragms, but instead includes a single diaphragm 272 within a space surrounded by peripheral seals 275 / 279. Although shown as having peripheral accumulations / protrusions 279, it should be understood that in some embodiments, the nitinol regions 272, 279 have a uniform thickness such that the periphery 279 of the nitinol layer is flush with the surface of the nitinol diaphragm 272. According to any of the examples disclosed herein, the diaphragm structure 270 can be bonded to a corresponding base structure (not shown for visual clarity). Figure 27A and Figure 27B (As shown in the image).

[0203] Figure 28A and Figure 28B Plan view and side cross-sectional view of a diaphragm structure 280 with redundant parallel gold-tin (AuSn) seals 285 according to one or more examples are shown respectively. According to any of the examples disclosed herein, the diaphragm structure 280 can be bonded to a corresponding base structure (not shown in the image for visual clarity). Figure 28A and Figure 28B (As shown in the image).

[0204] exist Figure 28A and Figure 28B In one example, AuSn seal 285 provides a parallel track seal 285 around the periphery of structure 280, wherein the periphery includes an externally accumulated NiTiN rail 289 around structure 280, on which AuSn 285 is formed to provide an hermetically tight seal around the internal diaphragm region 282. Redundant seals 289 / 285 can be implemented in any of the examples disclosed herein, such as those described above. Figure 25A / 25B、 Figure 26A / 26B or Figure 27A Implemented in any of the peripheral seals in the example of / 27B. Furthermore, although two parallel seals are shown, it should be understood that redundant seals according to the examples of this disclosure can have any number of parallel and / or non-parallel seals. Although shown as having peripheral accumulations / protrusions 289, it should be understood that in some embodiments, the nitinol regions 282, 289 have a uniform thickness such that the peripheral regions / tracks 289 and the nitinol diaphragm 282 of the nitinol layer are flush. In such embodiments, AuSn can simply be applied to a uniform nitinol layer in the illustrated seal track pattern.

[0205] Parallel tracks 285a / 289a and 285b / 289b may have a common width, or one track may be wider than the other. Parallel tracks 285 may provide lateral space 286 between adjacent tracks. This lateral space may be air-filled, vacuum-filled, or filled with a material suitable for providing insulation and / or structural support for the parallel tracks when the diaphragm structure 280 is assembled into a sensor device or other sealing assembly. Using multiple redundant tracks separated by lateral spacing between the tracks can increase flexibility in the sealing area. The corresponding bonding surfaces / structures of the base to which the bonding protrusions 299 / 295 and plate 290 can be bonded are subject to thermal expansion mismatch. Therefore, in contrast to the solid tracks of Figures 25-27, laterally discontinuous redundant tracks can help mitigate mismatch.

[0206] Figure 29A and Figure 29B Plan view and side cross-sectional view of a diaphragm structure 290 with parallel gold-tin (AuSn) seals 295 according to one or more embodiments are shown respectively. According to any of the embodiments disclosed herein, the diaphragm structure 290 can be hermetically bonded to a corresponding base structure using the AuSn seals 295 (not shown in the image for visual clarity). Figure 29A and 29B (As shown in the image).

[0207] exist Figure 29A and Figure 29B In one example, AuSn seal 295 provides three parallel track seals 295a, 295b, and 295c around the periphery of structure 290, wherein the periphery includes an externally accumulated NiTiN rail 299 around structure 290, on which AuSn 295 is formed / applied to provide an hermetically tight seal around the internal diaphragm region 292. Redundant seals 299 / 295 can be implemented in any of the examples disclosed herein, such as those described above. Figure 25A / 25B、 Figure 26A / 26B or Figure 27A Implemented in any of the peripheral seals in the example of / 27B. Furthermore, although three parallel seals are shown, it should be understood that redundant seals according to the examples of this disclosure can have any number of parallel and / or non-parallel seals. Although shown as having peripheral accumulations / protrusions 299, it should be understood that in some embodiments, the nitinol regions 292, 299 have a uniform thickness such that the peripheral regions / tracks 299 and the nitinol diaphragm 292 of the nitinol layer are flush. In such embodiments, AuSn can simply be applied to a uniform nitinol layer in the illustrated seal track pattern.

[0208] Parallel tracks 295a / 299a, 295b / 299b, and 295c / 299c may have a common width, or one track may be wider than the other. For example, in the illustrated example, the middle track 299b / 295b is wider than the inner tracks 299c / 295c and the outer tracks 299a / 295a; any combination of relative track widths can be implemented in conjunction with embodiments of this disclosure, including implementations in which the outermost track is wider than one or more inner tracks and / or the innermost track is wider than one or more outer tracks. The parallel tracks 299 may provide a lateral space 296 between adjacent tracks, which may be air-filled, vacuum-filled, or filled with a material suitable for providing insulation and / or structural support for the parallel tracks when the diaphragm structure 290 is assembled into a sensor device or other hermetically sealed assembly.

[0209] Figure 30 A plan view of a diaphragm structure 300 with a grid pattern of gold-tin seals 394, 395 according to one or more examples is shown. The seals may include a plurality of parallel tracks 395 extending along the periphery of the structure 300, and a plurality of tracks 394 perpendicular to the peripheral tracks, such that the tracks 395 and 394 intersect paths. This grid pattern can produce units 393 surrounded by the sealing tracks 394, 395, which may be air-filled, vacuum-filled, or filled with a material suitable for providing insulation and / or structural support for the parallel tracks. Although the tracks 394, 395 are shown as having a generally perpendicular arrangement, examples may include tracks with any suitable or desired relative angle.

