Electronic device

Abstract

Electronic Device This description relates to a method for manufacturing an electronic device (10), the method comprising: - the formation of a substrate (12) comprising at least a first insulating layer (12a) and conductive tracks (14); - the formation of a second insulating layer (18); - the formation of cavities (20) in the second insulating layer (18); and - the formation of a memory cell in a first location comprising: o the formation of a layer stack extending over the walls and bottom of the cavities (20), the stack comprising a layer (26) of a material capable of becoming ferroelectric situated between a first conductive layer (24) and a second conductive layer (28); and o the application of a laser to the layer stack at at least the first location so as to activate the ferromagnetic properties of the layer (26). Figure for the abstract: Fig. 1B

Description

Title of the invention: Electronic device Technical field

[0001] The present description relates generally to electronic devices and more particularly to memory devices. Prior art

[0002] Ferroelectricity is the property whereby a material has an electric polarization in the spontaneous state, a polarization that can be reversed by the application of an external electric field. The signature of a ferroelectric material is the hysteresis cycle of the polarization as a function of the applied electric field. Summary of the invention

[0003] One embodiment provides a method of manufacturing an electronic device, the method comprising: forming a support comprising at least a first insulating layer in which conductive tracks are located; forming a second insulating layer on the support; forming cavities in the second insulating layer; and forming a memory cell in a first location comprising: forming a stack of layers, the stack extending over the walls and bottom of the cavities, the stack comprising a layer of a material capable of becoming ferroelectric located between a first conductive layer and a second conductive layer, the formation of the stack comprising forming the first and second conductive layers and a dielectric layer between the first and second conductive layers;and applying a laser to the stack of layers at at least the first location so as to activate ferromagnetic properties of the layer into a material capable of becoming ferromagnetic.;

[0004] According to one embodiment, the laser is applied only to the first location.

[0005] According to one embodiment, the laser is applied to the entire device, portions of the second conductive layer surrounding the first location being protected, during application of the laser, by a protective mask.

[0006] According to one embodiment, when the laser is applied, the dielectric layer is entirely covered by the second conductive layer.

[0007] According to one embodiment, the method comprises forming a protective layer covering the second conductive layer, the step of applying the laser being carried out after the formation of the protective layer.

[0008] According to one embodiment, the protective layer is transparent to the wavelength of the laser.

[0009] According to one embodiment, the second conductive layer has a thickness and is made of a material allowing full absorption of the laser energy so as to heat the dielectric layer by diffusion.

[0010] According to one embodiment, the dielectric layer is heated to a temperature greater than 500°C.

[0011] According to one embodiment, the laser is applied by pulse of a duration less than 1 ps.

[0012] According to one embodiment, the laser has a wavelength of less than 400 nm.

[0013] According to one embodiment, the method comprises manufacturing at least one capacitor in a second location, the capacitor comprising the first and second conductive layers and the dielectric layer, the laser not being applied to the dielectric layer in the second location.

[0014] According to one embodiment, the side walls of the cavities are inclined and each form an angle of between 0.5° and 5° with a direction orthogonal to the plane of the bottom of the cavities.

[0015] According to one embodiment, the layer of a ferroelectric material is made of hafnium oxide or HzZrO2.

[0016] According to one embodiment, the layer of a ferroelectric material is made of hafnium oxide doped with silicon, the proportion of silicon being between 0.5% and 5%.

[0017] According to one embodiment, the method comprises forming a third conductive layer covering the second conductive layer, the third conductive layer filling the cavities. Brief description of the drawings

[0018] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0019] [Fig.1A] represents a perspective view of an embodiment of an electronic device;

[0020] [Fig.lB] represents a sectional view of an embodiment of the electronic device of [Fig.lA];

[0021] [Fig.lC] represents a sectional view of an embodiment of the electronic device of [Fig.lA];

[0022] [Fig. 2] represents a step of a manufacturing method of the embodiment of figures 1A, 1B and 1C;

