KR102597990B1 - Method for selective deposition of aluminum and nitrogen containing material - Google Patents

Abstract

Methods are provided for selectively depositing Al and N containing materials on a first conductive surface of the same substrate relative to a second dielectric surface of the substrate. In some aspects, methods are provided for forming an Al and N containing protective layer or etch stop layer for use in integrated circuit manufacturing.

Description

METHOD FOR SELECTIVE DEPOSITION OF ALUMINUM AND NITROGEN CONTAINING MATERIAL}

Cross-reference to related applications

This application is a continuation-in-part of U.S. Application No. 14/819,274, entitled “Selective Deposition of Aluminum and Nitrogen-Containing Materials,” the entire disclosure of which is incorporated herein by reference. This application also relates to U.S. Provisional Application No. 62/438,055, entitled “Atomic Layer Etching Method,” the entire disclosure of which is incorporated herein by reference.

The present invention relates to the selective deposition of aluminum and nitrogen containing materials, such as Al and N containing thin films, on a first surface relative to a second surface of a substrate.

Currently, integrated circuits are manufactured by sophisticated processes in which various layers of materials are sequentially constructed in a predetermined arrangement on a substrate.

A desired arrangement of layers of material on a substrate is often achieved by depositing material on the entire substrate surface and then removing the material from selected areas of the substrate, for example, by deposition of a mask layer and subsequent selective etching process.

In certain cases, the number of steps involved in fabricating an integrated circuit on a substrate can be reduced by using a selective deposition process, where a second surface is deposited on a second surface to eliminate or reduce the need for subsequent processing. Material is selectively deposited on the relative first surface. Disclosed herein are methods for selective deposition on a first surface of a substrate relative to a second surface of the substrate.

In some aspects, methods are provided for selectively depositing materials comprising aluminum and nitrogen. In some embodiments, a material comprising aluminum and nitrogen is deposited on a first surface of the same substrate relative to a second dielectric surface of the substrate in a method comprising one or more deposition cycles, wherein the deposition cycles comprise: Contacting the substrate with a first vapor phase precursor comprising aluminum and contacting the substrate with a second vapor phase precursor comprising nitrogen. In some embodiments, the material comprising aluminum and nitrogen is deposited on a first surface of the same substrate relative to a second Si-O surface of the substrate in a method comprising one or more deposition cycles, wherein the deposition cycle comprises: Contacting the substrate with a first vapor phase precursor comprising aluminum and contacting the substrate with a second vapor phase precursor comprising nitrogen. In some embodiments, a material comprising aluminum and nitrogen is deposited on a first surface of the same substrate relative to a second non-conductive surface of the substrate in a method comprising one or more deposition cycles, the deposition cycles comprising: Contacting the substrate with a first vapor phase precursor comprising aluminum and contacting the substrate with a second vapor phase precursor comprising nitrogen. In some implementations, the material comprising aluminum and nitrogen is deposited with a selectivity greater than about 50% on the first surface of the same substrate relative to the second dielectric surface of the substrate. In some implementations, the first surface includes at least one of copper, titanium nitride, tungsten, and silicon nitride. In some embodiments, the material comprising aluminum and nitrogen is a thin film of aluminum nitride. In some embodiments, the aluminum nitride thin film includes oxygen.

In some embodiments, the first vapor phase precursor is an organometallic aluminum compound. In some embodiments, the first vapor phase precursor comprising aluminum does not include any metals other than aluminum. In some embodiments, the first vapor phase precursor comprising aluminum has the formula R ₃ Al, where each R can be independently selected from C ₁ -C ₄ alkyl groups. In some embodiments, the first vapor phase precursor comprising aluminum does not include halides. In some embodiments, the first vapor phase precursor comprising aluminum includes one chlorine ligand and at least two alkyl ligands. In some embodiments, the first vapor phase precursor comprising aluminum includes one hydrogen ligand and at least one alkyl ligand. In some embodiments, the first vapor phase precursor comprising aluminum does not include nitrogen, silicon, or oxygen. In some embodiments, the first vapor phase precursor comprising aluminum comprises triethylaluminum (TEA), trimethylaluminum (TMA), or tritertbutylaluminum (TTBA) and the second vapor phase precursor comprising nitrogen comprises NH ₃ do.

In some implementations, the second dielectric surface includes Si-O bonds. In some embodiments, the method includes a thermal atomic layer deposition (ALD) process. In some embodiments, the method does not include plasma in at least two consecutive deposition cycles. In some implementations, the method further includes exposing the substrate to a pretreatment reactant prior to the first deposition cycle. In some embodiments, the pretreatment reactant includes plasma. In some embodiments, exposing the substrate to a pretreatment reactant prior to the first deposition cycle improves selectivity by a factor greater than about 2. In some implementations, the method further includes exposing the substrate after at least one deposition cycle. In some implementations, the substrate is exposed to plasma after more than 10 deposition cycles.

In some embodiments, a material comprising aluminum and nitrogen has etch selectivity for SiO ₂ in dilute HF. In some embodiments, the ratio of the material comprising aluminum and nitrogen deposited on the first surface of the same substrate relative to the second dielectric surface of the substrate is greater than about 10:1, and deposited on the first surface of the substrate , the thickness of the material containing aluminum and nitrogen is greater than about 5 nm. In some embodiments, the ratio of the material comprising aluminum and nitrogen deposited on the first surface of the same substrate relative to the second dielectric surface of the substrate is greater than about 10:1, and deposited on the first surface of the substrate , the thickness of the material containing aluminum and nitrogen is greater than about 1 nm. In some embodiments, the ratio of material comprising aluminum and nitrogen deposited on a first surface of the same substrate relative to a second dielectric surface of the substrate is greater than about 10:1, and the method comprises about 1 to 25 deposition cycles. Includes. In some embodiments, the ratio of material comprising aluminum and nitrogen deposited on the first surface of the same substrate to the second dielectric surface of the substrate is greater than about 10:1, and the method comprises 1 to 150 deposition cycles. Includes. In some implementations, a material comprising less than about 0.1 nm of aluminum and nitrogen is deposited on the second dielectric surface of the substrate after about 1 to 25 deposition cycles. In some embodiments, the ratio of the wet etch rate of the deposited aluminum and nitrogen-containing material to the wet etch rate of SiO ₂ is less than about 1:5.

In some implementations, the second dielectric surface of the substrate overlies the source/drain region, the method comprising removing the second dielectric surface of the substrate to expose the source/drain region of the substrate and exposing the source/drain region of the substrate. It further includes forming a contact on the area.

In some aspects, methods are provided for selectively depositing AlN on a first surface of the same substrate relative to a second dielectric surface of the substrate. In some embodiments, the method may include one or more cycles comprising alternating and sequentially contacting the substrate with vapor phase tritbutylaluminum (TTBA) and vapor phase NH. In some implementations, AlN is deposited with a selectivity greater than about 50% on the first surface of the same substrate relative to the second dielectric surface of the substrate. In some implementations, the second dielectric surface includes Si-O bonds. In some embodiments, the method includes a thermal atomic layer deposition (ALD) process. In some embodiments, the method does not include plasma in at least two consecutive deposition cycles. In some implementations, the method further includes exposing the substrate to a pretreatment reactant prior to the first deposition cycle. In some embodiments, the pretreatment reactant includes plasma. In some implementations, the methods may include some or all of the features of any other implementations herein described above.

In some aspects, methods are provided for forming an etch stop layer with self-aligned contact formation. In some implementations, the method includes providing a semiconductor substrate comprising a first surface and a second surface overlying a source/drain region, removing a portion of the first surface of the substrate to form a recess in the substrate. selectively depositing a material comprising aluminum and nitrogen on the first surface relative to the second dielectric surface, removing the second dielectric surface of the substrate to expose source/drain regions of the substrate. and forming a contact on the exposed source/drain region of the substrate. In some implementations, the first surface includes at least one of copper, titanium nitride, tungsten, and silicon nitride. In some embodiments, the material comprising aluminum and nitrogen is a thin film of aluminum nitride. In some embodiments, the aluminum nitride thin film includes oxygen. In some implementations, the methods may include some or all of the features of any other implementations herein described above.