[0210] Figure 31A , Figure 31B and Figure 31C Isolated views, exploded views, and bonding / assembly views of a material stack 325 comprising multiple gold-tin (AuSn) bonding portions 314, 324 according to one or more examples are shown. The processes disclosed herein can be implemented to produce one or more subsequent AuSn bonding portions after a first AuSn check portion is implemented through melting of the AuSn layer without interfering with / reprocessing the previous bonding portions. Such processes can allow multiple thin-film nitinol components 311, 321 to be assembled onto a single base 317. Figures 31A to 31C The double-sided AuSn bonding shown can be used in applications such as Figure 14A and Figure 14B In the application of the dual-sided diaphragm sensor 1400 shown, the application includes AuSn bonding portions on both sides of the base substrate 1401.

[0211] Figure 31AA material stack bonding / joint 310 is shown, having a hermetically sealed layer 311 previously implemented using a gold-tin alloy filler 314 between a thin-film nitinol (or other metal) layer 311 and a dissimilar substrate 317 (e.g., ceramic, glass), which can be similar to any gold-tin bonding structure disclosed herein. In some examples, the AuSn layer 314 may contain about 80% gold (Au) and 20% tin by weight (e.g., within 5%). This composition can provide a eutectic alloy, where the material melts or solidifies at a single temperature like a pure metal, rather than melting or solidifying over a range of temperatures like many alloys. The eutectic temperature of the AuSn layer 314 can advantageously be relatively low, such as about 280°C (536°F), which is significantly lower than the melting point of pure gold (1064°C or 1947°F).

[0212] A gold-tin (AuSn) layer 314 hermetically bonds a nickel-titanium 311 and a ceramic / glass 317 stack, each stack potentially having seed layers 312 / 313, 315 / 316, such as gold seed layers as described above. The seed layer materials 312, 316 to the respective gold layers 313, 315 may include titanium, nickel, chromium, or other materials described herein. As mentioned above, the gold (Au) layers 313, 315 can advantageously provide a barrier and / or promote adhesion. The bonded stack 310 can be formed using standard semiconductor packaging tools such as flip-chip bonding to precisely align and apply controlled forces and heat to create a hermetically sealed environment.

[0213] Except for the top side 308 of the base substrate 317 (relative to) Figure 31A In addition to the gold seed and gold-tin (AuSn) bonding implemented on the orientation of the substrate 317, the substrate 317 can be further prepared for bonding on the other side 309 of the substrate 317 (e.g., relative to the orientation of the substrate). Figure 31A Bonded on the bottom side of the orientation, wherein such further bonding can be performed after the AuSn bonding portion 314 has been completed. Therefore, as Figure 31A As shown, the bottom side 309 of the ceramic or glass (or other material) substrate 317 may be seeded, such as with a gold or other metal layer 319 and / or an intermediate metal / oxide layer 318 (e.g., titanium).

[0214] With the gold-tin (AuSn) bonding portion 314 already implemented, the stack 310 can then be bonded to another thin-film nickel-titanium structure 320, such as... Figure 31B and Figure 31CAs shown. That is, the second side 309 of the substrate 317 can be bonded to the nitinol layer 321 via an AuSn layer 324, which can be bonded to the nitinol 321 via a seed layer comprising gold, AuSn, titanium and / or other suitable materials. The AuSn alloy 314 can significantly increase its melting temperature after being reflowed onto the gold seed layers 313, 315 through eutectic alloying, thereby facilitating the subsequent bonding of the nitinol layer / stack 320 to the substrate 317 without interfering with the previously implemented bonding portion 314. For example, during the reflow of the AuSn layer 314, heat can cause the gold and tin atoms of the AuSn layer 314 to diffuse and mix at the interface between the gold seed layer and the deposited AuSn alloy, resulting in a change in its melting characteristics, thereby increasing the melting point of the AuSn bonding portion 314 due to the stoichiometric change.

[0215] Figure 32 This is a graph showing the relationship between the weight percentage of gold and tin in gold-tin (AuSn) alloys and their associated melting points according to one or more examples. As shown, gold (Au) melts at approximately 1000°C when the tin (Sn) concentration is negligible. However, as Sn is added to the alloy, the melting temperature tends to decrease sharply until a local minimum of approximately 280°C is reached at a ratio of 80% Au and 20% Sn. Above this temperature, the melting temperature will rise again by a certain amount and then gradually decrease, moving towards higher Sn concentrations. Since higher Au concentrations can provide better electrical conductivity, the lower melting point 303 associated with the local minimum on the Au side of the spectrum may be superior to alloys with higher Sn concentrations. Therefore, placing the melting point at or near the local minimum 303 (Au80Sn20) and the concentration near that point may be beneficial for the applications disclosed herein to allow reflow below the nickel-titanium transition temperature.