[0023] [Fig. 3] represents another step of a manufacturing method of the embodiment of figures 1A, 1B and 1C;

[0024] [Fig.4] represents another step of a manufacturing method of the embodiment of figures 1A, 1B and 1C;

[0025] [Fig. 5] represents another step of a manufacturing method of the embodiment of figures 1A, 1B and 1C;

[0026] [Fig. 6] represents another step of a manufacturing method of the embodiment of figures 1A, 1B and 1C;

[0027] [Fig.7] represents another step of a manufacturing method of the embodiment of figures 1A, 1B and 1C;

[0028] [Fig.8] represents another step of a manufacturing method of the embodiment of figures 1A, 1B and 1C;

[0029] [Fig. 9] schematically represents a top view of a device such as the device of figures 1A, 1B and 1C;

[0030] [Fig. 10] shows another embodiment of an electronic device; and

[0031] [Fig.l 1] represents another embodiment of an electronic device. Description of the embodiments

[0032] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0033] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed.

[0034] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0035] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made unless otherwise specified to the orientation of the figures.

[0036] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0037] Figures 1A, 1B and 1C represent an embodiment of an electronic device 10, comprising at least one memory cell 11. In the example of figures IA, IB, and IC, a single cell 11. More specifically, [Fig.lA] represents a perspective view of the device 10. [Fig.lB] represents a sectional view of the device 10 along a plane AA. [Fig.lC] represents a sectional view of the device 10 along a plane BB.

[0038] The memory cell 11 is a ferroelectric type cell. In other words, the cell contains a value programmed by an electrical polarization. For example, the device comprises a plurality of memory cells such as the cell 11, for example arranged in a matrix. The cell 11 is a non-volatile memory cell.

[0039] The device 10 comprises a substrate, or support, 12. The support 12 is for example a stack of insulating layers 12a and 12b. For example, the stack 12 comprises an alternation of layers 12a and 12b. The layers 12a are for example layers of silicon oxide. The layers 12b are for example layers of silicon nitride.

[0040] At least some of the layers of the support 12 comprise conductive tracks 14 made of copper. In particular, in the example of FIGS. 1A, 1B and 1C, tracks 14 are located in the upper layer of the support, i.e. the layer closest to the cell 11. The tracks 14 of said upper layer are preferably located so as to be flush with the upper face of the upper layer of the support 12.

[0041] The support 12, in particular the upper face of the upper layer of the support 12, is for example covered by a stack 15 of insulating layers. The stack 15 comprises, in the example of FIGS. 1A, 1B and 1C, an insulating layer 16 and an insulating layer 18. The layer 16 is for example made of silicon nitride. The layer 16 is for example made of the same material as the layers 12b. The layer 18 is for example made of silicon oxide. The layer 18 is for example made of the same material as the layers 12a.

[0042] Layer 16 is the lower layer of stack 15. Layer 18 is the upper layer of stack 15. Layer 16 is for example in contact with the upper face of the upper layer of support 12. Layer 18 is for example in contact with the upper face of layer 16.

[0043] The stack 15 is crossed by at least one opening, or cavity, 20, preferably by a plurality of cavities 20. In the example of Figures 1A, 1B and 1C, the stack 15 comprises a plurality of parallel lines of cavities 20. Said lines of cavities 20 extend in the direction orthogonal to the section plane of [Fig. 1B]. For example, the stack 15 comprises groups 22 of lines of cavities 20. In the example of Figures 1A, 1B and 1C, each group 22 comprises four lines of cavities 20. The lines of cavities 20 of the same group 22 are for example separated from each other by substantially the same distance. In other words, each line of a group 22 is separated from the neighboring lines of the same group by the same distance. The distances separating the lines of cavities 20 of a group 22 are for example substantially equal in all the groups 22. The groups 22 are for example all separated from each other by the same distance. The distance separating each group 22 is preferably greater than the distance separating the lines of the same group 22.

