Vertical nanostructure energy storage device with divided top electrode layer, and manufacturing method

Abstract

An energy storage device (11) comprising a first bottom electrode layer part (35), and a second bottom electrode layer part (37)conductively separated from the first bottom electrode layer part (35); a first plurality of conductive vertical nanostructures (39) on the first bottom electrode layer part (35); a second plurality of conductive vertical nanostructures (39) on the second bottom electrode layer part (37); a conduction controlling layer (41) conformally covering each nanostructure (39); a first top electrode layer part (45) conductively separated from the first bottom electrode (33) and arranged directly on a portion of the second bottom electrode layer part; and a second top electrode layer part (47) conductively separated from the second bottom electrode layer part (37) and arranged directly on a portion of the first bottom electrode layer part (35).

Description

[0001] VERTICAL NANOSTRUCTURE ENERGY STORAGE DEVICE WITH

[0002] DIVIDED TOP ELECTRODE LAYER, AND MANUFACTURING METHOD

[0003] Field of the Invention

[0004] The present invention relates to an energy storage device comprising a substrate and a plurality of nanostructures extending from the substrate, and to a method of manufacturing such an energy storage device.

[0005] Background of the Invention

[0006] To accommodate for increasing clock frequencies and decreased dimensions in electronic devices, there is a need for compact and high- capacity energy storage devices. Discrete MIM (metal-insulator-metal) capacitor components have been developed, that exhibit smaller size and higher capacitance.

[0007] US 2022 / 0013305 A1 discloses a discrete MIM energy storage component comprising a MIM-arrangement including first electrode layer; a plurality of conductive nanostructures grown from the first electrode layer; a conduction controlling material covering each nanostructure in the plurality of conductive nanostructures and the first electrode layer uncovered by the conductive nanostructures; and a second electrode layer covering the conduction controlling material; a first contact pad for external electrical connection of the capacitor component; a second contact pad for external electrical connection of the capacitor component; and an electrically insulating encapsulation material at least partly embedding the MIM-arrangement. The different configurations of the discrete MIM energy storage component in US 2022 / 0013305 A1 can be made very compact, and with a high energy storage capacity.

[0008] It would be desirable to provide an energy storage device having similar properties, enabling an advantageous electrical connection between the first electrode layer of the energy storage device and a first contact pad for external connection, and between the second electrode layer of the energy storage device and a second contact pad for external connection. Summary

[0009] According to a first aspect of the present invention, it is therefore provided an energy storage device comprising: a bottom electrode layer comprising a first bottom electrode layer part, and a second bottom electrode layer part conductively separated from the first bottom electrode layer part; a first plurality of conductive vertical nanostructures extending from and being conductively connected to the first bottom electrode layer part; a second plurality of conductive vertical nanostructures extending from and being conductively connected to the second bottom electrode layer part; a conduction controlling layer conformally covering each nanostructure in the first plurality of conductive vertical nanostructures and each nanostructure in the second plurality of conductive vertical nanostructures; and a top electrode layer comprising: a first top electrode layer part conductively separated from the first bottom electrode layer part by the conduction controlling layer; and a second top electrode layer part conductively separated from the second bottom electrode layer part by the conduction controlling layer, and conductively separated from the first top electrode layer part, the first top electrode layer part being arranged directly on a portion of the second bottom electrode layer part, thereby being conductively connected to the second bottom electrode layer part; and the second top electrode layer part being arranged directly on a portion of the first bottom electrode layer part, thereby being conductively connected to the first bottom electrode layer part.

[0010] In the context of the present application, the term “conformally covering” should be understood to mean covering in such a way that a thickness of the conformally covering layer is substantially the same regardless of an orientation of a surface covered by the layer. Various deposition method for achieving conformal coverage are well-known to those skilled in the art. Notable examples of deposition methods that may be suitable are various vapor deposition methods, such as CVD, ALD, and PVD.

[0011] The present invention is based on the realization that it would be desirable to enable conductive connection to the bottom electrode layer without the need for long connecting plugs. The present inventors have further realized that this can be achieved by providing the bottom electrode layer as conductively separated bottom electrode layer parts, providing the top electrode layer as conductively separated top electrode layer parts, and alternatingly conductively connecting top electrode layer parts to bottom electrode layer parts. Hereby, bottom electrode layer parts can be conductively connected to an external contact pad via top electrode layer parts. This obviates the need for long connecting plugs between the bottom electrode layer and the external contact pad, which, in turn, provides for facilitated manufacturing, and improved utilization of the substrate area. From this follows that energy storage devices can be manufactured with higher yield and / or higher energy storage capacity for a given energy storage device footprint. Additionally, the configuration according to aspects of the present disclosure allows for the use of longer vertically extending nanostructures, which may also contribute to higher energy storage capacity for a given energy storage device footprint.