[0216] Return to reference Figure 31A The diffusion of Sn outward into the Au seed layers 313 and 315 and / or the diffusion of Au from the Au seed layers 313 and 315 into the AuSn layer 314, along with the backflow diffusion of AuSn molecules from the AuSn layer 314, can advantageously lead to a higher concentration of gold (Au) and a lower concentration of tin (Sn) in the bonding layer 314, thus causing the melting point of layer 314 to move along... Figure 32The melting curve shown shifts upwards to a higher melting temperature (e.g., above 320°C, such as around 350°C). Therefore, as the melting temperature of the preceding bonding portion 314 increases, subsequent reflow of the AuSn bonding portion / layer 324 can be performed at a lower melting temperature (around 280°C) without melting / interfering with the layer 314 having a higher Au concentration. The diffusion of Au into the AuSn layer 314 can depend on the thickness of the Au layers 313 and 315. Therefore, the melting temperature of the AuSn layer 314 can be controlled at least in part by achieving a specific thickness of the Au layers 313 and 315. By raising the melting temperature of the AuSn layer 314 above 280°C, it can be raised to a minimum of above 280°C, and subsequent heating of layer 314 will not reach the eutectic melting temperature that would interfere with the bonding portion, which is an important aspect of hermetic sealing. Therefore, the diffusion of adjacent Au into AuSn can provide valuable benefits for the bonding of hermetic devices.

[0217] Figure 33A and Figure 33B An exploded and bonded / assembled view of a structure 330 with gold-tin bonding portions 401, 402 according to one or more examples is shown, which provide a hermetically sealed and electrically connected connection between a nitinol substrate 332 and a non-nitinol substrate 348, wherein the substrates 332, 348 integrate conductive paths, passive electronics, and / or active electronics electrically connected across the bonding portion 402. As described herein, in addition to forming a hermetically sealed connection, gold-tin (AuSn, e.g., Au80Sn20) can provide the ability to electrically connect a functional thin-film nitinol 332 to a passive (e.g., printed circuit board (PCB), flexible cable, or microelectromechanical system (MEMS) substrate) or an active (e.g., application-specific integrated circuit (ASIC), microprocessor, field-programmable gate array (FPGA), system-on-a-chip (SOC), microcontroller, radio frequency identification (RFID) chip, active MEMS, optoelectronic device) substrate 348.

[0218] Figure 33AA thin-film nitinol substrate 332 is shown, which may have a passive capacitor electrode 482 or other passive or active electrical element formed thereon. For example, electrode 482 may include a gold (Au) layer or other conductive layer applied to nitinol 332 by physical vapor deposition or other processes, as described in detail above. A high-k dielectric intermediate layer 373, such as titanium oxide or other suitable oxide, may be sandwiched between the gold layer 482 and nitinol 332. Furthermore, a gold-tin (AuSn) molding 471 may be applied to electrode 482 to provide electrical contact with electrode 482. Nitinol substrate 332 may also have AuSn bumps / tracks 335 outside the region of electrode 482 to provide a hermetically sealed portion for device / structure 330, wherein the bonding tracks 335 may be configured to provide a hermetically sealed area around electrode 482, making the assembled device 330 suitable for implantation and long-term maintenance, for example, in the human body. The hermetically sealed composite element 335 can be seeded by a seed material 333 (such as titanium or other suitable metals / oxides).

[0219] The base substrate 348 may include any suitable material on which electrical components can be integrated. In some embodiments, the base substrate 348 includes bonding bumps / tracks 346 that can be bonded to opposing AuSn bonds 335 to form a hermetically sealed seal 401. The substrate 348 may also include electrodes or other passive or active circuitry 481. Electrodes 481 may serve as counter electrodes to capacitor electrodes 482 associated with the nitinol substrate 332 and may be implemented on the seed layer 373. Thus, when as Figure 33B When combined as shown, electrodes 482 and 481 can operate as plates of a capacitor, which can be used in pressure sensing applications or other applications. Examples of such sensor devices have been described in detail above.

[0220] The base substrate 348 may also include electrical contacts 491, which may include gold or other conductive metals, wherein such contacts 491 are configured to bond to AuSn electrical contacts 471 associated with the nitinol substrate 332. Figure 33B The assembly configuration shown illustrates the formed internal electrical bonding portion 402 and the hermetically sealed peripheral bonding portion 401, which can connect any number / type of transducers directly integrated onto the thin-film nitinol substrate 332 to electronic devices / circuits associated with the corresponding active or passive substrate 348. Intermediate seed layers 247 and 377 can be implemented for the AuSn layers 347 and 491, respectively.

[0221] In some embodiments, the same bonding may be formed on the interior 402 and the exterior 401 of the device 330 in terms of material composition and / or arrangement. Figure 33BThe diagram illustrates the electrical connections / bondings via resistor icons. Generally, the AuSn bond portion 402 can provide sufficiently low resistance to suit use in sensor applications and other applications as described herein.

[0222] The bonding molding component 335 can be implemented as a flip-chip bump / molding component to allow flip-chip assembly, such as... Figure 33A and Figure 33B As shown in the figure. Therefore, according to various aspects of this disclosure, sensor electronics (e.g., multiple capacitive electrodes, multiple piezoelectric resistors) integrated onto a thin-film nitinol substrate can be connected to separate AuSn bonding forms, wherein conventional flip-chip bonding techniques can be used to create junctions to such bonding forms to bond nitinol to flexible cables or other substrates.

[0223] Figure 34A and Figure 34B Plan and side views of a nitinol sensor structure / device 351 with gold-tin (AuSn) electrical contacts 354 according to one or more examples are shown respectively. Figure 35 A nitinol sensor structure / device 351 according to one or more examples is shown, wherein gold-tin electrical contacts 354 are bonded to corresponding electrical contacts 366 of electrical devices / substrates 368.