[0044] Each cavity 20 passes through the stack 15, that is to say in the example of figures 1A, 1B and 1C the layers 16 and 18. In other words, the cavities 20 extend from the upper face of the layer 18 to the lower face of the layer 16. Each cavity 20 extends so as to uncover at least one track 14.

[0045] Each cavity 20 has for example a height, corresponding to the sum of the thicknesses of the layers 16 and 18, for example between 0.5 and 1.5 μm, for example substantially equal to 1 μm. The horizontal dimensions of each cavity 20, that is to say the dimensions in the plane of the upper face of the layer 18, are for example between 50 nm and 150 nm, for example substantially equal to 100 nm.

[0046] The cell 11 comprises layers 24. Each layer 24 is located in a cavity 20. Each cavity 20 comprises a layer 24. There are therefore preferably as many layers 24 as there are cavities 20.

[0047] Each layer 24 covers the side walls of the cavity 20 in which it is located, in other words the walls of the layers 16 and 18 located at the cavity. Each layer 24 covers the portion of the support 12 uncovered by the cavity in which it is located. In other words, each layer 24 covers the portion of the track 14 uncovered by the cavity in which it is located and possibly a portion of the layer 12a in which the track 14 is located. All the portions of the tracks 14 uncovered by the cavities 20 are covered by a layer 24. Preferably, the layer 24 does not extend outside the cavity 20. Thus, the layer 24 preferably does not extend over the lower and upper walls of the layers of the stack 15.

[0048] Each layer 24 is for example made of silicon-doped titanium nitride. Preferably, the percentage of silicon in the material of each layer 24 is preferably less than 20%, for example between 10% and 20%.

[0049] The layers 24 of the cell 11 are for example electrically connected to each other by tracks 14 of the support 12. The layers 24 constitute a first electrode of the cell 11.

[0050] The cell 11 further comprises a layer 26. The layer 26 is a ferroelectric layer. The layer 26 is for example made of an oxide, for example hafnium oxide (HfO2) doped with silicon, for example with a proportion of silicon between 0.5% and 5%. The layer 26 may, alternatively, be made of HfZrO2. As a variant, the layer 26 is for example a stack of ferroelectric layers.

[0051] Layer 26 preferably completely covers layers 24. Layer 26 covers for example at least a portion of the upper face of the layer 18. Preferably, the portions of the layer 26 located in the cavities 20, that is to say the portions covering the layers 24, are connected to each other by portions of the layer 26 located on the upper face of the layer 18.

[0052] The cell 11 further comprises a conductive layer 28, for example made of metal. The layer 28 is for example made of titanium nitride, tantalum nitride or doped polycrystalline silicon. The layer 28 constitutes the second electrode of the cell 11.

[0053] The layer 28 preferably completely covers the layer 26. The layer 28 therefore extends over the portions of the layer 26 covering the walls of the cavities 20, over the portions of the layer 26 covering the uncovered portions of the tracks 14 and of the stack 12, and over the portions of the layer 26 covering the upper face of the layer 18. Preferably, the layer 28 only covers the layer 26. Thus, the layer 28 is preferably not in contact with the layer 18.

[0054] The device 10 further comprises a layer 30. The layer 30 is made of an insulating material, for example a nitride, for example a silicon nitride. The layer 30 preferably covers entirely the layer 28. The layer 30 therefore extends over the portions of the layer 28 covering the walls of the cavities 20, over the portions of the layer 28 covering the uncovered portions of the tracks 14 and of the stack 12, and over the portions of the layer 28 covering the upper face of the layer 18. Preferably, the layer 30 covers only the layer 28. Thus, the layer 30 is preferably not in contact with the layer 18 or with the layers 24.

[0055] Preferably, portions 31 of the layer 18 are not covered by the layers 26, 28, 30. The portions 31 are preferably at least partially opposite tracks 14.

[0056] The device comprises a stack 38 of insulating layers 32, 34 and 36. Layer 32 constitutes the lower layer of stack 38. Layer 36 constitutes the upper layer of stack 38. Layer 34 constitutes an internal or intermediate layer of stack 38.

