The disclosure herein relates to hermetically-sealed electrical circuit apparatus, and further to fabrication methods for constructing such apparatus.
Electrical circuits (e.g., integrated circuits) include many types of active and passive devices (e.g., transistors, capacitors, resistors, etc.) that may be subject to damage from moisture (e.g., corrosion and functional changes to the system). For example, moisture may affect the operation and performance of circuitry, such as sensitive circuits used in implantable medical devices (e.g., sensor circuitry, pacing circuitry, timing circuitry, etc.).
Various attempts have previously been made to seal the interior of semiconductor device dies from moisture ingress. The bottom substrate in many semiconductor devices (e.g., silicon) effectively blocks moisture from entering the interior of the die from the bottom, but materials commonly employed in fabricating further layers above the substrate provide a path for moisture to enter from the top and/or sides of the die, e.g., after die separation. For example, certain commonly employed insulator materials such as silicon dioxide (SiO2) may be penetrated by moisture.
The disclosure herein relates generally to hermetically-sealed electrical circuit apparatus, and methods of fabrication of such apparatus. For example, as described in one or more embodiments herein, semiconductor substrates and semiconductor fabrication techniques may be used to provide a hermetic enclosure around a circuit device (e.g., a die that includes circuitry).
One exemplary apparatus disclosed herein includes an electrical circuit apparatus. The electrical circuit apparatus includes a first portion, a second portion, at least one circuit, and one or more seal portions. The first portion includes a planar connection surface, a substrate provided from a wafer (e.g., the substrate includes a substrate surface opposite the planar connection surface) and at least one side surface extending between the substrate surface and the planar connection surface. The second portion includes a planar connection surface, a substrate provided from a wafer (e.g., the substrate comprises a substrate surface opposite the planar connection surface), and at least one side surface extending between the substrate surface and the planar connection surface. The planar connection surface of the first portion is bonded to the planar connection surface of the second portion to form an interface defining at least one interface edge about the perimeter of the interface between the planar connection surfaces of the first portion and the second portion. The at least one circuit device includes electrical circuitry. Further, the at least one circuit device is encompassed by at least portions of the first portion and the second portion. The one or more seal portions cover at least the at least one interface edge of the interface to restrict moisture from ingressing into the apparatus.
One exemplary method disclosed herein includes providing at least one electrical circuit apparatus. The method includes providing a first portion, providing a second portion, and providing at least one circuit device comprising electrical circuitry. The first portion includes a planar connection surface, a substrate provided from a wafer (e.g., the substrate comprises a substrate surface opposite the planar connection surface), and at least one side surface extending between the substrate surface and the planar connection surface. The second portion includes a planar connection surface, a substrate provided from a wafer (e.g., the substrate comprises a substrate surface opposite the planar connection surface), and at least one side surface extending between the substrate surface and the planar connection surface. The method further includes coupling the planar connection surface of the first portion to the planar connection surface of the second portion to form an interface defining at least one interface edge about the perimeter of the interface between the planar connection surfaces of the first portion and the second portion. After such coupling, the at least one circuit device is encompassed by at least portions of the first portion and the second portion. The method further includes providing one or more seal portions covering at least the at least one interface edge of the interface to restrict moisture from ingressing into the apparatus.
The above summary is not intended to describe each embodiment or every implementation of the present disclosure. A more complete understanding will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.
In the following detailed description of illustrative embodiments, reference is made to the accompanying figures of the thawing which form a part hereof, and in which are shown, by way of illustration, specific embodiments which may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from (e.g., still falling within) the scope of the disclosure presented hereby.