[0224] As shown, AuSn solder bumps 354 can be directly patterned onto a thin-film nitinol substrate 352 to connect any number / type of sensors / transducers 353 on the nitinol 352, thereby forming an electrical connection. The electrical connection between the AuSn contacts 354 and the corresponding sensor elements 353 can be made via conductive traces 355 formed on the nitinol 352. Similar to solder bumps for flip-chip bonding, AuSn bonding pads 354 can be used for similar purposes. In the illustrated configuration, multiple AuSn bonding pads 354 are connected to one or more nodes of a sensor 353, which can be a passive or active electrical element implemented on the nitinol 352. For example, in some embodiments, the sensor 352 may include multiple (e.g., nine) gold, platinum, or other microelectrodes, or other types of electrodes, for capturing electrocardiogram (ECG) signals. Each microelectrode can be electrically connected to a corresponding AuSn solder bump 354 and wired to a base / substrate 368.

[0225] The substrate 368 can be a flexible cable or other passive (e.g., printed circuit board (PCB), flexible cable, or microelectromechanical system (MEMS) substrate) or active (e.g., application-specific integrated circuit (ASIC), microprocessor, field-programmable gate array (FPGA), system-on-a-chip (SOC), microcontroller, radio frequency identification (RFID) chip, active MEMS, optoelectronic device) substrate. The substrate 368 may have contact pads 366, which may include gold or other conductors seeded onto the substrate 368, wherein the pads 366 are aligned with the AuSn pads 354 in a flip-chip arrangement. Due to the low melting temperature of the AuSn pads 354, the Nitino structure configuration 351 provides the ability to bond multiple Nitino components to the same substrate 368 without adversely interfering with previous bonding.

[0226] When implemented as a gold-tin (AuSn) solder bump, contact pad 354 may not include a gold seed for the AuSn bump, as implementing the AuSn contacts as multiple pre-formed AuSn can be challenging. Instead, AuSn pad 354 can advantageously be directly sputtered onto nitinol 352. Contact 366 on substrate 368 can provide a gold seed layer for AuSn bonding. The illustrated layer 356 may include a nitinol mixture with some configuration, or other layers for generating adhesion, such as metals with a thickness between 5 nm and 100 nm.

[0227] The AuSn contact bump 354 can have any suitable height, such as above about 15 μm to 20 μm, which may be sufficient to achieve a solid bond and withstand the associated flatness tolerances. The AuSn bump 354 may not provide a hermetically tight seal due to its non-enclosed form / configuration. Therefore, the assembly 350 can be implemented with a peripheral seal, which may or may not include the AuSn as described in detail herein.

[0228] Vascular / cardiac access for sensor implantation

[0229] The encapsulated sensor implantation device according to one or more embodiments of this disclosure can be advanced into the relevant target chamber or blood vessel of the heart and / or vascular system using any suitable or desired procedure. Figure 36This is a cross-sectional view of a human heart 1 and associated vascular system based on one or more examples, illustrating certain catheter 111 access paths for an implantation procedure for the sensor device 370, which may be similar in one or more respects to any of the examples disclosed herein. Specifically, delivery systems 111, such as via the femoral artery or other transcatheter procedures, can be used to access the various chambers / vessels of the heart via the right atrium 5 and / or the inferior vena cava 16. This access is indicated by reference numeral 111a. Reference numeral 111b illustrates access to the right atrium 5 via the superior vena cava. In some embodiments, access to the left atrium 2 or ventricle can be used via transseptal access, which may pass through the inferior vena cava 16 or the superior vena cava 19 (as shown respectively) and proceed from the right atrium 5 through the septal wall 18 into the left atrium 2. For transaortic access, delivery catheter 111c may pass through the descending aorta 27, the aortic arch 12, the ascending aorta, and the aortic valve 7, and through the mitral valve 6 into the left atrium 2. For transapical access, the delivery catheter 111d can directly enter the left ventricle 3 through the apex 39 of the heart 1, and then enter the left atrium 2 through the mitral valve 6. Besides... Figure 36 In addition to those shown, other access routes are also possible. The various transcatheter delivery systems and routes shown may involve delivering the sensor implantation device 1900 within the axis / lumen of such instruments, and deploying the device 1900 from the delivery system at the target anatomical site.

[0230] Further description of the embodiments

[0231] A list of embodiments is provided below, each of which may include aspects of any other embodiments disclosed herein. Furthermore, aspects of any of the foregoing examples may be implemented in any of the numbered embodiments provided below.

[0232] Example 1: A sealing structure comprising a nitinol layer, a non-nitinol material layer, and a eutectic gold-tin interlayer, wherein the eutectic gold-tin interlayer is configured to bond the nitinol layer to the non-nitinol layer.

[0233] Example 2: A sealing structure as described in any of the embodiments herein, particularly Example 1, wherein the non-nickel-titanium material is ceramic or glass.

[0234] Example 3: The sealing structure as described in any of the embodiments herein, particularly Example 2, further includes a gold seed layer sandwiched between the eutectic gold-tin layer and the non-nickel-titanium material layer.

[0235] Example 4: A sealing structure as described in any of the embodiments herein, particularly Example 3, wherein the gold seed layer comprises a gold layer and a layer sandwiched between the non-nickel-titanium material layer and the gold layer, the layer comprising at least one of chromium, titanium, tungsten or palladium.

[0236] Example 5: The sealing structure as described in any of the embodiments herein, particularly Example 1, further includes a gold-tin seed layer sandwiched between the eutectic gold-tin layer and the nickel-tin layer.

[0237] Example 6: A sealing structure as described in any of the embodiments herein, particularly Example 1, wherein the eutectic gold-tin layer is 80% gold and 20% tin by weight prior to reflow.

