WO2018172321A1

WO2018172321A1 - Reactor device and method for producing thin layers, implementing a series of deposition steps, and uses of this method

Info

Publication number: WO2018172321A1
Application number: PCT/EP2018/056954
Authority: WO
Inventors: Fabien PIALLAT; Julien VITIELLO
Original assignee: Kobus Sas
Priority date: 2017-03-22
Filing date: 2018-03-20
Publication date: 2018-09-27
Also published as: FR3064283B1; FR3064283A1

Abstract

A depositing method comprising sequential implementation of at least two types of deposition from among an ALD type deposition and a pulsed CVD type deposition and a CVD type deposition. Each deposition optionally can be assisted by plasma. The various depositions are preferably carried out in the same chamber, allowing the various types of deposition to be implemented. The deposition sequences are carried out so as to obtain specific layer properties such as, for example, conformity with a determined value, a primer layer of specific quality or a barrier layer of specific quality. Use thereof, particularly for the production of interconnection holes (vias).

Description

"Process and reactor device for the production of thin layers implementing a succession of deposition steps, and applications of this process" FIELD OF THE INVENTION

The present invention relates to a method for producing layers implementing a succession of deposition steps.

It also relates to a reactor device for the implementation of this method, as well as applications of this method.

BACKGROUND OF THE INVENTION

For the realization of vias crossing through the silicon, designated in English under the term "Through Silicon Via" (TSV), with a form factor (ratio height: diameter) important (> 5: 1), it is currently necessary to deposit a thin dielectric layer before metallization. This one, called liner, must have characteristics of conformity (ratio of the thicknesses at the bottom and at the top of the via) and particular electrical properties. In addition, the acceptable deposition temperature can be limited due to the integration back-end of line, which adds constraints affecting the electrical properties.

CVD (Chemical Vapor Deposition) or PECVD (Plasma-Enhanced Chemical Vapor Deposition) deposits are no longer satisfactory in terms of compliance when the form factor is greater than 10: 1, despite the good electrical properties obtained.

Atomic Layer Deposition (ALD) allows deposits with very good compliance but is too slow for target thicknesses (> 100nm). This technique is therefore not considered a plausible replacement for CVD or PECVD.

On the other hand, the quality of the interface between the deposited material and the material of the substrate has a non-negligible importance on certain properties of the assembly, in particular on the hung properties or the electrical properties. However, it is known that deposition by ALD makes it possible to have a flawless interface thanks to the formation of perfectly formed monolayers. The pulsed CVD deposit, as described in particular in document WO 2015/140261, can respond to a wider range of compliance constraints and deposition rate. But it does not allow to adjust compliance characteristics as needed, or only in a very limited way.

Thus, TSV vias, as other applications (photonics ...), may require, to facilitate the realization of components, compliance characteristics that are not achievable using only one of the proposed techniques.

It is therefore interesting to combine the different types of deposit as needed.

Document US 2012/0015113 discloses a method for producing multilayer dielectric films by alternating CVD (thermal) and PE-CVD type deposition steps. The different deposits are made in the same reactor.

The document US 2012/0210937 discloses a method of producing multilayer deposits including ALD type deposits and CVD type, made by moving the substrate between different chambers of a cluster. Cluster means a set of several chambers of each technique, connected to a transfer module held under vacuum. CVD and ALD type deposits are generally made in separate chambers with different architecture.

This method has the disadvantage of leading to a lack of continuity between ALD and CVD-type deposits, especially if the sample has to be changed between the two deposits and therefore subjected to high temperature variations. and pressure.

An object of the present invention is to remedy these drawbacks by proposing a method for producing layers implementing a succession of ALD, pulsed CVD and / or CVD type deposition steps.

Another object of the present invention is also to provide a method for producing layers enabling the production of deposits with characteristics that can not be achieved with a deposit of a single known technique. SUMMARY OF THE INVENTION

This objective is achieved with a thin film production method comprising a sequential implementation on a substrate of at least two deposition processes among an ALD ("Atomic Layer Deposition") type deposition process, a method for depositing type CVD ("Chemical Vapor Deposition") pulsed and a CVD deposition process ("Chemical Vapor Deposition").