Exemplary apparatus, and methods of constructing such apparatus, shall be described with reference to
Wafer scale fabrication techniques may be used to provide each of the first and second portions 20, 40. In one or more embodiments, each of the first portion 20 and the second portion 40 includes a substrate 22, 42, respectively, provided from or as a part of a wafer (e.g., a portion of any size and shape of substrate usable in wafer scale fabrication processes, such as a circular silicon wafer, a glass substrate, a plastic substrate, etc.). In other words, multiple portions may be fabricated on a wafer (e.g., the first portions on a first wafer and the second portions on a second wafer). As such, the fabrication of each of the portions may be initiated with use of a wafer substrate (e.g., a semiconductor, conductor, or insulator substrate wafer). In one or more embodiments, the wafer substrate is a doped semiconductor wafer substrate (e.g., doped to either a bulk n-type or p-type wafer), such as those used as the base substrate for microelectronic devices (e.g., substrates built in and over using one or more microfabrication process steps such as doping, ion implantation, etching, deposition of various materials, and photolithographic patterning processes). In one or more embodiments, the wafer is a silicon wafer. However, other available types of semiconductor wafers may be used, such as, for example, a gallium arsenide wafer, a germanium wafer, a silicon on insulator (SOI) wafer, etc. Further, for example, in one or more embodiments, the substrate may be formed of one or more materials other than semiconductor material, such as a glass substrate, wherein the substrate includes a metal film. In other words, for example, the first portion 20 may include a substrate 22 provided from or as a part of a wafer and the second portion 40 may include a substrate 42 provided from or as a part of a wafer.
As shown in
At least in one embodiment, the second portion 40 may only include a substrate (e.g., substrate 42). In the embodiment depicted, the second portion 40 is substantially similar to the first portion 20. For example, the substrate 42 may include a substrate surface 43 located opposite a connection surface 45 of the second portion 40. The second portion 40 may further include one or more layers 44 formed on the substrate 42 terminating at the connection surface 45 (e.g., a planar connection surface, a connection surface orthogonal to the at least one side surface 41). Also, the second portion 40 may include at least one side surface 41 (e.g., one side surface, four side surfaces, etc.) extending between the substrate surface 43 and the connection surface 45 (e.g., defined by the substrate 42 and the one or more layers 44).
At least in one embodiment, the connection surfaces 25, 45, which may be defined at least partly by one or more layers; may include oxide material. For example, such oxide material may be oxide material formed, deposited or grown as part of one or more processing steps (e.g., oxides such as borophosphosilicate glass, silicon dioxide, native oxide, etc.).
The apparatus 10 may include one or more circuit devices 90 (e.g., at least one circuit device 90) encompassed by (e.g., within, surrounded by, etc.) at least portions of the first and the second portions 20, 40. In at least one embodiment (as shown in
The first and second portions 20, 40 may further include one or more contact pads 30, 50, respectively, electrically coupled to the one or more circuit devices 90 using one or more interconnects 32, 52 (represented schematically with dashed lines) and located at the connection surfaces 25, 45. When the first portion 20 is assembled (e.g., bonded) with the second portion 40, the contact pads 30, 50 are electrically coupled to each other such that the one or more circuit devices 90 are electrically coupled to each other. Further, although not depicted, the apparatus 10 (e.g., the first portion 20 and/or the second portion 40) may include one or more additional interconnects extending between the circuit devices 90 and any other surface (e.g., outside surface) or any other location of the apparatus 10 for any purpose.
Further, although not depicted, one or both of the first and second portions 20, 40 (e.g., the one or more layers 24, 44) may define a cavity and at least one of the one or more circuit devices 90 may be located within the cavity. As used herein, the one or more circuit devices 90 may be any device or devices that include electrical circuitry that performs one or more functions (e.g., die containing circuitry). In such embodiments, the one or more circuit devices 90 may be directly electrically coupled to the one or more contacts pads 30, 50 without the use of interconnects (e.g., interconnects 32, 52). For example, at least in one embodiment, the second portion 40 defines a cavity extending into the connection surface 45. A circuit device 90 may be located within the cavity and electrically coupled to the contact pads 30 of the first portion 20.
The one or more circuit devices 90, the one or more interconnects 32, 52, and the one or more contact pads 30, 50 may be formed using standard microelectronic fabrication processing techniques (e.g., such as etching of materials, deposition of materials, and photolithographic patterning process steps, etc.). Further, various portions of first and second portions 20, 40 may be formed during the same or different processing steps. The present disclosure is not limited to any particular processing, or timing or order, of such process steps. However, some types of processing and order thereof may be beneficial over other types.
