Semiconductor device comprising a capacitive stack and a pillar, and method for manufacturing same

Abstract

The invention relates to a semiconductor device comprising: • a substrate comprising at least one cavity, and • a three-dimensional structure formed in the substrate comprising: - a three-dimensional capacitor comprising a capacitive stack, the capacitive stack being at least partially housed in the at least one cavity in the substrate; - a pillar extending across the thickness of the substrate from the upper face of the substrate, characterised in that the at least one cavity extends across the thickness of the substrate from the upper face of the substrate, and the capacitor is configured to define, on the upper face of the substrate, a contour of an inscribed portion, the pillar being arranged inside the inscribed portion of the substrate. The invention is applicable more particularly in the field of capacitive storage components, in particular integrated solid-state supercapacitors.

Description

[0001] “Semiconductor device comprising a capacitive stack and a pillar and method of manufacturing the same”

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to the field of integration of microelectronic components, more particularly, for electronic products, related semiconductor products, and their manufacturing methods. The invention will find its application more particularly in the field of capacitive storage components, in particular integrated solid supercapacitors.

[0004] STATE OF THE ART

[0005] Capacitors are important components of integrated circuits (ICs) and semiconductor devices, for example, for use as information storage cells in memory devices, or energy storage. They are present in many electronic functions, such as analog signal processing and energy converters. Whether integrated on the silicon chip or externally by discrete components, they contribute significantly to the system size. Since the capacitance density available on silicon technologies is limited to a few nF / mm2, electronic circuits often use components external to the chip to implement the capacitance needs on the chip.

[0006] Silicon on-chip capacitors can have different architectures. For example, MIM (Metal / Insulator / Metal) capacitors, widely used in integrated circuits, comprise two metal plates with an insulator between the plates. Currently, MIM capacitors are normally manufactured in the back-end-of-line (BEOL) level. The space for integrating capacitors in particular is often limited and overlapped on the circuit surface to limit the additional footprint of these capacitors. Since the capacitance of a capacitor is linearly proportional to the capacitor area, the lack of layout space at the BEOL limits the number of conventional MIM capacitors placed there, resulting in insufficient power density when capacitors are used as energy storage devices.

[0007] In the search for high-performance on-chip integrated energy storage solutions, increasing the specific surface area of ​​the capacitive structure using a three-dimensional (3D) architecture has proven to be an excellent approach that significantly increases the capacitance density while allowing the reduction of the chip area. The technological interest of 3D capacitors lies in the fact that the capacitors are stackable and have a developed surface in the (x;y) plane of the substrate, but also on the height / thickness z, allowing significant space savings and a larger developed surface area of ​​the capacitor than a planar capacitor.

[0008] In pursuit of Moore's Law, today's processors are becoming faster and more power-hungry. For example, with the advent of 5G technology and three-dimensional integration for artificial intelligence and machine learning processors, power density remains a major challenge for capacitors used as energy storage. Similar capacitance challenges exist when capacitors are used as information storage devices.

[0009] For example, we know the document US 20210305358 A1 which proposes a new optimization approach to meet the specifications of new development applications. This document discloses leveraging the interconnection level to add capacitive functionality. Interconnections are often perpendicular to the useful silicon surface and actually represent a significant amount of space. This document proposes using the interconnection surface as one of the capacitor electrodes. Like a coaxial cable, the second capacitor electrode is wrapped around the interconnections. The benefit is therefore to densify the capacitance value per unit area of ​​useful silicon (in the horizontal plane) while benefiting from the cost reduction, because certain capacitor manufacturing steps can be shared with the interconnection manufacturing.However, this solution has limitations, in particular the electrical coupling between the interconnection and the first electrode of the capacitor, which certainly improves its local use, in storage filtering linked to the signal passing through the interconnections, but reduces the possibilities of independent use of the capacitor and the interconnection.

[0010] There is therefore a need to propose a solid ion capacity integration solution that can meet new needs in high capacity density and which at least partially overcomes the limitations of the state of the art.

[0011] SUMMARY OF THE INVENTION

[0012] To achieve this objective, according to one embodiment, a semiconductor device is provided comprising a substrate comprising at least one cavity, and a three-dimensional structure formed in the substrate comprising:

[0013] • a three-dimensional capacitor comprising a capacitive stack, the capacitive stack being at least partially housed in the at least one cavity of the substrate,

[0014] • a pillar extending along the thickness of the substrate from the upper face of said substrate,

[0015] Characterized in that the at least one cavity extends along the thickness of the substrate from the upper face of said substrate, and the three-dimensional capacitor is configured to delimit, on the upper face of the substrate, an outline of an inscribed portion, the pillar being arranged in the inscribed portion of the substrate.

[0016] According to the invention, the capacitive stack comprises a first electrode layer, an intermediate layer and a second electrode layer, and the three-dimensional structure comprises a first conformal layer comprising a first portion forming the first electrode layer of the capacitive stack and a second conformal portion arranged in the pillar, the first portion and the second portion being electrically disconnected from each other. Advantageously, the intermediate layer is an ionically conductive dielectric material.