According to some aspects, methods are provided for selectively forming AlN on a first surface relative to a second, different surface. In some embodiments, the method includes one or more super-cycles comprising selectively depositing AlN on a first surface relative to a second, different surface and etching the deposited AlN, wherein the deposition Etching the deposited AlN removes substantially all of the deposited AlN from the second surface of the substrate and does not remove all of the deposited AlN from the first surface of the substrate.

In some embodiments, the super-cycle further includes repeating selectively depositing AlN and etching the deposited AlN until an AlN thin film of a desired thickness is deposited on the first surface. In some embodiments, the super-cycle further includes exposing the substrate to a pretreatment reactant prior to selectively depositing AlN. In some embodiments, the pretreatment reactant includes plasma. In some embodiments, the plasma is generated from a gas containing H ₂ .

In some embodiments, selectively depositing AlN on a first surface relative to a second, different surface comprises contacting the substrate with a first vapor phase precursor comprising aluminum and the substrate with a second vapor phase precursor comprising nitrogen. performing one or more selective deposition sub-cycles comprising contacting the AlN with a selectivity greater than about 5% on a first surface of the same substrate relative to a second dielectric surface of the substrate. It is deposited with In some implementations, the selective deposition sub-cycle further includes repeating the selective deposition sub-cycle until a desired thickness of AlN is deposited on the first surface. In some implementations, selectively depositing AlN includes repeating the selective deposition sub-cycle until the selective deposition sub-cycle is no longer selective.

In some embodiments, the first vapor phase precursor comprising aluminum includes one of tritertbutylaluminum (TTBA), trimethylaluminum (TMA), or triethylaluminum (TEA). In some embodiments, the second vapor phase precursor comprising nitrogen comprises NH ₃ .

In some embodiments, etching the deposited AlN includes an atomic layer etching (ALE) process, wherein the atomic layer etching process includes contacting the substrate with a first gaseous halide etch reactant and a second gaseous halide etchant comprising aluminum. and one or more etching sub-cycles comprising contacting the substrate with a vapor phase etch reactant. In some embodiments, the first gaseous halide etch reactant includes NF ₃ or NbF ₅ . In some embodiments, the second vapor phase etch reactant comprising aluminum includes trimethylaluminum (TMA) or triethylaluminum (TEA). In some embodiments, the etch sub-cycle is performed at a process temperature of about 300°C. In some embodiments, the first surface comprises W and the second surface comprises SiO ₂ . In some implementations, the first surface comprises TiN and the second surface comprises SiO ₂ . In some embodiments, AlN is selectively formed on the first surface of the substrate relative to the second surface with a selectivity greater than about 99%.

In some embodiments, selectively depositing AlN on a first surface relative to a second, different surface includes performing a selective deposition sub-cycle, wherein the selective deposition sub-cycle is repeated 1 to about 300 times. The step of etching the deposited AlN includes an atomic layer etching (ALE) process in which the etching sub-cycle is repeated 1 to about 150 times.

In some embodiments, a method for selectively depositing AlN on a first surface of the same substrate relative to a second, different surface of the substrate includes a super-cycle, wherein the AlN is deposited on a different second surface of the substrate. Alternatingly sequentially contacting the substrate with a first vapor phase precursor comprising aluminum and a second vapor phase precursor comprising nitrogen to be deposited with a selectivity greater than about 5% on a first surface of the same substrate relative to two surfaces. a selective deposition sub-cycle comprising the step of removing substantially all of the deposited AlN from the second surface of the substrate and not substantially all of the deposited AlN from the first surface of the substrate. and an atomic layer etching sub-cycle comprising alternately and sequentially contacting the substrate with a first vapor halide etching reactant and a second vapor phase etching reactant containing aluminum.

In some embodiments, the super-cycle is repeated one or more times. In some implementations, the super-cycle further includes exposing the substrate to a plasma generated from a gas comprising H ₂ prior to the selective deposition step.

In some embodiments, the first vapor phase precursor comprising aluminum comprises TMA, the second vapor phase precursor comprising nitrogen comprises NH ₃ , and the first vapor phase halide etch reactant comprises NF ₃ and comprises aluminum. The second vapor phase etch reactant includes TMA. In some implementations, the first surface is a conductive surface and the second surface is a dielectric surface.

The present invention will be better understood from the detailed description and accompanying drawings, which are meant to illustrate the invention and not to limit it, wherein:
1 shows a deposition method flow for selectively depositing Al and N containing materials on a first surface of the same substrate relative to a second, different surface of the substrate;
Figure 2 shows a deposition method flow for selectively depositing AlN on a first surface of the same substrate relative to a second, different surface of the substrate;
3 shows a deposition method flow (including a selective deposition sub-cycle and an atomic layer etch sub-cycle) for selectively depositing Al and N containing materials on a first surface of the same substrate relative to a different second surface of the substrate. shows;
Figure 4 shows a method flow for forming self-aligned contact structures;
Figure 5 shows another method flow for forming self-aligned contact structures;
Figure 6 is a graph of deposited material thickness versus number of deposition cycles for Al and N containing materials selectively deposited on a first TiN surface relative to a second SiO ₂ surface;
Figure 7 is a graph of deposited material thickness versus number of deposition cycles for Al and N containing materials selectively deposited on a first TiN surface relative to SiO ₂ and native oxide second surfaces;
Figure 8 is a graph of deposited material thickness versus number of deposition cycles for Al and N containing materials selectively deposited on a first TiN surface relative to a second native oxide surface;
Figure 9 is a graph of deposited material thickness versus number of deposition cycles for Al and N containing materials selectively deposited on a first TiN or W surface relative to a second SiO ₂ surface;
Figure 10A is a scanning electron microscopy (SEM) image of AlN selectively deposited on tungsten interconnects relative to SiO2;
Figure 10b is a partial enlarged view of the SEM image of Figure 10a.

In some implementations, it is desirable to selectively deposit a material comprising aluminum (Al) and nitrogen (N), such as aluminum nitride (AlN), on one surface of the same substrate relative to a second, different surface of the substrate. For example, selective deposition of Al and N containing materials can be used to form etch stop layers, such as a capping layer, barrier layer, or contact etch stop layer. For example, Al and N containing materials can be deposited selectively on a first surface of a substrate, preferably on a second, different surface, such as a dielectric surface of the same substrate.

In some embodiments, a substrate is provided comprising a first surface and a different second surface, and Al and N containing materials are deposited on the first surface relative to the second surface using an ALD-type process comprising a plurality of deposition cycles. Deposited selectively, each deposition cycle includes sequentially contacting the substrate with a first vapor phase precursor and a second vapor phase precursor alternating with the substrate. In some embodiments, the selectively deposited Al and N containing material is AlN.

In some embodiments, Al and N-containing materials, such as AlN, are selectively deposited on metal surfaces of the substrate, including both conductive and dielectric surfaces. In some implementations, AlN is selectively deposited on a first conductive surface of the same substrate, such as a Cu, W or TiN surface, relative to a second dielectric surface of the substrate, such as a SiO ₂ or low k surface. In some implementations, AlN is selectively deposited on a first, non-conductive surface, such as a SiN surface, relative to a second dielectric surface of the substrate, such as a SiO ₂ or low k surface. In some implementations, AlN is selectively deposited on a Cu surface relative to a second, different surface. In some implementations, AlN is selectively deposited on the W surface relative to the second, different surface. In some implementations, AlN is selectively deposited on a TiN surface relative to a second, different surface. In some implementations, AlN is selectively deposited on a SiN surface relative to a second, different surface.

In some embodiments, methods for selectively depositing aluminum and nitrogen-containing materials, such as AlN, include selectively depositing aluminum and nitrogen-containing materials on a first surface relative to a second, different surface, and then subjecting the substrate to an etching process. wherein the etching process removes substantially all of the deposited aluminum and nitrogen-containing material from the second surface of the substrate and removes substantially all of the deposited aluminum and nitrogen-containing material from the first surface of the substrate. do not remove In some embodiments, the etching process may be an atomic layer etching process. In some embodiments, the atomic layer etching process may include sequentially alternately contacting the substrate with a first vapor phase etching reactant and a second vapor phase halide etching reactant containing aluminum.

