Patent Application
20240145528
The semiconductor industry has experienced rapid growth due to continuous improvements in the integration density of a variety of electronic components (e.g., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from repeated reductions in minimum feature size, which allows more components to be integrated into a given area. As the demand for shrinking electronic devices has grown, a need for smaller and more creative packaging techniques of semiconductor chips has emerged. To help perform high-density implementation of semiconductor chips, interposers are often employed that are formed from organic, inorganic (e.g., glass), or silicon materials. Such an assembly is often referred to as a Chip-on-Interposer or Chip-On-Wafer (CoW) structure when the interposer is formed from a semiconductor material (e.g., silicon). The CoW structure may then be attached to a build-up packaging substrate to form the CoWoS structure, and the resulting package may be finally connected to a printed circuit board. As part of the power delivery system to the chip, one or more decoupling capacitors are also typically employed so that any sudden requirement for current can be supplied to the chip with the voltage maintained constant or nearly constant. Unfortunately, however, increased switching speeds in chips have resulted in increased parasitic inductances. As such, a need currently exists for improved microelectronic assemblies that employ decoupling capacitors.
In accordance with one embodiment of the present invention, a microelectronic assembly is disclosed that comprises a semiconductor structure, an interposer that is electrically connected to the semiconductor structure, a package substrate that is electrically connected to the interposer, and a circuit board. The assembly also comprises a decoupling capacitor having a first surface and an opposing second surface, wherein the decoupling capacitor contains alternating dielectric layers and internal electrode layers. The internal electrode layers contain first internal electrode layers and second internal electrode layers. The capacitor further contains a first external terminal that is electrically connected to the first internal electrode layers and disposed on a first surface of the capacitor, a second external terminal that is electrically connected to the first internal electrode layers and disposed on the second surface of the capacitor, a third external terminal that is electrically connected to the second internal electrode layers and disposed on the first surface of the capacitor, and a fourth external terminal that is electrically connected to the second internal electrode layers and disposed on the second surface of the capacitor. The first external terminal and the third external terminal are electrically connected to the package substrate, and the second external terminal and the fourth external terminal of the decoupling capacitor are electrically connected to the circuit board.
Other features and aspects of the present invention are set forth in greater detail below.
A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
Repeat reference to characters in the present specification and figures is intended to represent same or analogous features or elements of the invention.
It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention.
Generally speaking, the present invention is directed to a microelectronic assembly that includes a semiconductor structure, an interposer that is electrically connected to the semiconductor structure, and an organic package substrate that is electrically connected to the interposer. The assembly further comprises a decoupling capacitor having a first surface and an opposing second surface. The decoupling capacitor contains alternating dielectric layers and internal electrode layers, wherein the internal electrode layer include first internal electrode layers and second internal electrode layers. A first external terminal is electrically connected to the first internal electrode layers and disposed on the first surface of the capacitor and a second external terminal is electrically connected to the first internal electrode layers and disposed on the second surface of the capacitor. Likewise, a third external terminal is electrically connected to the second internal electrode layers and disposed on a first surface of the capacitor and a fourth external terminal is electrically connected to the second internal electrode layers and disposed on the second surface of the capacitor. Typically, the first and second external terminals have the same polarity (e.g., positive) and the third and fourth external terminals have the same polarity (e.g., negative). Regardless, the first external terminal and the third external terminal of the decoupling capacitor are electrically connected to the package substrate, and the second external terminal and the fourth external terminal of the decoupling capacitor are electrically connected to a printed circuit board.
Various embodiments of the present invention will now be described in more detail below.
One or more semiconductor structures (e.g., dies, wafers, integrated circuit devices, etc.) may generally be employed within the microelectronic assembly. Generally speaking, a semiconductor structure may include an insulating material (e.g., a dielectric material formed in multiple layers, as known in the art) and multiple conductive pathways formed through the insulating material. The insulating material may include a dielectric material, such as silicon dioxide, silicon nitride, oxynitride, a polyimide material, a glass reinforced epoxy matrix material, or a low-k or ultra-low-k dielectric (e.g., a carbon-doped dielectric, a fluorine-doped dielectric, a porous dielectric, an organic polymeric dielectric, a photo-imagable dielectric, and/or a benzocyclobutene-based polymer). The insulating material may also include a semiconductor material, such as silicon, germanium, or a III-V material (e.g., gallium nitride), and one or more additional materials. For example, an insulating material may include silicon oxide or silicon nitride. The conductive pathways of a die may include conductive traces and/or conductive vias, and may connect any of the conductive contacts in the die in any suitable manner. The semiconductor structure may include a mixed-pitch die (in the sense that the die has sets of conductive contacts with different pitch), for example, the die may have “coarser” conductive contacts for coupling to the interposer of the microelectronic assembly. The structure may also include a single-sided die (only has conductive contacts on a single surface) and/or a double-sided die (conductive contacts on a first surface and on an opposing second surface). The conductive pathways in the dies may be bordered by liner materials, such as adhesion liners and/or barrier liners, as suitable. The semiconductor structure may also include a wafer. In some embodiments, the semiconductor structure includes a monolithic silicon, a fan-out or fan-in package die, or a die stack (e.g., wafer stacked, die stacked, or multi-layer die stacked).
The semiconductor structure may also have integrated circuit (“IC”) structures such that it is in the form of a discrete IC device or “chip.” Such an IC device may include one or more device layers disposed on a die substrate. The die substrate may be a semiconductor substrate composed of semiconductor material systems including, for example, n-type or p-type materials systems (or a combination of both). The die substrate may include, for example, a crystalline substrate formed using a bulk silicon or a silicon-on-insulator (SOI) substructure. In some embodiments, the die substrate may be formed using alternative materials, which may or may not be combined with silicon, that include, but are not limited to, germanium, indium antimonide, lead telluride, indium arsenide, indium phosphide, gallium arsenide, or gallium antimonide. Further materials classified as group II-VI, III-V, or IV may also be used to form the die substrate. The device layers may include one or more transistors (e.g., metal oxide semiconductor field-effect transistors (MOSFETs)), supporting circuitry to route electrical signals to the transistors, passive components (e.g., signal traces, resistors, capacitors, or inductors), and/or any other IC components. The device layers may include, for example, one or more source and/or drain (S/D) regions, a gate to control current flow in the transistors between the S/D regions, and one or more S/D contacts to route electrical signals to/from the S/D regions. Each transistor may include a gate formed of at least two layers, a gate dielectric and a gate electrode. The gate dielectric may include one layer or a stack of layers. The one or more layers may include silicon oxide, silicon dioxide, silicon carbide, and/or a high-k dielectric material. The high-k dielectric material may include elements such as hafnium, silicon, oxygen, titanium, tantalum, lanthanum, aluminum, zirconium, barium, strontium, yttrium, lead, scandium, niobium, and zinc. Examples of high-k materials that may be used in the gate dielectric include, but are not limited to, hafnium oxide, hafnium silicon oxide, lanthanum oxide, lanthanum aluminum oxide, zirconium oxide, zirconium silicon oxide, tantalum oxide, titanium oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, yttrium oxide, aluminum oxide, lead scandium tantalum oxide, and lead zinc niobate. In some embodiments, an annealing process may be carried out on the gate dielectric to improve its quality when a high-k material is used.
