Method for capacitively coupled plasma deposition of atomic layers - Patents.com

Abstract

The present invention relates to a method (4) and associated reactor for plasma deposition of an atomic layer, comprising the loading (40) of a substrate (2) into a plasma reactor (1) with a reaction chamber (10) and multiple cycles (41) of depositing an atomic layer on an exposed surface (20) of the substrate (2), the method comprising the injection (410) of a precursor based on a first species into the reaction chamber, and the plasma treatment (412) of the exposed surface (20) of the substrate (2) with a plasma generated by capacitive coupling between a plate (110) and a sidewall (100) of the reaction chamber (10) by bringing radio frequency power to the plate (110). The capacitive coupling makes it possible to generate a localized plasma in the vicinity of the substrate with low and finely adjustable ion energy and density.

Description

[Technical field]

[0001] The present invention relates to the field of plasma-enhanced atomic layer deposition methods, which are particularly advantageously applicable in the field of thin layer deposition, more particularly in the field of thin layers of controlled thickness, for example for the manufacture of microelectronic devices. [Background technology]

[0002] Atomic layer deposition methods (commonly referred to as ALD deposition) are routinely used to deposit thin layers, e.g., with thicknesses of 100 nm or less, on 2D or 3D substrates. In general, ALD deposition is a cyclical method that includes two main steps: - injection of a precursor, typically a metal precursor, - Injection of another precursor, typically a reagent such as an oxygen or nitrogen based reagent.

[0003] These processes are self-limiting, which allows conformal and uniform layers to be deposited on the substrate. The energy required for the precursor reaction is typically provided by temperature (this is called thermal ALD). This energy can be provided using plasma enhancement (commonly called PEALD, for plasma-enhanced ALD) to improve surface reactivity. This allows the operating temperature to be reduced, typically to temperatures below 250°C.

[0004] Plasma-enhanced ALD has been used to deposit many materials that are difficult to deposit by thermal ALD, which for some depositions may not be sufficiently reactive and / or may require complex organic precursors.

[0005] Conventionally, PEALD processes use capacitively coupled plasma or inductively coupled plasma (commonly referred to as CCP and ICP, respectively). As such, these processes are generally carried out in a reactor that includes a reaction chamber 10', a gaseous precursor inlet 12' configured to deliver gaseous precursors to the chamber 10', and a pumping module 13' for the chamber 10'. In a conventional CCP reactor 1', as shown in FIG. 1A for example, a plasma is typically generated at a pressure on the order of a few Torr between two electrodes 110', 18' by a radio frequency (RF) power device 16'3. The electrodes 110', 18' are arranged parallel to each other facing each other, with a substrate placed between them, the electrode 110' being a plate connected to ground 110' supporting the substrate 2. However, in conventional CCP techniques, ion bombardment on the plate is significant. To limit this ion bombardment, a gate can be added to the gap between the electrodes.

[0006] For example, in the ICP reactor 1' shown in Figure 1B, the plasma is generated in an offset manner 3 at a pressure typically on the order of 100 mTorr by an inductive source 15' with an RF power device 16' and then transported to the substrate 2 in the reaction chamber 10' by scattering. Thus, ion bombardment is limited.

[0007] Indeed, ion bombardment can result in isolated or widespread defects such as implantation, displacement of atoms, compressive stresses in the grown layer, or even sputtering thereof.

[0008] However, ion bombardment can be beneficial to tune surface reactivity and to improve deposition properties such as density, morphology, stress, conformality, etc., especially on 3D substrates, provided that the energy of this bombardment and its ion density are controlled.

[0009] To this end, some recently developed methods use an ICP plasma with additional RF polarization at the substrate holder, allowing ions to be extracted from the remote plasma with a controlled entrance energy when they reach the vicinity of the substrate.

[0010] In fact, the materials prepared in these reactors are, inter alia, oxides or nitrides, whose physicochemical properties may optionally be adjusted by additional polarization to extract ions from the plasma, which thus enhance the growth mechanism. Obtaining other materials remains limited.

[0011] Furthermore, poor control of the ion bombardment can affect the desired properties of the deposited layer and the substrate can be damaged by the ion bombardment. [Prior art documents] [Non-patent literature]

[0012] [Non-Patent Document 1] C. Torres, PG Reyes, F. Castillo, H. Martinez, Journal of Physics:Conference Series; Bristol Vol. 370, No. 1, (Jun 2012) Summary of the Invention [Problem to be solved by the invention]

[0013] It is therefore an object of the present invention to provide an improved plasma-enhanced deposition solution. A non-limiting object of the present invention can be to provide an improved plasma-enhanced atomic layer deposition method, in particular with regard to the layer deposited and / or deposition selectivity.

[0014] Other objects, features, and advantages of the present invention will become apparent from a study of the following description and accompanying drawings, and it should be understood that other advantages may also be incorporated. [Means for solving the problem]

[0015] To this end, according to one aspect, - providing a substrate having an exposed surface to a plasma reactor, the plasma reactor comprising a reaction chamber bounded by a wall and a conductive plate, the conductive plate having an upper surface on which the substrate is disposed, a sidewall of the reaction chamber being at least partially non-parallel to the upper surface of the plate and being conductive; - Each cycle Injecting a precursor based on a first species into a reaction chamber; Plasma treatment of the exposed surface of the substrate with a plasma generated by capacitive coupling between the plate and the sidewall by applying radio frequency power to the plate. a plurality of atomic layer deposition cycles on the exposed surface of the substrate, A plasma-enhanced atomic layer deposition method is provided, comprising:

[0016] As a result of the non-parallel configuration of the two electrodes, the capacitive coupling between the plate and the chamber wall allows the generation of a localized plasma in the vicinity of the substrate with low and finely adjustable ion energy and density, especially compared to conventional CCP reactors. These parameters can be adjusted depending on the RF power and pressure conditions. This therefore significantly limits the damage caused to the substrate by ion bombardment. Furthermore, this weaker ion current is more finely controllable compared to ICP reactors with substrate polarization, which allows a better compromise to be reached between damage caused to the substrate and ion bombardment efficiency. This therefore significantly limits the damage to the substrate compared to CCP reactors and ICP reactors with substrate polarization.

[0017] Furthermore, this allows for plasma parameters that allow deposition of a variety of chemistries and microstructures, as will be apparent from the description.

[0018] According to the second aspect, a reaction chamber bounded by a wall and comprising a conductive plate having an upper side intended to receive a substrate, - a gaseous precursor inlet configured to deliver a gaseous precursor to the reaction chamber; - a pumping module for the reaction chamber; - a power source configured to apply radio frequency power to the plate; A plasma enhanced deposition reactor is provided comprising:

[0019] A sidewall of the reaction chamber is at least partially non-parallel to the upper surface of the plate and is electrically conductive, the upper surface of the plate and the sidewall being separated by a distance configured to generate a capacitively coupled plasma between the plate and the sidewall.

[0020] The high frequency power applied to the plate and the distance between the plate and the sidewall make it possible to generate a capacitively coupled plasma between these two elements. The plasma is thus generated locally in the vicinity of the substrate as a result of the non-parallel configuration of the two electrodes, which has the advantages mentioned above. Finally, with or without substrate polarization, this reactor allows the deposition of layers of a greater variety of chemistries and fine structures than conventional ICP reactors.