[0057] The layer 32 rests on the layer 18, on the cell 11 and on the layer 30. In other words, at least a portion of the layer 18 is covered by, preferably in contact with, the upper face of the layer 32. The upper face of the layer 30 is covered, preferably in contact with, the layer 32. Preferably, the upper face of the layer 30 is entirely covered, preferably in contact with, the layer 32. The side walls of the portions of the layers 26, 28, 30 resting on the upper face of the layer 18 are covered, preferably in contact with the layer 32.

[0058] The layer 34 rests on the upper face of the layer 32. The layer 34 is for example in contact with the upper face of the layer 32.

[0059] The layer 36 rests on the upper face of the layer 34. The layer 36 is for example in contact with the upper face of the layer 34.

[0060] The layer 32 is for example made of an oxide, for example silicon oxide. The layer 34 is for example made of a nitride, for example silicon nitride. The layer 36 is for example made of an oxide, for example silicon oxide.

[0061] The device 10 comprises connection elements, or connection pads, 40. The elements 40 are for example made of metal, for example copper. The elements 42 pass through the layers 16, 18, 32, 34 and 36 so as to reach tracks 14, preferably the tracks 14 located in the upper layer of the stack 12. Preferably, each element 42 is in contact with a portion of the layer 28 located on the upper face of the layer 18, preferably between two groups of cavity lines 20. The elements 40 are for example connected together and to the layers 24 by the conductive tracks 14. The elements 40 are thus connected to the first electrode of the cell 11.

[0062] The device 10 comprises connection elements 42. The elements 42 are for example made of metal, for example copper. The elements 42 are in contact with the layer 28. More precisely, each element 42 passes through the layers 30, 32, 34 and 36 so as to reach the layer 28. Preferably, each element 42 is in contact with a portion of the layer 28 located on the upper face of the layer 18, preferably between two groups of cavity lines 20. The elements 42 are thus connected to the second electrode of the cell 11.

[0063] The elements 42 are for example connected to each other by tracks 44. The tracks 44 are for example made of metal, for example copper. The tracks 44 extend in the layers 34 and 36. For example, the tracks 44 extend from the lower face of the layer 34 to the upper layer of the layer 36.

[0064] During operation of the device 10, the cell 11 can be read by determining the electrical polarity of the layer 26. The programming of the cell 11 is thus carried out by applying the desired polarity to the layer 26, for example by applying a suitable voltage to the electrodes of the cell.

[0065] As a variant, the bottom of the cavities 20 may be made of insulating material. The layer comprises, for example, portions extending over the upper face of the layer 18. The device may comprise connection elements, for example insulated conductive vias, reaching the portions of the layer 24 extending over the upper face of the layer 18.

[0066] Figures 2 to 9 illustrate steps, preferably successive, of a method of manufacturing the embodiment of the device of Figures 1A, 1B and 1C.

[0067] [Fig. 2] represents a step of a manufacturing method of the embodiment of figures 1A, 1B and 1C.

[0068] During this step, the stack 12 and the tracks 14 are formed. In other words, the layers 12a and 12b are formed on top of each other so as to obtain an alternation of layers 12a and 12b. Preferably, the upper layer of the stack 12 is a layer 12a.

[0069] The tracks 14 are formed in the layers 12a. The tracks 14 of each layer 12a are for example formed during the formation of the layer 12a.

[0070] [Fig. 3] represents another step of a manufacturing method of the embodiment of Figures 1A, 1B and 1C.

[0071] During this step, the stack 15 is formed. In other words, the layer 16 is formed on, preferably in contact with, the upper face of the upper layer 12a of the stack 12 and on, preferably in contact with, the upper faces of the tracks 14 flush with the upper face of the upper layer 12a of the stack 12. Preferably, the layer 16 is formed on the entire upper face of the upper layer 12a of the stack 12 and on all the upper faces of the tracks 14 flush with the upper face of the upper layer 12a of the stack 12.