[0017] This device makes it possible to obtain a capacitor which has a much higher power density and charge density than with a non-ionic conductive dielectric known in the state of the art.

[0018] The advantage of the device according to the invention is to densify the capacitance value per surface unit of useful Silicon (in the horizontal plane) while benefiting from the cost reduction, because certain manufacturing steps of the three-dimensional capacitor can be shared with the manufacturing of the pillar while retaining the independent functionalities of the capacitor and the pillar.

[0019] The invention makes it possible to benefit from the surfaces around the pillars which can play various roles such as electrical, thermal or mechanical and at the same time overcome the limitations of the solutions proposed in the prior art.

[0020] The absence of electrical coupling between the three-dimensional capacitor and the pillar while having shared manufacturing steps makes it possible to reduce manufacturing costs.

[0021] The capacitor is said to be three-dimensional in that it has a three-dimensional structure allowing the developed surface area to be increased without increasing the horizontal silicon surface area and consequently increasing the associated storage capacity.

[0022] According to another aspect, the invention relates to a method for manufacturing a device as described above comprising a step a) comprising the production of a three-dimensional structure comprising at least one cavity of a three-dimensional capacitor and at least one pillar in a substrate, the capacitor is configured to delimit on the upper face of the substrate an outline of an inscribed portion, the pillar (400) being arranged in the inscribed portion of the substrate, a step b) comprising the conformal deposition of a first layer on the three-dimensional structure, i.e. in the cavity and in the pillar as well as on the upper face of the substrate, so that a first part of the first layer forms a first layer of a capacitive stack of the capacitor and a second part of the first layer is formed in the pillar, a step c) of filling the pillar,a step d) of partial removal of the first layer so as to electrically disconnect the first part of the first layer and the second part of the first layer, step d) being able to be carried out before or after step c). BRIEF DESCRIPTION OF THE FIGURES,

[0023] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0024] Figure 1 represents a top view of a semiconductor device according to a first embodiment of the invention.

[0025] Figure 2 represents a view along section AA of Figure 1.

[0026] Figure 3 represents a view along section BB of Figure 2.

[0027] Figure 4 represents a top view of a semiconductor device according to a second embodiment of the invention.

[0028] Figure 5 represents a view along section CC of Figure 4

[0029] Figure 6 represents a view along section DD of Figure 4.

[0030] Figure 7 represents a view along section EE of Figure 5.

[0031] Figure 8 shows a cross-sectional view of the semiconductor device in a complete stack.

[0032] Figures 9 to 15 represent the steps of a method of manufacturing a semiconductor device according to the invention.

[0033] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. In particular, the layers and the size ratios of the pillar and the cavities are not representative of reality.

[0034] DETAILED DESCRIPTION OF THE INVENTION

[0035] Before commencing a detailed review of embodiments of the invention, optional features which may optionally be used in combination or alternatively are set out below:

[0036] - For example, the ionically conductive dielectric material has an ionic conductivity at room temperature of at least 1 pS.cm-1;

[0037] -For example, the ionic conductive dielectric material has an associated activation energy less than or equal to 0.6eV;

[0038] - For example, pillar 400 is arranged in the center of the inscribed portion 202;

[0039] - For example, the transverse distance 104 to the thickness 103 of the substrate 100 between the center of a cavity and the center of the pillar 400 is less than or equal to 100 pm;

[0040] - For example, the transverse distance 104 to the thickness 103 of the substrate 100 between the center of a cavity and the center of the pillar 400 is less than or equal to 5 pm;

[0041] -For example, at least one cavity of the capacitor 300 is a trench 301;

[0042] - For example, trench 301 is circular and arranged in the form of a circle around pillar 400;

[0043] - For example, the capacitor 300 comprises at least two circular and concentric trenches 301;

[0044] -For example, at least one cavity of the capacitor is a column 302;

[0045] -For example, the capacitor 300 comprises a plurality of columns 302,

[0046] - For example, the plurality of columns 302 is arranged in a circular manner around the pillar 400;

[0047] - For example, the width 401 of a pillar is 20 times greater than the width 303 of a cavity of the three-dimensional capacitor 300, the widths 401, 303 being taken transversely to the thickness 103 of the substrate 100;

[0048] -For example, the three-dimensional capacitor 300 comprises from 2 to 20 cavities.

[0049] -For example, the pillar 400 comprises a metallic material so as to fill the pillar 400 at the level of the upper face 101 of the substrate 100;

[0050] -For example, the metallic material is different from the intermediate layer 502 so that the pillar 400 does not comprise a capacitive stack 500;

[0051] -For example, the cavity opens only on the upper face 101 of the substrate 100;

[0052] -For example, the pillar 400 only opens onto the upper face 101 of the substrate 100;

[0053] - For example, the semiconductor device comprises a layer sub-adjacent and a layer super-adjacent to the substrate;

[0054] - For example, the three-dimensional structure is intended to be arranged at the end of the interconnection line (BEOL);

[0055] - For example, the three-dimensional structure is located at interconnections coupled to a processor, or at the back of a processor,

[0056] In another aspect, the invention provides a processor comprising a semiconductor device as described above wherein the three-dimensional structure is located at interconnections coupled to the processor, or at the back of the processor.