The invention can thus notably comprise the sequential implementation, in any order:

an ALD type deposition process and a CVD type deposition process;

an ALD type deposition process and a pulsed CVD type deposition method;

a CVD type deposition process and a pulsed CVD type deposition method;

an ALD type deposition process, a CVD type deposition process, and a pulsed CVD type deposition process.

The various deposition methods can be implemented once, or a plurality of times according to identical or different implementation sequences.

According to embodiments, the pulsed CVD-type deposition method may comprise a sequential injection of the reactive species in the form of out-of-phase pulses.

It may in particular be implemented as described in WO 2015/140261.

According to embodiments, at least one of the deposition methods may comprise the generation of a plasma.

Plasma can be generated for a reactive species, or for a plurality of reactive species or for all reactive species. It can also be generated in the reactor ("in-situ plasma") or in a specific device attached to the reactor (remote plasma, "remote plasma").

According to embodiments, at least one of the deposition methods may comprise an injection of the reactive species by separate injection routes. According to embodiments, the method according to the invention may comprise a minimization of the variations of the environmental conditions of the substrate between the implementation of consecutive deposition processes.

The environmental conditions may include a temperature, a pressure, gases involved. Their variations can be minimized in the sense that the substrate is subjected to a minimum variation of these conditions, within the limits of the changes necessary to go from one deposition process to another. These variations can also be minimized in the sense that they are applied in a time interval long enough to avoid sudden transitions.

In particular, according to the invention, the substrate is not subjected to a passage to the vacuum or to the open air between the application of the various deposition methods.

According to embodiments, the method of the invention may comprise the implementation of at least two deposition methods in the same chamber.

In this case, the chamber is arranged to allow the implementation of the various depositing methods. It can in particular be arranged to allow the implementation of an ALD type deposition process and a CVD and / or pulsed CVD type deposition process.

According to other embodiments, the method of the invention may comprise the implementation of at least two deposition methods in separate chambers, with a transfer of the substrate from one chamber to the other, minimizing the variations in the environment conditions of the substrate during the transfer.

The transfer can in particular be carried out via a transfer chamber provided for transferring a substrate from one chamber to the other while minimizing variations in environmental conditions.

The separate chambers and the transfer chamber may also comprise a substantially identical environment, especially in terms of temperature and / or pressure.

According to embodiments, the method of the invention may comprise an implementation of at least two deposition methods. using identical reactive species.

In a particular embodiment of the invention, the method comprises a progressive variation of a ratio between reactive species of reactant / precursor type so as to change the stoichiometry of the reactant / precursor pair during the deposition and thereby form a gradient in the deposited material.

In an advantageous configuration of the method according to the invention, the implementation sequences of the deposition processes are carried out so as to obtain a layer conformance of a determined value.

Layer conformance is defined as a percentage change in layer thickness, for example in particular structures such as vias.

The implementation sequences of deposition processes can also be carried out so as to obtain a hook layer of particular quality, and / or to obtain a barrier layer of particular quality.

Thus, the technical effects that can be obtained thanks to the implementation of the method of producing layers according to the invention are as follows:

ability to adjust compliance,

an adaptation of the conformance to the needs of the integration necessary to realize a component,

an increase in the overall speed of deposit,

an ability to favor or disadvantage the crystalline arrangement of the material,

an improvement of the barrier properties of a layer,

a creation of a gradient in the material (gradient of stoichiometry, composition or crystallinity),

an improvement of the adhesion of the layer with the lower layers.

One of the advantages of the invention is the ability to obtain deposits with different properties in the same equipment. The ability to begin filing with ALD can also help to reduce the need for preprocessing without degrading the interface.

As a result, no change in the treatment chamber is necessary, thus avoiding the return to the air and thus any creation / change properties of the material deposited at the interface or the change of temperature when a cluster is used, which can lead to degradation.

Another advantage of the invention is to be able to adapt the properties of the deposit to the constraints of the application. This makes it possible to have only one equipment to solve various problems and thus to evolve with the needs of the applications. As an example, the vias TSV currently in production have dimensions of the order of 20xl00pm, but the dimensions of generations vias future TSV should be of the order of 10x100pm or 20x200pm. The integration constraints associated will also evolve and require to adapt the properties of the deposit.