[0012] In an example configuration, the conduction controlling layer may have a first opening over the portion of the first bottom electrode layer part, and a second opening over the portion of the second bottom electrode layer part; the first top electrode layer part may be arranged directly on the portion of the second bottom electrode layer part inside the second opening of the conduction controlling layer; and the second top electrode layer part may be arranged directly on the portion of the first bottom electrode layer part inside the first opening of the conduction controlling layer.

[0013] Advantageously, the top electrode layer may comprise a first top electrode sub-layer conformally covering the conduction controlling layer; and a second top electrode sub-layer conformally covering the first top electrode sub-layer. This configuration may facilitate formation of the first top electrode layer part and the second top electrode layer part.

[0014] The first top electrode sub-layer may advantageously have a first opening over the portion of the first bottom electrode layer part, and a second opening over the portion of the second bottom electrode layer part; the second top electrode sub-layer of the first top electrode part may be arranged directly on the portion of the second bottom electrode layer part inside the second opening of first top electrode sub-layer; and the second top electrode sub-layer of the second top electrode part may be arranged directly on the portion of the first bottom electrode layer part inside the first opening of the first top electrode sub-layer.

[0015] In example configurations of the energy storage device, the nanostructures of the first plurality of conductive vertical nanostructures may be grown from the first bottom electrode layer part; and the nanostructures of the second plurality of conductive vertical nanostructures may be grown from the second bottom electrode layer part.

[0016] Advantageously, the nanostructures of the first plurality of conductive vertical nanostructures and the nanostructures of the second plurality of conductive vertical nanostructures may be carbon nanofibers.

[0017] In example configurations, the conduction controlling layer may be made of solid dielectric material, and the energy storage device may be a capacitor.

[0018] In other example configurations, the conduction controlling layer may be an electrolyte. The electrolyte may be liquid or solid.

[0019] The energy storage device may comprise a non-conductive substrate, the bottom electrode layer being supported by the non-conductive substrate.

[0020] According to example configurations, the energy storage device may further comprise at least one first contact pad for external electrical connection of the energy storage device, the at least one first contact pad being conductively connected to the first top electrode layer part; and at least one second contact pad for external electrical connection of the energy storage device, the at least one second contact pad being conductively connected to the second top electrode layer part.

[0021] Advantageously, the at least one first contact pad may be conductively connected to the first top electrode layer part directly above the first plurality of conductive vertical nanostructures; and the at least one second contact pad may be conductively connected to the second top electrode layer part directly above the second plurality of conductive vertical nanostructures. This example configuration may provide for shorter conductive paths in the energy storage device, which may provide for lower ESR (electrical series resistance) and / or ESL (electrical series inductance), which, in turn, provides for improved high frequency properties of the energy storage device. This may, for example, be an important factor when the energy storage device is a capacitor used for decoupling purposes.

[0022] In an example configuration of the energy storage device, the energy storage device may comprise an electrically insulating encapsulation material at least partly forming an outer boundary surface of the energy storage device; and each of the first contact pad and the second contact pad may at least partly form the outer boundary surface of the energy storage device. This configuration provides for a discrete energy storage device component that is robust and suitable for rational electronics production using massproduction equipment of the so-called “pick-and-place” type.

[0023] The energy storage device according to various example configurations of the present invention may advantageously be included in an electronic system, further comprising a substrate with a substrate conductor pattern, the substrate having substrate pads included in the substrate conductor pattern; a semiconductor component with active circuitry, and component pads coupled to the active circuitry of the semiconductor component, the component pads being connected to the substrate pads of the substrate; and a power source interface for receiving power from a power source, the power source interface being connected to the substrate conductor pattern. The energy storage device may be conductively connected to a first component pad of the semiconductor component, and to a second component pad of the semiconductor component. In particular, the first top electrode layer part may be conductively connected to the first component pad and the second top electrode layer part may be conductively connected to the second component pad.

[0024] According to a second aspect of the present invention, there is provided a method of manufacturing an energy storage device, comprising: providing a non-conductive substrate with a bottom electrode layer patterned to include a first bottom electrode layer part, and a second bottom electrode layer part conductively separated from the first bottom electrode layer part; providing, on the first bottom electrode layer part, a first plurality of conductive nanostructures in such a way that each nanostructure in the first plurality of conductive nanostructures extends substantially vertically from the first bottom electrode layer part; providing, on the second bottom electrode layer part, a second plurality of conductive nanostructures in such a way that each nanostructure in the second plurality of conductive nanostructures extends substantially vertically from the second bottom electrode layer part; applying a conformal conduction controlling layer on the first plurality of conductive nanostructures and on the second plurality of conductive nanostructures; and providing a top electrode layer, including: providing a first top electrode layer part on a portion of the conduction controlling layer covering the first plurality of conductive nanostructures and directly on a portion of the second bottom electrode layer part, in such a way that the first top electrode layer part is conductively connected to the second bottom electrode layer part and conductively separated from the first bottom electrode layer part; and providing a second top electrode layer part on a portion of the conduction controlling layer covering the second plurality of conductive nanostructures and directly on a portion of the first bottom electrode layer part, in such a way that the second top electrode layer part is conductively connected to the first bottom electrode layer part and conductively separated from the second bottom electrode layer part and from the first top electrode layer part.