[0057] - For example, the removal of the first layer is carried out at the level of the upper face 101 of the substrate 100 between the cavity and the pillar 400;

[0058] - By way of example, the method comprises the conformal deposition of an intermediate layer then the conformal deposition of the second electrode layer; - By way of example, the conformal deposition of the intermediate layer is carried out only in the three-dimensional capacitor or the conformal deposition of the intermediate layer is carried out on the entire three-dimensional structure 200 then a step of removing the intermediate layer outside the capacitor is carried out; - By way of example, the method comprises the conformal deposition of the second electrode layer 503 is carried out only in the three-dimensional capacitor 30 or the conformal deposition of the second electrode layer 503 is carried out on the entire three-dimensional structure 200 and a step of removing the second electrode layer 503 outside the capacitor 300 is carried out forming a first part of the second layer 503 participating in the capacitive stack;

[0059] - By way of example, the removal of the second electrode layer 503 is carried out by keeping it at the level of the pillar 400 forming a second part of the second layer 503 on the pillar 400, the first part and the second part being electrically disconnected from each other.

[0060] A microelectronic component is any type of device made using microelectronics. These devices include, in addition to devices for purely electronic purposes, micromechanical or electromechanical devices (MEMS, NEMS, etc.),

[0061] Vertical means that which is directed along the thickness of the stack or substrate, that is, along the main direction of extension of the stack or substrate, and horizontal means that which is perpendicular to the vertical. The top and bottom are vertically opposed.

[0062] Transverse means a direction perpendicular to a longitudinal direction. The longitudinal direction is understood as the thickness of the stack or substrate. A transverse section is a section perpendicular to the longitudinal axis. A transverse section is a section perpendicular to the thickness of the substrate stack.

[0063] The width of a cavity or pillar is defined as the dimension of the cavity or pillar transverse to the thickness.

[0064] The term "upper" used in particular to describe a face of the substrate is used here only to designate the first of the two faces of the substrate (the other being the lower face), without making any assumption about the relative position of the faces, in a vertical direction. The upper face could thus also have been called the front face, as opposed to a rear face.

[0065] The shapes or dimensions given for certain components of the present invention are always only indicative and are understood as including substantially equivalent shapes and dimensions.

[0066] A parameter "substantially equal / greater / less than" or "of the order of" a given value means that this parameter is equal / greater / less than the given value, to within plus or minus 10%, or even plus or minus 5%, of this value.

[0067] It is specified that in the context of the present invention, the term "on", "overcomes", "covers", "above" or "underlying" or "below" or their equivalents do not necessarily mean "in contact with". For example, the deposition of a first layer on a second layer does not necessarily mean that the two layers are directly in contact with each other, but it does mean that the first layer at least partially covers the second layer either by being directly in contact with it, or by being separated from it by at least one other layer or at least one other element.

[0068] A substrate, film, layer, chip or protrusion “based on” a material A means a substrate, film, layer, chip or protrusion comprising this material A and possibly other materials, for example doping elements.

[0069] The term "coating" refers to a layer that is formed, in particular by modification of the underlying layer or by deposition on this underlying layer.

[0070] "Conformal" means a layer geometry which, within manufacturing tolerances, has an identical thickness despite changes in layer direction, for example at the level of protrusion flanks.

[0071] The word "dielectric" refers to a material whose electrical conductivity is low enough in the given application to serve as an insulator.

[0072] The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

[0073] The terms "first," "second," and "third," etc., are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0074] By "coupled" we mean that two or more elements are in direct physical or electrical contact.

[0075] A semiconductor device comprising a three-dimensional structure 200 formed in a substrate 100 is provided.

[0076] Basic capacitor structures are essentially stacks of layers in one direction, the thickness 103 of the substrate. In this sense, their shape is monotonous in this direction. The 3D shape here means a more complex geometry than a stack of layers in a single direction; it can be shapes defined by one or more cavities or trenches in which layers are present with a stack that extends in several directions, depending on the surface of the cavity or trench that is covered. 3D structures also cover structures with several cavities or trenches functionally connected, typically to form parts of the same capacitor 300.

[0077] The semiconductor device comprises a substrate 100.

[0078] The three-dimensional structure 200 may be implemented or realized in a substrate 100, such as a semiconductor substrate.

[0079] In one embodiment, the semiconductor substrate 100 may be a crystalline substrate formed using a bulk silicon or a silicon-on-insulator substructure.

[0080] In other implementations, the semiconductor substrate 100 may be formed using alternative materials, which may or may not be combined with silicon, which include, but are not limited to, germanium, indium antimonide, lead telluride, indium arsenide, indium phosphide, gallium arsenide, indium gallium arsenide, gallium antimonide, or other combinations of Group III-V or Group IV materials.