The gate electrode may be formed on the gate dielectric and may include at least one p-type work function metal or n-type work function metal, depending on whether the transistor is to be a PMOS or a NMOS transistor. In some implementations, the gate electrode may consist of a stack of two or more metal layers, where one or more metal layers are work function metal layers and at least one metal layer is a fill metal layer. Further metal layers may be included for other purposes, such as a barrier layer. For a PMOS transistor, metals that may be used for the gate electrode include, but are not limited to, ruthenium, palladium, platinum, cobalt, nickel, conductive metal oxides (e.g., ruthenium oxide), and any of the metals discussed below with reference to an NMOS transistor (e.g., for work function tuning). For an NMOS transistor, metals that may be used for the gate electrode include, but are not limited to, hafnium, zirconium, titanium, tantalum, aluminum, alloys of these metals, carbides of these metals (e.g., hafnium carbide, zirconium carbide, titanium carbide, tantalum carbide, and aluminum carbide), and any of the metals discussed above with reference to a PMOS transistor (e.g., for work function tuning). Electrical signals, such as power and/or input/output (I/O) signals, may be routed to and/or from the devices (e.g., transistors) of the device layer through one or more interconnect layers disposed on the device layer. For example, electrically conductive features of the device layer (e.g., the gate and the S/D contacts) may be electrically coupled with the interconnect structures that may optionally form a metallization stack (also referred to as an “ILD stack”) of the IC device. The interconnect structures may include lines and/or vias filled with an electrically conductive material, such as a metal. The lines may be arranged to route electrical signals in a direction of a plane that is substantially parallel with a surface of the die substrate upon which a device layer is formed. The vias may be arranged to route electrical signals in a direction of a plane that is substantially perpendicular to the surface of the die substrate upon which a device layer is formed.
The IC device may, for example, include a memory device (e.g., a random access memory (RAM) device, such as a static RAM (SRAM) device, a magnetic RAM (M RAM) device, a resistive RAM (RRAM) device, a conductive-bridging RAM (CBRAM) device, erasable-programmable read-only memory (EPROM) chip, a non-volatile memory (e.g., 3D XPoint), volatile memory (e.g., high bandwidth memory), stacked memory, etc.); logic device (e.g., an AND, OR, NAND, or NOR gate, programmable logic device, etc.); processor device (e.g., central processing unit (CPU), graphics processing unit (GPU), etc.); application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), platform controller hubs (PCH), and so forth, as well as any other suitable memory, logic, and/or processor device. Multiple devices may be combined on a single structure. For example, a memory array formed by multiple memory devices may be formed on a same die as a processing device or other logic that is configured to store information in the memory devices or execute instructions stored in the memory array.
The semiconductor structure may also be a “chiplet”, which is a small integrated circuit (IC) that contains a well-defined subset of functionality that is one part of a processing module that makes up a larger integrated circuit like a computer processor. In some embodiments, one or more chiplets are variously coupled to the host chip, wherein each of the one or more chiplets includes a respective cache—e.g., including a last level cache (LLC), which is accessible to one or more cores of the host chip. The host chip may include one or more processor cores that can each operate as a consumer of memory resources, and the chiplet may include one or more memory arrays coupled to be accessible each by a respective processor core of host chip. In this particular context, the terms “memory,” “memory array,” “memory resource” and related terms generally refer to either of cache memory or non-cache memory (such as system memory, for example). Similarly, the term “memory controller” generally refers to controller circuitry that provides access to one of cache memory or non-cache memory. The host chip may contain a processor core that is to operate as a consumer of memory resources. For example, the host chip may execute an operating system, a binary input/output system (BIOS), and/or any of various other software processes. To facilitate execution of such software, a chiplet may include one or more memory arrays coupled to be accessible to processor core via a hardware interface. In one embodiment, the memory array includes static random access memory (SRAM) cells or dynamic random access memory (DRAM) cells. Additionally or alternatively, the processor core may be coupled to cache data to memory array—e.g., wherein the processor core is coupled to access a last level cache (LLC) of memory array. In various other embodiments, the memory array may contain non-volatile memory (NVM) cells. The chiplet may also contain a memory controller coupled between the hardware interface and memory array to control memory access on behalf of a process which is executed with core. By providing the memory array in a chiplet disposed between hardware interface and host chip, the locality of data may be improved for use by one or more cores of packaged device. This improved data locality enables an access to memory resources which is relatively more space efficient, time efficient and/or power efficient.
The semiconductor(s) structures can be arranged in a two-dimensional configuration or array as is known in the art (e.g., 2D, 2.1 D, 2.3D, or 2.5D heterogenous integration) or stacked into a 3D configuration. When employing a stacked configuration, the semiconductor structure may contain two or more semiconductor substrates (e.g., chips, interposers, etc.) mounted on a circuit board. If implemented as semiconductor chips, the substrates may be any of a myriad of different types of circuit devices used in electronics, such as, for example, microprocessors, graphics processors, combined microprocessor/graphics processors, application specific integrated circuits, memory devices or the like, and may be single or multi-core. The substrates may be constructed of bulk semiconductor, such as silicon or germanium, or semiconductor-on-insulator materials, such as silicon-on-insulator materials. The circuit board may be a semiconductor chip package substrate, a circuit card, or virtually any other type of printed circuit board. A monolithic structure could be used for the circuit board, although a more typical configuration will utilize a build-up design. In this regard, the circuit board may consist of a central core upon which one or more build-up layers are formed and below which an additional one or more build-up layers are formed. The core itself may consist of a stack of one or more layers. Electrical pathways between the substrates and the circuit board as well as between any of the substrates may be provided by interconnect structures.
As indicated above, a semiconductor structure is electrically connected to one or more interposers so that the resulting microelectronic assembly is considered a “chip-on-interposer” structure. Among other things, the interposer may provide an intervening substrate to help bridge the circuit board and the semiconductor structure and to help spread a connection to a wider pitch or reroute a connection to a different connection. The semiconductor structure may be electrically connected to the interposer by one or more coupling components. The coupling components may electrically and mechanically couple the chip-on-interposer structure to the circuit board, and may include, for example, solder bumps, solder balls, male and female portions of a socket, adhesive, underfill material, and/or any other suitable electrical and/or mechanical coupling structure. The underfill material may be an insulating material, such as an appropriate epoxy material. When employed, an underfill material may include a capillary underfill, non-conductive film (NCF), or molded underfill. In some embodiments, the underfill material may include an epoxy flux that assists with soldering the semiconductor structure and then polymerizes and encapsulates the interconnects within the interposer.
The interposer generally includes an insulating material and one or more conductive pathways through the insulating material (e.g., including conductive traces and/or conductive vias, as shown). In one embodiment, for instance the insulating material may be an organic material, such as bismaleimide triazine (“BT”) resin materials (e.g., BT, BT-epoxy resins, etc.), epoxy resin materials (e.g., glass fiber-reinforced epoxy resin (e.g., FR4)), polyimide materials, low-k and ultra-low-k dielectrics (e.g., carbon-doped dielectric, fluorine-doped dielectric, porous dielectric, and an organic polymeric dielectric). The insulating material may also be an inorganic interposer, such as those formed from ceramic materials (e.g., glass), as well as from semiconductor materials, such as silicon, germanium, and other group III-V (e.g., gallium nitride) and group IV materials. The conductive pathways serve as a mechanism for electrically connecting the interposer to the semiconductor structure via the coupling components. Such pathways may include one or more metal interconnects and vias as is known in the art. In one embodiment, for example, the interposer may be formed from silicon and the vias may be formed therein may that are referred to as “through-silicon vias (“TSVs”).