In some implementations, methods for selectively depositing aluminum and nitrogen-containing materials, such as AlN, can include a plurality of super-cycles, wherein the plurality of super-cycles comprises a first surface of the substrate relative to a second surface of the substrate. 1 selectively depositing Al and N containing material on a surface and substantially all of the deposited Al and N containing material is removed from the second surface while at least a portion of the Al and N containing material is removed from the first surface. and etching the deposited Al and N containing material such that it remains in phase. This selective deposition super-cycle can be selectively repeated until the desired amount of Al and N containing material is deposited on the first surface of the substrate. In some embodiments, substantially no aluminum and nitrogen containing material remains on the second surface after each selective deposition super-cycle. In some embodiments, substantially no aluminum and nitrogen containing material remains on the second surface after the selective deposition process.

In some implementations, the selective deposition super-cycle may further include performing a pretreatment process prior to selectively depositing the Al and N containing materials. In some embodiments, the pretreatment process may include exposing the substrate to a pretreatment reactant: In some embodiments, the pretreatment reactant may include a plasma, such as a plasma generated from a gas comprising H ₂ there is.

ALD type process

ALD-type processes are based on controlled, self-limiting surface reactions of precursor chemicals. Gas phase reactions are avoided by alternately and continuously contacting the substrate with the precursor. The gas phase reactants are separated from each other on the substrate surface, such as by removing excess reactant and/or reactant by-products from the reaction chamber between reactant pulses. In some embodiments, one or more substrate surfaces are alternately and sequentially contacted with two or more vapor phase precursors or reactants. Contacting the substrate surface with a vapor phase reactant means that the reactant vapor is in contact with the substrate surface for a defined period of time. That is, the substrate surface is exposed to each vapor phase reactant for a limited period of time.

Briefly, a substrate comprising at least a first surface and a different second surface is heated to a suitable deposition temperature, typically at reduced pressure. The deposition temperature is generally below the thermal decomposition temperature of the reactants but is maintained at a sufficiently high level to avoid condensation of the reactants and provide activation energy for the desired surface reaction. Of course, the appropriate temperature range for any given ALD reaction will vary depending on the surface terminations and reactive species involved. Here, the temperature varies depending on the precursor in use and is preferably up to about 500°C, preferably about 250°C to about 500°C, more preferably about 275°C to about 450°C, more preferably about 300°C. to about 425°C, most preferably about 325°C to about 400°C.

The substrate surface is contacted with a vapor phase first reactant. In some embodiments, a pulse of vaporous first reactant is provided to the reaction space containing the substrate. In some embodiments, the substrate is moved to a reaction space containing a vapor phase first reactant. It is desirable to select conditions such that no more than about one monolayer of the first reactant is adsorbed on the substrate surface in a self-limiting manner. Appropriate contact times can be readily determined by those skilled in the art based on specific circumstances. If excess first reactant and reaction by-products are present, they are removed from the substrate surface, such as by purging with an inert gas or by removing the substrate from the presence of the first reactant.

Purging means that gaseous precursors and/or gaseous by-products are removed, for example by evacuating the chamber with a vacuum pump and/or replacing the gas inside the reactor with an inert gas such as argon or nitrogen. Typical purging times are about 0.05 to 20 seconds, more preferably about 1 to 10 seconds, and even more preferably about 1 to 2 seconds. However, if necessary, other purge times may be used, such as when highly conformal step coverage is required for very high aspect ratio structures or other structures with complex surface shapes.

The substrate surface is contacted with a vapor phase second gaseous reactant. In some implementations, a pulse of a second gaseous reactant is provided to the reaction space comprising the substrate. In some embodiments, the substrate is moved to a reaction space containing a vapor phase second reactant. If excess second reactant and gaseous by-products of the surface reaction are present, they are removed from the substrate surface. The contacting and removal steps are repeated until a thin film of the desired thickness is selectively formed on the surface of the substrate, with each cycle leaving behind only about one molecular monolayer. Additional steps, including alternately sequentially contacting the substrate surface with different reactants, may be included to form more complex materials, such as ternary materials.

As mentioned above, each step of each cycle is preferably self-limiting. Excess reactant precursor may be provided at each step to saturate the sensitive structural surfaces. Surface saturation ensures reactant occupancy of all available reaction sites (e.g., application of physically sized or “sterically hindered” reactants) and thus ensures good step coverage. Typically, less than one layer of molecular material is deposited using each cycle, but in some embodiments, more than one layer of molecular material is deposited during the cycle.

Removing excess reactant may include evacuating some of the contents of the reaction space and/or purging the reaction space with helium, nitrogen, or other inert gas. In some implementations, purging may include blocking the flow of reaction gas while continuously flowing an inert carrier gas into the reaction space.

The substrate may include various types of materials. When manufacturing integrated circuits, the substrate typically contains many thin films with varying chemical and physical properties. For example, and without limitation, the substrate may include a dielectric layer and a metal layer. In some implementations, the substrate can include metal carbide. In some implementations, the substrate can include a conducting oxide.

Preferably, the substrate has a first surface comprising a conductive surface such as a metal or a metal surface. In some implementations, the first surface includes metal nitride. In some implementations, the first surface can include one or more transition metals. Transition metals may be selected from the following groups: Ti, V, Cr, Mn, Nb, Mo, Ru, Rh, Pd, Ag, Au, Hf, Ta, W, Re, Os, Ir and Pt. In another embodiment, the transition metal is selected from the following group: Fe, Co, Ni. In some embodiments, the first surface preferably includes copper. In some implementations, the first surface includes a noble metal. The noble metal may be selected from the following groups: Au, Pt, Ir, Pd, Os, Ag, Re, Rh, and Ru. In some preferred embodiments, the first surface includes at least one of Cu, W, TiN, TaN, or SiN.

In some implementations, the first surface can include more than one material, such as TiN and SiN.

In some implementations, the first surface includes a metal silicide, such as a transition metal silicide. In some implementations, the first surface includes a metal film comprising a transition metal, such as a transition metal carbide or a carbon-containing transition metal material. In some implementations, the first surface can include Al. In some implementations, the first surface can include metals or an alloy of metal materials.

The second surface is preferably a dielectric surface, such as SiO ₂ , GeO ₂ , or a low k surface. In some embodiments, the dielectric includes SiO ₂ . In some implementations, the dielectric is a porous material. In some embodiments, the porous dielectric includes pores that are connected to each other, while in other embodiments, the pores are not connected to each other. In some implementations, the dielectric includes a low k material, defined as an insulator having a dielectric constant value of less than about 4.0. In some embodiments, the low k material has a dielectric constant value of less than about 3.5, less than about 3.0, less than about 2.5, and less than about 2.3. In some embodiments, the second surface includes Si-O bonds. In some implementations, the second surface is deactivated, such as by plasma treatment. In some implementations, the second surface is a non-conductive surface. In some embodiments, the second surface has a resistivity greater than about 1 ohm·m. In some embodiments, the second surface includes Si-O bonds and has a resistivity of less than about 1 ohm·m. The term dielectric is used herein for simplicity in distinguishing it from another first surface, that is, a metal or metallic surface. Unless otherwise specified for a particular embodiment, the term dielectric in the context of the present application can be understood to denote any surface having a very high resistivity.

If the precursors used in ALD-type processes are in the gas phase before contacting the substrate surface, they can be solid, liquid, or gaseous materials under standard conditions (room temperature and atmospheric pressure). Contacting a substrate surface with a vaporized precursor means that the precursor vapor is in contact with the substrate surface for a defined period of time. Typically, the contact time is about 0.05 to 10 seconds. However, depending on the substrate type and its surface area, the contact time can be much longer than 10 seconds. Contact time may be in minutes in some cases. The optimal contact time can be determined by one skilled in the art based on specific circumstances.

The mass flow rate of the precursor can also be determined by one skilled in the art. In some embodiments, the flow rate of the metal precursor is preferably, but not limited to, about 1 to 1000 sccm, more preferably about 100 to 500 sccm.

The pressure within the reaction chamber is typically from about 0.01 to about 20 mbar, more preferably from about 1 to about 10 mbar. However, in some cases the pressure may be higher or lower than these ranges, as can be determined by one of ordinary skill in the art given a particular situation.

Before beginning deposition of the film, the substrate is typically heated to an appropriate growth temperature. Growth temperature varies depending on the type of thin film formed and the physical properties of the precursor. Growth temperatures are discussed in more detail below with reference to each type of thin film formed. The growth temperature can be below the crystallization temperature for the deposited material so that an amorphous thin film can form, or the growth temperature can be above the crystallization temperature so that a crystalline thin film can be formed. The preferred deposition temperature may vary depending on a number of factors, including but not limited to the composition of the substrate, including reactant precursors, pressure, flow rate, configuration of the reactor, crystallization temperature of the deposited thin film, and the nature of the material to be deposited thereon. Specific growth temperatures can be selected by those skilled in the art.