[0081] Although a few examples of materials from which substrate 100 may be formed are described herein, any material that can serve as a foundation upon which a semiconductor device may be constructed falls within the spirit and scope of the present disclosure.

[0082] The three-dimensional structure 200 is formed in the substrate 100, more particularly in a portion of the substrate. It is defined for the remainder of the description that the substrate comprises an upper face 101 opposite a lower face 102.

[0083] The three-dimensional structure 200 comprises at least one pillar 400. Preferably, the three-dimensional structure comprises one pillar 400, but may comprise several pillars 400. The pillar 400 extends along the thickness 103 of the substrate 100. The pillar 400 opens out at the upper face 101 of the substrate 100. The pillar 400 may or may not open out at the lower face 102 of the substrate 100.

[0084] According to different embodiments, the pillar 400 is a vertical structure that can have different functions, whether electrical, thermal or packaging. For example, the pillar 400 can be an interconnection, a via or through-via (TSV for "Through Silicon Via" i.e. via through silicon; we can also find vias through glass called "TGV"), a vertical heat dissipation structure, a vertical encapsulation structure.

[0085] An example of implementation is illustrated in Figure 8 where we find a three-dimensional assembly 600 comprising two electronic chips, for example two processors 610, and a passive interposer 620 which allows their interconnection, and their connection to another level through copper pillars 630, thus achieving a level of redistribution of the signals. Advantageously, the three-dimensional structure 200 according to the invention is arranged at the level of the passive interposer 620.

[0086] The pillar 400 having a depth 402 extending along the thickness 103 of the substrate 100 and a width 401 extending transversely to the thickness 103 of the substrate 100. For example, the width 401 of the pillar 400 is greater than or equal to 2 μm.

[0087] The pillar 400 has side walls 403 having a vertical main component. Preferably, the side walls 403 of the pillar 400 are vertical, that is to say extending along the thickness 103 of the substrate 100.

[0088] According to a preferred embodiment, the pillar 400 has a cross-section across the thickness of the substrate of circular shape. Other shapes of pillar 400 may be envisaged such as for example polygonal, parallelepiped, oval.

[0089] The pillar 400 opens onto the upper face 101 of the substrate 100 and may or may not open onto the lower face 102 of the substrate 100. According to the embodiments illustrated in the figures, the pillars 400 do not open onto the lower face 102 of the substrate 100. Subsequent steps of manufacturing the semiconductor device may however comprise the addition of an underlying layer on the lower face 102 of the substrate 100 implying that the pillar 400 opens onto the lower face 102 of the substrate 100.

[0090] The semiconductor device according to the invention comprises a three-dimensional structure 200.

[0091] The three-dimensional structure 200 is formed in a portion of the substrate 100 and comprises a three-dimensional capacitor 300. The three-dimensional capacitor 300 comprises a capacitive stack 500 at least partially housed in a cavity formed in the substrate 100. The three-dimensional capacitor 300 thus has a three-dimensional structuring making it possible to increase the developed surface area and the associated storage capacity.

[0092] Advantageously, according to the invention, the substrate 100 comprises at least one cavity. The substrate 100, more specifically the three-dimensional structure 200, may comprise up to 20 cavities, more specifically from 2 to 10 cavities. Advantageously, in the case where the substrate comprises several cavities, the cavities comprise the same capacitive stack 500 so as to optimize the capacitance of the condenser 300. The following description is made with reference to a cavity, but applies to all of the cavities when the three-dimensional structure 200 comprises more than one cavity. The cavity extends along the thickness 103 of the substrate 100 from the upper face 101 of said substrate 100. The cavity thus penetrates into the substrate 100. Advantageously, the cavity and the pillar 400 extend along the same main direction parallel to the thickness 103 of the substrate 100.

[0093] The cavity opens onto the upper face 101 of the substrate 100 and advantageously does not open onto the lower face 102 of the substrate 100 so as to allow the arrangement of the capacitive stack 500 on the largest possible substrate surface area.

[0094] In the remainder of the description, the three-dimensional capacitor 300 may simply be referred to as capacitor 300.

[0095] According to the invention, the capacitor 300 is configured to delimit on the upper face 101 of the substrate 100, an outline 201 of an inscribed portion 202.

[0096] The contour 201 may be of various shapes such as for example circular, ovoid, parallelepiped, polygonal.

[0097] Advantageously, according to the invention, the inscribed portion 202 comprises at least one pillar 400. Preferably, the pillar 400 is arranged in the inscribed portion 202 defined by the capacitor 300.

[0098] According to a preferred embodiment, the pillar 400 is arranged in the center of the inscribed portion 202. More specifically, the center of the pillar 400 corresponds to the center of the inscribed portion 202.