[0238] Example 7: A sealing structure as described in any of the embodiments herein, particularly Example 6, wherein the eutectic gold-tin layer is configured to reflow, and the gold content by weight is increased from the gold layer sandwiched between the eutectic gold-tin layer and the nitinol layer or the non-nitinol material layer, thereby increasing the melting point of the gold-tin layer.

[0239] Example 8: A sealing structure as described in any of the embodiments herein, particularly Example 1, wherein the eutectic gold-tin layer is sputtered onto the nickel-titanium layer.

[0240] Example 9: A sealing structure as described in any of the embodiments herein, particularly Example 1, wherein the nitinol layer is a thin film layer formed using physical vapor deposition.

[0241] Example 10: A sealing structure as described in any of the embodiments herein, particularly Example 9, the sealing structure further comprising a sputtered gold layer applied to the nitinol layer, the sputtered gold layer being sandwiched between the nitinol layer and the eutectic gold-tin layer.

[0242] Example 11: A sealing structure as described in any of the embodiments herein, particularly Example 1, wherein the eutectic gold-tin layer is a preformed structure.

[0243] Example 12: A sealing structure as described in any of the embodiments herein, particularly Example 1, the sealing structure further comprising a hard stop formed between the nitinol layer and the non-nitinol material layer, the metal hard stop formed having a melting point higher than that of the eutectic gold-tin layer.

[0244] Example 13: A sealing structure as described in any of the embodiments herein, particularly Example 12, wherein the rigid stop molding has a track form.

[0245] Example 14: A sealing structure as described in any of the embodiments herein, particularly Example 12, wherein the rigid stop molding has a bump form.

[0246] Example 15: A sealing structure as described in any of the embodiments herein, particularly Example 12, wherein the hard stop molding is configured to laterally block the flow of the eutectic gold-tin layer across the metal hard stop molding when the eutectic gold-tin layer melts.

[0247] Example 16: A sealing structure as described in any of the embodiments herein, particularly Example 1, wherein the nitinol layer and the eutectic gold-tin layer are bonded to a first side of the non-nitinol material layer, and a second nitinol layer is bonded to a second side of the non-nitinol material layer via a second gold-tin layer.

[0248] Example 17: A sealing structure as described in any of the embodiments herein, particularly Example 1, wherein the eutectic gold-tin layer provides an electrical path that electrically couples a first conductor on the nitinol layer to a second conductor on the non-nitinol material layer.

[0249] Example 18: An implantable sensor device comprising: a vapor-deposited nitinol layer including one or more deflectable diaphragms; a non-nitinol base substrate; and one or more gold-tin molded elements bonded between the nitinol layer and the base substrate, the gold-tin molded elements providing a hermetically tight seal between the nitinol layer and the base substrate.

[0250] Example 19: An implantable sensor device as described in any of the embodiments herein, particularly Example 18, further comprising: a first capacitive electrode conformally formed on one of the one or more deflectable diaphragms of the nitinol layer; and a second capacitive electrode coupled to the base substrate, the second capacitive electrode and the first capacitive electrode forming a variable capacitor.

[0251] Example 20: An implantable sensor device as described in any of the embodiments herein, particularly Example 19, further includes one or more gold-tin electrical contacts that provide an electrical connection between the first capacitive electrode and an electrical component associated with the base substrate.

[0252] Example 21: An implantable sensor device as described in any of the embodiments herein, particularly Example 18, further comprising one or more gold contacts formed on the base substrate and configured to be bonded to the one or more gold-tin molded parts.

[0253] Example 22: An implantable sensor device as described in any of the embodiments herein, particularly Example 18, further comprising one or more gold-tin electrical contacts, each gold-tin electrical contact being electrically coupled to a corresponding sensor element in one or more sensor elements implemented on the nitinol layer.

[0254] Example 23: An implantable sensor device as described in any of the embodiments herein, particularly Example 22, further includes one or more electrical contacts implemented on the base substrate and arranged to be bonded to the one or more gold-tin contacts in a flip-chip manner.

[0255] Example 24: An implantable sensor device as described in any of the embodiments herein, particularly Example 22, wherein one or more gold-tin electrical contacts are arranged in a track around the periphery of the nitinol layer.

[0256] Example 25: An implantable sensor device comprising: a vapor-deposited nitinol layer including one or more deflectable diaphragms; a non-nitinol base substrate; and a hermetically sealed element formed between the nitinol layer and the base substrate, the hermetically sealed element being formed as a track around the periphery of the nitinol layer, the track comprising eutectic gold-tin.

[0257] Example 26: An implantable sensor device as described in any of the embodiments herein, particularly Example 25, wherein the track comprises one or more nitinol tracks on which gold-tin are formed.

[0258] Example 27: An implantable sensor device as described in any of the embodiments herein, particularly Example 26, wherein the one or more Nitinol orbitals comprise a plurality of redundant parallel orbitals.

[0259] Example 28: An implantable sensor device as described in any of the embodiments herein, particularly Example 27, wherein the plurality of parallel tracks consist of two parallel tracks extending along the periphery of the nitinol layer.

[0260] Example 29: An implantable sensor device as described in any of the embodiments herein, particularly Example 27, wherein the plurality of parallel tracks consists of three parallel tracks extending along the periphery of the nitinol layer.

[0261] Example 30: An implantable sensor device as described in any of the embodiments herein, particularly Example 29, wherein the width of the central track of the three parallel tracks is greater than the width of the inner and outer tracks of the three parallel tracks.

[0262] Example 31: An implantable sensor device as described in any of the embodiments herein, particularly Example 25, further comprising a metal hard stop structure disposed on the inner radius of the track, the metal hard stop structure defining the spacing between the nitinol layer and the base substrate.