Regardless of the manner which it is formed, the interposer may be passive or active depending on the particular embodiment. By “passive”, it is generally meant the interposer is generally free of embedded electronic components. On the other hand, an “active” interposer generally contains one or more electronic components embedded within the insulating material. Examples of such electronic components may include, for instance, capacitors (e.g., decoupling capacitors), resistors, inductors, fuses, diodes, transformers, sensors, electrostatic discharge (ESD) devices, and memory devices. More complex devices such as radio frequency devices, power amplifiers, power management devices, antennas, and microelectromechanical systems (MEMS) devices, may also be formed in the interposer. For instance, an active interposer may include an active layer and a bulk semiconductor layer. The front surface of active layer may be referred to herein as an “active side” and the opposing surface of the bulk semiconductor layer may be referred to as a “backside.” In one embodiment, the active layer may include one or more electronic components formed at the active side, such as level one (L1) memory elements used as memory caches for storing configuration bit streams for configuring logic sectors in a coprocessor. The active layer may optionally include decryption/decompression circuitry for processing encrypted and/or decompressed configuration bit streams. The semiconductor layer may include TSVs that connect electronic components (e.g., L1 memory elements) in the active layer to coupling elements (e.g., solder balls). For example, L1 caches may receive configuration bit streams from a host processor through solder balls and TSVs. In this manner, the energy efficiency of transferring signals and power between the active layer of the interposer and the package substrate may be improved.
In addition to an interposer, the microelectronic assembly further includes a “build-up” package substrate to help bridge high density interconnects and functionality between the semiconductor structure, interposer, and a circuit board. The package substrate generally includes an organic insulating material and one or more conductive pathways through the insulating material (e.g., including conductive traces and/or conductive vias, as shown). The organic insulating material may include, for instance, bismaleimide triazine (“BT”) resin materials (e.g., BT, BT-epoxy resins, etc.), epoxy resin materials (e.g., glass fiber-reinforced epoxy resin (e.g., FR4)), polyimide materials, low-k and ultra-low-k dielectrics (e.g., carbon-doped dielectric, fluorine-doped dielectric, porous dielectric, and an organic polymeric dielectric). In some embodiments, the insulating material may be a laminate or a build-up film (e.g., Ajinomoto build-up film). The conductive pathways may couple the semiconductor structure to the circuit board and decoupling capacitor. Any suitable arrangement of conductive pathways through any suitable number of insulating layers may generally be employed. The conductive pathways may be made of any suitable conductive material, such as copper. The conductive pathways may be bordered by liner materials, such as adhesion liners and/or barrier liners, as suitable. In certain embodiments, the package substrate may be a lower density medium and the semiconductor structure and/or interposer may be a higher density medium. As used herein, the term “lower density” and “higher density” are relative terms indicating that the conductive pathways (e.g., including conductive lines and conductive vias) in a lower density medium are larger and/or have a greater pitch than the conductive pathways in a higher density medium. For example, a higher density medium may be manufactured using a modified semi-additive process or a semi-additive build-up process with advanced lithography (with small vertical interconnect features formed by advanced laser or lithography processes), while a lower density medium may be a PCB manufactured using a standard PCB process (e.g., a standard subtractive process using etch chemistry to remove areas of unwanted copper, and with coarse vertical interconnect features formed by a standard laser process).
As indicated above, at least one decoupling capacitor is electrically connected to the package substrate and a circuit board (e.g., printed circuit board). Generally speaking, the decoupling capacitor contains a main body that include alternating dielectric layers and internal electrode layers. The internal electrode layers include at least first internal electrode layers and second internal electrode layers. The capacitor may, for example, include at least two, such as at least three, such as at least four sets of internal electrode layers. Of course, it should be understood that the capacitor may include any number of sets of alternating dielectric layers and internal electrode layers and is not necessarily limited.
Typically, the capacitor includes an upper surface (e.g., first surface) and a lower surface (e.g., second surface) opposite the upper surface. The capacitor also includes at least one side surface, in particular at least two side surfaces, that extend between the upper surface and the lower surface. The capacitor may also include at least one end surface, in particular at least two end surfaces, that extend between the upper surface and the lower surface. The side surfaces may extend in a length (L) direction and have a generally longer dimension than end surfaces that extend in a width (W) direction and have a generally shorter dimension. In one embodiment, the capacitor may have a parallelepiped shape, such as a rectangular parallelepiped shape. The overall dimensions of the capacitor may depending on the particular application. Typically, however, the height or thickness of the capacitor is from about 10 μm to about 5,000 μm, in some embodiments from about 20 μm to about 2,500 μm, in some embodiments from about 50 μm to about 1,500 μm, and in some embodiments, from about 100 μm to about 1,000 μm. When surrounded by a ball grid array, the height of the capacitor may be within 10%, such as within 7%, such as within 5%, such as within 3%, such as within 2%, such as within 1% the height (or diameter) of the balls of the ball grid array. For instance, such height may be the original height prior to any reflow. The length of the capacitor in the “L” direction may likewise be from about 50 μm to about 10,000 μm, in some embodiments from about 100 μm to about 7,500 μm, and in some embodiments, from about 1,000 μm to about 5,000 μm and the width of the capacitor in the “W” direction may be from about 25 μm to about 5,000 μm, in some embodiments from about 50 μm to about 3,500 μm, and in some embodiments, from about 500 μm to about 2,500 μm.
The first internal electrode layers and second internal electrode layers may be interleaved in an opposed and spaced apart relation with a dielectric layer located between each internal electrode layer. The respective sets of alternating dielectric layers and internal electrode layers may be separated from an adjacent set by a certain distance. For instance, that distance may be greater than the thickness of an individual dielectric layer in the set, such as at least 2, in some embodiments at least 3, in some embodiments at least 5, and in some embodiments, at least 10 times the thickness of a dielectric layer in the set. Each set of internal electrode layers and/or the entire capacitor may include from about 10 to about 4,000, in some embodiments from about 50 to about 2,000, and in some embodiments, from about 100 to about 1,000 internal electrode layers. The thickness of the dielectric layers and/or internal electrode layers is not limited and can be any thickness as desired depending on the performance characteristics. For instance, the thickness of the internal electrode layers and/or individual dielectric layers may range from about 100 nm to about 10 μm, in some embodiments from about 500 nm to about 8 μm, and in some embodiments, from about 1 μm to about 5 μm. In certain embodiments, if the capacitor includes a second set of alternating dielectric layers and internal electrode layers, the distance between the first internal electrode layer of one set and the last internal electrode layer of another set may be greater than the distance between adjacent internal electrode layers within a given set. For instance, the distance between the first internal electrode layer of a first set and the last internal electrode layer of a second set may be greater than the distance between the first internal electrode layer and the second internal electrode layer of the first set.