[0099] Advantageously, the three-dimensional structure 200 comprises a first conformal layer comprising a first part forming the first electrode layer 501 of the capacitive stack 500 and a second part 404 arranged in the pillar 400 more specifically covering the side walls 403 of the pillar 400. The first electrode layer 501 and the second part 404 are advantageously identical in particular since they are preferably formed at the same time by a single deposition of a first layer. Preferably, the first part forming the first electrode layer 501 and the second part 404 arranged in the pillar 400 are electrically disconnected from each other. The electrical disconnection of the first part forming the first electrode layer 501 and of the second part 404 arranged in the pillar 400 is advantageously done by partial removal 504 of the first layer, in particular on the upper face 101 of the substrate 100.

[0100] The arrangement of the three-dimensional capacitor 300 in a three-dimensional structure 200 comprising a pillar 400 allows space to be saved by using a conventionally used portion of substrate 100 while allowing a sharing of the steps, in particular the deposition of the first layer, without however involving a functional link between the capacitor 300 and the pillar 400.

[0101] According to a preferred embodiment, the width 401 of the pillar 400 is at least 20 times greater than the width 303 of a cavity, preferably 50 times greater than the width 303 of a cavity.

[0102] According to a first embodiment, the cavity of the capacitor 300 is a trench 301. Trench 301 is understood to mean a cavity in the substrate 100 having a length of dimension greater than its width 303. The length being understood as the direction transverse to the thickness and to the width. Preferably, the ratio between the length and the width is greater than or equal to 2, preferably greater than or equal to 20. By way of example, the trench 301 has a depth, that is to say a dimension extending in a direction parallel to the thickness 103 of the order of 20 μm.

[0103] According to this first embodiment, the trench 301 is rectilinear or curved. The rectilinear trench 301 may be a straight line extending in a single direction or extending in several directions and thus forming a broken line. The curved trench 301 may be a continuous curve in a single direction or extending in several directions and thus forming a curved line.

[0104] According to a preferred possibility of this first embodiment, the capacitor

[0105] 300 may comprise a trench 301 defining by itself the contour 201 of the inscribed portion 202. The trench 301 is thus closed on itself, the ends of the trench 302 meet. Depending on the shape of the trench 301, the inscribed portion 202 may be of any variable shape. Preferably, the trench 301 is for example circular or even polygonal or parallelepiped.

[0106] In this possibility, the pillar 400 is in the center of the inscribed portion 202 and the trench 301 forms the outline 200 of the inscribed portion 202.

[0107] The capacitor 300 may comprise several cavities and in particular several trenches 301. According to the preferred possibility, the capacitor 300 comprises several trenches 301 closed on itself and concentric. Preferably, the trenches

[0108] 301 are circular as illustrated in Figures 1 and 3. The trenches 301 advantageously comprise the same capacitive stack 500 so as to increase the surface area of ​​the capacitance of the capacitor 300.

[0109] According to a second embodiment, the cavity of the capacitor 300 is a column 302. By column is meant a cavity in the substrate 100 having a length of dimension substantially equivalent to its width. Preferably, the ratio between the length and the width is of the order of 1. For example, the length and the width are 10 pm and the depth is of the order of 20 pm.

[0110] Each column 302 has a cross-section with a circular, ovoid, parallelepiped, or polygonal thickness. All columns 302 may or may not have the same cross-sectional shape.

[0111] Advantageously, in this second embodiment, the capacitor 300 comprises at least three columns 302. The columns 302 are thus advantageously arranged so as to define an outline 201 of an inscribed portion 202.

[0112] Advantageously, the contour 201 of the inscribed portion 202 is formalized by the set of lines 203 connecting successive columns 302 to one another. Preferably, the contour 201 is formed by the set of lines 203 connecting the columns 302 closest to the pillar 400.

[0113] The columns 302 are advantageously arranged around the pillar 400 so as to form an advantageously circular contour 201 as illustrated in FIG. 4.

[0114] As a preferred example, the transverse distance 104 to the thickness 103 separating the center of the pillar 400 from the center of a cavity is less than or equal to 100 pm.

[0115] As a preferred example, the transverse distance 104 to the thickness 103 separating the center of the pillar 400 from the center of a cavity is greater than or equal to 5 pm.

[0116] According to a third embodiment, the first embodiment and the second embodiment are combined. The capacitor 300 comprises at least one trench 301 and at least one column 302.

[0117] Whatever the embodiment described above, the capacitor 300 comprises a capacitive stack 500 comprising a first electrode layer 501 advantageously formed at least by the first part of a first layer 501, an intermediate layer 502 and a second electrode layer 503.

[0118] Preferably, the first electrode layer 501 covers the side walls of at least one cavity, preferably of all the cavities of the three-dimensional structure 200, and of the upper face 101 of the substrate 100 exposed between the cavities. As a preferred example, the first electrode layer 501 is chosen from TiN, TaN, W, Ni, Pt, Ru materials.