Linking deposits in the same room avoids the creation of an interface between the two deposits made with different techniques. This interface may be due to a change in environmental conditions, such as a passage in the open during a transfer (which generates a possible contamination) or a cooling of the material (with a risk of creating constraints) .

The aspects that differentiate the method according to the invention from that of the prior art implementing a sequence with several conventional clustered chambers are:

the continuity of the conditions (temperature, pressure, environment),

the possibility of making a more gradual variation without breaking the conditions, or the temporal sequences applied. There are clusters that make ALD and (PE) CVD but not

CVD pulsed combined with something else. However, the pulsed CVD process can be considered as a transition or intermediate technique between the ALD and CVD processes, which makes it possible to obtain deposit qualities that would not otherwise be accessible.

For example, one can continuously vary the conformity of 0 to

100% with two or three of the aforementioned techniques, unlike the use of one or two techniques that allows only discrete values of compliance.

The pulsed CVD method can be applied according to temporally variable time sequences to continuously evolve a deposition of type ALD at a CVD deposit.

The method of producing layers according to the invention thus differs from the prior art by the use of several techniques or processes in the same deposition reactor in order to optimize one or more characteristics of the deposit (such as conformity, membership or interface).

Although the ALD and CVD techniques are known and widely used, the sequence of ALD and CVD deposits in the same reactor is not known, particularly because of the very great disparity of the two techniques at both the process and the hardware level.

However, it has been discovered that a reactor developed for implementing a pulsed CVD type deposition process, for example as described in the document WO 2015/140261, can be adapted to implement ALD type processes or CVD. Since the pulsed CVD process is at the boundary between ALD and CVD, the transition from one of these two techniques to the pulsed CVD, or vice versa, makes it possible to preserve a homogeneous material, without discontinuities or abrupt transitions (unlike the use of several separate equipment).

In addition, it avoids the change of treatment chamber in a cluster that generally requires a passage of the sample under vacuum, or air, or in a purge gas, with a large variation in temperature conditions, the ambient treatment temperature.

According to another aspect of the invention, there is provided a thin film deposition reactor arranged to implement the method according to the invention, which reactor comprises means for sequentially implementing on a substrate at least two processes. deposition of an ALD ("Atomic Layer Deposition") deposition method, a pulsed CVD ("Chemical Vapor Deposition") deposition method and a CVD ("Chemical Vapor Deposition") type deposition process.

The reactor may in particular be designed to allow the implementation of an ALD type deposition process, and a CVD and / or pulsed CVD type deposition process.

The reactor according to the invention may advantageously comprise: two separate injection routes, allowing a separate injection reactive species,

means for injecting reactive species, arranged to provide a very fast opening / closing in order to be able to inject the species in the form of separate time pulses,

means for injecting a purge gas, arranged to provide an evacuation of the reactive species from the chamber between injection phases.

In a particular embodiment, the reactor according to the invention further comprises an electrical generator (such as a voltage source) for generating a plasma of at least one reactive species.

This voltage can be applied directly to the reactor to form a plasma in-situ or on a device glued to the reactor to form a remote plasma (English "remote plasma").

In a first version of the invention, the reactor comprises a deposition chamber in which at least two deposition processes are carried out.

In a second version of the invention, the reactor comprises at least two separate deposition chambers in each of which at least one deposition process is performed, and a transfer chamber provided for transferring a substrate from a deposition chamber into the deposition chamber. other by minimizing variations in environmental conditions of the substrate during transfer.

According to yet another aspect of the invention, it is proposed an application of the method of producing layers according to the invention, for the deposition of silicon dioxide (Si0 ₂ ) on a hole through the silicon (TSV) or via spared in a substrate, successively implementing ALD ("Atomic Layer Deposition"), pulsed CVD ("Chemical Vapor Deposition") and plasma-enhanced CVD ("Plasma Enhanced Chemical Vapor Deposition") deposition processes, to carry out on the and at the periphery of said via a layer of Si0 ₂ with a predetermined conformity value.