Reactors that can be used to grow thin films can also be used for deposition. These reactors include ALD reactors as well as CVD reactors equipped with appropriate equipment and means for providing precursors. According to some implementations, a showerhead reactor may be used.

Examples of suitable reactors that can be used include commercially available equipment, such as the F-120 ^® reactor, F-450 ^® reactor, Pulsar ^® reactor from ASM America Inc. (Phoenix, Arizona) and ASM Europe BV (Almere, Netherlands). Reactors (e.g. Pulsar ^® 2000 and Pulsar ^® 3000), EmerALD ^® reactors and Advance ^® 400 series. Commercially available reactors include those from ASM Japan KK (Tokyo, Japan) under the trade names ^Eagle® XP and XP8.

In some embodiments, a batch reactor may be used. Suitable batch reactors include, but are not limited to, reactors commercially available from ASM Europe B.V. (Almere, Netherlands) under the trade names ALDA400 ^TM and A412 ^TM . In some embodiments, vertical batch reactors are used, such as A412®, in which the boat rotates during processing. As such, in some implementations, the wafer rotates during processing. In some embodiments where a batch reactor is used, the wafer-to-wafer uniformity is less than 3% (1 sigma), less than 2%, less than 1%, or even less than 0.5%.

The growth process can optionally be performed in a reactor or reaction space connected to a cluster tool. In a cluster tool, because each reaction space is dedicated to one type of process, the temperature of the reaction space within each module can be kept constant, which allows for higher throughput compared to a reactor where the substrates are heated to the process temperature before each run. improves

The stand-alone reactor may be equipped with a load-lock. In this case, there is no need to cool down the reaction space between each run.

Preferably, to form the Al and N containing materials, each ALD cycle includes at least two distinct steps. Removing excess first precursor and reaction by-products from the substrate surface after contacting the substrate with the first precursor may be considered as steps and include: first step, first precursor step, Al step, Al precursor step, first Al step , may be referred to as the first AL precursor step. For the deposition cycle, in the first step, the substrate is contacted with a first precursor comprising Al forming only one monolayer on the substrate. In a second step, the substrate may be contacted with a second precursor containing nitrogen and convert the adsorbed first precursor into Al and N containing material. Removing excess second precursor and reaction by-products from the surface of the substrate after contacting the substrate with the second precursor can be considered steps and include the second step, the second precursor step, the nitriding step, the N step, the N precursor step, and the second step. It may be referred to as a 1 N stage, and/or a 1 N precursor stage. One or more precursors are N ₂ , It can be provided with the help of a carrier gas such as Ar or He. Additional steps may be added and steps may be removed as desired to control the composition of the final film.

Referring to Figure 1 and according to a preferred embodiment, Al and N containing materials are deposited on a first surface of a substrate comprising a first surface and a different second surface by an ALD-type deposition process 100 comprising at least one cycle. and wherein at least one cycle comprises the following steps:

contacting the substrate with a first vapor phase precursor containing Al in step 120;

If excess first precursor and reaction by-products are present in step 130, removing the excess first precursor and reaction by-products from the substrate;

contacting the substrate with a second vapor phase precursor containing nitrogen in step 140;

removing excess second precursor and any gaseous by-products from the substrate at step 150; and

Optionally repeating the contacting and removing steps at step 160 until an Al and N containing material of the desired thickness is formed.

In some implementations, a pretreatment process may be performed on one or more surfaces of the substrate prior to starting the deposition process 100. In some implementations, a pretreatment process can improve the selectivity of the selective deposition process 100. In some implementations, a pretreatment process prior to starting the deposition process 100 can enhance the deposition of Al and N containing materials on one surface relative to one or more different surfaces. In some implementations, a pretreatment process prior to starting the deposition process 100 may inhibit deposition of Al and N containing materials on one surface relative to one or more different surfaces. In Figure 1, this is represented as step 110, where the substrate may be exposed to a pretreatment reactant, such as a plasma, prior to deposition of the Al and N containing materials.

In some embodiments, the pretreatment process can include exposing the substrate to a pretreatment reactant: In some embodiments, the pretreatment reactant can include oxygen. In some embodiments, the pretreatment reactant includes oxygen radicals, oxygen atoms, oxygen plasma, or combinations thereof. In some embodiments, the pretreatment reactant may include nitrogen. In some embodiments, the pretreatment reactant includes nitrogen radicals containing nitrogen, atomic nitrogen, nitrogen plasma, or combinations thereof. In some embodiments, the pretreatment reactant may include hydrogen. In some embodiments, the pretreatment reactant includes hydrogen radicals, atomic hydrogen, hydrogen plasma, or combinations thereof.

In some embodiments, when using a pretreatment process in which the substrate is exposed to a pretreatment reactant comprising an oxygen plasma, the O ₂ is, for example, about 1 to about 2000 sccm, more preferably about 5 to about 1000 sccm, most preferably Can be provided at about 50 to about 500 sccm. In some embodiments, O ₂ may be provided at about 300 sccm. In some embodiments, when using a pretreatment process in which the substrate is exposed to a pretreatment reactant comprising a nitrogen plasma, N ₂ is, for example, about 1 to about 5000 sccm, more preferably about 5 to about 2000 sccm, most preferably Can be provided at about 50 to about 500 sccm. In some embodiments, N ₂ may be provided at about 300 sccm. In some embodiments, when using a pretreatment process in which the substrate is exposed to a pretreatment reactant comprising a hydrogen plasma, the H ₂ is, for example, from about 1 to about 2000 sccm, more preferably from about 5 to about 1000 sccm, most preferably Can be provided at about 10 to about 100 sccm. In some embodiments, H ₂ may be provided at about 50 sccm. Similar conditions can be used for other types of plasma.

In some embodiments, the pretreatment process may include exposing the substrate to a pretreatment reactant at a temperature: In some embodiments, the pretreatment temperature may exceed about 20°C. In some embodiments, the pretreatment temperature may be from about 20°C to about 500°C, more preferably from about 50°C to about 450°C, more preferably from about 150°C to about 400°C. In some implementations, the pretreatment temperature can be approximately the same as the deposition temperature. In some implementations, the pretreatment temperature may be different from the deposition temperature. In some implementations, the plasma may be generated at a power output of less than about 2500 watts, such as about 1 to about 1000 watts, about 1 to about 500 watts, or about 1 to about 200 watts or less. In some implementations, the plasma can be generated at a power of 50 W. In some implementations, the plasma can be generated at a power of 100 W.

In some embodiments, the plasma is provided for less than about 200 seconds, less than about 180 seconds, less than about 60 seconds, less than about 30 seconds, less than about 10 seconds, or less than about 3 seconds.

In some embodiments, a plasma is formed within a reactor. In some implementations, the plasma may be formed in situ on top of or in close proximity to the substrate. In another embodiment, a plasma is formed upstream of the reaction chamber in a remote plasma generator and the plasma products are directed to the reaction chamber and contact the substrate. As those skilled in the art will appreciate, for remote plasmas the path to the substrate can be optimized to maximize electrically neutral species and minimize ion survival before reaching the substrate.

In some embodiments, the treated substrate is not exposed to an atmospheric environment after the pretreatment process and prior to the start of the selective deposition process. In some embodiments, the treated substrate is not exposed to air after the pretreatment process and prior to beginning the selective deposition process.

In some implementations, a pretreatment process can be used to improve the selectivity of a subsequent selective deposition process. In some implementations, a pretreatment process can enhance selective deposition of Al and N-containing materials on a first surface relative to a second dissimilar surface. In some embodiments, a pretreatment process can improve the selectivity of a subsequent selective deposition process by a factor of greater than about 2, greater than about 5, or greater than about 10.

In some implementations, the pretreatment process may be performed in the same reaction chamber or reactor as the subsequent deposition process 100. In some implementations, the pretreatment process may be performed in a different reaction chamber or reactor than the subsequent deposition process 100.

Referring back to Figure 1, in step 120 the substrate is contacted with a first precursor comprising Al. In some embodiments, the first precursor is guided into the reaction chamber in the form of a gas phase pulse and contacts the substrate surface. Conditions are preferably selected such that only one monolayer of the precursor is adsorbed on the substrate surface in a self-limiting manner. However, in some embodiments, conditions may be selected such that only one monolayer of precursor can be formed.