[0025] According to an example, providing the top electrode layer may comprise conformally covering the conduction controlling layer with a first top electrode sub-layer to form a stacked layer configuration including the conduction controlling layer and the first top electrode layer; removing the stacked layer configuration over the portion of the first bottom electrode layer part such that the portion of the first bottom electrode layer part becomes exposed, and over the portion of the second bottom electrode layer part such that the portion of the second bottom electrode layer part becomes exposed; conformally covering the stacked layer configuration, the portion of the first bottom electrode layer part, and the portion of the second bottom electrode layer part with a second top electrode sub-layer; and selectively removing the first top electrode sub-layer and the second electrode sub-layer to form the first top electrode layer part and the second electrode layer part.

[0026] In summary, aspects of the present invention thus relates to an energy storage device comprising a first bottom electrode layer part, and a second bottom electrode layer part conductively separated from the first bottom electrode layer part; a first plurality of conductive vertical nanostructures on the first bottom electrode layer part; a second plurality of conductive vertical nanostructures on the second bottom electrode layer part; a conduction controlling layer conformally covering each nanostructure; a first top electrode layer part conductively separated from the first bottom electrode and arranged directly on a portion of the second bottom electrode layer part; and a second top electrode layer part conductively separated from the second bottom electrode layer part and arranged directly on a portion of the first bottom electrode layer part.

[0027] Brief Description of the Drawings

[0028] These and other aspects of the present invention will now be described in more detail, with reference to the appended drawings, wherein:

[0029] Fig 1 schematically illustrates an application for energy storage devices according to examples of the present invention, in the form of a schematic mobile phone;

[0030] Fig 2 schematically illustrates an example of a circuit board according to the prior art, which may represent a typical circuit board in a current electronic device;

[0031] Fig 3 schematically illustrates possible implications of replacing the conventional energy storage components on the circuit board in fig 2 with energy storage devices according to examples of the present invention;

[0032] Fig 4 is a schematic illustration of an energy storage device according to an example configuration; Fig 5 is a schematic cross-section view of the energy storage device in fig 4 of a cross-section taken along a first line;

[0033] Figs 6A-C are enlarged views of different parts the energy storage device in fig 5;

[0034] Figs 7A-B are views corresponding to figs 6B-C of a cross-section taken along another line, that may be parallel to the first line defining the cross-section in fig 5;

[0035] Fig 8 is a flow-chart illustrating an example method;

[0036] Fig 9 is a flow-chart illustrating an example method; and

[0037] Figs 10A-K schematically illustrate different steps of the method in fig 9.

[0038] Detailed Description of Examples

[0039] Fig 1 schematically illustrates an electronic device according to an embodiment of the present invention, here in the form of a mobile phone 1. In the simplified and schematic illustration in fig 1 , it is indicated that the mobile phone, like most electronic devices, comprises an electronic system 3, including a circuit substrate, populated with semiconductor components 5, and passive components, including energy storage devices, here in the form of capacitors 7.

[0040] In fig 2, which is an exemplary illustration of an electronic system 3 using technology that is currently available for rational and cost-efficient mass-production, there is a large number of capacitors 7 mounted on the circuit substrate 9, which may be provided in the form of a printed circuit board (PCB). The capacitors 7 presently used are often so-called multilayer ceramic capacitors (MLCCs), with a minimum package height of about 0.4 mm.

[0041] To provide for even more compact electronic devices, with even higher processing speeds, it would be desirable to reduce the space occupied by the capacitors 7 needed for decoupling and temporary energy storage, and to reduce the distance between a semiconductor component 5 and the capacitors 7 serving that semiconductor component 5. This can be achieved using energy storage devices according to examples of the present invention, such energy storage devices can be made with a considerably smaller package height than conventional MLCCs with the same capacitance and footprint.

[0042] Fig 3 is a schematic illustration of an electronic system 3 comprising a circuit substrate 9, a semiconductor component 5, a power source interface 15, and a plurality of energy storage devices according to examples of the present invention. In fig 3, only two energy storage devices 11 a-b are indicated by reference numerals to avoid cluttering the drawing. The circuit substrate 9 has a circuit substrate conductor pattern 17, and circuit substrate pads 19 included in the circuit substrate conductor pattern 17. The semiconductor component has active circuitry (not visible in fig 3) and component pads 13 coupled to the active circuitry. The component pads 13 are connected to the circuit substrate pads 19 of the circuit substrate 9. The power source interface 15 is configured to receive power from a power source, and is connected to the circuit substrate conductor pattern 17.