[0263] Example 32: A method for bonding a nitinol structure to a non-nitinol structure. The method includes providing a first thin-film nitinol structure, providing a non-nitinol base structure, disposing a first eutectic gold-tin mold between the first nitinol structure and a first side of the base structure, and reflowing the first gold-tin mold to bond the first nitinol structure to the first side of the base structure.

[0264] Example 33: The method as described in any of the embodiments herein, particularly Example 32, wherein, prior to the reflow, the first gold-tin molded part is a solid preform structure.

[0265] Example 34: The method described in any of the embodiments herein, particularly Example 32, further includes forming a seed layer on the first side of the base structure prior to the reflow of the first gold-tin molded part.

[0266] Example 35: The method described in any of the embodiments herein, particularly Example 34, wherein the seed layer comprises a gold layer.

[0267] Example 36: The method described in any of the embodiments herein, particularly Example 35, further includes increasing the melting point of the first gold-tin mold by diffusing gold from the seed layer into the first gold-tin mold during the reflow of the first gold-tin mold.

[0268] Example 37: The method described in any of the embodiments herein, particularly Example 36, further includes: after reflowing the first gold-tin molded part, reflowing the second gold-tin molded part on the second side of the base structure to bond the second thin-film nitinol structure to the second side of the base structure.

[0269] Example 38: The method described in any of the embodiments herein, particularly Example 37, wherein when the second gold-tin molded part is reflowed, the second gold-tin molded part does not melt because the melting point of the second gold-tin molded part is lower than that of the first gold-tin molded part.

[0270] Example 39: The method described in any of the embodiments herein, particularly Example 32, further includes pressing the nitinol structure against the base structure while reflowing the gold-tin molded part to promote the bonding.

[0271] Example 40: The method as described in any of the embodiments herein, particularly Example 32, further includes pressing the nitinol structure against the base structure to compress the gold-tin molded part between the nitinol structure and the base structure.

[0272] Example 41: The method described in any of the embodiments herein, particularly Example 40, wherein the compression of the gold-tin molded part is limited by a non-nickeltinol hard stop molded part disposed between the nickeltinol structure and the base structure.

[0273] Example 42: The method as described in any of the embodiments herein, particularly Example 32, further includes transmitting an electrical signal from a first electrical element on the first nitinol structure to a second electrical element on the base structure via a bonding portion.

[0274] Example 43: The method described in any of the embodiments herein, particularly Example 32, wherein the reflow of the first gold-tin molded part is implemented using the first nitinol structure and the base structure arranged in a flip chip configuration.

[0275] Example 44: A sealing structure comprising: a first substrate including a sputtered material layer; a second substrate including a non-sputtered material layer; and a eutectic gold-tin interlayer configured to bond the first substrate and the second substrate.

[0276] Example 45: A sealing structure as described in any of the embodiments herein, particularly Example 44, wherein the sputtering material is nitinol.

[0277] Example 46: A sealing structure as described in any of the embodiments herein, particularly Example 44, wherein the sputtering material is titanium.

[0278] The methods and structures disclosed herein for treating patients also encompass similar methods and structures for performing or placing on simulated patients, which can be used for, for example, training; demonstration; program and / or device development; and so on. Simulated patients can be physical, virtual, or a combination of physical and virtual. Simulations can include simulations of all or part of a patient, such as the whole body, parts of the body (e.g., chest), systems (e.g., cardiovascular system), organs (e.g., heart), or any combination thereof. Physical elements can be: natural, including human or animal carcasses or parts thereof; synthetic; or any combination of natural and synthetic. Virtual elements can be entirely in silica or overlaid on one or more physical components. Virtual elements can be presented on any combination of a screen, headphones, holography, projection, speakers, pressure transducers, temperature transducers, or any combination using suitable technologies.

[0279] Any of the various systems, apparatuses, devices, etc. disclosed herein can be sterilized (e.g., using heat, radiation, ethylene oxide, hydrogen peroxide, etc.) to ensure their safe use in patients, and the methods herein may include sterilizing the associated systems, apparatuses, devices, etc. (e.g., using heat, radiation, ethylene oxide, hydrogen peroxide, etc.).

[0280] As illustrated by the examples, certain actions, events, or functions of any process or algorithm described herein may be performed in a different order, or may be added, combined, or omitted entirely. Therefore, in some instances, not all described actions or events are necessary for the practical process.

[0281] The conditional language used herein, such as “may,” “can,” “may,” “possibly,” “for example,” etc., unless otherwise specified or understood in the context in which they are used, is generally intended, and usually intended, to express that some instances include certain features, elements, and / or steps, while other instances do not include certain features, elements, and / or steps. Therefore, such conditional language is not generally intended to imply that features, elements, and / or steps are necessary in any one or more instances, or that one or more instances must include, with or without author input or prompting, logic for determining whether such features, elements, and / or steps are included in or will be performed in any particular instance. The terms “comprise,” “include,” “have,” etc., are synonyms used in their ordinary sense and in an open-ended manner, without excluding additional elements, features, actions, operations, etc. Furthermore, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that, for example, when used to connect a series of elements, the term “or” means one, some, or all of the elements in the list. Unless otherwise specified, connective language such as the phrase “at least one of X, Y, and Z” is generally understood in context to mean that an item, term, element, etc., can be X, Y, or Z. Therefore, such connective language is generally not intended to imply that certain instances require the presence of at least one of X, at least one of Y, and at least one of Z.