The first precursor pulse is preferably supplied in gaseous form. For purposes of this disclosure, a first precursor gas is considered “volatile” if the species exhibits sufficient vapor pressure under process conditions to deliver the species to the workpiece in a concentration sufficient to saturate the exposed surfaces.

In some embodiments, the first precursor is heated for about 0.01 seconds to about 60 seconds, about 0.02 seconds to about 30 seconds, about 0.025 seconds to about 20 seconds, about 0.05 seconds to about 5.0 seconds, about 0.05 seconds to about 0.05 seconds. It is in contact with the substrate for 2.0 seconds, or about 0.1 seconds to about 1.0 seconds.

If the first precursor used in an ALD-type process exists in a gas phase before being introduced into the reaction chamber and contacting the substrate surface, the first precursor may be a solid, liquid, or gaseous material under standard conditions (room temperature and atmospheric pressure).

If first precursor and reaction by-products are present in step 130, they are removed from the substrate surface, such as by purging with pulses of an inert gas, such as nitrogen or argon. Purging a reaction chamber means removing gaseous precursors and/or gaseous by-products from the reaction chamber, for example by evacuating the chamber with a vacuum pump and/or replacing the gas inside the reactor with an inert gas such as argon or nitrogen. Typical purging times are about 0.05 to 20 seconds, more preferably about 1 to 10 seconds, and even more preferably about 1 to 2 seconds. However, if necessary, other purging times may be used, such as when it is necessary to deposit a layer over a very high aspect ratio structure or other structure with a complex surface morphology. Appropriate purging times can be readily determined by those skilled in the art based on specific circumstances.

However, in other embodiments, if there is an excess of the first precursor and reaction by-product, removal of the excess first precursor and reaction by-product may include moving the substrate such that the first precursor is no longer in contact with the substrate. there is. In some implementations, no precursor may be removed from various parts of the chamber. In some implementations, the substrate is moved from one part of the chamber containing the first precursor to another part of the chamber containing the second precursor or no precursor. In some implementations, the substrate is moved from the first reaction chamber to a second, different reaction chamber.

In step 140 the substrate is contacted with a vapor phase precursor comprising N. In some implementations, a second precursor is pulsed into the chamber where it reacts with the first precursor bound to the first surface of the substrate. Typically, this reaction forms about one monolayer of material containing Al and N on the substrate. However, in some embodiments, more than one molecular layer of material containing Al and N is formed on the substrate.

In some embodiments, the second precursor can include nitrogen plasma or nitrogen radicals. In this embodiment, nitrogen can be activated within the reaction chamber or upstream of the reaction chamber. Where plasma is required, after the substrate has been exposed to the nitrogen plasma for the desired period of time, the plasma generator can be turned off and the flow of nitrogen precursor itself activated to be used to remove excess nitrogen plasma and unreacted by-products from the reaction chamber. The flow of unused second precursor may include one type of purge gas.

Although those skilled in the art will recognize that any number of suitable second precursors may be used, suitable second precursors preferably include nitrogen-containing compounds that react with the ligands of the previously or later deposited first precursor. Accordingly, the selection of an appropriate second precursor may depend on the specific first precursor used and the nature of the ligands in the first precursor.

In some embodiments, the second precursor is heated for about 0.01 seconds to about 60 seconds, about 0.02 seconds to about 30 seconds, about 0.025 seconds to about 20 seconds, about 0.05 seconds to about 5.0 seconds, about 0.05 seconds to about 0.05 seconds. It is in contact with the substrate for 2.0 seconds, or about 0.1 seconds to about 1.0 seconds. However, depending on the reactor type, substrate type and its surface area, the second precursor contact time can be much longer than 10 seconds. In some implementations, contact time can be in minutes. The optimal contact time can be easily determined by one skilled in the art based on specific circumstances.

The concentration of the second precursor within the reaction chamber may be from about 0.01 volume % to about 99.0 volume %. Additionally, the second precursor may flow from the reaction chamber at a rate of about 1 standard cm ³ /min and about 4000 standard cm ³ /min.

At step 150, if there is excess second precursor and gaseous by-products of the surface reaction, these excess second precursors and gaseous by-products are removed from the substrate, as described above for step 130. In some embodiments, excess precursor and reaction by-products are removed, preferably with the aid of inert gases.

The contacting and removal steps may optionally be repeated in step 160 until the desired thickness of Al and N containing material is formed on the surface of the substrate, with each cycle leaving behind only one molecular monolayer. In some cases, it may be desirable to at least partially decompose at least one of the various precursors. As such, in some implementations, conditions may be selected such that only one molecular layer of Al and N containing material is formed on the substrate in each deposition cycle.

The ALD process for Al and N containing materials of the present disclosure may include one or more cycles. Some embodiments include repetition of at least about 5 cycles, at least about 10 cycles, or at least about 50 cycles. In some embodiments, no more than 100 cycles are performed to form a thin film of the desired thickness.

In some embodiments, the substrate surface and/or Al and N containing materials may optionally be subjected to a plasma treatment process. In Figure 1 this is indicated as step 170. In some implementations, the plasma treatment process may be performed after more than one deposition cycle has been performed. In some implementations, the plasma treatment process may be performed before the deposited Al and N containing material films are continuous or closed. In some implementations, the plasma treatment process may be performed approximately every 10 deposition cycles, approximately every 20 deposition cycles, or approximately every 50 deposition cycles. In some implementations, at least two consecutive deposition cycles are performed without a plasma treatment process. In some implementations, at least 5 or 10 deposition cycles are performed without a plasma treatment process. In some implementations, the plasma treatment process may be performed before any deposition is performed, i.e., before any deposition cycles are performed.

In some implementations, the plasma treatment process may be performed in the same reaction chamber or reactor as the deposition process 100. In some implementations, the plasma treatment process may be performed in a different reaction chamber or reactor than the deposition process 100.

In some embodiments, a plasma is formed within a reactor. In some implementations, the plasma may be formed in situ on top of or in close proximity to the substrate. In another embodiment, a plasma is formed upstream of the reaction chamber in a remote plasma generator and the plasma products are directed to the reaction chamber and contact the substrate. As those skilled in the art will appreciate, for remote plasmas the path to the substrate can be optimized to maximize electrically neutral species and minimize ion survival before reaching the substrate.

In some embodiments, the Al and N containing materials may be deposited using multiple deposition cycles, and plasma treatment may be performed, such as prior to deposition, after each deposition cycle, at intervals during deposition, or at desired thicknesses of Al and N-containing materials. It may be applied one or more times, including after the N-containing material has been deposited.

In some implementations, the plasma treatment process includes exposing the substrate directly to plasma. In some implementations, the plasma treatment process includes exposing the substrate to a remote plasma. In some implementations, the plasma treatment process includes exposing the substrate to excited or atomic species generated in a plasma discharge, but not including substantial amounts of ions, if any. In some implementations, the plasma can include oxygen. In some implementations, the plasma can include nitrogen. Although referred to as a plasma treatment process, in some implementations, reactive oxygen species that do not involve plasma, such as ozone, may be used. In some implementations, the plasma can include hydrogen.

In some embodiments, the use of a pretreatment process or plasma treatment process in which the substrate is exposed to a reactant includes an oxygen plasma. O ₂ may be provided as a source gas at, for example, about 1 to about 2000 sccm, more preferably about 5 to about 1000 sccm, and most preferably about 50 to about 500 sccm. In some embodiments, O ₂ may be provided at about 300 sccm.

In some embodiments, the use of a pretreatment process or plasma treatment process in which the substrate is exposed to a reactant includes a nitrogen plasma. N ₂ may be provided as a source gas at, for example, about 1 to about 5000 sccm, more preferably about 5 to about 2000 sccm, and most preferably about 50 to about 500 sccm. In some embodiments, N ₂ may be provided at about 300 sccm.

In some embodiments, the use of a pretreatment process or plasma treatment process in which the substrate is exposed to a reactant includes hydrogen plasma. In some embodiments, H ₂ may be provided as a source gas, such as from about 1 to about 2000 sccm, more preferably from about 5 to about 1000 sccm, and most preferably from about 10 to about 100 sccm. In some embodiments, H ₂ may be provided at about 50 sccm. Similar conditions can be used for other types of plasma.