Another application of the method of producing layers according to the invention concerns the deposition of silicon dioxide (Si0 ₂ ) on a hole through the silicon (TSV) or via a molded in a substrate, putting into successively (i) a CVD ("Chemical Vapor Deposition") deposition process pulsed to perform on the walls and at the periphery of said via a first Si0 ₂ layer and (ii) a CVD-type deposition process activated by plasma ("Plasma Enhanced Chemical Vapor Deposition") for producing at the periphery of said via a second Si0 ₂ layer extending substantially beyond the outer edge of said via.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages will become apparent in the following description of embodiments of a processing chamber according to the invention, given by way of non-limiting examples, with reference to the appended drawings in which:

- Figure 1 shows a block diagram of a deposition chamber used for the present invention;

- Figure 2 shows a schematic sectional view of a via made with a method according to the invention, chaining three deposits ALD, CVD pulsed and CVD;

FIG. 3 is a schematic sectional view of a via made with a method according to the invention, linking two pulsed CVD and PECVD deposits;

FIG. 4a illustrates an example of an Si0 ₂ -Al ₂ 0 ₃ interface without defects following an Al ₂ O ₃ deposition by ALD; and

- Figure 4b illustrates an example of interface Si0 ₂ - Al ₂ 0 ₃ with defects due to Al ₂ 0 ₃ deposited by CVD.

DETAILED DESCRIPTION OF EMBODIMENTS OF

THE INVENTION

These embodiments being in no way limiting, it will be possible to consider variants of the invention comprising only a selection of characteristics described or illustrated subsequently isolated from the other characteristics described or illustrated (even if this selection is isolated within a sentence including these other characteristics), if this selection of characteristics is sufficient to confer an advantage technique or to differentiate the invention from the state of the art. This selection comprises at least one preferably functional characteristic without structural details, and / or with only a part of the structural details if this part alone is sufficient to confer a technical advantage or to differentiate the invention from the state of the art. earlier.

With reference to FIG. 1, an example of a reactor adapted to the implementation of the invention will be described.

The described reactor is derived from a pulsed CVD reactor, as disclosed in WO 2015/140261.

In particular, it has a double-channel shower above the substrate, which allows separate injection and homogeneous diffusion of the reactive species, and provides the functionality of drawing gases into a CVD-type chamber. It thus makes it possible to make depots of type ALD, pulsed CVD or CVD (in all three cases with or without plasma assistance) in the same chamber.

More specifically, the reactor comprises an enclosure 30, or deposition chamber 30, with a substrate holder 60 adapted to receive a substrate 20. This substrate 20 can be placed on the substrate holder 60 so as to have a free surface 10 on which a treatment, such as a layer deposition or an etching operation, can be performed.

The free surface 10 of the substrate 20 is opposite an injection system 100 of the chemical species, or "injection shower" 100. The injection system 100 comprises a first injection route 40 and a second injection route. injection 50 distinct from the first injection route 40.

The first injection route 40 may be used to inject a first chemical species, and the second injection route 50 may be used to inject a second chemical species, or vice versa.

The first injection route 40 and the second injection route 50 are respectively fed by a system of fast valves (not shown) which make it possible to inject the first chemical species and the second chemical species independently in the form of impulses of duration and concentration well mastered.

The first injection route 40 comprises a first plurality of channels 70 opening out of the injection system 100. The second injection path 50 comprises a second plurality of channels 80 opening out of the injection system 100.

The ends of the channels of the first plurality of channels 70 and the second plurality of channels 80 are arranged facing the free surface 10 of the substrate 20.

The channels of the first plurality of channels 70 and the second plurality of channels 80 are preferably evenly distributed in the injection system. The regular distribution of the channels of the first plurality of channels 70 and the second plurality of channels 80 improves the uniformity of the layer formed on the free surface 10 of the substrate 20.

This regular distribution is obtained for example by maintaining a predetermined distance between the channels of the first plurality of channels 70 as well as between the channels of the second plurality of channels 80 resulting in a pattern of equidistant distribution. This distribution can be of triangular type for the two types of channels in order to optimize the use of the space in the plane opposite the free surface 10.

The injection system comprises a heating system (not shown) for injecting chemical species according to the first injection route 40 and the second injection route 50 in the gaseous state and at a predetermined temperature.