Although by no means required, dielectric regions of the decoupling capacitor may also include one or more voids. In this regard, the dielectric region may be a region that includes dielectric material but does not include the internal electrode material. The dielectric region may thus constitute a region that does not include alternatively arranged dielectric layers and internal electrode layers. Accordingly, the dielectric region may include the dielectric material between the respective sets of alternating dielectric layers and internal electrode layers in a “W” direction. In addition, the dielectric region may include the dielectric material between a lateral edge of the electrodes in a given set of alternating dielectric layers and internal electrode layers and an adjacent end surface in the longitudinal direction, for instance to the extent such internal electrode layers do not extend to the end surface such that they are offset from the end surface. It should be understood that while such dielectric regions may be formed from ceramic green sheets of alternating dielectric layers and internal electrode layers, such regions do not include any internal electrode material or corresponding layers. As a result, air voids may be provided within such regions. In addition, the dielectric regions may include the dielectric material present between the first internal electrode layer of the respective sets and an adjacent side surface of the capacitor. The dielectric regions may also include the dielectric material present between the last internal electrode layer of the respective sets and an adjacent side surface of the capacitor. The dielectric regions may also include the dielectric material between lateral edges of adjacent lead tabs that extend from the main body of the internal electrode layers. In one particular embodiment, the dielectric region may include the region within the capacitor present between two external terminals. In addition, it should be understood that the dielectric region may include a combination of any of the aforementioned regions.
As indicated above, the dielectric regions include those that include dielectric material but do not include the internal electrode material. Accordingly, not considering the air voids, the dielectric regions may include 90 vol. % or more, such as 93 vol. % or more, such as 95 vol. % or more, such as 97 vol. % or more, such as 98 vol. % or more, such as 99 vol. % or more, such as 100 vol. % of dielectric material. Such air voids may not include any material, in particular any dielectric material or internal electrode material. In one embodiment, the air voids may be enclosed, such as partially or completely, by an enclosure material. In one embodiment, the air voids may be partially enclosed by an enclosure material. By partially enclosed, the enclosure material is only partially present around the interior of the air void such that it is partially separated from the dielectric material. In this regard, at least a certain perimeter of the air void may be in direct contact with the dielectric material of the dielectric region. In another embodiment, the air voids may be completely or entirely enclosed by an enclosure material. By entirely enclosed, the enclosure material is present around the interior of the air void such that it is entirely separated from the dielectric material. Regardless, the enclosure material may be utilized to serve as a barrier between the interior of the air void and the dielectric material of the dielectric region. In one embodiment, the enclosure material may be a non-conductive material. However, it should be understood that in one embodiment, the air voids may not be enclosed, even partially, by an enclosure material.
The voids may be provided without any barrier between the air void and the dielectric material of the dielectric region. The air void may have any shape and is not necessarily limited. For instance, the shape may be a sphere, a cylinder, etc. In one embodiment, the shape may be a sphere. The air void may have a maximum dimension (e.g., length, width, diameter, etc.) of from about 5 μm to about 5,000 μm, in some embodiments from about 50 μm to about 2,500 μm, and in some embodiments, from about 100 μm to about 1,000 μm. The voids may be formed using any known technique, such as by printing particular patterns in the ceramic green sheets and thereafter laminating and firing the stacked laminated. Alternately, the voids may be formed using various drilling techniques in order to provide any desired shape within the dielectric material of the dielectric region. The voids may also be presented using one or more vias (e.g., through-hole vias). The vias may be unfilled with material, such as any conductive or nonconductive material, such that air is present within the interior. In addition, in one embodiment, the vias may be provided such that they are only present within the dielectric region. In this regard, the vias may be provided that such that they do not contact any of the internal electrode layers. In one embodiment, the vias may extend from the upper surface of the capacitor to the lower surface of the capacitor. In this regard, the vias may be columnar extending through the thickness of the capacitor. Accordingly, the via may be a through hole conductive via. In another embodiment, the vias may only partially extend through the thickness of the capacitor. For instance, the vias may extend only partially through the capacitor thickness, such as from about 10% to about 90%, and in some embodiments, from about 20% to about 80% of the capacitor thickness.
In addition to alternating internal electrode layers and dielectric layers, the decoupling capacitor also includes a first external terminal that is electrically connected to the first internal electrode layers and disposed on a first surface of the capacitor (e.g., upper surface) and a second external terminal that is electrically connected to the first internal electrode layers and disposed on a second surface of the capacitor (e.g., lower surface). Likewise, a third external terminal is electrically connected to the second internal electrode layers and disposed on the first surface of the capacitor and a fourth external terminal is electrically connected to the second internal electrode layers and disposed on the second surface of the capacitor. Typically, the first and second external terminals have the same polarity (e.g., positive) and the third and fourth external terminals have the same polarity (e.g., negative). Regardless, the first external terminal and the third external terminal of the decoupling capacitor are electrically connected to the package substrate, and the second external terminal and the fourth external terminal of the decoupling capacitor are electrically connected to a printed circuit board.
The capacitor may also include external terminals on opposing end surfaces. For instance, one or more of the external terminals may extend from the first surface (e.g., upper surface) and/or second surface (e.g., lower surface) to an end surface. When present on the end surface, the external terminal may only be present partially on the end surface such that it does not cover the entire end surface. In another embodiment, the capacitor may not include any external terminals on opposing end surfaces. In one particular embodiment, the external terminals may not be present on a side surface of the capacitor. Regardless, the external terminals generally include at least one first polarity terminal and at least one second and opposite polarity terminal. The capacitors may include at least one, such as at least two, such as at least four, such as at least six, such as at least eight first polarity terminals and/or second and opposite polarity terminals on an upper surface of the capacitor. Additionally, the capacitors may include the aforementioned amounts of terminals on a lower surface of the capacitor.
The capacitors may include an equal number of first polarity terminals and/or second polarity terminals on the upper and lower surfaces of the capacitor. The number of first polarity terminals may equal the number of second and opposite polarity terminals on an upper surface of a capacitor. The number of first polarity terminals may equal the number of second and opposite polarity terminals on a lower surface of a capacitor. The total number of terminals present on an upper surface of the capacitor may equal to the total number of terminals present on a lower surface of the capacitor. The total number of first polarity terminals present on an upper surface and a lower surface of the capacitor may equal the total number of second and opposite polarity terminals present on an upper surface and a lower surface of the capacitor. Typically, the like polarity terminals on the lower surface of the capacitor that correspond to a particular set of alternating dielectric layers and internal electrode layers are electrically connected to the like polarity terminals on the upper surface of the capacitor. The like polarity terminals located on an upper surface and a lower surface of a capacitor may not be interdigitated. In this regard, corresponding like polarity terminals on a top and a lower surface may not be offset by a terminal position but may instead be positioned directly above or below another like polarity terminal on the opposite top or lower surface. In other words, corresponding like polarity terminals that correspond to a particular set of alternating dielectric layers and internal electrode layers, and in particular corresponding lead tabs of such set, may be substantially aligned. By substantially aligned, it is meant that the offset from a side edge of one lateral edge of a polarity terminal on an upper surface is within +/−10%, such as within +/−5%, such as within +/−4%, such as within +/−3%, such as within +/−2%, such as within +/−1%, such as within +/−0.5% of the offset from a side edge of a corresponding polarity terminal on a lower surface.
The pitch (i.e., nominal distance between the centers also referred to as center-to-center spacing) of the external terminals may be dictated by the particular circuit board configuration. The pitch between external terminals in one direction (i.e., x or y direction) may be the same as the pitch between adjacent external terminals in the other direction (i.e., y or x direction, respectively). That is, the pitch between any two adjacent external terminals may be substantially the same as the pitch between any other two adjacent external terminals. The pitch may, for example, range from about 0.1 to about 2 mm, in some embodiments from about 0.2 to about 1.5 mm, and in some embodiments, from about 0.4 to about 1.4 mm.