[0119] Preferably, the intermediate layer 502 is a dielectric ionic material and covers the first electrode layer 501. The intermediate layer 502 may be a solid-state electrolyte. As a preferred example, the dielectric is an ionic conductor. For example, the ionic conductor has a high ionic conductivity at room temperature (preferably between 20°C and 25°C, preferably at 25°C), at least 1 pS.cm-1, and advantageously also has a low associated activation energy, generally less than 0.6eV.The intermediate layer 502 may comprise AI2O3, HfO2, ZrO2, TiO2, Nb2O5, Ta2O5, SrTiOx, BaTiOx, Ga2O3, Y2O3, a rare earth oxide, a solid state electrolyte, a glass electrolyte, a ceramic electrolyte, LiPON, an ionic antiperovskite, LiSCIO, a doped Li(3-2x)DxCIO where D is a divalent cationic dopant, hafnium silicate, zirconium silicate, hafnium dioxide, hafnium zirconate, zirconium dioxide, aluminum oxide, titanium oxide, silicon nitride, carbon-doped silicon nitride, silicon carbide and nitride hafnium silicate, a high-k dielectric material, or an alloy thereof.

[0120] The intermediate layer 502 of dielectric ionic material makes it possible to obtain a capacitor which has a power density and a charge density much greater than with a non-ionic conductive dielectric known in the state of the art.

[0121] Preferably, the second electrode layer 503 covers the intermediate layer 502. As a preferred example, the second electrode layer 503 is TiN, TaN, W, Ni, Pt, Ru.

[0122] The first electrode layer 501, the second electrode layer 503, and the second portion 404 may comprise W, Mo, Ti, Ta, Al, TaN, TiN, TiC, WN, MoN, MoC, Co, Ni, Cu, Ru, Pd, Pt, Ir, IrOx, graphene, MnO2, Li, RuOx, ITO, SrRuOx, a metal oxide, graphitic carbon, an alkali metal, a low work function metal, a transition metal oxide, a Co oxide, LiCoO2, NaCoO2, a transition metal dichalcogenide, a spinel oxide, LiMn2O4, LiNiMnO4, a conductive polymer, or a conductive metal.

[0123] Advantageously, the first electrode layer 501 overhangs at its ends on the upper face 101 relative to the intermediate layer 502 and the second electrode layer 503 so as to allow the connection of the first electrode layer 501 and the second electrode layer 503 separately.

[0124] According to one possibility, either or both of the first electrode layer 501 and the second electrode layer 503 is an ion intercalation electrode. In the case where the first electrode layer 501 and the second electrode layer 503 are both intercalation electrodes, the semiconductor device comprises a microbattery.

[0125] Advantageously, the pillar 400 comprises the second portion 404 of the first conformal layer covering the side walls 403. According to one possibility, the pillar 400 comprises a metallic material 405 filling the entire remaining volume and ensuring a level with the upper face 101 of the substrate 100. The presence of the second portion 404 of the first conformal layer in the pillar 400 may be of interest as an interdiffusion barrier between the substrate 100 and the metallic material 405, or also a diffusion barrier for ions from the metallic material 405 to the substrate 100. The second portion 404 of the first conformal layer acts as a diffusion barrier between the substrate 100 and the metallic material 405, or also as an additional chemical barrier to improve the encapsulation of the components. Preferably, the metallic material 405 is different from the intermediate layer 502 of the capacitive stack.Preferably, the metallic material 405 is different from the first electrode layer 501 and preferably from the second electrode layer 503. The metallic material 405 is chosen according to the objective of the pillar 400 being preferentially different from electronic conduction and being for example heat dissipation, encapsulation, packaging etc.

[0126] Preferably, the pillar 400 does not include a capacitive stack 500.

[0127] According to one possibility, the pillar 400 comprises a portion of the second electrode layer 503. A portion of the second electrode layer 503 is arranged on the metallic material 405 so as to at least partially cover the metallic material 405. This portion of the second electrode layer 503 makes it possible to facilitate / optimize the electrical, thermal or mechanical contact between the metallic material 405 and the following levels. For example, this portion of the second electrode layer 503 is identical to the second electrode layer 503 described above with reference to the capacitive stack.

[0128] By "inscribed" is meant that the capacitor 300 has a three-dimensional shape which extends to the upper face 101 of the substrate, delimiting for this upper face 101 two surface parts: a part inside the capacitor 300 which is the inscribed one, and an outer part. The shape of the capacitor 300 provides it with an inner edge (this is the case for a circular trench 301), or a border for placing the cavities (this is the case if the capacitor 300 is formed with several cavities, for example of the column type 302 which surrounds an inner part according to a profile, regular or not, for delimiting this surface). By joining the edges of these cavities spaced around the inscribed surface, the shape of this border is revealed. The cavities are then like posts delimiting a surface of the ground, barriers joining the posts revealing the shape of this surface which is the inscribed surface.The outline of this surface, formed by the capacitor, can therefore be continuous (as in the case of a trench with a closed outline, for example circular) or discrete as in the case of via-shaped cavities.

[0129] According to one possibility, the semiconductor device according to the invention is produced on the rear face of CMOS technology.