[0072] In addition, layer 18 is formed on, preferably in contact with, layer 16. Preferably, layer 18 covers, preferably is in contact with, the entire layer 16, more precisely the entire upper face of layer 16.

[0073] [Fig.4] represents another step of a manufacturing method of the embodiment of Figures 1A, 1B and 1C.

[0074] During this step, the cavities 20 are formed in the layers 16 and 18. More precisely, the groups 22 of lines of cavities 20 are formed in the layers 16 and 18. Each cavity 20 uncovers a portion of a conductive track 14, preferably a conductive track 14 located in the upper layer 12a of the stack 12. Preferably, all the tracks 14 of which a portion is uncovered by the cavities 20 are connected to each other, for example by tracks 14 located in one or more layers of the stack 12.

[0075] [Fig. 5] represents another step of a manufacturing method of the embodiment of Figures 1A, 1B and 1C.

[0076] During this step, the layers 24 are formed. More precisely, a layer 24 is formed in each cavity 20.

[0077] For example, the formation of the layers 24 comprises the formation of a layer not shown in the material of the layers 24. Said layer is formed so as to have a thickness substantially equal to the thickness of the layers 24. Said layer is formed conformally on the structure resulting from the step of [Fig. 4]. Said layer covers the walls and the bottom of the cavities formed by the cavities 20. In particular, the portion of a track 14 located at the bottom of the cavity is entirely covered by the layer 24. Thus, the tracks 14 are entirely covered by the layer 18 or 24 layers.

[0078] The layer 24 is preferably formed by an atomic layer deposition (ALD) process. Such a process makes it possible to deposit layers having thicknesses of a few nanometers using gas, which makes it possible to form conformal layers completely covering the exposed surfaces. In particular, it is thus possible to completely cover the portions of the exposed tracks 14. In addition, such a process allows good control of the dopant concentration and can be used in "Back end" type processes. The portions of said layer located outside the cavities 20 are then removed.

[0079] [Fig. 6] represents another step of a manufacturing method of the embodiment of Figures 1A, 1B and 1C.

[0080] During this step, a layer 27 is formed. More precisely, the layer 27 is formed conformally over the entire structure resulting from the step of [Fig.5]. The layer 27 covers the layers 24. In other words, the layer 27 extends over the walls and the bottom of the cavity formed by each cavity 20. The layer 27 further extends over the upper face of the layer 18.

[0081] Layer 27 is made of a dielectric material that can be made ferroelectric by an annealing step. Layer 27 is, for example, made of hafnium oxide (HfO2) doped with silicon, for example with a proportion of silicon between 0.5% and 5%. Layer 27 may, alternatively, be made of HfZrO2.

[0082] [Fig.7] represents another step of a manufacturing method of the embodiment of Figures 1A, 1B and 1C.

[0083] During this step, layer 28 is formed. More precisely, layer 28 is formed in a conformal manner over the entire structure resulting from the step of [Fig.6]. Layer 28 covers layer 27. Thus, layer 28 extends over the walls and the bottom of the cavity formed by each cavity, as well as the upper face of layer 18. In particular, layer 28 completely covers the portion of layer 27 corresponding to layer 26 of cell 11.

[0084] [Fig. 8] represents another step of a manufacturing method of the embodiment of Figures 1A, 1B and 1C.

[0085] During this step, the layer 30 is formed over the entire structure resulting from step 7. The layer 30 is for example sufficiently thick to fill the cavities 20.

[0086] The step of [Fig.8] also comprises a step of annealing the structure forming the layer 26. More precisely, the step of [Fig.8] comprises the annealing of the portions of the layer 27 corresponding to the layer 26 of the cell 11. The annealing step makes it possible to make the portions of the layer 27 corresponding to the layer 26 of the cell 11 ferroelectric.