[0021] The objectives, objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the present invention, as illustrated in the accompanying drawings. [Brief description of the drawings]

[0022] [Figure 1A] FIG. 1A shows a cross-sectional view of an example of a prior art CCP reactor. [Figure 1B] FIG. 1B shows a cross-sectional view of an example of a prior art ICP reactor. [Diagram 2] FIG. 2 is a diagram of a deposition method according to an example embodiment. [Figure 3A] FIG. 3A is a diagram of a metal layer deposition cycle according to some example embodiments. [Figure 3B] FIG. 3B is a diagram of a metal layer deposition cycle according to some example embodiments. [Figure 3C] FIG. 3C is a diagram of a metal layer deposition cycle according to some example embodiments. [Figure 3D] FIG. 3D is a diagram of a metal layer deposition cycle according to some example embodiments. [Figure 3E] FIG. 3E is a diagram of a metal layer deposition cycle according to some example embodiments. [Figure 4A] FIG. 4A illustrates a deposition cycle of oxide, nitride, and / or sulfide layers according to some example embodiments. [Figure 4B] FIG. 4B illustrates a deposition cycle of oxide, nitride and / or sulfide layers according to some example embodiments. [Figure 4C] FIG. 4C illustrates a deposition cycle of oxide, nitride and / or sulfide layers according to some example embodiments. [Diagram 5] FIG. 5 is a cross-sectional view of a plasma reactor according to an example embodiment in which the sidewall is cone-shaped. [Figure 6] FIG. 6 is a cross-sectional view of a plasma reactor according to another example embodiment in which the sidewall is cone-shaped. [Figure 7] FIG. 7 is a cross-sectional view of another example embodiment of a plasma reactor coupled to an ICP source. [Figure 8] FIG. 8 is a cross-sectional view of the plasma reactor shown in FIG. 5 equipped with an ellipsometer. [Figure 9A] FIG. 9A shows flow graphs of ions generated by a plasma as a function of plasma parameters at constant power and pressure. [Figure 9B]FIG. 9B shows a graph of the flow of ions produced by the plasma as a function of plasma parameters at constant power and pressure. [Figure 9C] FIG. 9C shows a graph of the flow of ions produced by the plasma as a function of plasma parameters at constant power and pressure. [Figure 9D] FIG. 9D shows a graph of the flow of ions produced by the plasma as a function of plasma parameters at constant power and pressure. [Figure 10A] FIG. 10A shows a graph of the flow of ions produced by a plasma as a function of plasma parameters at constant power and pressure. [Figure 10B] FIG. 10B shows a graph of the flow of ions produced by the plasma as a function of plasma parameters at constant power and pressure. [Figure 10C] FIG. 10C shows a graph of the flow of ions produced by the plasma as a function of plasma parameters at constant power and pressure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The drawings are presented by way of example and not by way of limitation of the invention. They form a schematic representation of principles intended to facilitate understanding of the invention and are not necessarily drawn to scale in actual applications. In particular, the relative dimensions of the substrate, the layer to be deposited and the reactor are not representative of reality.

[0024] Before commencing a detailed discussion of the embodiments of the present invention, optional features of the method and plasma reactor, which may optionally be used in combination or alternating in some cases, are presented below.

[0025] According to one example, the plate is polarized with respect to ground.

[0026] According to one example, the multiple deposition cycles further include injecting a precursor based on a second species into the reaction chamber.

[0027] According to one example, the plasma treatment is carried out simultaneously with at least one injection of the precursor into the reaction chamber or following at least one injection of the precursor into the reaction chamber, which allows the surface reaction to be regulated during the injection or between two injections, which is possible in particular as a result of the low density plasma generated.

[0028] According to one example, the radio frequency polarization power may be 80 W or less. The pressure in the reaction chamber may be 80 mTorr or less. The duration of the plasma treatment during the deposition cycle may be 1 minute or less. During the development of the invention, it was demonstrated that these parameters make it possible to activate and / or modify the surface reactivity during the precursor injection. These plasma conditions may advantageously modify the properties of the deposited material.

[0029] According to one example, the radio frequency polarization power can be 50 W or more. The pressure in the reaction chamber can be 20 mTorr or less. The duration of the plasma treatment during the deposition cycle is 1 minute or more. During the development of the present invention, it was demonstrated that these parameters make it possible to remove or sputter the chemisorbed precursors on the surface. These plasma conditions can be useful for selective deposition on 3D substrates.

[0030] According to one example, when generating the plasma, the plasma treatment is performed using a rare gas, also called an inert gas, preferably argon, and optionally H 2 and injecting it into the reaction chamber. The so-called argon-based "inert" plasma is low-energy compared to other species. This, in combination with the low-density capacitive plasma that is generated, allows for tuning of the surface reactions by minimizing the risk of damaging the exposed surfaces of the substrate.

[0031] According to one example, the plasma treatment is performed simultaneously with and / or after the injection of a precursor based on a first species, the first species being based on a metal. Thus, the plasma treatment can be performed by injecting an inert gas, such as argon, or a reducing agent, such as H 2 The creation of pendant bonds when generating a plasma from allows for the removal of ligands from the metal precursor, thus allowing for metal-on-metal adsorption.

[0032] According to one example, a plasma treatment is performed between and / or simultaneously with at least one of the injections of a precursor based on a first species and a precursor based on a second species, the first species being based on a metal and the second species being based on a metal.

[0033] According to one example, when generating the plasma, the plasma treatment is free of injection of dihydrogen. During the development of the invention, it was demonstrated in practice that this method does not require reduction of the growing layer by dihydrogen.

[0034] Preferably, when the first species is a metal, the radio frequency polarization power may be less than or equal to 80 W. The pressure in the reaction chamber may be less than or equal to 80 mTorr. The duration of the plasma treatment during the deposition cycle may be less than or equal to 1 minute. The dose provided by the ion bombardment makes it possible to remove and / or modify the ligands of the precursor to facilitate the deposition of the metal layer. The amount deposited is limited, which further improves the removal of the ligands without the risk of removing the deposited metal.

[0035] According to one example, metals have an electronegativity between 1.1 and 2.4.

[0036] Preferably, the metal is selected from the group consisting of titanium, tantalum, aluminum, silver, zinc, ruthenium, platinum and copper.

[0037] According to one example, the first species includes a metal and an alkyl, amine, oxygenated (eg, carbonyl) or halogenated ligand.

[0038] According to one example, the plasma treatment is carried out simultaneously with the injection of a precursor based on the first species, and the plasma treatment and the injection of the precursor are carried out simultaneously or by successive pulses, respectively, between the plasma treatment and the injection of the precursor. Thus, the in-situ reduction of the precursor is carried out either in the gas phase or in the adsorbate. The resulting method can be described as a pulsed CVD mode, which is self-limiting with a phase shift between the precursor pulse and the plasma treatment. Preferably, according to this example, the first species includes a metal and an alkyl ligand.

[0039] According to one example, a plasma treatment is performed after injection of a precursor based on a first species, e.g., before and / or simultaneously with injection of a precursor based on a second species, and / or after injection of a precursor based on a second species, the first species being metal-based and the second species comprising at least one of the elements oxygen, nitrogen and sulfur. Depending on the amount of metal precursor deposited, the amount and reactivity of the oxygen, nitrogen or sulfur-based precursor can be limited to adjust the surface reaction before injection of the metal precursor of a subsequent cycle.

[0040] According to one example, the plasma treatment is performed simultaneously with the injection of a precursor based on a second species, the second species being O 2 , N 2 (Optionally, H 2 mixed with NH 3 , H 2 S.

[0041] According to one example, the plasma treatment is performed after the injection of a precursor based on a second species, the second species being H 2 O, O 2 , N.H. 3 is selected from the group consisting of:

[0042] According to an example, when the first species is based on a metal and the second species includes at least one of the elements oxygen, nitrogen and sulfur, the radio frequency polarization power can be 80 W or less. The pressure in the reaction chamber can be 80 mTorr or less. The duration of the plasma treatment during the deposition cycle is 1 minute or less. Thus, the surface reactivity between the precursor based on the first species, the precursor based on the second species (thermal reactant or plasma), and / or the radicals of the oxidizing, nitriding or sulfiding plasma can be activated and / or modified. These plasma conditions can advantageously modify the properties of the deposited material.

[0043] According to one alternative example, when the first species is based on a metal and the second species includes at least one of the elements oxygen, nitrogen and sulfur, the radio frequency polarization power can be 50 W or more. The pressure in the reaction chamber can be 20 mTorr or less. The duration of the plasma treatment during the deposition cycle is 1 minute or more. Thus, the precursors chemisorbed on the surface can be removed or sputtered. These plasma conditions can be useful for selective deposition on 3D substrates.

[0044] According to one example, the plate is configured to be adjusted in height in the reaction chamber, and the method includes adjusting the height of the plate before the plasma treatment, preferably before the deposition cycle. Thus, the distance d can be adjusted by the height of the plate as needed, for example, for different pressure or polarization voltage values. Thus, the reactor becomes more versatile. If the reactor further comprises an inductively coupled plasma source offset from the reaction chamber, this further allows the distance d between the plate and the sidewall to be adjusted, which is particularly advantageous in synergy with an additional ICP source. Thus, it is possible to couple or decouple the CCP and ICP plasmas as needed.