If desired, the external terminals may be positioned similar to the configuration of a ball-grid array. For instance, the external terminals may be provided to make contacts as typically employed by a ball-grid array, in particular a surrounding ball-grid array. In this regard, the pitch of the external terminals may be the same as the pitch of a surrounding ball-grid array. That is, the pitch may be within 10%, such as within 5%, such as within 2%, such as within 1%, such as within 0.5%, such as within 0.1% of the pitch of a surrounding ball-grid array. In addition, like a ball-grid array, the external terminals may be provided in rows and columns. That is, the external terminals may be provided such that they exist in at least one row and at least two columns. For instance, the external terminals may be presented in at least two rows, such as at least three rows, such as at least four rows. The number of rows can be dictated by the number of different sets of alternating dielectric layers and internal electrode layers. In addition, the external terminals may be presented in at least two columns, such as at least three columns, such as at least four columns. The number of columns can be dictated by the number of different columnar tabs of the internal electrodes.
The length (i.e., extending in the longitudinal direction from an end surface to another end surface) of an external terminal extending along the upper surface may be the same as the length of a corresponding external terminal extending along the lower surface. For example, the length of an external terminal may be from about 0.3 to about 1.1 mm, in some embodiments from about 0.4 to about 1 mm, and in some embodiments, from about 0.5 to about 0.9 mm. The length of an external terminal may also be less than the length of the capacitor, such as 50% or less, such as 40% or less, such as 30% or less, such as 25% or less, such as 20% or less, such as 15% or less the length of the capacitor. If desired, each external terminal may have a different length. For instance, the external terminal adjacent an end surface may have a length greater than the external terminal offset from the end surface. In this regard, the ratio of the length of the external terminal adjacent an end surface to the length of the external terminal offset from the end surface may be from about 0.3 to about 5, in some embodiments from about 0.5 to about 4, and in some embodiments, from about 0.7 to about 3. The width of an external terminal extending from a side surface to an opposing side surface may be same on the upper surface and the lower surface. For instance, the width may range from about 0.3 to about 1.1 mm, in some embodiments from about 0.4 to about 1 mm, and in some embodiments, from about 0.5 to about 0.9 mm.
Referring to
The capacitor 10 also includes dielectric layers (not shown) and internal electrode layers 110, as illustrated in
As illustrated in
The lead tabs 120 and 140 may be arranged in parallel with lead tabs 130 and 150, respectively, extending from the internal electrode layers 105 and 115 such that the lead tabs extending from alternating electrode layers 105 and 115 may be aligned in a respective column. For instance, lead tabs 120 and 130 of internal electrode layer 105 may be arranged in a respective stacked configuration while lead tabs 140 and 150 of internal electrode layer 115 may be arranged in a respective stacked configuration.
It will be appreciated that lead tabs 120 connect to external terminal 12 while lead tabs 140 connect to external terminal 14. Accordingly, respective lead tabs 120 will be interdigitated with respective lead tabs 140 in a manner similar to external terminals 12 and 14. The interdigitated lead tabs can provide multiple, adjacent current injection points onto the associated main electrode portions.
The distance between adjacent exposed lead tabs of the internal electrode layers in a given column may be specifically designed to help ensure guided formation of terminations. The distance between exposed lead tabs of the internal electrode layers in a given column may, for example, range from about 0.25 to about 10 μm, in some embodiments from about 0.5 to about 5 μm, and in some embodiments, from about 1 to about 4 μm. Additionally, the distance between adjacent columnar stacks of electrode tabs may be, while not limited, greater by at least a factor of two than the distance between adjacent lead tabs in a given column to ensure that distinct terminations do not run together. In some embodiments, the distance between adjacent columnar stacks of exposed metallization may be about 4× the distance between adjacent exposed electrode tabs in a particular stack. However, such distance may vary depending on the desired capacitance performance and circuit board configuration. For example, the distance may be from about 0.1 to about 1.5 mm, in some embodiments from about 0.2 to about 1.3 mm, and in some embodiments, from about 0.3 to about 1 mm, as determined based on the center-point of each lead tab or based on the distance between adjacent lateral edges of the lead tabs. In addition, such distance may correspond to the separation distance of the ball on a ball grid array.
In the embodiments illustrated in
In the embodiments illustrated in
The capacitor 20 also includes internal electrode layers 210 containing first internal electrode layers 205 and second internal electrode layers 215 in an alternating arrangement. The internal electrode layers 205, 215 include at least one lead tab 220a-b, 230a-b, 240a-b, 250a-b extending from a top edge and a bottom edge of the main body of the internal electrode layers. The lead tabs 220a-b, 230a-b, 240a-b, 250a-b of the internal electrode layers 205, 215 extend to the upper surface and the lower surface of the capacitor and assist in forming the external terminals. In this regard, the lead tabs 220a-b, 230a-b, 240a-b, 250a-b may be exposed on the upper surface and the lower surface of the capacitor and allow for connection between the main body of the internal electrode layers and the external terminals. For instance, lead tabs 220a-b, 230a-b, 240a-b, 250a-b may contain leading edges 223a-b, 233a-b, 243a-b, 253a-b that extend to an edge of a dielectric layer and allows for formation of the external terminals. The internal electrode layers 205, 215 include at least two lead tabs 220a-b, 230a-b, 240a-b, 250a-b along a top edge and a bottom edge. A first internal electrode layer 205 includes two lead tabs 220a-b, 230a-b along each top edge 205c and bottom edge 205d and extending from main body 235. A second internal electrode layer 215 includes two lead tabs 240a-b, 250a-b along each top edge bottom edge and extending from main body 245.
The lead tabs 220a-b, 230a-b on the top edge 205c and the bottom edge 205d of first internal electrode layer 205 may be aligned in the vertical direction. That is, a lateral edge 221a, 222a of a first lead tab 220 along a top edge 205c may be aligned with a lateral edge 231a, 232a of a first lead tab 230 along a bottom edge 205d opposite the top edge 205c. In addition, such lateral edges 221a, 231a may be aligned with the side edge 205a of the internal electrode layer 205. However, it should be understood that both lateral edges 221a, 222a of the first lead tab 220a along a top edge 205c may be aligned with the lateral edges 231a, 232a of a first lead tab 230a along a bottom edge 205d opposite the top edge 205c. In other words, both lateral edges 222a, 232a may be offset from the side edges 205a-b the same distance along a bottom edge 205d and the top edge 205c. When a top edge 205c and a bottom edge 205d contain at least two lead tabs 220a-b, 230a-b, at least one lateral edge of each lead tab on a top edge 205c may be aligned with a corresponding lateral edge of a lead tab on the bottom edge 205d. Also, both lateral edges of each lead tab on a top edge 205c may be aligned with corresponding lateral edges of the lead tabs on the bottom edge 205d. Similarly, the lead tabs 240a-b, 250a-b on the top edge and the bottom edge of second internal electrode layer 215 may be aligned in the vertical direction. That is, a lateral edge 241a, 242a of a first lead tab 240 along a top edge may be aligned with a lateral edge 251a, 252a of a first lead tab 250 along a bottom edge opposite the top edge.