The substrate holder 60 also comprises a heating system (not shown) for heating the substrate 20.

The device also comprises a purge gas injection system 110 arranged for example so as to circulate the purge gas in the deposition chamber 30 from the bottom of the substrate holder 60 opposite the substrate 20 and between the substrate holder 60 and the wall of the deposition chamber 30.

A gas evacuation system 120 is disposed in the deposition chamber 30 for discharging unreacted chemical species onto the free surface 10 of the substrate 20, and the purge gas.

The device further comprises, optionally, a source of electrical energy 90 which makes it possible to generate a plasma of the first chemical species and / or the second chemical species in the deposition chamber 30. The electrical energy source 90 is arranged so as to allow the application of an electric potential on the injection system 100 (or the "injection shower" 100), particularly at the ends of the channels of the first plurality of channels 70 and the second plurality of channels 80. The substrate 20 is electrically biased to the reference potential (ground or earth) of the device via the substrate holder 60. Thus, it is possible to establish an electric potential difference capable of generating a plasma between the injection shower 100 and the substrate 20, directly opposite the free surface 10 of the substrate 20.

Examples of deposit techniques

The deposition techniques used in the thin film production method according to the invention will now be described briefly in light of the functionalities required to ensure an operational sequence of the deposits.

The ALD technique makes it possible to perform a deposition by successive atomic layers, with a 100% conformity. It implements a sequential injection, by separate routes, reactive species of the precursor and reactive type. A purge gas is injected between each reagent injection to strictly limit the reaction at the surface of the substrate. The reactive (or reactive) species are injected as a single pulse or a sequence of pulses. The duration of the pulses is typically between 0.02 s and 30 s, with a delay between pulses between 0.02 and 10 s. The pressure in the deposition chamber is typically greater than about 6.7 Pa (50 mTorr). It is possible to ignite a plasma during a reactant pulse. A depot of the ALD type thus comprises cycles of injection of the precursor, then purge, then injection of the reagent, and then again purge which are long. It has the disadvantage of producing very slow growths of layers.

The pulsed CVD technique as implemented in the invention is described in particular in document WO 2015/140261. It performs a chemical deposition with an injection by separate routes of reactive species (or reactants) of the precursor and reactive type in pulses out of phase with time. The reagents are injected in the form sequences of pulses, thus with precursor and reactant pulses partially superimposed or separated in time. The duration of the pulses for each reagent is typically between 0.02 and 5 s. The delay between pulses for each reagent can be between 0.02 s and 10 s. The pressure in the deposition chamber is typically greater than about 67 Pa (500 mTorr) or even greater than 1 Torr. It is possible to light a plasma during the pulses. The pulsed CVD technique is therefore different from the ALD technique in particular because the reagents are injected according to interleaved pulse sequences, without a purge phase.

The CVD technique makes it possible to deposit chemically with a simultaneous injection of the reactive species. This injection is usually carried out continuously. The injection of the species can also be carried out in pulses, but with the reactive species injected simultaneously, which distinguishes it from the pulsed CVD technique. Plasma activation (PECVD) may optionally be provided. The pressure in the deposition chamber can range from about 133 Pa (1 Torr) to about 1333 Pa (10 Torr).

As explained above, the CVD, pulsed CVD and ALD techniques as implemented in the invention may include activation or assistance. In this case, the chemical reactions take place during the process after the formation of a plasma from the gases of one or more of the reactive species. Plasma is usually created from this gas by an electric discharge that can be generated from radio frequency sources (between a few hundred kHz and a few tens of MHz), microwave (about 2.45 GHz) or by an electric shock. continuous between two electrodes. Plasma-assisted CVD techniques are generally also referred to as PECVD for "Plasma Enhanced Chemical Vapor Deposition".

Those skilled in the art will also be able to refer favorably to the abundant existing prior art technical literature for a more detailed description of the generic techniques ALD and CVD, assisted or not by plasma.

We will now describe, with reference to FIGS. 2, 3, 4a and 4b, several nonlimiting examples of implementation of the method for producing thin layers according to the invention. These examples of implementation can to be carried out with the reactor described with reference to FIG.