[0045] According to one example, the plasma process is configured such that the plasma has the following ion flow characteristics: - Power density: 0.05~0.5W / cm 2 , - Ion flow: 10 12 ~10 14 ions / (cm 2 .s), - Ion energy: 0~300eV

[0046] Therefore, the pressure in the chamber, the radio frequency polarization frequency and the radio frequency polarization power may be specifically adapted, as described in more detail below.

[0047] According to one example, the reactor is a plasma enhanced atomic layer deposition reactor.

[0048] According to one example, the reactor is substantially 14 ion.cm -2 .s -1 It is configured to generate a plasma having an ion density of: This low density plasma, localized near the substrate, allows for more sophisticated use of ion bombardment.

[0049] According to one example, the distance between the upper surface of the plate and the side wall, e.g. the minimum distance, is 5 cm to 15 cm, preferably 5 cm to 12 cm. This distance range that allows the discharge to be self-sustained is determined by the pressure P in the reactor and the minimum average voltage U of the RF power. min is determined by Paschen's law depending on: min = Pd. This results in a plasma with very low density of 10 14 cm -2 .s -1 This makes it possible to obtain an ion density of 100 mTorr or less, and makes it easier to adjust the plasma characteristics. Furthermore, this makes it possible to obtain a low-density plasma without excessively lowering the pressure in the reaction chamber in the case of a pressure on the order of 1 mTorr to several hundred mTorr, for example, 200 mTorr.

[0050] According to one example, the distance d is proportional to, and preferably equal to, the ratio U / P, where P is the pressure in the reactor, U is the average voltage of the high frequency polarization applied to the plates, and U is the minimum average high frequency self-polarization voltage value U min That's all.

[0051] According to one example, the side walls are arranged at least partially perpendicular to the main extension plane of the upper side of the plate, so that the side walls are substantially vertical.

[0052] According to one example, the side walls are arranged at least partially obliquely with respect to the main extension of the upper side of the plate, so that end effects are avoided and the field lines on the substrate are attenuated with respect to vertical walls.

[0053] According to one example, the sidewall is arranged relative to the main extension of the upper side of the plate so as to form an angle between 15° and 85°, preferably between 30° and 80°. According to one example, in particular if the sidewall is dome-shaped, a tangent to the sidewall defines an angle between 15° and 85°, preferably between 30° and 80°. The tangent to the sidewall may be tangent to a point on the sidewall that lies in the main extension of the upper side of the plate.

[0054] According to one example, the conductive sidewall is disposed at least partially above the plate, protruding along a vertical plane or substantially perpendicular to the upper side of the plate.

[0055] According to one example, the sidewall has rotational symmetry about a direction perpendicular to and substantially central to the top surface of the plate, which symmetry allows arcing of the plasma over the entire surface of the top surface, thus making the plasma more homogenous.

[0056] According to one example, the side wall does not have rotational symmetry around a direction perpendicular and substantially centered on the upper side of the plate, for example the conductive side wall may project in a plane parallel to the main extension of the upper side of the plate and only partially surround the plate.

[0057] According to one example, the side wall at least partially forms a cone above the plate, preferably the side wall has a conical shape with a substantially central axis of rotation relative to the plate.

[0058] According to one example, the sidewall at least partially forms a dome above the plate, and preferably the sidewall has at least partially a hemispherical shape and is preferably substantially centred relative to the plate.

[0059] According to one example, the reactor is configured such that plasma is generated only in the reaction chamber by power applied to the substrate holder, and thus the reactor has a simplified configuration and therefore lower cost than conventional ICP PEALD reactors.

[0060] According to one example, the reactor is configured such that the plasma is generated only between two electrodes, and the reactor is configured such that the plate forms one of the two electrodes. In comparison, in an ICP reactor, the ICP plasma is generated only by rotation provided by RF power.

[0061] According to one example, the reactor does not have an additional ICP plasma type source.

[0062] According to one embodiment, the plates are not configured to be height adjusted within the reaction chamber, thus further simplifying the construction of the reactor.

[0063] According to one example, the reactor further comprises an inductively coupled plasma source offset from the reaction chamber. This reactor is therefore a multi-mode reactor, which allows for enhanced deposition, if desired, by ICP plasma and / or by plasma generated between the plate and the sidewall. This reactor therefore allows for various deposition methods to be carried out, if desired.

[0064] If the reactor further comprises an inductively coupled plasma source offset from the reaction chamber, the reactor may optionally comprise two independent plasma sources that can be used: a power supply for CCP coupling and an inductively coupled plasma source for ICP coupling. The polarization powers applied by these two sources can be set independently.

[0065] According to one example, the plate is not configured to be adjusted in height within the reaction chamber.

[0066] According to one example, the plate is configured to be adjusted in height within the reaction chamber. Thus, the distance d can be adjusted by the height of the plate as needed, for example, for different pressure or polarization voltage values. Thus, the reactor becomes more versatile. If the reactor further comprises an inductively coupled plasma source offset from the reaction chamber, the distance d between the plate and the side wall can be adjusted, which is particularly advantageous for adjusting the characteristics of the plasma in the vicinity of the substrate. Thus, the two CCP and ICP type plasmas can be decoupled or coupled as needed.

[0067] According to one example, the gaseous precursor inlet and pumping module is configured to maintain a pressure in the reaction chamber of substantially between 5 and 200 mTorr, preferably between 5 and 100 mTorr, and preferably between 5 and 80 mTorr, in the reaction chamber, at least when the plasma is generated. These pressures correspond to a high secondary vacuum.

[0068] According to one example, the gaseous precursor inlet and pumping module is configured to maintain a pressure within the reaction chamber substantially below 200 mTorr, preferably below 100 mTorr, at least when generating the plasma.

[0069] According to one example, the gaseous precursor inlet and pumping module is configured to maintain a pressure within the reaction chamber substantially equal to or greater than 10 mTorr, preferably equal to or greater than 15 mTorr, at least when generating the plasma.

[0070] According to one example, the power supply is configured to apply radio frequency power at a frequency of 2 to 100 MHz when the plasma is generated by capacitive coupling between the plate and the sidewall, or an equivalent technique for generating a capacitively coupled plasma between the plate and the sidewall.

[0071] According to one example, the power source (for CCP coupling) is configured to apply radio frequency power at a power of 100 W or less when the plasma is generated by capacitive coupling between the plate and the sidewall. According to one example, a non-zero radio frequency power of 100 W or less is applied to the plate.

[0072] An inductively coupled plasma source offset from the reaction chamber can be configured to apply radio frequency power at a non-zero power between 0 and 300 W absolute value.

[0073] According to one example, the method further includes adjusting at least two plasma parameters, including the distance d, the pressure P in the reactor, and the average voltage U of the radio frequency power applied to the plate, such that: - d is proportional to and preferably equal to the ratio U / P, - U is the minimum average self-polarization voltage U min And that's it. Preferably, this adjustment is performed prior to plasma treatment of the exposed surfaces, so that the parameters can be adjusted without affecting the deposition on the substrate.

[0074] According to one example, the reactor plate is configured to be adjusted in height within the reaction chamber, and the method includes adjusting the distance d by height movement of the plate to reach a distance d that allows plasma generation. It is thus possible to position the plate at a distance that does not allow plasma generation and move it until plasma is observed. Preferably, this adjustment is performed prior to plasma treatment of the exposed surface.

[0075] According to one example, during plasma processing, the pressure in the reaction chamber is substantially between 5 and 200 mTorr, preferably between 5 and 100 mTorr. For example, the precursor supply can be configured to reach this pressure before plasma generation. The gaseous precursor inlet and pumping module can be configured to maintain this pressure.

[0076] According to one example, when performing the adjustment of the plasma parameters, the method further comprises applying a high frequency power, the above parameters making it possible to obtain the following ion current characteristics of the plasma at the plate: - Power density: 0.05~0.5W / cm 2 , - Ion flow: 10 12 ~10 14 ions / (cm 2 .s), - Ion energy: 0~300eV

[0077] According to one example, the power supply comprises an attenuator configured to limit the radio frequency polarizing power of the plasma generated by capacitive coupling.