Both lateral edges 241a, 242a of the first lead tab 240 along a top edge may be aligned with the lateral edges 251a, 252a of a first lead tab 250 along a bottom edge opposite the top edge. The relationship between lateral edges of a first lead tab on a top edge and a first lead tab on a bottom edge as mentioned with respect to internal electrode layer 205 may also apply to internal electrode layer 215. With such an arrangement, a gap may be formed between any of the lead tabs along a top edge 205c of first internal electrode layer 205, of second internal electrode layer 215, or both. For instance, a gap may be formed between any of lead tabs 220a-b, 240a-b that extend from the top edges of the respective internal electrode layers. Additionally, a gap may be formed between any of the lead tabs along a top edge 205d of first internal electrode layer 205, of second internal electrode layer 215, or both. For instance, a gap may be formed between any of lead tabs 230a-b, 250a-b that extend from the top edges of the respective internal electrode layers. Also, the size of a gap between two respective tabs that extend from a top edge, whether from the same internal electrode layer or adjacent internal electrode layers, may be substantially the same as the size of a gap between the corresponding two respective tabs that extend from a bottom edge. For example, the gap between lead tabs 220a and 220b may be substantially the same as the gap between lead tabs 230a and 230b. Similarly, the gap between lead tabs 220a and 240a may be substantially the same as the gap between lead tabs 230 and 250a.
Any or all of lead tabs 220a-b, 240a-b may be arranged in parallel with lead tabs 230a-b, 250a-b, respectively, extending from the layers 205 and 215 such that the lead extending from alternating electrode layers 205 and 215 may be aligned in a respective column. For instance, lead tabs 220a-b and 230a-b of internal electrode layer 205 may be arranged in a respective stacked configuration while lead tabs 240a-b and 250a-b of internal electrode layer 215 may be arranged in a respective stacked configuration. It will be appreciated that lead tabs 220a-b connect to external terminals 22a-b, respectively, while lead tabs 240a-b connect to external terminal 24a-b, respectively. Accordingly, respective lead tabs 220a-b will be interdigitated with respective lead tabs 240a-b, respectively, in a manner similar to external terminals 22a-b and 24a-b. The interdigitated lead tabs can provide multiple, adjacent current injection points onto the associated main electrode portions.
In the embodiments discussed above, the external terminals are arranged in a linear fashion (e.g. 1×2 or 1×4 configuration) in a single dimension. Of course, it should be understood that multi-dimensional arrays of external terminals may also be employed. Referring to
The capacitor 10 includes alternating dielectric layers and internal electrode layers 110 that include first internal electrode layers 105 and second internal electrode layers 115 in an alternating arrangement. Similar to the embodiment discussed above in
Similarly, the lead tabs 140, 150 on the top edge and the bottom edge of second internal electrode layer 115 may be aligned in the vertical direction. That is, a lateral edge 141, 142 of a first lead tab 140 along a top edge may be aligned with a lateral edge 151, 152 of a first lead tab 150 along a bottom edge opposite the top edge. In one embodiment, both lateral edges 141, 142 of the first lead tab 140 along a top edge may be aligned with the lateral edges 151, 152 of a first lead tab 150 along a bottom edge opposite the top edge. The relationship between lateral edges of a first lead tab on a top edge and a first lead tab on a bottom edge as mentioned with respect to internal electrode layer 105 may also apply to internal electrode layer 115. With such arrangement a gap may be formed between lead tab 120 of the first internal electrode layer 105 and lead tab 140 of the second internal electrode layer 115. A gap may be formed between lead tab 130 of the first internal electrode layer 105 and lead tab 150 of the second internal electrode layer 115. The size of each respective gap may be substantially the same.
The lead tabs 120 and 140 may be arranged in parallel with lead tabs 130 and 150, respectively, extending from the internal electrode layers 105 and 115 such that the lead tabs extending from alternating electrode layers 105 and 115 may be aligned in a respective column. For instance, lead tabs 120 and 130 of internal electrode layer 105 may be arranged in a respective stacked configuration while lead tabs 140 and 150 of internal electrode layer 115 may be arranged in a respective stacked configuration. It will be appreciated that lead tabs 120 connect to external terminal 12 while lead tabs 140 connect to external terminal 14. Accordingly, respective lead tabs 120 will be interdigitated with respective lead tabs 140 in a manner similar to external terminals 12 and 14. The interdigitated lead tabs can provide multiple, adjacent current injection points onto the associated main electrode portions.
As shown in
Referring to
The capacitor 20 also includes and two sets 210a and 210b of alternating internal electrode layers 210 as illustrated in
The lead tabs 220a-b, 230a-b on the top edge 205c and the bottom edge 205d of first internal electrode layer 205 may be aligned in the vertical direction. That is, a lateral edge 221a, 222a of a first lead tab 220 along a top edge 205c may be aligned with a lateral edge 231a, 232a of a first lead tab 230 along a bottom edge 205d opposite the top edge 205c. In other words, a lateral edge 221a, 222a of a first lead tab 220 along a top edge 205c may be offset (indicated by “◯”) from a side edge 205a-b the same distance as a lateral edge 231a, 232a of a first lead tab 230 along a bottom edge 205d opposite the top edge 205c. Also, both lateral edges 221a, 222a of the first lead tab 220 along a top edge 205c may be aligned with the lateral edges 231a, 232a of a first lead tab 230 along a bottom edge 205d opposite the top edge 205c. That is, both lateral edges may be offset from a side edge 205a-b the same distance. When a top edge 205c and a bottom edge 205d contain at least two lead tabs 220a-b, 230a-b, at least one lateral edge of each lead tab on a top edge 205c may be aligned with a corresponding lateral edge of a lead tab on the bottom edge 205d. Also, both lateral edges of each lead tab on a top edge 205c may be aligned with corresponding lateral edges of the lead tabs on the bottom edge 205d.
Similarly, the lead tabs 240a-b, 250a-b on the top edge and the bottom edge of second internal electrode layer 215 may be aligned in the vertical direction. That is, a lateral edge 241a, 242a of a first lead tab 240 along a top edge may be aligned with a lateral edge 251a, 252a of a first lead tab 250 along a bottom edge opposite the top edge. Both lateral edges 241a, 242a of the first lead tab 240 along a top edge may be aligned with the lateral edges 251a, 252a of a first lead tab 250 along a bottom edge opposite the top edge. The relationship between lateral edges of a first lead tab on a top edge and a first lead tab on a bottom edge as mentioned with respect to internal electrode layer 205 may also apply to internal electrode layer 215. With such arrangement, a gap may be formed between any of the lead tabs along a top edge 205c of first internal electrode layer 205, of second internal electrode layer 215, or both. For instance, a gap may be formed between any of lead tabs 220a-b, 240a-b that extend from the top edges of the respective internal electrode layers. Additionally, a gap may be formed between any of the lead tabs along a top edge 205d of first internal electrode layer 205, of second internal electrode layer 215, or both. For instance, a gap may be formed between any of lead tabs 230a-b, 250a-b that extend from the top edges of the respective internal electrode layers. Also, the size of a gap between two respective tabs that extend from a top edge, whether from the same internal electrode layer or adjacent internal electrode layers, may be substantially the same as the size of a gap between the corresponding two respective tabs that extend from a bottom edge. For example, the gap between lead tabs 220a and 220b may be substantially the same as the gap between lead tabs 230a and 230b. Similarly, the gap between lead tabs 220a and 240a may be substantially the same as the gap between lead tabs 230 and 250a.