In some implementations, a plasma treatment process may include exposing a substrate to a reactant at a processing temperature. In some embodiments, the processing temperature may exceed about 20°C. In some embodiments, the processing temperature may be from about 20°C to about 500°C, more preferably from about 50°C to about 450°C, more preferably from about 150°C to about 400°C. In some implementations, the processing temperature may be approximately the same as the deposition temperature and/or pretreatment temperature. In some implementations, the processing temperature may be different from the deposition temperature and/or pretreatment temperature.

In some implementations, the plasma may be generated at a power of less than about 2500 watts, such as about 1 to about 1000 watts, about 1 to about 500 watts, or about 1 to about 200 watts or less. In some implementations, the plasma can be generated at a power of 50 W. In some implementations, the plasma can be generated at a power of 100 W.

In some embodiments, the plasma is provided for less than about 200 seconds, less than about 180 seconds, less than about 60 seconds, less than about 30 seconds, less than about 10 seconds, or less than about 3 seconds.

In some implementations, the plasma treatment process 170 may be substantially the same as the pretreatment process 110.

The depicted deposition cycle of Al and N-containing materials begins with contacting the surface of the substrate with a first vapor phase precursor comprising Al; however, in other embodiments, the deposition cycle begins with contacting the surface of the substrate with a second vapor phase precursor comprising nitrogen. It starts by making contact with. Those skilled in the art will understand that contacting the substrate with a first vapor phase precursor comprising Al and a second vapor phase precursor comprising nitrogen can be interchanged in a deposition cycle.

In some implementations, the substrate is moved so that the different reactants alternately and sequentially contact the surface of the substrate in a desired order for a desired amount of time. In some implementations, removal steps 130 and 150 are not performed. In some implementations, no reactant may be removed from various parts of the chamber. In some implementations, the substrate is moved from one part of the chamber containing the first precursor to another part of the chamber containing the second reactant. In some implementations, the substrate is moved from the first reaction chamber to a second, different reaction chamber.

One skilled in the art can determine the optimal reactant evaporation temperature based on the properties of the selected precursors. One skilled in the art can determine the optimal reactant contact time through routine experimentation based on the properties of the selected precursor and the desired properties of the deposited Al and N containing materials.

The growth rate of Al and N containing materials will vary depending on reaction conditions. As described below, in initial experiments, the growth rate varied between approximately 0.01 Å/cycle and 2.0 Å/cycle. In some embodiments, the growth rate can be from about 0.01 Å/cycle to about 3.0 Å/cycle, preferably from about 0.1 Å/cycle to about 2.5 Å/cycle, more preferably from 0.3 Å/cycle to about 2.0 Å/cycle. there is.

In some embodiments, the deposited Al and N containing material comprises a thin film. In some embodiments, the deposited Al and N-containing material comprises AlN, and in some embodiments the deposited Al and N-containing material is AlN. In some embodiments, Al and N containing materials consisting essentially of Al and N are formed. In some embodiments, additional reactants, such as oxygen, may be used to incorporate or contribute to the aluminum oxynitride film to form the film. In some implementations where non-metallic components other than nitrogen are needed, the ALD method for forming Al and N containing materials may include steps other than the initial Al and N steps. For example, if a metallic aluminum oxynitride film is desired, the method may include an oxidation step. In the oxidation step, oxygen or an oxygen-containing precursor is provided to the reaction chamber and brought into contact with the substrate surface. The oxygen phase may be part of one or more deposition cycles. In some implementations, a second metal step can be provided in one or more deposition cycles. The oxygen step, or other preferred step, may be performed after the Al step or the N step, but in some circumstances, in some embodiments, excess oxygen (or other reactants) and any reaction by-products are removed from the reaction space before proceeding to the next step. It is desirable to remove it from. In some embodiments, additional steps, such as oxygen or additional metal steps, may be provided intermittently after the final deposition cycle or during the deposition process.

In some embodiments, the deposition of Al and N containing material on the first surface of the substrate relative to the second surface of the substrate is at least about 90% selective, at least about 95% selective, at least about 96%, 97%, 98% or More than 99% selective. In some embodiments, deposition of Al and N containing materials occurs only on the first surface and not on the second surface. In some implementations, deposition on the first surface of the substrate relative to the second surface of the substrate is at least about 80% selective, which may be selective enough for some special applications. In some implementations, the deposition on the first surface of the substrate relative to the second surface of the substrate is at least 50% selective, which may be sufficiently selective for some special applications. In some embodiments, the deposition on the first surface of the substrate relative to the second surface of the substrate is at least about 1%, at least about 2.5%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, or at least about 40%, all of which may be sufficiently selective for some specific applications.

In some implementations, the ratio of Al and N containing material deposited on the first surface of the substrate relative to the second surface of the substrate can be at least about 10:1, at least about 20:1, or at least about 40:1. In some embodiments, when the thickness of the Al and N containing material deposited on the first surface is greater than about 5 nm, the Al and N containing material deposited on the first surface of the substrate relative to the second surface of the substrate The ratio may be at least about 10:1, at least about 20:1, or at least about 40:1. In some embodiments, when the thickness of the Al and N containing material deposited on the first surface is greater than about 2.5 nm, the Al and N containing material deposited on the first surface of the substrate relative to the second surface of the substrate The ratio may be at least about 10:1, at least about 20:1, or at least about 40:1. In some embodiments, when the thickness of the Al and N containing material deposited on the first surface is greater than about 1 nm, the Al and N containing material deposited on the first surface of the substrate relative to the second surface of the substrate The ratio may be at least about 10:1, at least about 20:1, or at least about 40:1.

In some embodiments, when the method of depositing Al and N containing materials comprises about 0 to about 25 deposition cycles, about 0 to about 50 deposition cycles, about 0 to about 100 deposition cycles, or about 0 to about 150 deposition cycles, The ratio of Al and N containing material deposited on the first surface of the substrate relative to the second surface of the substrate may be at least about 10:1, at least about 20:1, or at least about 40:1. In some embodiments, when the method of depositing Al and N containing materials comprises about 0 to about 25 deposition cycles, about 0 to about 50 deposition cycles, about 0 to about 100 deposition cycles, or about 0 to about 150 deposition cycles, Less than about 0.1 nm of Al and N containing material is deposited on the second surface of the substrate.

In some embodiments, the Al and N containing materials have an etch selectivity toward SiO ₂ , i.e. the Al and N containing materials have an etch rate that is less than that of SiO ₂ , for example in dilute HF. In some embodiments, the Al and N containing materials have a wet etch rate (WER) of less than one-fifth of the thermal oxide removal rate of about 2-3 nm per minute using diluted HF (0.5%). In some embodiments, the wet etch rate of Al and N containing materials relative to the wet etch rate of thermally oxidized silicon (SiO ₂ , TOX) is less than about 0.2 at 0.5% dHF. In some embodiments, the wet etch rate of Al and N containing materials relative to the wet etch rate of TOX is less than about 0.1 at 0.5% dHF. In some embodiments, the wet etch rate of Al and N containing materials relative to the wet etch rate of TOX is less than about 0.05 at 0.5% dHF.

2, in some implementations, a substrate is provided comprising a first surface and a second dielectric surface and AlN is deposited on the first surface of the substrate by a cyclic deposition method 200 comprising at least one cycle. is selectively deposited on, wherein one cycle includes:

contacting the substrate with vapor phase trimethylaluminum (TMA) at step 220;

At step 230, if excess TMA and reaction by-products are present, removing excess TMA and reaction by-products from the surface;

contacting the substrate with vapor phase NH ₃ in step 240;

At step 250, removing excess NH ₃ and any reaction by-products from the surface; and

At step 260, optionally repeating the contacting and removing steps until an AlN thin film of the desired thickness is formed.

The illustrated AlN deposition cycle begins with contacting the substrate with TMA, but in other implementations, the deposition cycle may begin with contacting the substrate with NH ₃ . Those skilled in the art will understand that the steps of contacting the substrate surface with TMA and NH ₃ may be interchanged in the deposition cycle.

In some implementations, a pretreatment process may be performed on one or more surfaces of the substrate prior to starting the deposition process. In some implementations, a pretreatment process can improve the selectivity of the selective deposition process 200. In some implementations, a pretreatment process can enhance the deposition of AlN on one surface relative to one or more different surfaces before starting the deposition process. In some implementations, a pretreatment process can inhibit deposition of AlN on one surface relative to one or more different surfaces prior to starting the deposition process. In Figure 2, this is represented as step 210, where the substrate may be exposed to a pretreatment reactant, such as a plasma, prior to deposition of the Al and N containing materials.