[0078] In the following description, the term "on" does not necessarily mean "directly on". Thus, when a part or member A is indicated as bearing "on" a part or member B, this does not mean that parts or members A and B are necessarily in direct contact with the other. These parts or members A and B may be in direct contact or bear against each other through one or more other parts. The same applies to other expressions such as the expression "A acts on B", which may mean "A acts directly on B" or "A acts on B through one or more other parts".

[0079] In this patent application, the term movable corresponds to a rotational or translational movement or a combination of movements, for example a combination of rotation and translation.

[0080] In the detailed description that follows, terms such as "horizontal", "vertical", "longitudinal", "transverse", "upper", "lower", "top", "bottom", "front", "rear", "inner", "outer" and the like may be used. These terms should be interpreted relatively with reference to the normal position of use of the reactor. For example, the terms "horizontal" and "longitudinal" correspond to the main direction of extension of the upper side of the plates.

[0081] A reference system is also used where the longitudinal or left / right direction corresponds to the x-axis, the transverse or rear / front direction corresponds to the y-axis, and the vertical or bottom / top direction corresponds to the z-axis.

[0082] Microelectronic devices are understood to mean any type of device produced using microelectronic means. In addition to devices for purely electronic purposes, these devices include in particular micromechanical or electromechanical devices (MEMS, NEMS, etc.) and optical or optoelectronic devices (MOEMS, LEDs, etc.).

[0083] This may consist of a device intended to perform an electronic, optical, mechanical function, etc. It may also consist of an intermediate product intended only to create another microelectronic device.

[0084] Furthermore, a plasma based on a species may be based on or equivalently formed from a chemistry that includes only this species and, optionally, one or more other species, e.g., a noble gas such as argon or helium.

[0085] The term "step" should be understood as the completion of a portion of a method and may refer to a series of substeps. The term "step" does not necessarily imply that operations performed during a step are simultaneous or immediately consecutive. In particular, some operations of a first step may be followed by operations related to a different step, and other operations of the first step may be performed thereafter. Thus, the term "step" does not necessarily imply a single operation that is inseparable in time and in the order of steps of the method.

[0086] In this patent application, when gas mixtures are expressed in percentages, these percentages correspond to the proportion of the total flow rate of gases injected into the reactor. Thus, if a gas mixture intended to form a plasma, etc., contains x% of gas A, this means that the injection flow rate of gas A corresponds to x% of the total flow rate of gases injected into the reactor to form a plasma.

[0087] A parameter "substantially equal to / greater than / less than" a given value is understood to mean that this parameter is equal to / greater than / less than the given value within approximately 10% of this value. A parameter "substantially between" two given values ​​is understood to mean that this parameter is at least equal to the lowest given value within approximately 10% of this value, and at most equal to the highest given value within approximately 10% of this value.

[0088] The plasma enhanced atomic layer deposition method 4 and the reactor 1 will now be described in more detail according to example embodiments.

[0089] 2 illustrates method 1 according to an example embodiment. Optional steps are indicated by dotted lines. Initially, method 4 includes providing 40 a substrate 2 having an exposed surface 20. The substrate 2 is provided in a plasma reactor 1 comprising a reaction chamber 10. The reactor 1 is configured to generate a capacitively coupled plasma between a plate 110 and a sidewall 100 of the reaction chamber 10 of the reactor 1. An example of the plasma reactor 1 is described in more detail below.

[0090] Following the provision 40 of the substrate 2, the method 4 comprises a number of atomic layer deposition cycles 41 on the exposed surface 20 of the substrate 2. The deposition cycle 41 comprises an injection of a precursor based on a first species 410 into the reaction chamber 10. The cycle 41 further comprises a plasma treatment 412 of the exposed surface 20 of the substrate 2 with a plasma generated by capacitive coupling between the plate 110 and the sidewall 100 of the reaction chamber 10. As will be seen hereinafter, any relative order between precursor injection and plasma treatment can be envisaged, including a plasma treatment followed by precursor injection.

[0091] The plasma is generated by applying high frequency power to the plate 110. Thus, the plasma is generated locally in the vicinity 3 of the substrate 2 with a much lower ion current than in conventional CCP reactors. This reactor 1 makes it possible to improve the properties of materials (density, purity, crystal structure, internal stress) using low energy ion bombardment. Moreover, it opens new development routes for methods related to metals, oxides, nitrides and sulfides on 2D and 3D substrates as well as surface and topography selective deposition methods.

[0092] 2, cycle 41 may further include an injection of a precursor based on a second species 413. Cycle 41 may be repeated multiple times n until a desired layer thickness is reached. Depending on the relative order between precursor injections 410, 413 and plasma treatment 412, and depending on the parameters of plasma treatment 412, the surface reactions and thus the properties of the grown layer may be modified. Some examples of deposition cycles 41 are described below as non-limiting examples. It is understood that these features may also be combined to arrive at other example embodiments, unless explicitly stated otherwise.

[0093] According to an example, the plasma treatment 412 is performed in the reaction chamber 10 simultaneously with at least one of the injections 410, 413 or subsequent to at least one of the injections 410, 413. By "simultaneously" it is meant that the plasma treatment 412 is performed at least partially simultaneously with the injections 410, 413. There may be an interval between the plasma treatment 412 and the injections 410, 413.

[0094] During the development of the invention, several plasma treatment modes have been demonstrated depending on the deposition required. According to a first example, the polarization power can be 80 W or less, the pressure in the reaction chamber 10 can be 80 mTorr or less and the duration of the plasma treatment 412 during cycle 41 can be 1 minute or less. These parameters make it possible to activate and / or modify the surface reactivity between precursor injections of the same cycle 41 or between successive cycles. In particular, these parameters make it possible to adjust the reactivity of the ligands of the precursors to influence the growing layer. According to a second example, the radio frequency polarization power can be 50 W or more, the pressure in the reaction chamber 10 can be 20 mTorr or less and the duration of the plasma treatment 412 during cycle 41 can be 1 minute or more. These parameters make it possible to remove the precursors chemisorbed on the surface. Thus, the material to be deposited can grow in localized layer portions. These conditions therefore allow selective deposition, for example on 3D substrates.

[0095] Each implantation 410, 413 and / or each plasma treatment 412 may be followed by a purge step 414. This purge 414 makes it possible to remove species that are not deposited on the exposed surface 20 of the substrate 2 and to remove reaction products.

[0096] During plasma generation, the plasma treatment 412 can include injecting a rare gas, also called an inert gas, such as helium or argon, into the reaction chamber 10. Additionally, this gas can be dihydrogen H 2In fact, argon-based plasmas are low energy compared to other species. Surface reactions can be further fine-tuned in synergy with the generated low density volumetric plasma while limiting the risk of damaging exposed surfaces 20.

[0097] Plasma treatment 412 uses a capacitive, and therefore low-density, plasma generated between the plate 110 and the sidewall 100, and method 4 enables the deposition of a wide variety of layers, particularly layers for which deposition by conventional plasma-enhanced deposition methods remains limited.

[0098] For example, method 4 allows for the deposition of a metal layer on exposed surface 20 of substrate 2. An example of metal layer deposition will now be described.

[0099] Cycle 41 may include an injection 410 of a metal-based precursor. Cycle 41 may include only one injection of a first metal-based precursor. Alternatively, cycle 41 may include an injection 413a of a second metal-based precursor, in particular a precursor based on a metal other than the first metal. When using several precursors based on different metals, the method allows the deposition of a metal alloy layer.

[0100] To deposit a metal layer, the precursors injected during the cycle are preferably all metal-based. Neutral gases or hydrogen H 2 The precursors of the gases injected into the chamber 10 during plasma treatment 412 intended to form the reactive atmosphere of the plasma, such as, are distinguished and may be free of metals according to this example.

[0101] To deposit a metal layer, the plasma treatment 412 can be performed simultaneously and / or after the injection 410 of a first metal-based precursor. Alternatively or additionally, the plasma treatment 412 can be performed simultaneously and / or after the injection 413a of a second precursor. Thus, the plasma treatment 412 makes it possible to remove ligands from the metal precursor, which creates pendant bonds that facilitate metal-metal absorption during layer growth.