[0130] According to one possibility, the semiconductor device comprises an underlying layer such as for example a substrate comprising a transistor and / or an overlying layer.

[0131] According to one possibility, the semiconductor device is produced at the end of the interconnection line also called Back end of Line (BEOL).

[0132] An example of integration of a semiconductor device according to the invention is illustrated in Figure 8.

[0133] According to another aspect, the invention relates to a method of manufacturing a semiconductor device as described above. The different steps of the method are illustrated in Figures 9 to 15.

[0134] According to one aspect, the method of manufacturing a semiconductor device comprises the following steps:

[0135] • formation of at least one cavity of the capacitor 300 in the substrate 100 and extending along the thickness 103 of the substrate 100 from the upper face 101 of the substrate 100,

[0136] • formation of a pillar 400 in the substrate 100 and extending along the thickness 03 of the substrate 100 from the upper face 101 of said substrate 100, characterized in that the capacitor 300 is configured to delimit on the upper face 101 of the substrate 10) an outline 201 of an inscribed portion (202), the pillar 400 being arranged in the inscribed portion 202 of the substrate 100.

[0137] For example, the method comprises the following steps:

[0138] - conformal deposition of a first layer on the surface of the three-dimensional structure 200 so that a first part of the first layer forms a first layer 501 of the capacitive stack 500 of the capacitor 300 and a second part 404 of the first layer is formed in the pillar 400 and,

[0139] - removing a portion of the first layer 500 on the upper face 101 of the substrate 100 between the pillar 400 and the capacitive stack 500 so that the pillar 400 and the capacitive stack 500 are not electrically connected.

[0140] The manufacturing process begins as illustrated in Figure 9 with the presence of substrate 100.

[0141] The manufacturing method advantageously comprises a step a) comprising the production of at least one cavity and at least one pillar 400 in a substrate 100. This first production step is carried out by a plasma-type etching step, more commonly called deep reactive ion etching or DRIE and known to those skilled in the art. Advantageously, the arrangement of the at least one cavity and the pillar 400 is defined so that the cavity defines an outline of an inscribed portion with the pillar arranged in the inscribed portion. The semiconductor device obtained at the end of step a) is illustrated in FIG. 10.

[0142] Following step a), the method comprises a step b) comprising the conformal deposition of a first layer on the three-dimensional structure 200, i.e. in the cavity and in the pillar as well as on the upper face 101 of the substrate 100. The conformal deposition is carried out by conventional methods known to those skilled in the art such as: chemical vapor deposition (CVD), or atomic deposition (ALD). The semiconductor device obtained at the end of step b) is illustrated in Figure 11.

[0143] Preferably, the method then comprises a step c) of filling the pillar 400. The filling is carried out by conventional methods known to those skilled in the art such as: electrochemical deposition or electroless deposition. The semiconductor device obtained at the end of step c) is illustrated in Figure 12.

[0144] Preferably, the method comprises a step d) of advantageously partial removal 504 of the first layer so as to electrically disconnect a first part of the first layer 501 and a second part 404 of the first layer. Preferably, the removal of the first layer is carried out at the upper face 101 of the substrate 100, preferably between the cavity and the pillar 400. The removal is carried out by conventional methods known to those skilled in the art such as: chemical etching or plasma etching, both coupled with photolithography for the definition of the patterns. The semiconductor device obtained at the end of step d) is illustrated in Figure 13.

[0145] This step d) can be done before or after step c).

[0146] Preferably, the method then comprises the successive steps for producing the remainder of the capacitive stack 500. The method comprises the conformal deposition of the intermediate layer 502 then the conformal deposition of the second electrode layer 503. The production of the capacitive stack 500 is carried out by conventional methods known to those skilled in the art such as: atomic deposition or ALD.

[0147] According to one possibility, the conformal deposition of the intermediate layer 502 is carried out only as illustrated in FIG. 14 or the conformal deposition of the intermediate layer 502 is carried out on the entire three-dimensional structure 200 and the method comprises a step of removing the intermediate layer 502 outside the capacitor 300.

[0148] In the same way, the conformal deposition of the second electrode layer 503 is carried out only as illustrated in FIG. 15 or the conformal deposition of the second electrode layer 503 is carried out on the entire three-dimensional structure 200 and the method comprises a step of removing the second electrode layer 503 outside the capacitor 300 and advantageously the pillar 400 forming a first part of the second layer 503 participating in the capacitive stack and a second part of the second layer 503 on the pillar 400. The first part and the second part are electrically disconnected from each other. The invention is not limited to the embodiments previously described and extends to all the embodiments covered by the invention.