In some embodiments, the substrate surface and/or AlN thin film may optionally undergo a plasma treatment process. In Figure 2 this is indicated as step 270. In some implementations, this plasma treatment process is substantially identical to the plasma treatment process 170 described above with respect to FIG. 1 . In some implementations, plasma treatment process 270 may be substantially the same as pretreatment process 210. In some implementations, the plasma treatment process may be performed after more than one deposition cycle has been performed. In some implementations, the plasma treatment process can be performed before the deposited AlN film is continuous or closed. In some implementations, the plasma treatment process may be performed after about 10 deposition cycles, after about 20 deposition cycles, or after about 50 deposition cycles. In some implementations, the plasma treatment process may be performed in the same reaction chamber or reactor as the deposition process 200. In some implementations, the plasma treatment process may be performed in a different reaction chamber or reactor than the deposition process 200.

In some embodiments, a substrate is provided comprising a first surface and a second dielectric surface, and the Al and N containing materials are selectively deposited on the first surface of the substrate using a cyclic deposition process comprising at least one deposition cycle. and the at least one deposition cycle includes alternately and sequentially contacting the substrate with a first vapor phase precursor and a second vapor phase precursor. In some implementations, the first precursor can include Al and the second precursor can include N. In some embodiments, the first precursor can include tritbutylaluminum and the second precursor can include NH ₃ .

In some implementations, a substrate is provided comprising a first surface and a second dielectric surface, wherein AlN is selectively deposited on the first surface of the substrate using a cyclic deposition process comprising at least one deposition cycle, The at least one deposition cycle includes alternately and sequentially contacting the substrate with a first vapor phase precursor and a second vapor phase precursor. In some implementations, the first precursor can include Al and the second precursor can include N. In some embodiments, the first precursor can include tritbutylaluminum and the second precursor can include NH ₃ .

In some embodiments, a substrate is provided, and AlN is deposited on a portion of the substrate using a cyclic deposition process comprising at least one deposition cycle, wherein the at least one deposition cycle comprises a vapor phase first precursor and a vapor phase precursor. It includes sequentially contacting the second precursor with the substrate alternately, and the second precursor may include NH ₃ .

In some implementations, the substrate may undergo a pretreatment process prior to deposition. In some implementations, a pretreatment process can improve the selectivity of a selective deposition process. In some implementations, a pretreatment process can enhance the deposition of AlN on one surface relative to one or more different surfaces before starting the deposition process. In some implementations, a pretreatment process can inhibit deposition of AlN on one surface relative to one or more different surfaces prior to starting the deposition process. In some implementations, the pretreatment process may include exposing the substrate to a certain reactant, such as a plasma, prior to deposition of AlN.

In some embodiments, the substrate surface and/or AlN thin film may optionally undergo a plasma treatment process. In some implementations, this plasma treatment process is substantially identical to the plasma treatment processes 170 and 270 described above with respect to FIGS. 1 and 2. In some implementations, the plasma treatment process can be substantially the same as the pretreatment process. In some implementations, the plasma treatment process may be performed after more than one deposition cycle has been performed. In some implementations, the plasma treatment process can be performed before the deposited AlN film is continuous or closed. In some implementations, the plasma treatment process can be performed after less than about 10 deposition cycles, after less than about 20 deposition cycles, or after less than about 50 deposition cycles. In some implementations, the plasma treatment process can be performed in the same reaction chamber or reactor as the deposition process. In some implementations, the plasma treatment process may be performed in a different reaction chamber or reactor than the deposition process.

Referring to FIG. 3 and according to some embodiments, the Al and N containing materials are separated into different sections of a substrate comprising a first surface and a different second surface by a process 300 comprising at least one super-cycle 301. deposited selectively on a first surface relative to the two surfaces, wherein at least one super-cycle comprises the following steps:

depositing Al and N containing materials on a first surface of the substrate relative to a second, different surface at step 320;

etching the deposited Al and N containing material such that substantially all of the deposited Al and N containing material is removed from the first surface at step 330 and substantially all of the deposited Al and N containing material is removed from the first surface;

Optionally repeating the selective deposition and etching steps at step 340 until a desired thickness of Al and N containing material is formed on the first surface of the substrate relative to the second, different surface.

In some implementations, when starting super-cycle 301, one or more surfaces of the substrate may undergo a pretreatment process. In some implementations, a pretreatment process can improve the selectivity of the selective deposition process step 320. In some implementations, a pretreatment process prior to selective deposition step 320 may enhance deposition of Al and N containing material on one surface relative to one or more different surfaces. In some implementations, a pretreatment process prior to the selective deposition step 320 may inhibit deposition of Al and N containing material on one surface relative to one or more different surfaces. In Figure 3, this is represented as step 310 of super-cycle 301, where the substrate may be exposed to a pretreatment reactant, such as a plasma, prior to selective deposition of Al and N containing materials in step 320.

In some implementations, the pretreatment process may be the same as the pretreatment process 110 and/or 210 described herein with respect to FIGS. 1 and 2. In some embodiments, the pretreatment process can include exposing the substrate to a pretreatment reactant: In some embodiments, the pretreatment reactant can include hydrogen. In some embodiments, the pretreatment reactant includes hydrogen radicals, atomic hydrogen, hydrogen plasma, or combinations thereof. In some implementations, the pretreatment reactant may include a plasma, such as a plasma generated from a gas comprising H ₂ .

In some embodiments, a plasma is formed within a reactor. In some implementations, the plasma may be formed in situ on top of or in close proximity to the substrate. In another embodiment, a plasma is formed upstream of the reaction chamber in a remote plasma generator and the plasma products are directed to the reaction chamber and contact the substrate. As those skilled in the art will appreciate, for remote plasmas the path to the substrate can be optimized to maximize electrically neutral species and minimize ion survival before reaching the substrate.

In some implementations, the processed substrate is not exposed to an atmospheric environment after the pretreatment process (310) and prior to the start of the selective deposition step (320). In some implementations, the treated substrate is not exposed to air after the pretreatment process 310 and prior to the start of the selective deposition process at step 320.

In some implementations, a pretreatment process can be used to improve the selectivity of a subsequent selective deposition process. In some implementations, the pretreatment process can enhance selective deposition of Al and N containing materials on a first surface relative to a second different surface, such as the first and second surfaces described herein. In some embodiments, a pretreatment process can improve the selectivity of a subsequent selective deposition process by a factor of greater than about 2, greater than about 5, or greater than about 10.

In some implementations, pretreatment process 310 may be performed in the same reaction chamber or reactor as the subsequent selective deposition step 320. In some implementations, pretreatment process 310 may be performed in a different reaction chamber or reactor than the subsequent selective deposition step 320.

Referring again to Figure 3, at step 320 Al and N containing materials are selectively deposited on a first surface of the substrate relative to the second surface. In some embodiments, selectively depositing Al and N containing materials in step 320 may include a selective deposition process comprising one or more deposition sub-cycles, wherein the one or more sub-cycles include a first vapor phase aluminum precursor and and sequentially contacting the second vapor phase nitrogen precursor with the substrate in alternating order. In some implementations, the deposition sub-cycle can be repeated 1 to 1000 times, 1 to 500 times, 1 to 300 times, 1 to 200 times, 1 to 50 times, 1 to 100 times, or 1 to 50 times.

In some implementations, selectively depositing Al and N-containing materials in step 320 may include, for example, a selective deposition process described herein with respect to FIGS. 1 and 2. In some embodiments, selectively depositing Al and N containing materials in step 320 may include an ALD type deposition process comprising at least one sub-cycle, wherein the at least one sub-cycle includes: :

contacting the substrate with a first vapor phase precursor containing Al;

If excess first precursor and reaction by-products are present, removing excess first precursor and reaction by-products from the substrate;

contacting the substrate with a second vapor phase precursor containing nitrogen;

removing excess second precursor and any gaseous by-products from the substrate; and

Optionally repeating the contacting and removal steps until an Al and N containing material of the desired thickness is formed.