[0043] One of the indicated energy storage devices 11 a is arranged between the circuit substrate 9 and the semiconductor component 5. A first contact pad 21 of the energy storage device 11 a is conductively connected to a first component pad 13a of the semiconductor component 5, and a second contact pad 23 of the energy storage device 11 a is conductively connected to a second component pad 13b of the semiconductor component 5.

[0044] The other one of the indicated energy storage devices 11 b is embedded in the circuit substrate 9. A first contact pad 21 of the energy storage device 11 b is conductively connected to a first circuit substrate pad 19a of the circuit substrate conductor pattern 17, and a second contact pad 23 of the energy storage device 11 b is conductively connected to a second circuit substrate pad 19b of the circuit substrate conductor pattern 17.

[0045] As is evident from fig 3, the decreased package height of the energy storage devices 11 allows placement of the energy storage devices 11 under the semiconductor component 5, and / or embedded in the substrate 9. Obviously, this arrangement of the energy storage devices 11 allows for a smaller substrate 9, and thus for a more compact electronic system 3. Shorter distances between active circuitry in the semiconductor component 5 and the energy storage devices 11 are clearly also provided for, which reduces the ESL (electrical series inductance).

[0046] Fig 4 is a schematic illustration of an energy storage device 11 according to an example configuration. The exemplary energy storage device 11 in fig 4 has an outer boundary surface that is at least partly formed by an electrically insulating encapsulation material 25. In the example configuration of fig 4, a substrate 27 of the energy storage device 11 also partly forms the outer boundary surface of the energy storage device 11 .

[0047] The exemplary energy storage device 11 in fig 4 is a discrete capacitor component, that is connectable to, for example, a semiconductor component 5 or a substrate conductor pattern 17 by means of a plurality of first contact pads 21 and a plurality of second contact pads 23 substantially evenly distributed across a top surface of the energy storage device 11 . Through the provision of multiple first contact pads 21 and multiple second contact pads 23, the ESR and / or ESL of the energy storage device 11 can be reduced, providing for improved decoupling properties.

[0048] Fig 5 is a schematic cross-section view of the energy storage device 11 in fig 4, of a section taken along the line A-A’ in fig 4. Referring first to fig 5, the energy storage device 11 comprises the above-mentioned substrate 27, a plurality of first nanostructure MIM (metal-insulator-metal) arrangements 29, a plurality of second nanostructure MIM (metal-insulator- metal) arrangements 31 (only one of these second nanostructure MIM arrangements is visible in fig 5), the above-mentioned first contact pads 21 , and the above-mentioned second contact pads 23 (only one of these second contact pads 23 is visible in fig 5). The substrate 27, may be substantially non-conductive, and may, for example, be made of undoped silicon.

[0049] The energy storage device 11 , comprises a bottom electrode layer 33 comprising at least one first bottom electrode part 35 and at least one second bottom electrode part 37 conductively separated from the at least one first bottom electrode part 35. In the example configuration of fig 5, the bottom electrode layer 33 comprises a plurality of first bottom electrode parts 35 and a plurality of second bottom electrode parts 37 (only one of these second bottom electrode parts 37 is visible in fig 5). Referring to fig 4, there may be one first bottom electrode part under each first contact pad 21 , and one second bottom electrode part under each second contact pad 23.

[0050] With continued reference to fig 5, each first nanostructure MIM arrangement 29 comprises a first plurality of conductive vertical nanostructures 39 extending from and being conductively connected to the corresponding first bottom electrode part 35. As is best seen in fig 6A, which is an enlarged view of a portion of an interior of the first nanostructure MIM arrangement 29, the first nanostructure MIM arrangement 29 further comprises a conduction controlling layer 41 , and a top electrode layer 43.

[0051] Each second nanostructure MIM arrangement 31 comprises a second plurality of conductive vertical nanostructures 39 extending from and being conductively connected to the corresponding second bottom electrode part 37. As was described above for the first nanostructure MIM arrangement 29, the second nanostructure MIM arrangement 31 also comprises a conduction controlling layer 41 , and a top electrode layer 43.

[0052] The conductive vertical nanostructures 39 may advantageously be grown nanostructures, and may be so-called carbon nanofibers (CNF). Other possibilities, however, exist, and may be advantageous depending on application. Although not shown in the figures, it should be understood that the conductive vertical nanostructures 39 in example configurations of the energy storage device 11 may be electrically conductive at least partly by virtue of a conductive, such as metallic, layer conformally covering the grown nanostructures. In example configurations, the grown nanostructures may be intrinsically electrically insulating, and conformally covered by an electrically conductive layer.

[0053] The conduction controlling layer 41 may advantageously be made of a so-called high-k dielectric. The high k-dielectric materials may e.g. be HfOx, TiOx, TaOx or other well-known high k dielectrics. Alternatively, the conduction controlling layer 41 can be polymer based e.g. polypropylene, polystyrene, poly(p-xylylene), parylene etc.. Other well-known dielectric materials, such as SiOx or SiNx, etc may also be used for the conduction controlling layer 41 . The conduction controlling layer 41 may be a multi-layer structure, which may include sub-layers of different material compositions.