Any or all of lead tabs 220a-b, 240a-b may be arranged in parallel with lead tabs 230a-b, 250a-b, respectively, extending from the layers 205 and 215 such that the lead extending from alternating electrode layers 205 and 215 may be aligned in a respective column. For instance, lead tabs 220a-b and 230a-b of internal electrode layer 205 may be arranged in a respective stacked configuration while lead tabs 240a-b and 250a-b of internal electrode layer 215 may be arranged in a respective stacked configuration. It will be appreciated that lead tabs 220a-b connect to external terminals 22a-b, respectively, while lead tabs 240a-b connect to external terminal 24a-b, respectively. Accordingly, respective lead tabs 220a-b will be interdigitated with respective lead tabs 240a-b, respectively, in a manner similar to external terminals 22a-b and 24a-b. The interdigitated lead tabs can provide multiple, adjacent current injection points onto the associated main electrode portions.
As shown in
Referring to
In the embodiments referenced above, the internal electrode layers are generally oriented in a vertical configuration. Of course, this is by no means required and it is equally suitable to use other geometric configurations, such as a horizontal configuration. Referring to
If desired, the capacitor 20 may also include a first shield region 255 and a second shield region 265, and each of the shield regions may include one or more shield electrode layers 275. As shown, the shield regions are provided above and below the active electrode region and active electrode layers 205, 215.
The first conductive via 225 extends through and electrically contacts the first plurality of internal electrode layers 205. However, the first conductive via 225 extends through a non-contact hole 105 wherein a gap 105 is formed between the first conductive via 225 and the electrodes of the second plurality of internal electrode layers 215. Such a gap 105 allows for insulation of the second plurality of internal electrode layers 215 from first conductive via 225. Similarly, the second conductive via 285 extends through and electrically contacts the second plurality of internal electrode layers 215. However, the second conductive via 285 extends through a non-contact hole 115 wherein a gap 115 is formed between the second conductive via 285 and the electrodes of the first plurality of internal electrode layers 205. Such a gap 115 allows for insulation of the first plurality of internal electrode layers 205 from second conductive via 285. When anchor (or dummy) electrodes are present as illustrated
The dielectric layers of the decoupling capacitor described herein are typically formed from a ceramic material. The ceramic material may have a relatively high dielectric constant. For instance, the dielectric constant may be 3 or more, in some embodiments from about 10 to about 20,000, in some embodiments from about 50 to about 10,000, in some embodiments from about 60 to about 9,000, and in some embodiments, from about 80 to about 8,000. Particularly suitable examples of ceramic materials having a high dielectric constant are those designated as NPO (COG) (up to about 100), X7R (from about 3,000 to about 7,000), X7S, Z5U, and/or Y5V based on standard classifications established by the Electronic Industries Alliance (EIA). Such materials may include a pervoskite, such as barium titanate ceramic materials (e.g., barium titanate, barium-strontium titanate, barium calcium titanate, barium zirconate titanate, barium strontium zirconate titanate, barium calcium zirconate titanate, etc.), lead titanate ceramic materials (e.g., lead zirconate titanate, lead lanthanum zirconate titanate), sodium bismuth titanate, and so forth. In one particular embodiment, for instance, barium strontium titanate (“BSTO”) of the formula BaxSr1-xTiO3 may be employed, wherein x is from 0 to 1, in some embodiments from about 0.15 to about 0.65, and in some embodiments, from about from 0.25 to about 0.6. Other suitable barium titanate ceramic materials may include, for instance, BaxCa1-xTiO3 where x is from about 0.2 to about 0.8, and in some embodiments, from about 0.4 to about 0.6; barium calcium zirconium titanate (BaCaZrTiO3); A[B11/3B22/3]O3 materials where A is BaxSr1-x (x can be a value from 0 to 1), B1 is MgyZn1-y (y can be a value from 0 to 1), and B2 is TazNb1-z (z can be a value from 0 to 1); and so forth. Other suitable ceramic materials may include, for instance, PbxZr1-xTiO3 (“PZT”) where x ranges from about 0.05 to about 0.4; lead lanthanum zirconium titanate (“PLZT”); lead titanate (PbTiO3); and so forth.
The internal electrode layers may be formed from any of a variety of different metals as is known in the art. The internal electrode layers may be made from a metal, such as a conductive metal. The materials may include precious metals (e.g., silver, gold, palladium, platinum, etc.), base metals (e.g., copper, tin, nickel, chrome, titanium, tungsten, etc.), and so forth, as well as various combinations thereof. Sputtered titanium/tungsten (Ti/W) alloys, as well as respective sputtered layers of chrome, nickel and gold, may also be suitable. In one particular embodiment, the internal electrode layers may include nickel or an alloy thereof. Likewise, the external terminals may be formed from any of a variety of different metals as is known in the art. The external terminals may be made from a metal, such as a conductive metal. The materials may include precious metals (e.g., silver, gold, palladium, platinum, etc.), base metals (e.g., copper, tin, nickel, chrome, titanium, tungsten, etc.), and so forth, as well as various combinations thereof. In one particular embodiment, the external terminals may comprise copper or an alloy thereof. The external terminals may have an average thickness of about 100 μm or less, in some embodiments from about 1 μm to about 70 μm, and in some embodiments, from about 5 to about 50 μm.
The external terminals can be formed using any method generally known in the art. The external terminals may be formed using techniques such as sputtering, painting, printing, electroless plating or fine copper termination (FCT), electroplating, plasma deposition, propellant spray/air brushing, and so forth. The external terminals may be formed such that the external terminal is a thin-film plating of a metal. Such thin-film plating can be formed by depositing a conductive material, such as a conductive metal, on an exposed portion of an internal electrode layer. For instance, a leading edge of an internal electrode layer may be exposed such that it may allow for the formation of a plated terminal. A plated terminal may be formed by techniques known in the art, such as electroless plating, electrolytic plating, or combinations thereof. When multiple layers are used to form an external terminal, the external terminal may include an electroplated layer and an electroless plated layer. For instance, electroless plating may first be employed to deposit an initial layer of material. The plating technique may then be switched to an electrochemical plating system which may allow for a faster buildup of material. When forming the plated terminals with either plating method, a leading edge of the lead tabs of the internal electrode layers that is exposed from the main body of the capacitor is subjected to a plating solution. By subjecting, in one embodiment, the capacitor may be dipped into the plating solution.
The plating solution used in a plating process may include a conductive material, such as a conductive metal. For instance, the plating solution may be a nickel sulfamate bath solution or other nickel solution such that the plated layer and external terminal comprise nickel. Alternatively, the plating solution may be a copper acid bath or other suitable copper solution such that the plated layer and external terminal comprise copper. Additionally, it should be understood that the plating solution may contain other additives as generally known in the art. For instance, the additives may include other organic additives and media that can assist in the plating process. Additionally, additives may be employed in order to employ the plating solution at a desired pH level. In one embodiment, resistance-reducing additives may be employed in the solutions to assist with complete plating coverage and bonding of the plating materials to the capacitor and exposed leading edges of the lead tabs of the internal electrode layers. The capacitor may be exposed, submersed, or dipped in the plating solution for a predetermined amount of time. The exposure time is not necessarily limited but may be for a sufficient amount of time to allow for enough plating material to deposit in order to form the plated terminal. In this regard, the time should be sufficient for allowing the formation of a continuous connection among the desired exposed, adjacent leading edges of lead tabs of a given polarity of the respective internal electrode layers within a set of alternating dielectric layers and internal electrode layers.