[0087] The annealing step is carried out by applying a laser to the entire structure, in particular to the portion of layer 27 corresponding to layers 26. The wavelength of the laser, the material of layer 28 and the thickness of layer 28 are chosen in such a way that layer 28 absorbs the laser and heats, in particular by diffusion, layer 27 located in contact with the portions of layer 28 having absorbed the laser. Preferably, the laser is entirely absorbed by layer 28. Preferably, layer 27 is heated to a local temperature greater than 400°C, for example greater than 500°C.

[0088] The wavelength of the laser is for example less than 1100 nm, for example less than 400 nm, for example less than 360 nm, for example equal to 308 nm. For example, for a wavelength equal to 308 nm, a layer 28 of titanium nitride having a thickness of between 20 nm and 30 nm makes it possible to completely absorb the laser and to make the portions of the layer 27 corresponding to the layer 26 ferroelectric.

[0089] According to one embodiment, the laser is configured to have known dimensions and shape and to only reach the location of the cell 11, i.e. the portions of the layer 28 located in contact with the portions of the layer 27 corresponding to the layer 26.

[0090] According to another embodiment, the laser is configured to have dimensions allowing it to reach the location of the cell 11 and at least a portion of the structure surrounding the location of the cell. For example, the laser is configured to be applied to the entire device. The annealing step then comprises the formation of a protective mask covering at least said portion, for example the entire device, in such a way that the laser is reflected on the mask and only reaches the location of the cell.

[0091] The material of the layer 30 is configured to be transparent to the wavelength of the laser. The layer is for example silicon nitride.

[0092] Preferably, the laser is applied to the structure in the form of short pulses, so as not to heat and not to damage the metals of the structure, in particular the material of the layer 24. The pulses have for example a duration of less than 1 ps, for example less than 200 ns, for example less than 100 ns.

[0093] The power of the pulses and their duration depend for example on the dimensions of the cavities 20. For example, the cavities 20 have a height less than 600 nm, and dimensions in the plane of the upper face of the layer 18 less than 170 nm, for example less than 100 nm. If the cavities 20 have larger dimensions, the power of the laser making the entire layer 26 ferroelectric would cause damage to the rest of the structure.

[0094] The stack of layers 26, 28 and 30 is then etched at locations 31. In other words, a portion of the stack of layers 26, 28 and 30 is etched between each group 22 of lines of cavities 20. Thus, at locations 31, layers 26, 28 and 30 are etched so as to uncover layer 18.

[0095] The portions of layer 30 located opposite the cavities or in the cavities are not etched.

[0096] Each of the locations 31 is located opposite a track 14. Said tracks 14 are preferably connected to each other. Said tracks 14 are preferably not connected to the tracks 14 being in contact with the layers 24.

[0097] The manufacturing method of the embodiment of Figure 1 comprises steps subsequent to the step of [Fig. 8]. During these steps, the stack 38 of insulating layers is formed on the structure resulting from the step of [Fig. 8] and the connection elements 40, 42 and 44 are formed.

[0098] Alternatively, the annealing step may be performed between the step of forming layer 28 and the step of forming layer 30.

[0099] More generally, the annealing step is carried out while the layer 28 completely covers the structure, i.e. before a step of etching the layer 28, so as to protect the underlying structures of the laser, in particular the copper structures, for example the tracks 14. Thus, the steps of FIGS. 7 and 8 can comprise, in this order, either the formation of the layer 28, the formation of the layer 30 and the annealing or the formation of the layer 28, the annealing and the formation of the layer 30.

[0100] [Fig.9] schematically represents a top view of a device 46 comprising cells 11 as described in relation to figures 1A, 1B and 1C.

[0101] More specifically, the device 46 comprises non-volatile memory cells 11 and volatile memory cells 48.

[0102] The capacitors 48 are metal-oxide-metal (MOM) type capacitors. The capacitors 48 are each made up of layers 24, 26, 28, the layer 26 not having undergone the annealing step at the location of the capacitor 48.