[0054] The top electrode layer 43 comprises at least one first top electrode layer part 45 conductively separated from the corresponding first bottom electrode layer part 35 by the conduction controlling layer 41 , and at least one second top electrode layer part 47 conductively separated from the corresponding second bottom electrode layer part 37 by the conduction controlling layer 41 , and conductively separated from each first top electrode layer part 45. The block arrow 49 in fig 6B and the block arrow 51 in fig 6C indicate where the second top electrode layer part 47 is conductively separated from the first top electrode layer parts 45 to the left (Fig 6B) and to the right (Fig 6C) of the second top electrode layer part 47.

[0055] As is schematically shown in fig 6B and fig 6C, the second top electrode layer part 47 is arranged directly on a portion 53 of each of the first bottom electrode layer parts 35 (left and right), and is thereby conductively connected to the first bottom electrode layer part 35.

[0056] Similarly, but in another cross-section than the cross-section A-A’ in fig 5 and figs 6A-C, the first top electrode layer part 45 is arranged directly on a portion of the second bottom electrode layer part 37, and is thereby conductively connected to the second bottom electrode layer part 37. The connection between the first top electrode layer part 45 and the second bottom electrode layer part 37 may, in cross-section, look like the illustrations in fig 7A and fig 7B, which are substantially mirror images of the illustrations in fig 6B and fig 6C, respectively. In figs 7A-B, the above-mentioned portion of the second bottom electrode layer part 37 is labeled 55.

[0057] Referring to figs 6B-C and figs 7A-B, in this example configuration, the conduction controlling layer 41 has a first opening 57 over the portion 53 of the first bottom electrode layer part 35, and a second opening 59 over the portion 55 of the second bottom electrode layer part 37. The first top electrode layer part 45 is arranged directly on the portion 55 of the second bottom electrode layer part 37 inside the second opening 59 of the conduction controlling layer 41 , and the second top electrode layer part 47 is arranged directly on the portion 53 of the first bottom electrode layer part 35 inside the first opening 57 of the conduction controlling layer 41 .

[0058] In the example configuration shown in fig 5, figs 6A-C, and figs 7A-B, the top electrode layer 43 comprises a first top electrode sub-layer 61 conformally covering the conduction controlling layer 41 , and a second top electrode sub-layer 63 conformally covering the first top electrode sublayer 61 . Referring to figs 6B-C and to figs 7A-B, the first top electrode sublayer 61 has a first opening over the portion 53 of the first bottom electrode layer part 35, and a second opening over the portion 55 of the second bottom electrode layer part 37. As is illustrated in figs 7A-B, the second top electrode sub-layer 63 of the first top electrode part 45 is arranged directly on the portion 55 of the second bottom electrode layer part 37 inside the second opening of first top electrode sub-layer. As is illustrated in figs 6B-C, the second top electrode sub-layer 63 of the second top electrode part 47 is arranged directly on the portion 53 of the first bottom electrode layer part 35 inside the first opening of the first top electrode sub-layer.

[0059] The first contact pads 21 are conductively connected to the first top electrode layer parts 45. In the example configuration shown in fig 5, the conductive connection between the first contact pads 21 and the first top electrode layer parts 45 is achieved using first electrode plugs 65. The first contact pads 21 are conductively unconnected to the second top electrode layer parts 47.

[0060] The second contact pads 23 are conductively connected to the second top electrode layer parts 47 (only one of these is shown in fig 5). In the example configuration shown in fig 5, the conductive connection between the second contact pads 23 and the second top electrode layer parts 47 is achieved using second electrode plugs 67. The second contact pads 23 are conductively unconnected to the first top electrode layer parts 45.

[0061] The first contact pads 21 and the second contact pads 23 may be on the same vertical level in relation to the substrate 27. Fig 8 is a flow-chart illustrating an example method of manufacturing an energy storage device 11 . Further references are made to fig 5, figs 6A-C, and figs 7A-B as indicated.

[0062] In a first step 801 , a non-conductive substrate 27 is provided with a bottom electrode layer 33 patterned to include at least one first bottom electrode layer part 35, and at least one second bottom electrode layer part 37 conductively separated from the first bottom electrode layer part 35.

[0063] In a subsequent step 802, a first plurality of conductive nanostructures 39 is provided on each first bottom electrode layer part 35 in such a way that each nanostructure 39 in the first plurality of conductive nanostructures extends substantially vertically from the first bottom electrode layer part 35, and a second plurality of conductive nanostructures 39 is provided on each second bottom electrode layer part 37 in such a way that each nanostructure 39 in the second plurality of conductive nanostructures extends substantially vertically from the second bottom electrode layer part 37.

[0064] A conformal conduction controlling layer 41 is applied 803 on each first plurality of conductive nanostructures 39 and on each second plurality of conductive nanostructures 39.