The different between electrolytic plating and electroless plating is that electrolytic plating employs an electrical bias, such as by using an external power supply. The electrolytic plating solution may be subjected typically to a high current density range, for example, ten to fifteen amp/ft2 (rated at 9.4 volts). A connection may be formed with a negative connection to the capacitor requiring formation of the plated terminals and a positive connection to a solid material (e.g., Cu in Cu plating solution) in the same plating solution. That is, the capacitor is biased to a polarity opposite that of the plating solution. Using such method, the conductive material of the plating solution is attracted to the metal of the exposed leading edge of the lead tabs of the internal electrode layers.
Prior to submersing or subjecting the capacitor to a plating solution, various pretreatment steps may be employed. Such steps may be conducted for a variety of purposes, including to catalyze, to accelerate, and/or to improve the adhesion of the plating materials to the leading edges of the lead tabs. Additionally, prior to plating or any other pretreatment steps, an initial cleaning step may be employed. This step may be employed to remove any oxide buildup that forms on the exposed lead tabs of the internal electrode layers. The cleaning step may be particularly helpful to assist in removing any buildup of nickel oxide when the internal electrodes or other conductive elements are formed of nickel. Component cleaning may be effected by full immersion in a preclean bath, such as one including an acid cleaner. In one embodiment, exposure may be for a predetermined time, such as on the order of about 10 minutes. Cleaning may also alternatively be effected by chemical polishing or harperizing steps.
In addition, a step to activate the exposed metallic leading edges of the lead tabs of the internal electrode layers may be performed to facilitate depositing of the conductive materials. Activation can be achieved by immersion in palladium salts, photo patterned palladium organometallic precursors (via mask or laser), screen printed or ink-jet deposited palladium compounds or electrophoretic palladium deposition. It should be appreciated that palladium-based activation is presently disclosed merely as an example of activation solutions that often work well with activation for exposed tab portions formed of nickel or an alloy thereof. However, it should be understood that other activation solutions may also be utilized and thus are not necessarily limited. Also, in lieu of or in addition to the aforementioned activation step, the activation dopant may be introduced into the conductive material when forming the internal electrode layers of the capacitor. For instance, when the internal electrode layer comprises nickel and the activation dopant comprises palladium, the palladium dopant may be introduced into the nickel ink or composition that forms the internal electrode layers. Doing so may eliminate the palladium activation step. It should be further appreciated that some of the above activation methods, such as organometallic precursors, also lend themselves to co-deposition of glass formers for increased adhesion to the generally ceramic body of the capacitor. When activation steps are taken as described above, traces of the activator material may often remain at the exposed conductive portions before and after termination plating. Additionally, post-treatment steps after plating may also be employed as desired or necessary. Such steps may be conducted for a variety of purposes, including enhancing and/or improving adhesion of the materials. For instance, a heating (or annealing) step may be employed after performing the plating step. Such heating may be conducted via baking, laser subjection, UV exposure, microwave exposure, arc welding, etc.
Thus, as described above, the external terminals employed in the capacitor may contain at least one plated layer. In one embodiment, the external terminals may contain only one plating layer. However, it should be understood that the external terminals may comprise a plurality of plating layers. For instance, the external terminals may comprise a first plating layer and a second plating layer. In addition, the external terminals may also comprise a third plating layer. Furthermore, the materials of these plating layers may be any of the aforementioned and as generally known in the art. For instance, one plating layer, such as a first plating layer, may contain copper or an alloy thereof. Another plating layer, such as a second plating layer, may contain nickel or an alloy thereof. Alternatively, another plating layer, such as the second plating layer, may contain cooper or an alloy thereof. Another plating layer, such as a third plating layer, may comprise tin, lead, gold, or a combination, such as an alloy. Alternatively, an initial plating layer may include nickel, following by plating layers of tin or gold. In another embodiment, an initial plating layer of copper may be formed and then a nickel layer.
In one embodiment, the initial or first plating layer may be a conductive metal (e.g., copper). This area may then be covered with a second layer containing a resistor-polymeric material for sealing. The area may then be polished to selectively remove resistive polymeric material and then plated again with a third layer containing a conductive, metallic material (e.g., copper). The aforementioned second layer above the initial plating layer may correspond to a solder barrier layer, for example a nickel-solder barrier layer. In some embodiments, the aforementioned layer may be formed by electroplating an additional layer of metal (e.g., nickel or copper) on top of an initial electrolessly or electrolytically plated layer (e.g., plated copper). Other exemplary materials for layer the aforementioned solder barrier layer include nickel-phosphorus, gold, and silver. A third layer on the aforementioned solder-barrier layer may in some embodiments correspond to a conductive layer, such as plated Ni, Ni/Cr, Ag, Pd, Sn, Pb/Sn or other suitable plated solder. In addition, a layer of metallic plating may be formed followed by an electroplating step to provide a resistive alloy or a higher resistance metal alloy coating, for example, electroless Ni—P alloy over such metallic plating. It should be understood, however, that it is possible to include any metal coating as those of ordinary skill in the art will understand from the complete disclosure herewith. It should be appreciated that any of the aforementioned steps can occur as a bulk process, such as barrel plating, fluidized bed plating and/or flow-through plating termination processes, all of which are generally known in the art. Such bulk processes enable multiple components to be processed at once, providing an efficient and expeditious termination process. This is a particular advantage relative to conventional termination methods, such as the printing of thick-film terminations that require individual component processing.
The semiconductor structure, interposer, package substrate, and decoupling capacitor may generally be arranged on a circuit board in a variety of different configurations. Referring to
Notably, a decoupling capacitor 10 (see e.g.,
In the embodiment shown in
Another embodiment of a microelectronic assembly 800 that contains an active interposer 802 is also shown in
If desired, an additional semiconductor structure 812 (e.g., auxiliary chip) may be directly electrically connected to the substrate 832. The structure 812 may include an active layer 816 and a bulk semiconductor layer 814 (sometimes referred to as inactive layer 814). The active layer 816 may include level two (L2) memory elements 809 formed at the active side, which may be used as memory caches for storing configuration bit streams. For example, configuration bit streams stored in L1 memory elements 808 on interposer 802 may be transferred to L2 memory elements 809 to make room on L1 memory elements 808 for new incoming configuration bit streams (e.g., received at L1 memory elements 808 from a host processor). The active layer 816 may face the package substrate 832 and may be electrically connected thereto through coupling components 822 and 824 (e.g., solder balls or bumps). A bridge 826 may also be used to connect the semiconductor structure 812 to the interposer 802. The bridge 826 may contain interconnects 828 formed in a silicon substrate that is embedded in the package substrate 832. The interconnects 828 may electrically connect the portion of coupling components 824 connected to the semiconductor structure 812 to the portion of coupling components 824 connected to interposer 802. A heat sink 830 may also be placed into contact with the semiconductor structures 310 and 812 as is known in the art. Although not explicitly shown herein, the package substrate 104 is in turn connected to a circuit board and decoupling capacitor in a manner such as described above.
These and other modifications and variations of the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.
The present application is based upon and claims priority to U.S. Provisional Patent Application Ser. No. 63/420,736, having a filing date of Oct. 31, 2022, which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63420736 | Oct 2022 | US |