[0102] For example, as shown in Figure 3A, cycle 41 can include injection 410 of a metal-based precursor. Concurrent with this injection, a plasma treatment 412 can be performed.

[0103] According to one example, the injection and / or plasma treatment can be continuous. According to one example, the injection 410 and / or plasma treatment 412 can be intermittent within the cycle 41. The use of pulses, especially precursor pulses, can make it possible to modulate the growth mechanism. These pulses include H 2 Metal layer deposition with Ar / Ar or Ar-only plasmas is particularly advantageous, especially for pendant bond formation. In fact, it is more difficult to form this type of layer compared to oxides / nitrides / sulfides, which are much simpler to form by ligand reactivation (chemical substitution).

[0104] As shown in FIG. 3B, the plasma treatment 412 may include several plasma pulses. In cycle 41, the application of radio frequency power to the plate 110 may be intermittent, in order to generate plasma only intermittently, i.e. the plasma treatment 412 may include phases of applying RF power to the plate 110 separated by phases of not applying RF power. Similarly, the injection 410 may be intermittent, i.e. the injection 410 may include phases of injecting a metal-based precursor into the chamber 10 separated by phases of not injecting the precursor into the chamber 10. The phases of application of RF power and injection each form a pulse. As shown in FIG. 3B, these pulses may be simultaneous between the injection 410 and the plasma treatment 412. Alternatively, as shown by the dotted lines in FIG. 3B, these pulses may be offset in time.

[0105] Note that this example of plasma pulsing and / or pulsing during precursor injection may also be applied to the injection 413a of the second metal-based precursor, either for only a portion of the injections 410, 413a or for each injection 410, 413a of cycle 41.

[0106] Preferably, the plasma treatment 412 and the injection of the precursor 410, 413a are performed simultaneously or in successive pulses, respectively. "Successive" means that the pulses are not completely simultaneous between the injection and the plasma treatment, and preferably, the pulses do not overlap in time between the injection and the plasma treatment. This allows an in situ reduction of the precursor either in the gas phase or in the adsorbate on the exposed layer 20 of the substrate 2. The pulse durations can be substantially identical between the injection 410, 413a and the plasma treatment 412, or these durations can be independent. This mode is self-limiting with a phase shift between the precursor pulses and the plasma treatment. The metal precursor does not react by itself, so that once the surface of the substrate is saturated with the adsorbate, no further reaction can take place. The plasma treatment allows the reduction of the ligands of the adsorbate, and a new metal precursor pulse can again generate new adsorbates by release from the anchor sites. The pulse durations for the injection of the precursor and the plasma treatment can be adapted depending on the circumstances, in particular depending on the expansion maintained by the precursor at the inlet to the chamber. For example, the injection of the precursor may be on for 1 second or less and the plasma duration may be 20 seconds or less.

[0107] Preferably, when a metal-based precursor is injected by pulsing, the precursor comprises a metal and an alkyl ligand. The ligand is preferably not halogenated, since halogenated ligands can damage the reactor walls by forming etching chemicals. Furthermore, halogens are highly electronegative, and they strengthen the metal-halogen bond, thereby making the creation of the pendant bond even more difficult.

[0108] According to one example, as shown in Figures 3C and 3D, the injection 410, 413a of a metal-based precursor may be followed by a plasma treatment 412. This may be applied to the injection 410 of a first metal-based precursor, as shown in Figure 3C, and / or may be applied to the injection 413a of a second metal-based precursor, as shown in Figure 3D.

[0109] As shown in FIG. 3E, when a cycle 41 includes several injections 410, 413a of metal-based precursors, each injection can be performed simultaneously with a plasma treatment 412, with the injection and associated plasma treatment 412 being separated from the injection 413a and the next plasma treatment 412 by a purge step 414.

[0110] It should be noted that combinations of these examples are possible, for example injection 410 of a first metal-based precursor simultaneous with plasma treatment 412, followed by injection 413a of a second metal-based precursor itself followed by plasma treatment 412.

[0111] According to one example, the plasma treatment 412 may include an injection of argon mixed with dihydrogen in the reaction chamber 10, for example, as shown in FIG. 3C, if the plasma treatment 412 is performed following the injection of a precursor based on the first metal. When generating the plasma, the plasma treatment 412 may not include an injection of hydrogen into the reaction chamber 10. In fact, during the development of the present invention, it was demonstrated that it is not necessary to inject a reducing gas, such as hydrogen, into the chamber in order to reduce the metal to be deposited. The properties of the plasma generated by capacitive coupling combined with the injection of the metal precursor are sufficient to grow a metal layer on the exposed surface 20 of the substrate 2. This is particularly true when the injections 410, 413a and the plasma treatment 412 are simultaneous, especially when the metal precursor contains alkyl-type ligands. If the plasma treatment 412 and / or the injections 410, 413a of the precursors are performed by pulsing, the plasma treatment still preferably includes an injection of dihydrogen into the reaction chamber 10. With simultaneous injection, it is possible to avoid the risk of reactive plasmas (e.g. H ) that may destroy the precursor. 2 It is preferable to avoid deposition of a CVD type growth (i.e. not layer / layer, since it is not self-limiting). In continuous mode, it may be acceptable to use a reactive plasma, since only the adsorbate ligands are treated by this plasma.

[0112] Concerning the plasma generation parameters, for metal layer growth, these parameters are preferably selected to modify and / or remove the precursor ligands and to promote the deposition of the metal layer by metal-metal adsorption. Thus, the RF polarization power can be 80 W or less, the pressure in the reaction chamber 10 can be 80 mTorr or less and the duration of the plasma treatment during cycle 41 can be 1 minute or less. Thus, the amount deposited is limited, thereby improving the removal of the ligands without the risk of removing the deposited metal.

[0113] With regard to the type of metal, the method is particularly suitable for the deposition of metals such as titanium, tantalum, aluminum, silver, zinc, ruthenium, platinum, copper, etc.

[0114] The first metal-based precursor and the second metal-based precursor are preferably organometallic precursors dedicated to the ALD process. The process can be adapted depending on the metal precursor. For example, in the case of chlorinated metal precursors, N 2 / H 2 Conversely, in the case of organometallic precursors, an inert plasma, in particular an Ar plasma, is chosen to remove the organic ligands.

[0115] An example of deposition will now be described with reference to Figures 4A to 4C.

[0116] To deposit a metal oxide, nitride and / or sulfide layer on the exposed surface 20, the method includes injection 410 of a metal-based precursor and injection 413b of a precursor containing at least one of the elements oxygen, nitrogen and sulfur. Preferably, in cycle 41, injection 413b of oxygen-, nitrogen- and / or sulfur-based precursor follows injection 410 of the metal-based precursor. A plasma treatment 412 can be performed before and / or simultaneously with and / or after injection 413b of oxygen-, nitrogen- and / or sulfur-based precursor. Thus, the amount and reactivity of oxygen-, nitrogen- and / or sulfur-based precursor is limited to adjust the surface reactivity before injection 410 of the metal-based precursor of the subsequent cycle 41. Depending on the relative order between the plasma treatment 412 and the injection 413b of an oxygen, nitrogen and / or sulfur based precursor, this precursor may be referred to as a "thermal reactant" if the plasma treatment 412 follows injection 413b, or as a "plasma reactant" if the plasma treatment 412 is simultaneous with injection 413b.

[0117] For example, as shown in Figure 4A, injection 410 of a metal-based precursor is followed by injection 413b of an oxygen, nitrogen and / or sulfur-based precursor, followed by plasma treatment 412. According to this example, the oxygen, nitrogen and / or sulfur-based precursors are oxidized using an ozone generator with H 2 O, O 2 , N.H. 3 , or O 3 The metal precursor may be heat treated with a second precursor prior to the plasma treatment 412. The plasma treatment 412 may be argon-based.