[0282] It should be understood that in the above description of the examples, various features are sometimes combined in a single example, drawing, or description for the purpose of simplifying this disclosure and aiding in the understanding of one or more aspects of the invention. However, this approach of the disclosure should not be construed as reflecting an intention in any claim to require more features than those expressly recited in the claim. Furthermore, any component, feature, or step illustrated and / or described in the specific examples herein can be applied to or used in conjunction with any other example. Further, for each example, no component, feature, step, or group of components, features, or steps is necessary or indispensable. Therefore, the scope of the invention disclosed herein and claimed below should not be limited by the specific examples described above, but should be determined solely by a careful reading of the appended claims.

[0283] It should be understood that certain ordinal terms (e.g., "first" or "second") may be provided for ease of reference and do not necessarily imply physical characteristics or order. Therefore, as used herein, ordinal terms used to modify elements (e.g., "first," "second," "third," etc.) do not necessarily indicate the priority or order of said element relative to any other element, but rather can generally distinguish said element from another element with a similar or identical name (but using ordinal terms). Additionally, as used herein, indefinite articles ("a (a)" and "an (an)") may indicate "one or more" rather than "one." Furthermore, an operation performed "based on" a condition or event may also be performed based on one or more other conditions or events not explicitly stated.

[0284] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the example instances pertain. It should be further understood that, unless expressly defined herein, terms (as defined in a common dictionary) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense.

[0285] The spatial relative terms “external,” “internal,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” and similar terms are used herein to describe the relationship between one element or component and another, as illustrated in the figures. It should be understood that, in addition to the orientations depicted in the figures, the spatial relative terms are intended to cover different orientations of the device in use or operation. For example, in the case where the device shown in the figures is flipped, a device positioned “below” or “below” another device may be placed “above” the other device. Therefore, the illustrative term “below” can include both lower and upper positions. The device may also be oriented in another direction, and thus the spatial relative terms can be interpreted differently depending on the orientation.

[0286] Unless otherwise explicitly stated, comparative and / or quantitative terms such as “less,” “more,” and “greater” are intended to encompass the concept of equality. For example, “less” may mean not only “less” in the strictest mathematical sense, but also “less than or equal to.”

Claims

1. An implantable sensor device, the implantable sensor device comprising: A sealing structure, the sealing structure comprising: Nickel-Titanium layer; Non-nickel-titanium material layer; and A eutectic gold-tin interlayer is configured to bond the nitinol layer to the non-nitinol layer.

2. The implantable sensor device as claimed in claim 1, wherein: The non-nickel-titanium material is ceramic or glass; and The sealing structure also includes a gold seed layer sandwiched between the eutectic gold-tin layer and the non-nickel-titanium material layer.

3. The implantable sensor device of claim 2, wherein the gold seed layer comprises a gold layer and a layer sandwiched between the non-nickel-titanium material layer and the gold layer, the layer comprising at least one of chromium, titanium, tungsten or palladium.

4. The implantable sensor device according to any one of claims 1 to 3, wherein the implantable sensor device further comprises a gold-tin seed layer sandwiched between the eutectic gold-tin layer and the nickel-tin oxide layer.

5. The implantable sensor device according to any one of claims 1 to 3, wherein: Prior to reflow, the eutectic gold-tin layer consisted of 80% gold and 20% tin by weight; and The eutectic gold-tin layer is configured for reflow, and the gold content by weight is increased from the gold layer sandwiched between the eutectic gold-tin layer and the nitinol layer or the non-nitinol material layer, thereby increasing the melting point of the gold-tin layer.

6. The implantable sensor device according to any one of claims 1 to 3, wherein the eutectic gold-tin layer is sputtered onto the nickel-titanium layer.

7. The implantable sensor device according to any one of claims 1 to 3, wherein: The nickel-titanium layer is a thin film layer formed using physical vapor deposition; and The sealing structure also includes a sputtered gold layer applied to the nitinol layer, the sputtered gold layer being sandwiched between the nitinol layer and the eutectic gold-tin layer.

8. The implantable sensor device according to any one of claims 1 to 3, wherein the eutectic gold-tin layer is a pre-formed structure.

9. The implantable sensor device according to any one of claims 1 to 3, wherein the implantable sensor device further comprises a metal rigid stop formed between the nitinol layer and the non-nitinol material layer, wherein: The melting point of the metal hard stop molding is higher than that of the eutectic gold-tin layer; and The metal hard stop molding is configured to laterally block the flow of the eutectic gold-tin layer across the metal hard stop molding when the eutectic gold-tin layer melts.

10. The implantable sensor device according to any one of claims 1 to 3, wherein: The nickel-titanium layer and the eutectic gold-tin layer are bonded to the first side of the non-nickel-titanium material layer; and The second nitinol layer is bonded to the second side of the non-nitinol material layer via a second gold-tin layer.

11. The implantable sensor device of any one of claims 1 to 3, wherein the eutectic gold-tin layer provides an electrical path that electrically couples a first conductor on the nitinol layer to a second conductor on the non-nitinol material layer.

12. An implantable sensor device, the implantable sensor device comprising: A vapor-deposited nitinol layer, the nitinol layer comprising one or more deflectable membranes; Non-nickel-titanium base substrate; and One or more gold-tin molded parts are bonded between the nitinol layer and the base substrate, the one or more gold-tin molded parts providing an hermetically tight seal between the nitinol layer and the base substrate.