First example of implementation

A first example of implementation of the method of producing layers according to the invention relates to a deposition of Si0 ₂ (silicon dioxide) on through holes or vias TSV, with a challenge of compliance. In this application, it is more particularly sought to obtain a conformity with a particular value, which can not be achieved with a known method.

The SiO ₂ deposition is carried out by reaction between a tetraethyl orthosilicate precursor (TEOS) and a plasma-activated reactive gas O ₂ , with reference to FIG. 2. Another oxygen-supplying gas may be used (in particular N ₂ 0, H ₂ 0, 0 ₃ , ...). This figure 2 is not representative of the real and relative dimensions of the via.

A silicon substrate 200, in which a via 204 was previously formed, was placed in a deposition reactor such as that illustrated in FIG. 1 and successively subjected to three deposition operations with the method of producing layers according to the invention. invention.

A first layer 201 was first deposited by ALD technique on the silicon substrate 200, in the via 240 and at its periphery 210. During this first deposition step, the temperature in the deposition chamber is between 150 ° C and 350 ° C and the pressure between about 13.3 Pa (0.1 Torr) and about 533 Pa (4 Torr).

The plasma injection power is between 20 and 500 W. The TEOS flow is between 10 and 100 mg (milligram min) and the flow of oxygen is between 10 and 500 sccm (standard cubic centimeter).

The pulse injection duration of TEOS and 0 ₂ is between 0.2 and 10s while the purge time is between 0.5 s and 20 s. The deposition rate of the layer produced by ALD is less than 5 nm / min.

After the end of injection of the purge gas into the deposition chamber, a second deposition step of pulsed CVD type is initiated to deposit a second layer 202 superimposed on the first layer 201 made by the ALD technique.

During this deposition step, the temperature is between 150 ° C and 350 ° C, the gas pressure in the deposition chamber is between about 67 Pa (500 mTorr) and about 1066 Pa (8 Torr). The plasma injection power is between 50 and 1000 W. The flow of TEOS is between 10 and 500 mgmin (milligram minute), while the flow of 0 ₂ is between 100 and 3000 sccm (standard cubic centimeter). ).

The TEOS gas and oxygen O ₂ are injected respectively in the form of pulses of duration between 0.2 s and 5 s, with a period between pulses between 0.1 s and 10 s. The pulses of TEOS gas and of oxygen O ₂ are separated in time, without overlap. The deposition rate of the layer 202 according to the pulsed CVD technique is between 10 and 100 nm / min.

At the end of this pulsed CVD deposition step and after circulation of the purge gas in the deposition chamber, a third deposition step according to the plasma-assisted CVD technique (PECVD) is undertaken so as to produce a third layer. 203 superimposed on the second layer 202.

During this PECVD deposition step, the temperature is between 150 ° C. and 350 ° C., and the pressure of the gases in the deposition chamber is between about 267 Pa (2 Torr) and about 1067 Pa (8 Torr). The power of plasma injection is between 200 and 2000 W. The TEOS gas flow is between 100 and 1000 mgmin (milligram. Minute) and the flow of oxygen 0 ₂ between 100 and 3000 sccm (standard cubic centimeter), for a deposition rate of the order of 500 nm / min or more.

Finally, a via 204 is obtained with three layers 201, 202, 203 providing an Si0 ₂ coating with the desired level of conformity, even when the respective dimensions of the width 206 and the height 205 of the via correspond to shape factors. very high. Obtaining this desired level of conformity is made possible with the filing sequences provided by the method according to the invention.

For vias with a shape factor greater than 15: 1, the ALD technique allows a 100% compliance with a deposition rate of 5nm / min, the pulsed CVD technique allows a 40% compliance with a deposition speed of 50nm / min, and the PECVD technique allows 5% compliance with a deposition rate of 500nm / min.

Thus, it is for example possible to obtain a 50% conformity in using a 66 nm ALD deposit with 100% compliance and a 134 nm pulsed CVD deposit with 40% compliance.

A combination of two or three of the preceding techniques therefore makes it possible to continuously vary the conformity between 5 and 100% while minimizing the necessary deposit time. Without this combination of techniques, only discrete values of compliance are possible (5%, 40% and 100%).