[0065] A top electrode layer 43 is then provided 804 on the conduction controlling layer 41 , by providing at least one first top electrode layer part 45 and at least one second top electrode layer part 47 on the conduction controlling layer 41 .

[0066] The at least one first top electrode layer part 45 is provided on at least one portion of the conduction controlling layer 41 covering each first plurality of conductive nanostructures 39 and directly on a portion 55 of the second bottom electrode layer part 37, in such a way that each first top electrode layer part 45 is conductively connected to a corresponding second bottom electrode layer part 37 and conductively separated from each first bottom electrode layer part 35.

[0067] The at least one second top electrode layer part 47 is provided on at least one portion of the conduction controlling layer 41 covering each second plurality of conductive nanostructures 39 and directly on a portion 53 of the first bottom electrode layer part 35, in such a way that each second top electrode layer part 47 is conductively connected to a corresponding first bottom electrode layer part 35 and conductively separated from each second bottom electrode layer part 37, and from each first top electrode layer part 45.

[0068] Fig 9 is a flow-chart illustrating an example method of manufacturing an energy storage device 11 , and figs 10A-K schematically illustrate different steps of the method in fig 9. Further references are made to fig 5, figs 6A-C, and figs 7A-B as indicated.

[0069] In a first step 901 , a non-conductive substrate 27 with a patterned bottom electrode layer 33 is provided. According to an example, the substrate 27 may be a silicon substrate. A continuous metal layer may be applied, for instance including a sputtered metal layer stack, which may for example comprise a thin Ti layer and a thin TiW layer, and a W layer applied by CVD on the sputtered metal layer stack. Other metals may be possible to use, such as Ti, Al, Si, Ni, Pt, or Cr, or combinations thereof. Lithography and dry etching, for example, may then be used to form the patterned bottom electrode layer 33 shown in fig 10A, comprising at least one first bottom electrode layer part 35 and at least one second bottom electrode layer part 37. To facilitate subsequent nanostructure growth, an additional conductive layer 69 may optionally be applied continuously on the patterned bottom electrode layer 33, as is schematically shown in fig 10B.

[0070] In the subsequent step 902, a first plurality of conductive nanostructures 39 is provided on each first bottom electrode layer part 35 in such a way that each nanostructure 39 in the first plurality of conductive nanostructures extends substantially vertically from the first bottom electrode layer part 35. A second plurality of conductive nanostructures 39 is provided 803 on each second bottom electrode layer part 37 in such a way that each nanostructure 39 in the second plurality of conductive nanostructures extends substantially vertically from the second bottom electrode layer part 37.

[0071] As a first part of the procedure for providing the nanostructures 39, a patterned catalyst layer 71 may be formed on the patterned bottom electrode layer 33. In this particular example, the patterned catalyst layer 71 is provided on the additional layer 69.

[0072] For example, a continuous layer of a suitable catalyst material may first be deposited using a suitable deposition technique, such as PVD, sputtering, or CVD. Thereafter, the continuous layer may be patterned using, perse, well-known patterning techniques to form the patterned catalyst layer 71 defining desired locations for nanostructure growth, as is schematically shown in fig 10C. Suitable materials for the catalyst layer 71 can, for example, include nickel, iron, platinum, palladium, nickel-silicide, cobalt, molybdenum, Au or alloys thereof, or in combination with other materials (e.g., silicon).

[0073] Nanostructures 39 are then grown on the catalyst layer 71 , as is schematically shown in fig 10D. Vertically grown carbon nanofibers (CNF) may be particularly suitable for energy storage devices 11 . The use of vertically grown nanostructures 39 allows extensive tailoring of the properties of the nanostructures 39. For instance, the growth conditions may be selected to achieve a morphology giving a large surface area of each nanostructure 39, which may in turn increase the charge storing capacitance or capacitance per 2D footprint. As an alternative to CNF, the nanostructures may be metallic carbon nanotubes or carbide-derived carbon nanostructures, nanowires such as copper, aluminum, silver, silicide or other types of nanowires.

[0074] Advantageously, the catalyst material, and growth gases etc. may be selected in, perse, known ways to achieve so-called tip growth of the nanostructures 39, which may result in catalyst layer material at tips of the nanostructures 39. After growth of the nanostructures 39, the additional metal layer 69 is removed where it is not covered, for example using maskless dry etch, resulting in the configuration schematically shown in fig 10E.