[0118] According to a second example, for example as shown in FIG. 4B, injection 410 of a metal-based precursor may be followed by injection 413b of an oxygen, nitrogen and / or sulfur-based precursor and may be performed simultaneously with plasma treatment 412. According to this example, the oxygen, nitrogen and / or sulfur-based precursor may be O 2 , N 2 , N.H. 3 and H2 S. 2 O and O 3 The precursor H is not used because it does not form a plasma. 2 In the case of S, a simultaneous plasma treatment is required to activate the reaction energy. Thus, if the injection 413b of the second precursor is simultaneous with the plasma treatment 412, preferably a layer of metal oxide, nitride, or sulfide, respectively, is deposited. Oxygen, nitrogen and / or sulfur based precursors may be injected 413b together with argon.

[0119] According to a third example shown in FIG. 4C, injection of a metal-based precursor 410 may be followed by a plasma treatment 412, followed by injection of an oxygen and / or nitrogen and / or sulfur-based precursor, where the plasma treatment is also performed simultaneously with the sulfur injection 413b.

[0120] The above two plasma treatment 412 modes can be used for the deposition of oxide, nitride and / or sulfide layers. According to a first example, the radio frequency polarization power can be 80 W or less, the pressure in the reaction chamber can be 80 mTorr or less, and the duration of the plasma treatment during a deposition cycle can be 1 minute or less. These parameters make it possible to adjust the surface reactivity between the metal-based precursors, the oxygen, nitrogen and / or sulfur-based precursors (thermal or plasma reactants), and the plasma radicals.

[0121] According to a second example, the RF polarization power can be 50 W or more, the pressure in the reaction chamber can be 20 mTorr or less, and the duration of the plasma treatment during the deposition cycle can be 1 minute or more. Thus, again, the precursors chemisorbed on the surface can be removed. Thus, the material to be deposited can grow in localized layers. These conditions therefore allow selective deposition, for example on 3D substrates.

[0122] According to one example, the metal-based precursor comprises a metal and an amino group. In the case of the amino precursor, the plasma parameters can be adjusted to not only desorb the ligand from the metal to deposit a metal atomic layer (duration and energy of the ion current), but also to break the N-C bond of the ligand to promote the deposition of nitride. For example, the precursor can have one of the following chemical formulas:

[0123] [ka]

[0124] An example of the reactor 1 will now be described with reference to Figures 5 to 8. The parameters of the plasma treatment 412 will now be further described.

[0125] Reactor 1 is more particularly intended for plasma-enhanced atomic layer deposition.

[0126] The reactor 1 comprises a reaction chamber 10 intended to accommodate a substrate 2, in which a deposition is intended to be carried out. This chamber 10 is bounded by one or more side walls 100, an upper wall 101 and a lower wall 102.

[0127] To carry out the deposition of a layer on the substrate 2, the reactor 1 comprises an inlet and an outlet for gaseous precursors and / or gaseous species for plasma formation. The reactor 1 comprises a gaseous precursor inlet 12 arranged to transport the gaseous precursors to the chamber 10, as indicated by the arrows at the top of the reactor in Figs. 5 to 8. Furthermore, the gaseous precursor inlet 12 may be arranged to introduce a gas for plasma formation, for example a noble gas such as helium or argon, into the chamber 10. The reactor 1 further comprises a pumping module 13 for the chamber 10. The pumping module 13 makes it possible to exhaust the gaseous species present in the chamber, as indicated by the two arrows at the bottom of the reactor in Figs. 5 to 8. These species may in particular be exhausted between different ALD deposition cycles. Furthermore, the pumping module 13 together with the inlet 12 makes it possible to maintain a given pressure in the chamber 10, which is typically lower than atmospheric pressure.

[0128] The substrate 2 is accommodated in the reaction chamber 10 by a sample holder 11. The sample holder may comprise a plate 110 connected to an arm 111 and configured to receive the substrate 2. The plate 110 may in particular have a planar upper side 110a for supporting the substrate 2. The upper side 110a is, for example, substantially horizontal. It is noted that the plate 110 may have other inclined surfaces, for example edges or a rounded lower side.

[0129] The reactor 1 is configured such that the plasma is generated by capacitive coupling between the upper surface 110a of the plate 110 and the sidewall 100 and is polarized at ground, as shown in Figures 5 to 8. Therefore, the plate 110 is conductive. The plate 110 may be at least partially formed from a conductive material. The sidewall 100 is at least partially conductive. The sidewall 100 may be at least partially formed from a conductive material. The reactor 1 further comprises a power supply 14 configured to apply high frequency power to the plate 110. The power supply 14 may comprise, for example, a high frequency power generator 142 connected to a high frequency transmission member 140 leading to the plate 110.

[0130] The power supply 14 comprises a regulation device 141, which induces an RF voltage, also called the self-polarization voltage, on the plate 110, making it possible to generate a CCP plasma. Preferably, the regulation device 141 comprises an automatic matching unit, which matches the impedance of the plasma in the chamber 10 to the impedance of the RF power generator 142, in order to minimize the reflected power and to allow the discharge to be self-sustaining. The power supply 14 is configured to generate the plasma and to allow the self-polarization of the plate 110. In fact, it supplies the plasma with power, and the matching unit matches the impedance to minimize the reflected power and to allow the discharge to be self-sustaining. The plasma is a discharge with its own impedance depending on its degree of ionization and on the chemical nature of the gases and on the parameters of the geometric reactor and the power supply. In a reactor receiving substrates with a maximum diameter of 200 mm, the self-polarization voltage can typically be between 50V and 300V, with a power varying between 10W and 100W. The regulation device 141 may in particular comprise an attenuator configured to limit the power of the generator 142.

[0131] The sidewall 100 is at least partially non-parallel to the upper surface 110a of the plate 110. The upper surface 110a of the plate 110 and the sidewall 100 at least in its part non-parallel to the upper surface of the plate are separated by a distance d configured to generate plasma by capacitive coupling between the plate 110 and the sidewall 100, each of which acts as an electrode for plasma generation. During the development of the present invention, it was demonstrated that in fact it is possible to generate plasma by capacitive coupling in the vicinity of the substrate 2 in the zone 3 for generating plasma by arranging the sidewall 100 and the upper surface 110a non-parallel and coupling them at a certain distance d.

[0132] Thus, the plasma is generated locally in the vicinity 3 of the substrate 2 with a much lower ion current than in the case of conventional CCP reactors. This reactor 1 makes it possible to improve the properties of the material (density, purity, crystal structure, internal stress) by using low energy ion bombardment. Moreover, as explained above with respect to method 4, this opens new development paths for methods related to metals, oxides, nitrides and sulfides on 2D and 3D substrates, as well as surface and topography selective deposition methods. This reactor 1 therefore makes it possible to carry out a wide variety of deposition types, unlike existing reactors that are more limited. In fact, this plasma generation mode makes it possible to carry out the deposition of metal layers, in particular of transition metals and / or rare earths. Furthermore, the deposition of oxide, nitride and / or sulfide layers, in particular of transition metals and / or rare earths, is also possible.

[0133] The distance d that allows the plasma discharge to be self-sustained is determined by the pressure P in the reactor and the minimum average RF self-polarization voltage U min is determined by Paschen's law depending on: min = Pd. Thus, the distance d is a function of the pressure P in the chamber 10 and the minimum average voltage U set by the power supply 14. min It is understood that the amount of oxygen consumed may vary depending on the amount of oxygen consumed.

[0134] This distance d is the shortest distance between the two electrodes formed by the plate 110 and the side wall 100. This distance can be, for example, the distance between one or two ends of the plate 110 and the side wall 100, more specifically, the distance between one or two ends of the upper surface 110a of the plate 110 and the side wall 100, preferably the distance between the upper surface of the plate 110 and the side wall 100, more specifically, the distance between one or two ends of the upper surface 110a of the plate 110 and the side wall 100. During plasma generation, the plate 110 and the side wall 100 are separated from each other by the distance d.