Second example of implementation

Another possible use of the method of making layers according to the invention relates to the formation of over-depositions angle (in English "overhang", colloquially referred to as "Mickey's ears"), at the top of via, such as shown in Figure 3.

This form of deposition can be obtained by favoring certain deposition parameters of the plasma-assisted CVD technique (PECVD) known to those skilled in the art, such as high pressure or larger flows of precursor and reactive gas, by example to make the deposit the most anisotropic possible.

Starting from a silicon substrate 300 in which a via 304 has been previously provided, a first step of the method according to the invention consists in depositing on the bottom 306, the wall 305 and the periphery 310 of via a first layer 302 of Si0 ₂ using the pulsed CVD technique or ALD. Then, in a second step, a second layer 303 of Si0 ₂ is deposited on the portion of the first layer 302 covering the periphery of the via 304, using the PECVD technique as indicated above.

This gives an overflow of the second layer 303 of Si0 ₂ beyond the wall of the via. This overflow of the Si0 ₂ layer at the top of via makes it possible to protect the flanks of the via during a subsequent step called "via reveal" or etching the bottom of via to make contact with a microelectronic or electrical device (no shown in Figure 3) located under this via 304.

This additional protection at the top of the via and in the angle is therefore useful for the step of etching the lower contact. Indeed the implemented scheme includes the realization of a contact between two levels, of type TSV, and to connect it via 304 underneath, it is necessary to remove the layer of Si0 ₂ deposited on the bottom 306 without removing the one on the sides that will serve as insulation. Overlay made overflow at the top of the via with the second layer 303 allows for this etching while ensuring that the upper part of the flank of the via is not attacked because protected by this overlay.

Third example of implementation

With reference to FIG. 4a and FIG. 4b, the method of producing layers according to the invention can also allow the production of a hooked layer, contributing to the improvement of the interface between a substrate and a substrate. deposited material. The ALD deposition technique, by its operating principle, perfectly covers the substrate and thus minimizes interface defects. Thus, for example, alumina (Al ₂ O ₃ ) deposited by the CVD technique contains carbon residues (CH _X ) 401 or holidays 400 in its structure, with reference to FIG. 4b, whereas a deposit Al ₂ 0 ₃ made by ALD technique, with reference to Figure 4a, has no or few defects and an interface of very good quality despite a possible difference in mesh parameter depending on the materials.

Other aspects, such as crystallinity, may vary depending on the method of deposition and sequencing may favor one aspect. For example, the deposit Hf0 ₂ by ALD is crystalline for a thickness greater than 20 nm, whereas the Hf0 ₂ deposited by CVD crystallizes from 50 nm.

According to the invention, a deposit can therefore be initiated by ALD for its good quality, and then after 10 nm in thickness, the deposition technique is changed for CVD in order to grow an amorphous layer.

Fourth example of implementation

ALD deposit properties can also be used to improve the barrier effect of some materials. For example, a layer providing an oxygen barrier function typically has a thickness of about 50 to 100 nm. However, it is the 10 to 20 nm exposed to the air that is most important for the barrier function. It is therefore possible to implement the method for producing a layer according to the invention for depositing a layer of 40 to 90 nm by a CVD or CVD deposition technique. pulsed at a deposition rate greater than 50 nm / min, then finish the layer by an ALD deposit with a thickness of 10 nm.

In the same way, the method for producing a layer according to the invention can be implemented for producing a barrier layer by a final deposit ALD on a titanium nitride (TiN) layer previously deposited by CVD to make a barrier to copper Cu migration.

Of course, the invention is not limited to the examples that have just been described and many adjustments can be made to these examples without departing from the scope of the invention.

For example, the number of successive deposits made in the context of the method according to the invention is not limited to two or three as in the case of the embodiments just described. Furthermore, the order of implementation of the various deposition techniques is not limited to those embodiments described above, the only possible limitations being those induced by physical or technological considerations.

In addition, the substrate on which the different layers are successively produced is not limited to silicon alone but may consist of any material having physical properties compatible with a treatment in a deposition chamber suitable for producing thin layers with thin films. CVD, pulsed CVD or ALD techniques.

Claims

A thin-film production method comprising a sequential implementation on a substrate of at least two deposition processes among an Atomic Layer Deposition (ALD) type deposition method, a CVD type deposition method ( Chemical Vapor Deposition ") and a CVD deposition process (" Chemical Vapor Deposition ").