The method further includes bonding (e.g., oxide bonding, plasma-enhanced direct wafer bonding, etc.) the first portion 20 to the second portion 40 to form an interface 12 defining at least one interface edge 14 about the perimeter of the interface 12 (e.g., the interface 12 between the planar connection surfaces 25, 45 of the first and the second portions 20, 40) (see
In one or more embodiments, bonding the first and second portions 20, 40 together to assemble the apparatus 10 may be implemented using any wafer or die bonding process (e.g., bonding a wafer including the first portions with a wafer including the second portions, which also refers to the bonding of an individual die to a full wafer, an individual die to another individual die, etc.), such as chemical bonding processes (e.g., those using adhesion promoters, high temperature bonding processes, hydrogen bonding processes, plasma-enhanced bonding processes, oxide bonding processes, etc.). For example, use of plasma-enhanced bonding permits oxide surfaces (e.g., portions of the connection surfaces 25, 45 of the first and second portions 20, 40 including a dioxide material, such as silicon oxide or native oxide) to be bonded together.
Further, for example, in one or more embodiments, the connection surfaces 25, 45 may be each etched, polished, or planarized (e.g., using a chemical mechanical planarization or polishing) to expose any conductive portions thereof (e.g., the contact pads 30, 50 at connection surfaces 25, 45) to be exposed. For example, when the oxide portions and the conductive portions (e.g., contact pads 30) located at the connection surface 25 (e.g., a planar surface) are aligned with the oxide portions and the conductive portions (e.g., contact pads 50) located at the connection surface 45 (e.g., a planar surface), plasma-enhanced bonding may be performed. Further, plasma-enhanced bonding processes may form a bond between oxide portions of the connection surfaces 25, 45 of the first and second portions 20, 40 without the need for adhesives or other intermediate layers. For example, at least in one embodiment, the bonding at the interface 12 may be formed by driving off any existing water present between the connection surfaces 25, 45 and forming silicon-oxygen bonds throughout the structure such that a covalent bond is formed.
The method further includes providing one or more seal portions 60 at least covering the at least one interface edge 14 that, e.g., restricts moisture from entering the interface between the connection surfaces 25, 45 (e.g., planar connection surfaces) of the first and second portions 20, 40, respectively. As shown in
The one or more seal portions 60 may be provided by forming or depositing (e.g., physical deposition, chemical deposition, etc.) the one or more seal portions 60 as part of one or more processing steps (e.g., masking and depositing). For example, in at least one embodiment, the one or more seal portions 60 are provided by sputtering metals or polysilicon. Further, for example, in at least one embodiment, the one or more seal portions 60 are provided by chemical-vapor deposition.
The one or more seal portions 60 may include various materials such as, e.g., oxide materials, semiconductor materials, conductor materials, insulator materials, polysilicon, metals, phosphosilicate glass, borophosphosilicate glass, silicon nitride, tetraethyl orthosilicate, silox, etc. Further, such material of the one or more seal portions 60 may be biocompatible (e.g., such as for use in implantable medical devices). The one or more seal portions 60 may have a thickness of about 1 angstrom. Further, the one or more seal portions 60 may have a thickness of about 1 angstrom or more (in other words, at least about 1 angstrom), about 2 angstroms or more, about 5 angstroms or more, about 10 angstroms or more, about 50 angstroms or less, about 25 angstroms or less, about 10 angstroms or less, about 7 angstroms or less, about 5 angstroms or less, about 2 angstroms or less, or about 1 angstroms or less, etc. In at least one embodiment, the one or more seal portions 60 have a thickness that is thicker than the thickness of any material that may naturally form or grow on the first and second portions 20, 40 (e.g., native oxide).
In at least one embodiment, the one or more seal portions 60 may include one or more layers of the same or various materials formed in the same or different process. Further, each layer of the one or more layers forming the one or more seal portions 60 may have a thickness of at least about 1 angstrom. For example, the one or more seal portions 60 may include atomic layer deposition of dielectrics, sputtering of metals, chemical-vapor deposition of silicon nitride, etc
The apparatus 10 as shown in
The process flow presented in
Although not limited thereto, in one or more embodiments, the apparatus 10 is beneficial circuitry for packaging used in implantable medical devices. For example, the one or more circuit devices 90 of the apparatus 10 may be a part of an implantable medical device. Further, the apparatus 10 may be biocompatible. For example, the implantable medical device may be a device implantable in a body near a human heart. For example, the implanted medical device may be any implantable cardiac pacemaker, defibrillator, cardioverter-defibrillator, or pacemaker-cardioverter-defibrillator (PCD). Further, for example, the implantable medical device may be an implantable nerve stimulator or muscle stimulator, an implantable monitoring device (e.g., a hemodynamic monitoring device), a brain stimulator, a gastric stimulator, a drug pump, or any other implantable device that would benefit from moisture protection. Therefore, the apparatus 10 may find wide application in any form of implantable medical device. As such, any description herein making reference to any particular medical device is not to be taken as a limitation of the type of medical device which can benefit from and which can employ apparatus 10 as described herein.