13. The implantable sensor device of claim 12, further comprising: A first capacitor electrode is conformally formed on one of the one or more deflectable membranes of the nitinol layer; and A second capacitor electrode is coupled to the base substrate, and the second capacitor electrode and the first capacitor electrode form a variable capacitor.

14. The implantable sensor device of claim 13, further comprising one or more gold-tin electrical contacts providing an electrical connection between the first capacitive electrode and an electrical component associated with the base substrate.

15. The implantable sensor device of any one of claims 12 to 14, further comprising one or more gold contacts formed on the base substrate and configured to be bonded to the one or more gold-tin molded parts.

16. The implantable sensor device of any one of claims 12 to 14, wherein the implantable sensor device further comprises: One or more gold-tin electrical contacts, each gold-tin electrical contact being electrically coupled to a corresponding sensor element in one or more sensor elements implemented on the nitinol layer; and One or more electrical contacts are implemented on the base substrate and arranged to be bonded to the one or more gold-tin electrical contacts in a flip-chip manner.

17. The implantable sensor device of any one of claims 12 to 14, further comprising one or more gold-tin electrical contacts, each gold-tin electrical contact being electrically coupled to a corresponding sensor element among one or more sensor elements implemented on the nitinol layer, wherein the one or more gold-tin electrical contacts are arranged in a track around the periphery of the nitinol layer.

18. An implantable sensor device, the implantable sensor device comprising: A vapor-deposited nitinol layer, the nitinol layer comprising one or more deflectable membranes; Non-nickel-titanium base substrate; and An hermetic seal is formed between the nitinol layer and the base substrate, the hermetic seal being formed as a track around the periphery of the nitinol layer, the track comprising eutectic gold-tin.

19. The implantable sensor device of claim 18, wherein: The orbital includes one or more Nitinol orbitals on which gold-tin are formed; and The one or more Nitinol orbitals include two or more redundant parallel orbitals extending along the periphery of the Nitinol layer.

20. The implantable sensor device of claim 18 or claim 19, further comprising a metal hard stop structure disposed on the inner radius of the track, the metal hard stop structure defining the spacing between the nitinol layer and the base substrate.

21. A method for bonding a nitinol structure to a non-nitinol structure, the method comprising: Provides a first thin-film nitinol structure; Provide non-nickel-titanium base structures; A first eutectic gold-tin molding is provided between the first nickel-titanium structure and the first side of the base structure; as well as The first gold-tin molded part is reflowed to bond the first nitinol structure to the first side of the base structure.

22. The method of claim 21, further comprising: Prior to the reflow of the first gold-tin molded part, a gold seed layer is formed on the first side of the base structure; During the reflow of the first gold-tin molded part, the melting point of the first gold-tin molded part is increased by diffusing gold from the seed layer into the first gold-tin molded part; as well as After reflowing the first gold-tin molded part, the second gold-tin molded part is reflowed on the second side of the base structure to bond the second thin-film nitinol structure to the second side of the base structure. When the second gold-tin molded part is reflowed, it does not melt because the melting point of the second gold-tin molded part is lower than that of the first gold-tin molded part.

23. An implantable sensor device for measuring blood pressure, the implantable sensor device comprising: A first substrate, the first substrate comprising a sputtered nitinol or titanium layer; A second substrate, the second substrate comprising a non-sputtered material layer; and A eutectic gold-tin interlayer is configured to bond the first substrate and the second substrate.

24. The implantable sensor device of claim 23, further comprising an anchoring structure for securing the sensor device to a blood vessel.

25. The implantable sensor device of claim 24, wherein the anchoring structure is shaped for anchoring within the pulmonary artery.

26. An implantable sensor device, the implantable sensor device comprising: Inorganic non-metallic shell; A vapor-deposited thin-film nitinol separator layer, the thin-film nitinol separator layer comprising: A deflectable portion, configured to deflect in response to changes in pressure conditions outside the implantable sensor device; and The surrounding area cannot be deflected; A eutectic gold-tin (AuSn) layer, wherein the eutectic gold-tin (AuSn) layer bonds the inorganic non-metallic shell to the peripheral portion of the thin-film nitinol separator layer, the eutectic AuSn layer having a melting point lower than the transition temperature of the thin-film nitinol separator layer; and A capacitive sensor element disposed within a chamber at least partially hermetically sealed by the eutectic AuSn layer and surrounded on at least one side by the deflectable portion of the thin-film nitinol membrane layer.

27. The implantable sensor device of claim 26, further comprising: A first seed layer containing titanium is directly applied to the peripheral portion of the thin-film nickel-titanium diaphragm layer; A first gold layer is disposed between the first seed layer and the eutectic AuSn layer; A second seed layer containing titanium is directly applied to the inorganic non-metallic shell; and A second gold layer is disposed between the second seed layer and the eutectic AuSn layer.

28. The implantable sensor device of claim 26, further comprising: A first seed layer containing titanium is directly applied to the peripheral portion of the thin-film nickel-titanium separator layer, and the eutectic AuSn layer is directly disposed on the first seed layer; A second seed layer containing titanium is directly applied to the inorganic non-metallic shell; and A gold layer disposed between the second seed layer and the eutectic AuSn layer.

29. The implantable sensor device according to any one of claims 26 to 28, the implantable sensor device further comprising a gold hard stop molded member laterally disposed on the outer side of at least a portion of the eutectic AuSn layer.

30. The implantable sensor device of any one of claims 26 to 28, wherein the chamber is filled with an incompressible fluid configured to transmit pressure on the deflectable portion of the thin-film nitinol diaphragm layer to the capacitive sensor element.

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