2. Method according to claim 1, characterized in that the pulsed CVD-type deposition process comprises a sequential injection of the reactive species in the form of pulses out of phase with time.

3. Method according to one of claims 1 or 2, characterized in that at least one of the deposition processes comprises the generation of a plasma.

4. Method according to one of the preceding claims, characterized in that at least one of the deposition processes comprises an injection of the reactive species by separate injection routes.

5. Method according to one of the preceding claims, characterized in that it comprises a minimization of the variations of the environmental conditions of the substrate between the implementations of consecutive deposition processes.

6. Method according to one of claims 1 to 5, characterized in that it comprises an implementation of at least two deposition processes in the same chamber (30).

7. Method according to one of claims 1 to 5, characterized in that it comprises an implementation of at least two deposition processes in separate chambers, with a transfer of the substrate from one chamber to the other minimizing variations in conditions the environment of the substrate during the transfer.

8. Method according to any one of the preceding claims, characterized in that it comprises an implementation of at least two deposition processes using identical reactive species.

9. Process according to any one of the preceding claims, characterized in that it comprises a progressive variation of a ratio between reactive species of the reactant / precursor type so as to change the stoichiometry of the reactant / precursor pair during the deposition. and thus form a gradient in the deposited material.

10. Method according to any one of the preceding claims, characterized in that the implementation sequences of deposition processes are performed so as to obtain a layer conformance of a determined value.

11. Method according to any one of the preceding claims, characterized in that the implementation sequences of deposition processes are performed so as to obtain a hook layer of particular quality, and / or a barrier layer of particular quality. .

12. Thin film deposition reactor arranged to implement the method according to any one of the preceding claims, characterized in that it comprises means for sequentially implementing on a substrate at least two deposition processes among an ALD ("Atomic Layer Deposition") type deposition process, a pulsed CVD ("Chemical Vapor Deposition") deposition method, and a CVD ("Chemica l Vapor Deposition") deposition process.

13. Reactor according to claim 12, characterized in that it comprises:

two separate injection channels (40, 50), allowing a separate injection of reactive species into a deposition chamber (30),

means for selectively injecting reactive species, arranged to provide very fast opening / closing to be able to inject the species in the form of separate time pulses,

means for selectively injecting a purge gas, arranged to provide an evacuation of the reactive species from the chamber between injection phases.

14. Reactor according to one of claims 12 or 13, characterized in that it further comprises an electrical generator for generating a plasma of at least one reactive species.

15. Reactor according to one of claims 12 to 14, characterized in that it comprises a deposition chamber (30) in which at least two deposition processes are performed.

16. Reactor according to one of claims 12 to 14, characterized in that it comprises at least two separate deposition chambers in each of which at least one deposition method is implemented, and a transfer chamber provided to transfer a substrate of a deposition chamber in the other by minimizing the variations of environmental conditions of the substrate during transfer.

17. Application of the method of producing layers according to any one of claims 1 to 11, for the deposition of silicon dioxide (Si0 ₂ ) on a through-hole silicon (TSV) or via (204) formed in a substrate ( 200), successively implementing ALD ("Atomic Layer Deposition"), pulsed CVD ("Chemical Vapor Deposition") and plasma-enhanced CVD ("Plasma Enhanced Chemical Vapor Deposition") deposition processes, to carry out on the walls (205, 206) and at the periphery (210) of said via a layer of Si0 ₂ with a predetermined conformity value.

18. Application of the method of producing layers according to any one of claims 1 to 11, for the deposition of silicon dioxide (Si0 ₂ ) on a through silicon (TSV) or via (304) formed in a substrate ( 300), successively implementing (i) a deposit method CVD type ("Chemical Vapor Deposition") pulsed to produce on the walls (305, 306) and on the periphery (310) of said via (304) a first layer (302) of Si0 ₂ and (ii) a deposition process plasma-enhanced CVD type (Plasma Enhanced Chemical Vapor Deposition) for producing at the periphery (310) of said via (304) a second SiO2 layer (303) extending substantially beyond the outer edge of said via (304); ).