[0135] According to one example, the distance d between the upper surface 110a of the plate 110 and the side wall 100 is 5 cm to 15 cm, preferably 5 cm to 12 cm, and even more preferably 5 to 8 cm. This range of the distance d is, for example, when the pressure PU is 80 mTorr or less (1 mTorr=10 -3 Torr and 1 Torr≈133.322 Pa), and the absolute value is substantially between 0 V (excluding 0) and 300 V [0 V; 300 V], preferably between 50 V and 300 V [50 V; 300 V], more preferably between 100 V and 300 V. min (self-polarization voltage). Therefore, it is essentially 10 14 cm -2 .s -1 A sufficiently low ion current can be obtained below:

[0136] For capacitively coupled ALD deposition according to the invention, the pressure is of the order of 1 mTorr to several hundred mTorr, for example 200 mTorr. Typically the applied RF power is less than or equal to 100 W, and this power is non-zero. The pressure, the self-polarization voltage and the distance parameters are interdependent to obtain a capacitively coupled plasma generation. As will be explained in more detail hereinafter, in the reactor 1, it is possible to set d and to adjust the self-polarization voltage and the pressure within the corresponding ranges mentioned above. Alternatively, the distance d can be adjustable, for example by means for setting the height of the plate 110, as will be explained hereinafter.

[0137] It should be noted that the type of gas can affect Paschen's law. These data are tabulated and known to those skilled in the art, for example as described for argon in C. Torres, PG Reyes, F. Castillo, H. Martinez, Journal of Physics: Conference Series; Bristol Vol. 370, No. 1, (Jun 2012). Thus, those skilled in the art can adapt these parameters, for example by adjusting the self-polarization voltage and pressure (d fixed), or additionally by adjusting the distance d, especially within the ranges mentioned above.

[0138] To generate a plasma, the conductive sidewall 100 may be at least partially disposed above the plate 110, protruding from said wall in a plane perpendicular to the upper side 110a of the plate 110. It is therefore understood that at least a portion of the wall 100 is disposed facing the upper side of the plate, so that a capacitively coupled plasma may be generated between the sidewall 100 and the upper side 110a of the plate 110 on which the substrate 2 is disposed.

[0139] According to one example, the reaction chamber 10, and more specifically the side wall 100, has a rotational symmetry about a direction parallel to the z-axis and substantially centered with respect to the upper side 110a of the plate 110. This symmetry allows the plasma to arc across the entire surface of the upper side 110a of the plate 110. When the plasma is ignited, it propagates across the lower electrode (the upper side 110a of the plate 110). Thus, the plasma becomes more homogeneous.

[0140] According to one example, the side wall 100 is arranged perpendicular to the main extension plane (x, y) of the upper side 110a of the plate 110. However, the perpendicular wall generates very dense field lines at the edge of the substrate, thus generating a more localized (and therefore energetic) plasma. The more localized plasma can lead to disruptive phenomena and therefore edge effects at the edge of the substrate.

[0141] To limit this, as shown in figures 5 and 6, the side walls 100 are preferably arranged at least partially obliquely to the main extension plane (x, y) of the upper side 110a of the plate 110. Equivalently, the side walls are arranged neither parallel nor perpendicular to the main extension plane (x, y) of the upper side 110a. This oblique arrangement makes it possible in particular to improve the plasma obtained by limiting edge effects. The plasma generated is therefore more homogeneous for better layer deposition.

[0142] The side wall 100 may include several portions 100a, 100b. The first portion 100a may be arranged substantially perpendicular to the main extension plane (x, y) of the upper side 110a. The second portion 100b may be arranged obliquely to the main extension plane (x, y) of the upper side 110a of the plate 110. Hereinafter, the portion 100b of the side wall is non-limitingly considered as being arranged obliquely to the plane (x, y).

[0143] For example, as shown in Fig. 5, the second portion 100b of the side wall 100 may have a conical shape above the plate 110. This shape may be selected more specifically depending on the distance d. The portion 100b may for example be in the form of a cone truncated by the upper side wall 101. The truncated cone shape prevents the side wall from forming a cavity in which the species generated by the plasma can accumulate. Preferably, the second portion 100b has a conical shape with its axis of rotation substantially central with respect to the plate 110.

[0144] For example, as shown in FIG. 6, the second portion 100b of the side wall 100 may form a dome above the plate 110. The portion 100b may, for example, be in the form of a hemisphere above the plate 110. Again, this shape may be selected, more specifically, depending on the distance d. The dome-like shape, more specifically the hemispherical shape, allows to make the volume of the chamber smaller (thus consuming less reactants and making the chamber easier to pump) and to limit the dead volume in the chamber. Preferably, the second portion 100b has a hemispherical shape and is preferably substantially central with respect to the plate 110. The dome may be truncated by the upper plate 101. Alternatively, the side wall 100 may form a dome that is not truncated.

[0145] For example, with respect to the dome-shaped configuration discussed above, it will be appreciated that the side wall 100 may extend to form all or a portion of the upper wall 101 .

[0146] According to an example, the plate 110 may not be height adjustable in the chamber 10. Equivalently, the plate 110 may not be movable in the chamber 10 at least along the vertical direction z. However, the plate 110 may also be configured to be movable, for example in rotation, to a set height in the chamber 10, for example to improve the uniformity of the deposition. This rotation may be about the axis of its arm 111. Alternatively, the plate 110 may be completely fixed in the chamber 10. In particular, if the plate 110 is not height adjustable, the shape of the side wall 110 may be adapted relative to the sample holder to obtain a distance d that allows plasma generation. Thus, the reactor 1 may be of simplified construction and therefore less costly.

[0147] According to another example, the plate 110 may be adjustable in height within the chamber 10, as indicated by the vertical double arrow in Figures 5 to 8. Equivalently, the plate 110 may be movable at least along the vertical direction z within the chamber 10. Thus, the distance d may be adjusted, for example, to accommodate different pressures or minimum voltages U, as required. min The value can be adjusted by the height of the plate 110. Moreover, the plasma properties can be adjusted by adjusting the height of the plate 110, while being careful not to extinguish the plasma 3. Moreover, height adjustment of the plasma 110 can be particularly advantageous when the reactor 1 comprises an additional plasma source, as will be explained in more detail hereinafter. Moreover, the plate 110 may be configured to be movable, for example in rotation, for example to improve the deposition uniformity. Again, this rotation can be about the axis of its arm 111.

[0148] The movement of the plate 110 may be driven, for example, by a motor, not shown.

[0149] For example, as shown in Fig. 5 and Fig. 6, the reactor 1 may be configured to only form plasma by capacitive coupling between the plate 110 and the side wall 100 in the reaction chamber. The plasma may in particular only be generated between two electrodes. The plate 110 may form one of the electrodes. The side wall 100 may form the other electrode. The reactor 1 may only comprise capacitive coupling generation between the plate 110 and the side wall 100 as the plasma source. Thus, the configuration of the reactor 1 is simplified and therefore less costly. It should be noted that according to this example, the height of the plate 110 can be adjusted.

[0150] For example, as shown in Fig. 7, the reactor 1 may include an inductively coupled plasma source 15 offset from the chamber 10. The reactor 1 may thus be an ICP and / or CCP multimode reactor. If desired, the plasma may be generated in ICP mode and / or CCP mode. To that end, the reactor 1 may include a high frequency induction source including a coil 15 supplied by a high frequency power generating device 16. The power supply 14 and the induction source 15, 16 are configured such that the RF power applied to the plate 110 is independent of the RF power of the induction source.

[0151] When the reactor 1 operates in CCP mode, plasma generation is performed by capacitive coupling between the upper surface 110a of the plate 110 and the side wall 100, as previously explained. When the reactor 1 operates in ICP mode, plasma generation is performed by an inductively coupled plasma source 15. The power supply 14 can then be used as a polarizing device configured to induce a polarization voltage at the substrate 2, allowing ions to be extracted from an offset plasma with a controlled incident energy when they reach the vicinity of the substrate 2.

[0152] The gaseous precursor inlet 12 may be located at the induction source 15, 16. The induction source 15, 16 may be isolated from the chamber 10 by a valve 120 having an open configuration for circulating plasma species from the source to the chamber 10 and a closed configuration for blocking these species. It should be noted that another gaseous precursor inlet may be located directly at the chamber 10 without passing through an induction source.

[0153] Preferably, the plate 110 is adjustable in height if the reactor 1 may comprise an inductively coupled plasma source 15 offset from the chamber 10. Thus, depending on the distance d between the plate 110 and the sidewall 100, the plasma may be generated only by the inductive sources 15, 16 or by both the inductive sources 15, 16 and the capacitive coupling between the plate 110 and the sidewall 100. Note that according to this example, the plate 110 is adjustable in height.