[0075] A conduction controlling layer 41 is then provided 903 using a deposition technique resulting in conformal covering of the conductive nanostructures 39, as well as uncovered portions of the bottom electrode layer 33 and uncovered portions of the substrate 27. For instance, ALD deposition may be used to form the conduction controlling layer 41 as an oxide stack. The conduction controlling layer 41 may, for example, be made of a so-called high-k dielectric. The high k-dielectric materials may e.g. be HfOx, TiOx, TaOx or other well-known high k dielectrics. Alternatively, the conduction controlling layer 41 can be polymer based e.g. polypropylene, polystyrene, poly(p-xylylene), parylene etc.. Other well-known dielectric materials, such as SiOx or SiNx, etc may also be used as the conduction controlling layer 41. In fig 10F, the conduction controlling layer 41 is schematically shown to collectively cover the groups of nanostructures 39. It should be noted that this is only for illustrative purposes, and that the conduction controlling layer 41 conformally covers each individual nanostructure 39, as was indicated in fig 6A.

[0076] In the next step 904, the conduction controlling layer 41 is conformally covered with a first top electrode sub-layer 61 to form a stacked layer configuration including the conduction controlling layer 41 and the first top electrode layer 61 . The first top electrode sub-layer 61 may, for example, be deposited using ALD (atomic layer deposition). For example, a thin layer of TiN (or similar) may be deposited. The resulting structure is schematically shown in fig 10G. In fig 10G, the first top electrode sub-layer 61 is schematically shown to collectively cover the groups of nanostructures 39. It should be noted that this is only for illustrative purposes, and that the first top electrode sub-layer 61 conformally covers each individual nanostructure 39, as was indicated in fig 6A.

[0077] The stacked layer configuration formed by the conduction controlling layer 41 and the first top electrode sub-layer 61 is then patterned, in step 905, by removing the stacked layer configuration over a portion 53 of the first bottom electrode layer part 35 such that the portion 53 of the first bottom electrode layer part 35 becomes exposed, and over a portion 55 of the second bottom electrode layer 37 part such that the portion 55 of the second bottom electrode layer part 37 becomes exposed. The cross-section view in fig 10H shows the portion(s) 55 of the second bottom electrode layer part 37 being exposed, but the portion(s) 53 of the first bottom electrode layer part 35 being exposed are not visible in the cross-section view in fig 10H. Reference is also made to figs 6B-C and figs 7A-B. The stacked layer configuration formed by the conduction controlling layer 41 and the first top electrode sub-layer 61 , the exposed portion 53 of the first bottom electrode layer part 35, and the exposed portion 55 of the second bottom electrode layer part 37 are then covered 906 with a second top electrode sub-layer 63. The second top electrode sub-layer 63 may, for example, be a metal layer, such as a W layer deposited using CVD or any other suitable deposition technique. The resulting configuration is schematically shown in fig 101. In fig 101, the second top electrode sublayer 63 is schematically shown to collectively cover the groups of nanostructures 39. It should be noted that this is only for illustrative purposes, and that the second top electrode sub-layer 63 conformally covers each individual nanostructure 39, as was indicated in fig 6A.

[0078] The first top electrode sub-layer 61 and the second electrode sublayer 63 are then selectively removed 907 along a border line 73 between adjacent first top electrode layer parts 45 and second electrode layer parts 47, thereby defining the first top electrode layer parts 45 and the second top electrode layer parts 47, as is schematically indicated in fig 10J.

[0079] Finally, in step 908, the energy storage component 11 is finished by depositing an encapsulation material 25 and forming first 21 and second 23 contact pads. The contact pads may be formed using, perse, well known BEOL processes. A typical example is shown in fig 10K.

[0080] The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0081] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS1 . An energy storage device comprising: a bottom electrode layer comprising a first bottom electrode layer part, and a second bottom electrode layer part conductively separated from the first bottom electrode layer part; a first plurality of conductive vertical nanostructures extending from and being conductively connected to the first bottom electrode layer part; a second plurality of conductive vertical nanostructures extending from and being conductively connected to the second bottom electrode layer part; a conduction controlling layer conformally covering each nanostructure in the first plurality of conductive vertical nanostructures and each nanostructure in the second plurality of conductive vertical nanostructures; and a top electrode layer comprising: a first top electrode layer part conductively separated from the first bottom electrode layer part by the conduction controlling layer; and a second top electrode layer part conductively separated from the second bottom electrode layer part by the conduction controlling layer, and conductively separated from the first top electrode layer part, the first top electrode layer part being arranged directly on a portion of the second bottom electrode layer part, thereby being conductively connected to the second bottom electrode layer part; and the second top electrode layer part being arranged directly on a portion of the first bottom electrode layer part, thereby being conductively connected to the first bottom electrode layer part.

2. The energy storage device according to claim 1 , wherein: the conduction controlling layer has a first opening over the portion of the first bottom electrode layer part, and a second opening over the portion of the second bottom electrode layer part;the first top electrode layer part is arranged directly on the portion of the second bottom electrode layer part inside the second opening of the conduction controlling layer; and the second top electrode layer part is arranged directly on the portion of the first bottom electrode layer part inside the first opening of the conduction controlling layer.

3. The energy storage device according to claim 2, wherein the top electrode layer comprises: a first top electrode sub-layer conformally covering the conduction controlling layer; and a second top electrode sub-layer conformally covering the first top electrode sub-layer.