[0103] More specifically, the method for manufacturing the device 46 comprises the steps of FIGS. 2 to 8, the annealing step being carried out in such a way that only the locations of the cells 11 undergo the annealing step. The capacitors 48 are obtained by the steps of FIGS. 2 to 8 with the exception of the annealing step. The capacitors 48 and the cells 11 are for example formed simultaneously, the steps of FIGS. 2 to 8 other than the annealing being carried out simultaneously for at least some of the cells 11 and the capacitors 48, preferably for all of the cells 11 and all of the capacitors 48.

[0104] The capacitors 48 and the cells 11 are for example located in the same level, for example in the same stack 15.

[0105] At least some of the capacitors 48 and at least some of the cells 11 are for example located in the same region. Thus, a capacitor 48 can be located between two cells 11 and a cell 11 can be located between two capacitors 48.

[0106] [Fig. 10] shows another embodiment of an electronic device. More Specifically, [Fig. 10] represents a part of a cell 11 according to a variant. [Fig. 10] represents a sectional view of a cell 11.

[0107] The cell 11 differs from the cell 11 of Figures 1A to 1C in that, unlike the cell of Figures 1A to 1C, the side walls of the cavities 20 of the cell 11 are not vertical, i.e. are not perpendicular to a horizontal axis, i.e. are not perpendicular to the plane of the upper face of the support 12.

[0108] The side walls of the cavities 20 of the cell 11 of [Fig. 10] are inclined. More precisely, the side walls of the cavities 20 are inclined outwards. In other words, the surface area of ​​the opening of the cavity is greater than the surface area of ​​the bottom of the cavity. Preferably, all the walls of each cavity 20 are inclined. Each side wall forms with a vertical axis X, that is to say an axis X orthogonal to the plane of the upper face of the support 12, an angle A. The angle A is preferably between 0.5° and 10°, for example between 0.5° and 5°.

[0109] [Fig. 11] shows another embodiment of an electronic device 50. More specifically, [Fig.l 1] represents a sectional view of an embodiment of the device 50 according to the same plane as [Fig.lB].

[0110] The device 50 comprises the elements of the device 10 of Figures 1A to 1C. Thus, the device 50 comprises: - the support 12, in which the conductive tracks 14 are located; - insulating layers 16 and 18; - cavities 20; - layers 24, 26, 28, located in cavities 20; - the insulating layers 30, 32, 34, 36; - the conductive elements 40; and - the conductive tracks 44.

[0111] The device 50 differs from the device 10 in that the device 50 comprises a layer 52 between the layer 28 and the layer 30. The layer 52 is a conductive layer, for example made of metal, for example tungsten. The layer 52 is for example made of a different material from the layer 28.

[0112] The layer 52 preferably completely covers the layer 28. The layer 52 therefore extends over the portions of the layer 28 covering the walls of the cavities 20, over the portions of the layer 28 covering the uncovered portions of the tracks 14 and the stack 12, and on the portions of the layer 28 covering the upper face of the layer 18. The layer 52 fills for example the cavities 20. Preferably, the layer 52 covers only the layer 28. Thus, the layer 52 is preferably not in contact with the layer 18 or with the layers 24.

[0113] The device 50 comprises, like the device 10 of figures 1A to 1C, the layer 30. The layer 30 of the device 50 differs from the layer 30 of the device 10 in that the layer 30 covers the layer 52. Thus, the layer 30 is for example not located in the cavities 20. The layer 30 thus rests on the layer 52, preferably only on the layer 52. The layer 30 is thus separated from the layer 28 by the layer 52. As in figures 1A to 1C, the layer 30 is preferably not in contact with the layers 24, 26, 28 or with the layer 18.

[0114] The method of manufacturing the device 50 differs from the method of manufacturing the device 10 in that the method further comprises the formation of the layer 52 between the formation of the layer 28 and the formation of the layer 30. The layers 28, 52, 30 are for example etched during the same etching step.

[0115] The annealing step, corresponding for example to the step of [Fig.6], is for example carried out after deposition of layer 28, after deposition of layers 52 and 28, or after deposition of layer 30.