[0149] LIST OF REFERENCES nel first layer of el

Claims

CLAIMS 1. Semiconductor device comprising: • a substrate (100) comprising at least one cavity, and • a three-dimensional structure (200) formed in the substrate (100) comprising: i. a three-dimensional capacitor (300) comprising a capacitive stack (500), the capacitive stack (500) being at least partially housed in the at least one cavity of the substrate (100), ii. a pillar (400) extending along the thickness (103) of the substrate (100) from the upper face (101) of said substrate (100), Characterized in that the at least one cavity extends along the thickness (103) of the substrate (100) from the upper face (101) of said substrate (100), and the three-dimensional capacitor (300) is configured to delimit, on the upper face (101) of the substrate (100), a contour (201) of an inscribed portion (202), the pillar (400) being arranged in the inscribed portion (202) of the substrate (100) and the capacitive stack (500) comprises a first electrode layer (501), an intermediate layer (502) and a second electrode layer (503), and the three-dimensional structure (200) comprises a first conformal layer comprising a first part forming the first electrode layer (501) of the capacitive stack (500) and a second conforming part (404) arranged in the pillar (400), the first part (501) and the second part (404) being electrically disconnected from each other, and the intermediate layer (502) is an ionically conductive dielectric material.

2. Semiconductor device according to the preceding claim in which the ionic conductive dielectric material has an ionic conductivity at room temperature at least equal to 1 pS.cm-1.

3. Semiconductor device according to any one of the preceding claims in which the ionic conductive dielectric material has an associated activation energy less than or equal to 0.6eV.

4. Semiconductor device according to any one of the preceding claims wherein the pillar (400) is arranged in the center of the inscribed portion (202).

5. Semiconductor device according to any one of the preceding claims wherein the transverse distance (104) to the thickness (103) of the substrate (100) between the center of a cavity and the center of the pillar (400) is less than or equal to 100 pm.

6. Semiconductor device according to any one of the preceding claims wherein the transverse distance (104) to the thickness (103) of the substrate (100) between the center of a cavity and the center of the pillar (400) is less than or equal to 5 pm.

7. A semiconductor device according to any preceding claim wherein at least one cavity of the capacitor (300) is a trench (301).

8. Semiconductor device according to the preceding claim wherein the trench (301) is circular and arranged in the form of a circle around the pillar (400).

9. Semiconductor device according to any one of the two preceding claims in which the capacitor (300) comprises at least two circular and concentric trenches (301).

10. A semiconductor device according to any one of claims 1 to 6 wherein at least one cavity of the capacitor is a column (302).

11. Semiconductor device according to the preceding claim, the capacitor (300) comprises a plurality of columns (302).

12. Semiconductor device according to the preceding claim wherein the plurality of columns (302) is arranged in a circular manner around the pillar (400).

13. Semiconductor device according to any one of the preceding claims wherein the pillar (400) comprises a metallic material so as to fill the pillar (400) at the upper face (100) of the substrate (100).

14. Semiconductor device according to the preceding claim in which the metallic material is different from the intermediate layer (502) so that the pillar (400) does not comprise a capacitive stack (500).

15. A processor comprising a semiconductor device according to any preceding claim wherein the three-dimensional structure is located at interconnections coupled to the processor, or at the rear of the processor.

16. A method of manufacturing a device according to any one of claims 1 to 14 comprising a step a) comprising the production of a three-dimensional structure (200) comprising at least one cavity of a three-dimensional capacitor (300) and at least one pillar (400) in a substrate (100), the capacitor (300) is configured to delimit on the upper face (101) of the substrate (100) an outline (201) of an inscribed portion (202), the pillar (400) being arranged in the inscribed portion (202) of the substrate (100), a step b) comprising the conformal deposition of a first layer on the three-dimensional structure (200), i.e. in the cavity and in the pillar (400) as well as on the upper face (101) of the substrate (100), so that a first part of the first layer forms a first layer (501) of a capacitive stack (500) of the capacitor (300) and that a second part (404) of the first layer is formed in the pillar (400),a step c) of filling the pillar (400), a step d) of partial removal of the first layer so as to electrically disconnect the first part of the first layer (501) and the second part (404) of the first layer, step d) being able to be carried out before or after step c)., 17. Method according to the preceding claim in which the removal (504) of the first layer is carried out at the level of the upper face (101) of the substrate (100) between the cavity and the pillar (400).

18. Method according to any one of the two preceding claims comprising the conformal deposition of an intermediate layer (502) then the conformal deposition of the second electrode layer (503).

19. Method according to the preceding claim in which the conformal deposition of the intermediate layer (502) is carried out only in the three-dimensional capacitor (300) or the conformal deposition of the intermediate layer (502) is carried out on the whole of the three-dimensional structure (200) then a step of removing the intermediate layer (502) outside the capacitor (300) is carried out.

20. Method according to any one of the four preceding claims comprising the conformal deposition of the second electrode layer (503) is carried out only in the three-dimensional capacitor (300) or the conformal deposition of the second electrode layer (503) is carried out on the entire three-dimensional structure (200) and a step of removing the second electrode layer (503) outside the capacitor (300) is carried out forming a first part of second layer 503 participating in the capacitive stack.

21. Method according to the preceding claim wherein the removal of the second electrode layer (503) is carried out by keeping it at the pillar (400) forming a second part of second layer (503) on the pillar (400), the first part and the second part being electrically disconnected from each other.

Images