4. The energy storage device according to claim 3, wherein: the first top electrode sub-layer has a first opening over the portion of the first bottom electrode layer part, and a second opening over the portion of the second bottom electrode layer part; the second top electrode sub-layer of the first top electrode part is arranged directly on the portion of the second bottom electrode layer part inside the second opening of first top electrode sub-layer; and the second top electrode sub-layer of the second top electrode part is arranged directly on the portion of the first bottom electrode layer part inside the first opening of the first top electrode sub-layer.

5. The energy storage device according to any one of the preceding claims, wherein: the nanostructures of the first plurality of conductive vertical nanostructures are grown from the first bottom electrode layer part; and the nanostructures of the second plurality of conductive vertical nanostructures are grown from the second bottom electrode layer part.

6. The energy storage device according to any one of the preceding claims, wherein the nanostructures of the first plurality of conductive vertical nanostructures and the nanostructures of the second plurality of conductive vertical nanostructures are carbon nanofibers.

7. The energy storage device according to any one of the preceding claims, wherein the conduction controlling layer is made of solid dielectric material.

8. The energy storage device according to any one of claims 1 to 6, wherein the conduction controlling layer is an electrolyte.

9. The energy storage device according to any one of the preceding claims, wherein the energy storage device comprises a non-conductive substrate, the bottom electrode layer being supported by the non-conductive substrate.

10. The energy storage device according to any one of the preceding claims, wherein the energy storage device further comprises: a first contact pad for external electrical connection of the energy storage device, the first contact pad being conductively connected to the first top electrode layer part; and a second contact pad for external electrical connection of the energy storage device, the second contact pad being conductively connected to the second top electrode layer part.11 . The energy storage device according to claim 10, wherein: the first contact pad is conductively connected to the first top electrode layer part directly above the first plurality of conductive vertical nanostructures; andthe second contact pad is conductively connected to the second top electrode layer part directly above the second plurality of conductive vertical nanostructures.

12. The energy storage device according to claim 10 or 11 , wherein: the energy storage device comprises an electrically insulating encapsulation material at least partly forming an outer boundary surface of the energy storage device; and each of the first contact pad and the second contact pad at least partly forms the outer boundary surface of the energy storage device.

13. An electronic system comprising: a circuit substrate with a circuit substrate conductor pattern, the circuit substrate having circuit substrate pads included in the circuit substrate conductor pattern; a semiconductor component with active circuitry, and component pads coupled to the active circuitry of the semiconductor component, the component pads being connected to the circuit substrate pads of the circuit substrate; a power source interface for receiving power from a power source, the power source interface being connected to the circuit substrate conductor pattern; and an energy storage device according to any one of the preceding claims being conductively connected to a first component pad of the semiconductor component, and to a second component pad of the semiconductor component.

14. A method of manufacturing an energy storage device, comprising: providing a non-conductive substrate with a bottom electrode layer patterned to include a first bottom electrode layer part, and a second bottom electrode layer part conductively separated from the first bottom electrode layer part;providing, on the first bottom electrode layer part, a first plurality of conductive nanostructures in such a way that each nanostructure in the first plurality of conductive nanostructures extends substantially vertically from the first bottom electrode layer part; providing, on the second bottom electrode layer part, a second plurality of conductive nanostructures in such a way that each nanostructure in the second plurality of conductive nanostructures extends substantially vertically from the second bottom electrode layer part; applying a conformal conduction controlling layer on the first plurality of conductive nanostructures and on the second plurality of conductive nanostructures; and providing a top electrode layer, including: providing a first top electrode layer part on a portion of the conduction controlling layer covering the first plurality of conductive nanostructures and directly on a portion of the second bottom electrode layer part, in such a way that the first top electrode layer part is conductively connected to the second bottom electrode layer part and conductively separated from the first bottom electrode layer part; and providing a second top electrode layer part on a portion of the conduction controlling layer covering the second plurality of conductive nanostructures and directly on a portion of the first bottom electrode layer part, in such a way that the second top electrode layer part is conductively connected to the first bottom electrode layer part and conductively separated from the second bottom electrode layer part and from the first top electrode layer part.

15. The method according to claim 14, wherein providing the top electrode layer comprises: conformally covering the conduction controlling layer with a first top electrode sub-layer to form a stacked layer configuration including the conduction controlling layer and the first top electrode layer;removing the stacked layer configuration over the portion of the first bottom electrode layer part such that the portion of the first bottom electrode layer part becomes exposed, and over the portion of the second bottom electrode layer part such that the portion of the second bottom electrode layer part becomes exposed; covering the stacked layer configuration, the portion of the first bottom electrode layer part, and the portion of the second bottom electrode layer part with a second top electrode sub-layer; and selectively removing the first top electrode sub-layer and the second electrode sub-layer to form the first top electrode layer part and the second electrode layer part.

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