[0154] For example, as shown in figure 8, the reactor 1 may further comprise a module 17 for determining the thickness of the deposited layer. This module 17 may comprise an ellipsometer coupled to the reactor 1, for example at the side wall 100 of the reactor 1. Figure 8 represents the principle. In fact, the two intersection points of the emitted and reflected light rays intersect at the surface of the substrate where the growth takes place.

[0155] Example operating parameters for reactor 1 will now be described.

[0156] The RF power and pressure conditions within the chamber 10 allow the plasma ion flow characteristics to be finely tailored.

[0157] The gaseous precursor inlet 12 and pumping module 13 may be configured to maintain a pressure of substantially 5-200 mTorr, preferably 5-100 mTorr, preferably 5-80 mTorr, within the reaction chamber 10 at least during the plasma treatment 412. Preferably, the pressure within the reaction chamber is substantially equal to or less than 100 mTorr, at least during the plasma treatment 412.

[0158] The power supply 14 may be configured to apply radio frequency power at a power of 100 W or less.

[0159] The power supply 14 may be configured to apply high frequency power at a frequency between 2 and 100 MHz when the plasma is generated by capacitive coupling.

[0160] It should be noted that when the reactor is equipped with an inductively coupled plasma source 15 and operated in ICP mode, the power supply acting as a polarization device configured to induce a polarization voltage in the substrate 2 may be operated at a higher power and / or at a frequency other than the range specified above.

[0161] These parameters, within the ranges shown, make it possible to obtain the following ion current characteristics of the plasma generated between the sidewall 100 and the plate 110, adapted for PEALD deposition: - Power density: 0.05~0.5W / cm 2 - Ion flow: 10 12 ~10 14 ions / (cm 2 .s) - Ion energy: 0~300eV (1eV≒1.60218.10 -19 J).

[0162] The following table sets forth examples of plasma generation parameters according to the present invention for an argon plasma without an offset ICP source: The distance d corresponding to these measurements is 5-6 cm.

[0163] [Table 1]

[0164] The parameters Vdc probe and flex give the self-polarization voltage corresponding to the impedance match between the plasma and the matching unit of the reactor. Vdc probe is given by a probe measurement (which allows the ion current to be determined) and Vdc flex is given directly by the matching unit of the reactor. With RF power applied to the reactor, the self-polarization voltage remains zero if the plasma is not ignited or self-sustained. In this case, all power is stored in the matching unit.

[0165] 9A-9D show the RF power W applied to the plate 110 for the generated ion current 4 (arbitrary units) at a constant pressure P and as a function of the self-polarization voltage U for the example parameters of Table 1. CCP It explains the impact of.

[0166] 10A-10C show the relationship between the constant RF power W applied to plate 110 for the example parameters in Table 1. CCP 1 illustrates the effect of a pressure P applied to the plate 110 on the generated ion current 4 (in arbitrary units) at 100 V and as a function of the self-polarization voltage U and the ion energy E.

[0167] In view of the foregoing description, it is clear that the present invention provides an improved plasma enhanced deposition solution, which is improved in particular with respect to the type of layer deposited and / or deposition selectivity. The PEALD method allows for better ion bombardment control, in particular a gentler plasma enhancement than existing solutions, and therefore, thereby resulting in less defect induction. It is clear that the present invention provides an improved plasma enhanced deposition reactor, which in particular allows for a gentler plasma enhancement than existing solutions, and therefore, thereby, resulting in less defect induction.

[0168] The present invention is not limited to the above-mentioned embodiments, but includes all embodiments covered by the present invention. The present invention is not limited to the above-mentioned examples. Many other variations are possible, for example by combining the above-mentioned features, without departing from the scope of the present invention. Furthermore, features described with respect to one aspect of the present invention can be combined with another aspect of the present invention. In particular, the method may include any steps resulting from the implementation of the functions of a reactor, and the reactor may have any features that allow, for example, elements configured for the implementation of the steps of the method.

[0169] In the example shown, the inlet 12 is represented on the upper side 101 of the reactor 1. Other arrangements are possible, for example on the side wall 100. The same applies to the pumping module 13. [Explanation of symbols]

[0170] 1' Reactor 2. Substrate 3...Generation 4. Ion flow 10' Reaction chamber 11. Sample holder 12' Gaseous precursor inlet 13' Pumping module 14...Power supply 15 Inductively Coupled Plasma Source 15'...Induction source 16' ···Radio Frequency (RF) Power Devices 18'...electrode 20...exposed surface 100...Wall 100a...First part 100b...Second part 101... Wall 102...lower wall 110 Conductive plate 110'...electrode 110a...Top side 111 Arm 120···Valve 140 High-frequency transmission components 141 Regulating device 142 High frequency power generator d distance

Claims

1. - A supply (40) of a substrate (2) having an exposed surface (20) to a plasma reactor (1), wherein the plasma reactor comprises a reaction chamber (10) separated by walls (100, 101) and a conductive plate (110) having an upper surface (110a) on which the substrate (2) is placed, and the side wall (100) of the reaction chamber is at least partially non-parallel to the upper surface (110a) of the plate (110) and is conductive, supply (40), Each cycle is, - Injection of a precursor based on the first species into the reaction chamber (410) - Plasma treatment (412) of the exposed surface (20) of the substrate (2) by applying high-frequency power to the plate (110) and the plasma generated by capacitive coupling between the plate (100) and the side wall (110), A plurality of atomic layer deposition cycles (41) on the exposed surface (20) of the substrate (2), including Plasma-enhanced atomic layer deposition method (4).

2. The method according to claim 1 (4), wherein the plurality of deposition cycles (41) further comprises the injection (413) of a precursor based on a second species into the reaction chamber.

3. The method according to claim 1 or 2 (4), wherein the plasma treatment (412) is performed simultaneously with or following at least one injection of the precursor into the reaction chamber (410, 413).

4. The method according to claim 1 or 2 (4), wherein the high-frequency power is 80 W or less, the pressure in the reaction chamber (10) can be 80 mTorr or less, and the duration of the plasma treatment (412) during the deposition cycle (41) is 1 minute or less.

5. The method according to claim 1 or 2 (4), wherein the high-frequency polarization power is 50 W or more, the pressure in the reaction chamber (10) is 20 mTorr or less, and the duration of the plasma treatment (412) during the deposition cycle (41) is 1 minute or more.

6. The method according to claim 1 or 2 (4), wherein the plasma treatment (412) when generating the plasma includes injecting a noble gas into the reaction chamber.

7. The method according to claim 1 (4), wherein the plasma treatment (412) is performed simultaneously with and / or after the injection (410) of the precursor based on the first species, and the first species is based on a metal.

8. The method according to claim 7 (4), wherein when generating the plasma, the plasma treatment (412) does not involve the injection of dihydrogen.

9. The method according to claim 7 or 8 (4), wherein the metal has an electronegativity of 1.1 to 2.

4.

10. The method according to claim 7 or 8 (4), wherein the first species comprises a metal and an alkyl, amine, oxygenated, or halogenated ligand.

11. The method according to claim 7 (4), wherein the plasma treatment (412) is performed simultaneously with the injection (410) of the precursor based on the first seed, and the plasma treatment (412) and the injection (410) of the precursor are performed simultaneously or by continuous pulses between the plasma treatment (412) and the injection (410) of the precursor.

12. The method according to claim 2 (4), wherein the plasma treatment (412) is performed after the injection of the precursor based on the first species and / or after the injection of the precursor based on the second species, wherein the first species is based on a metal and the second species comprises at least one of the elements such as oxygen, nitrogen and sulfur.

13. The plasma treatment (412) is performed simultaneously with the injection (413) of the precursor based on the second seed, and the second seed is O ２ , N2 , NH ３ , H ２ The method according to claim 12 (4), selected from the group consisting of S.

14. The plasma treatment (412) is performed after the injection (413) of the precursor based on the second seed, and the second seed is H ２ O, O ２ NH ３ The method according to claim 12 (4), selected from the group consisting of the following.

15. The method according to claim 1 or 2 (4), wherein the plate (110) is configured to be height-adjustable within the reaction chamber (10), and the height of the plate is adjusted before the plasma treatment (412).

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