[0116] The embodiment of [Fig. 1 1] can for example be combined with the embodiment of [Fig. 10]. Thus, the walls of the cavities 20 of the device 50 can be inclined, as described in relation to [Fig. 10].

[0117] An advantage of the described embodiments is that it is possible to form ferroelectric non-volatile memory cells.

[0118] Another advantage of the described embodiments is that it is possible to simultaneously form memory cells and capacitors.

[0119] Another advantage of the described embodiments is that the formation of the cells comprises only one additional step compared to the formation of the capacitors.

[0120] An advantage of the embodiment of [Fig.l 1] is that the laser reaches more easily, during the annealing step, the portions of the layer 27 extending on the side walls of the cavity 20. The power of the laser can thus be lower than the power used in the case where the walls are vertical. There is therefore less risk of damaging the structure.

[0121] An advantage of the embodiment of [Fig.l 1] is that it makes it possible to heat, and therefore make ferroelectric, the layer 27, or the layer 26, more homogeneously, thanks to improved conduction of the heat by the layer 52 which fills the cavity 20.

[0122] Various embodiments and variations have been described. The person skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art.

[0123] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. A method of manufacturing an electronic device (10, 46), the method comprising: - forming a support (12) comprising at least a first insulating layer (12a) in which conductive tracks (14) are located; - forming a second insulating layer (18) on the support (12); - forming cavities (20) in the second insulating layer (18); and - the formation of a memory cell in a first location comprising: • the formation of a stack of layers, the stack extending over the walls and the bottom of the cavities (20), the stack comprising a layer (26) of a material capable of becoming ferroelectric located between a first conductive layer (24) and a second conductive layer (28), the formation of the stack comprising the formation of the first (24) and second (28) conductive layers and a dielectric layer (27) between the first (24) and second (28) conductive layers;and • applying a laser to the stack of layers at at least the first location so as to activate ferroelectric properties of the layer into a material capable of becoming ferroelectric (26).;

2. The method of claim 1, wherein the laser is applied only to the first location.

3. The method of claim 1, wherein the laser is applied to the entire device, portions of the second conductive layer (28) surrounding the first location being protected, during application of the laser, by a protective mask.

4. A method according to any one of claims 1 to 3, wherein, upon application of the laser, the dielectric layer (27) is entirely covered by the second conductive layer (28).

5. A method according to any one of claims 1 to 4, wherein the method comprises forming a protective layer (30) covering the second conductive layer (28), the step of applying the laser being carried out after the formation of the protective layer (30).

6. The method of claim 5, wherein the protective layer (30) is transparent to the wavelength of the laser.

7. Method according to any one of claims 1 to 6, in which the second conductive layer (28) has a thickness and is made of a material allowing full absorption of the laser energy so as to heat the dielectric layer (27) by diffusion.

8. The method of claim 7, wherein the dielectric layer (27) is heated to a temperature above 500°C.

9. A method according to any one of claims 1 to 8, wherein the laser is applied in pulses of less than 1 ps duration.

10. A method according to any one of claims 1 to 9, wherein the laser has a wavelength of less than 400 nm.

11. A method according to any one of claims 1 to 10, wherein the method comprises fabricating at least one capacitor in a second location, the capacitor comprising the first (24) and second (28) conductive layers and the dielectric layer (27), the laser not being applied to the dielectric layer (27) in the second location.

12. A method according to any one of claims 1 to 11, wherein the side walls of the cavities (20) are inclined and each form an angle of between 0.5° and 5° with a direction orthogonal to the plane of the bottom of the cavities.

13. A method according to any one of claims 1 to 12, wherein the layer of ferroelectric material (26) is hafnium oxide or HzZrO2.

14. A method according to any one of claims 1 to 13, wherein the layer of ferroelectric material (26) is hafnium oxide doped with silicon, the proportion of silicon being between 0.5% and 5%.

15. A method according to any one of claims 1 to 14, comprising forming a third conductive layer (52) overlying the second conductive layer (20), the third conductive layer (52) filling the cavities (20).

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