Further, although the apparatus 10 may be beneficial for implantable medical devices, such structure is in no manner limited to such applications. For example, such testing structure may be beneficial for many different types of circuitry (e.g., whether for medical use or not, whether for an implantable medical device or not). For example, one or more types of circuits that may benefit from such testing structure may include circuits such as sensor circuits, pacing circuits, timing circuits, telemetry circuits, etc.
The electrical circuit apparatus 210 may be similar to the electrical circuit apparatus 10 and components thereof described herein with reference to
The one or more seal portions 260 are located in various locations on the exemplary electrical circuit apparatus 210 depicted in
Further, the apparatus 210 depicted in
The formation of interconnects 232, 252 and the contact pads 230, 250 may be formed using standard microelectronic fabrication processing techniques (e.g., such as etching of materials, deposition of materials, photolithographic patterning process steps, etc.). Further, interconnects 232, 252 may be formed of various structures including, e.g., stacked vias, through-silicon vias, metal layers, etc. Various portions of first and second portions 220, 240 may be formed during the same or different processing steps. For example, a portion of an interconnect 232 may be formed within a layer of the one or more layers 224 during formation of device 290. Still further, for example, process steps to form interconnects 232, 252 may be completely separate therefrom, such as in the formation of a through-silicon via after other layer processing is completed. The present disclosure is not limited to any particular processing, or timing or order, of such process steps. However, some types of processing and order thereof may be beneficial over other types.
Still further, in one or more embodiments, the first and second portions 220, 240 may not include interconnects or vias connecting the circuit devices to contact pads on the outside of the apparatus 210. For example, in at least one embodiment, the apparatus 210 may include various apparatus and/or structures to wirelessly communicate to other devices/apparatus outside of apparatus 210.
One or more seal portions 260 cover a larger portion of the side surfaces 221, 241 of the electrical circuit apparatus 210 in
The apparatus 210 depicted in
Further, for example, one or more seal portions 260 may cover the substrate surface 243 of the second portion 240 and a portion of the side surfaces 221, 241 of the electrical circuit apparatus 210 as shown in
The apparatus 210 depicted in
Still further, for example, one or more seal portions 260 may cover at least a portion of the substrate surface 243 of the second portion 240 and a portion of the side surfaces 221, 241 of the electrical circuit apparatus 210 as shown in
The apparatus 210 depicted in
The apparatus 210 depicted in
The apparatus 210 depicted in
The one or more seal portions 260 are located in substantially the same locations on the exemplary electrical circuit apparatus 210 depicted in
Further, the apparatus 210 depicted in
Any features, components, and/or properties of any of the embodiments described herein may be incorporated into any other embodiment(s) described herein.
All patents, patent documents, and references cited herein are incorporated in their entirety as if each were incorporated separately. This disclosure has been provided with reference to illustrative embodiments and is not meant to be construed in a limiting sense. As described previously, one skilled in the art will recognize that other various illustrative applications may use the techniques as described herein to take advantage of the beneficial characteristics of the apparatus and methods described herein. Various modifications of the illustrative embodiments, as well as additional embodiments of the disclosure, will be apparent upon reference to this description.
This application claims the benefit of U.S. Provisional Application Ser. No. 61/185,881 filed 10 Jun. 2009, entitled “FARADAY CAGE FOR CIRCUITRY USING SUBSTRATES,” U.S. Provisional Application Ser. No. 61/229,867 filed 30 Jul. 2009, entitled “APPARATUS FOR RESTRICTING MOISTURE INGRESS,” U.S. Provisional Application Ser. No. 61/229,869 filed 30 Jul. 2009, entitled “HERMETICITY TESTING,” and U.S. Provisional Application Ser. No. 61/235,745 filed 21 Aug. 2009, entitled “HERMETICALLY-SEALED ELECTRICAL CIRCUIT APPARATUS,” all of which are incorporated herein by reference in their respective entireties.
Number | Date | Country | |
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61235745 | Aug 2009 | US | |
61229869 | Jul 2009 | US | |
61229867 | Jul 2009 | US | |
61185881 | Jun 2009 | US |