In some embodiments, selectively depositing Al and N containing materials in step 320 may include an ALD type deposition process comprising at least one sub-cycle, wherein the at least one sub-cycle includes: :

contacting the substrate with a first vapor phase precursor comprising trimethylaluminum (TMA);

If excess first precursor and reaction by-products are present, removing excess first precursor and reaction by-products from the substrate;

contacting the substrate with a second vapor phase precursor containing NH ₃ ;

removing excess second precursor and any gaseous by-products from the substrate; and

Optionally repeating the contacting and removal steps until an Al and N containing material of the desired thickness is formed.

In some implementations, selectively depositing Al and N containing materials in step 320 may include one or more sub-cycles. Some embodiments have at least about 5 sub-cycles, at least about 10 sub-cycles, at least about 50 sub-cycles, at least about 100 sub-cycles, at least about 150 sub-cycles, at least about 200 sub-cycles, at least about 300 sub-cycles. -comprises repetition of a cycle, at least about 500 sub-cycles, or at least about 1000 sub-cycles. In some implementations, the selective deposition sub-cycle can be repeated until the selective deposition sub-cycle is no longer selective. In some implementations, the selective deposition sub-cycle can be repeated until the selective deposition sub-cycle is no longer significantly selective. In some implementations, the selective deposition sub-cycle may be repeated until the selective deposition sub-cycle loses a significant amount of selectivity. In some embodiments, the selective deposition sub-cycle is maintained at about 50% selectivity, about 40% selectivity, about 30% selectivity, etc., until the selective deposition sub-cycle no longer achieves the desired level of selectivity. The selective deposition sub-cycle may be repeated until a selectivity of about 20% selectivity, about 10% selectivity, about 5% selectivity, about 2% selectivity, about 1% or less is no longer achieved. . That is, in some embodiments, selectively depositing Al and N containing material in step 320 means that the sub-cycle no longer selectively deposits Al and N containing material on the first surface of the substrate relative to the second surface. and repeating a selective deposition sub-cycle, such as an ALD deposition cycle as described herein, until the selective deposition sub-cycle is removed. In some embodiments, selectively depositing Al and N containing materials in step 320 may be achieved by selective sub-cycles until the selectivity of the sub-cycles falls below a predetermined selectivity, such as ALD deposition as described herein. It may include repeating the cycle. For example, in some embodiments, selectively depositing Al and N containing materials in step 320 may cause the selective deposition sub-cycle to be less than about 50%, less than about 25%, less than about 15%, less than about 10%, It may include repeating the selective deposition sub-cycle until the selectivity is less than about 5%, less than about 2%, less than about 1% or less.

After selectively depositing the Al and N containing materials in step 320, the deposited Al and N containing materials are etched, such as by undergoing an etching process in step 330. In some embodiments, the etch process removes substantially all of the deposited Al and N-containing material from the second surface of the substrate and does not remove substantially all of the deposited Al and N-containing material from the first surface of the substrate. In some embodiments, the etching process may remove the same or similar amounts or thicknesses of Al and N containing material from the first and second surfaces of the substrate, but in step 320 the Al and N containing material may be removed from the first and second surfaces relative to the second surface. Because it was selectively deposited on the first surface, at least some of the thickness of the Al and N containing material remains on the first surface of the substrate, while all or any of the Al and N containing material that was deposited on the second surface of the substrate All are removed by an etch process in step 330.

In some implementations, etching the deposited Al and N-containing material in step 330 may include subjecting the deposited Al and N-containing material to a vapor phase etch process. In some implementations, the vapor phase etch process may be a periodic vapor etch process. In some embodiments, the etching process may include an atomic layer etching (ALE) process. In some implementations, more than a sub-monolayer of material may be removed from a substrate by an atomic layer etch (ALE) process that includes contacting the substrate surface with at least one vapor phase reactant in a reaction space. In some embodiments, one or more gaseous halide reactants are used. Halide reactants can be metal halides or non-metal halides, semi-metal halides, semi/non-metal oxyhalides, and organic (oxy) halides. In some implementations, surface contamination, such as B or C contamination, can be removed from the substrate surface.

In some embodiments, the ALE process includes alternatingly contacting the substrate with at least first and second vapor phase reactants in a reaction space. In some embodiments, one or more of the gas phase reactants is a halide reactant. One or more etch cycles or sub-cycles may be provided in the ALE process as part of a selective deposition process or a selective deposition super-cycle. In some implementations, the etch cycle includes exposing the substrate to two different reactants. In some implementations, the etch cycle includes exposing the substrate to three different reactants. In some implementations, the etch cycle includes exposing the substrate to four different reactants. In some implementations, the etch cycle includes exposing the substrate to five or more different reactants. In some embodiments, reactant exposures are sequential. Each stage of exposure to reactants can be separated by purging the reaction space or pumping down the reaction chamber to remove reaction by-products and excess reactants.

In some embodiments, the substrate to be etched is exposed to one or more reactants selected from halides, oxygen compounds, oxygen scavengers, halide exchange drivers, ligand exchangers, and metal organic or inorganic reactants. Oxygen compounds may include, for example, H ₂ O, O ₂ or O ₃ . Oxygen scavengers or halide exchange drivers may include, for example, Ch _y Cl _x or CCl ₄ . In some embodiments, the oxygen scavenger or halide exchange driver is a halide described herein, including non-metallic (or semi-metallic) halides. The ligand exchanger, or metal or inorganic reactant, may include, for example, Hacac, or TMA/Sn(acac) ₂ . In some embodiments, the ligand exchanger can be a halide described herein, including a non-metallic or semi-metallic halide.

In some embodiments, the etch cycle includes a saturating, self-limiting adsorption step in which the substrate is contacted with at least one vapor phase reactant, such as a halide reactant. For example, after the substrate has been contacted with a first vapor phase reactant, a second exposure step may be performed in which the substrate is contacted with a second vapor phase reactant. In the first adsorption step, the first reactant is adsorbed in a self-limiting manner to the material to be etched on the substrate. The second exposure step then leads to the formation of volatile by-products comprising adsorbate atoms, second precursor atoms and some atoms from the surface being etched. In this way, etching of the desired material on the substrate surface can be closely controlled.

In some embodiments, the reaction is not self-limiting. However, etching can be controlled by supplying an adjusted amount of one or more reactants.

In some embodiments, vapor phase reactions are avoided by alternately and sequentially supplying precursors into the reaction chamber. The gaseous reactants are separated from each other in the reaction chamber, for example by removing excess reactant and/or reaction by-products from the reaction chamber between reactant pulses. Reactants may be removed from proximate the substrate surface using purge gas and/or vacuum. In some embodiments, excess reactant and/or reactant by-products are removed from the reaction space, such as by purging with an inert gas. Because of the separation of reactants and the self-limiting nature of the reaction, less than one monolayer of material is typically removed in each ALE etch cycle. However, in some implementations, more than one monolayer of material may be removed in each cycle. In some implementations, pulses of reactants may partially or completely overlap. For example, in some embodiments, one reactant may flow continuously into the reaction space while one or more additional reactants are provided intermittently at desired intervals.

In some embodiments, the ALE method disclosed herein is a thermal etch process as opposed to a plasma etch process. Therefore, plasma reactants are not used in this thermal ALE etch cycle. Although referred to as a thermal ALE process to differentiate it from processes using plasma reactants, in some embodiments, the ALE reaction may have zero activation energy and thus may not require any additional thermal energy. Accordingly, the reaction may also be referred to as a chemical etch process. Because the thermal ALE method may cause less damage to the underlying substrate, the thermal ALE method may be preferable to the plasma ALE method depending on the situation. Additionally, the thermal ALE method enables isotropic etching of non-line-of-sight (NLOS) properties.

However, in some implementations, the etch process may include an ALE process involving plasma. In some implementations, the ALE process may include contacting the deposited Al and N containing material with at least one vapor phase etch reactant. In some implementations, the etching process may be a dry etching process, such as a reactive ion etching process. In some implementations, the dry etching process may be a thermal dry etching process. In some implementations, the dry etch process may include the use of plasma.

In some embodiments, the etch process of step 330 may include an ALE process comprising one or more etch sub-cycles, wherein the one or more etch sub-cycles combine the deposited Al and N containing materials with a first vapor phase etch reactant and a second etch reactant. 2. It includes contacting with a vapor phase etching reactant. In some implementations, the etch sub-cycle can be repeated 1 to 1000 times, 1 to 500 times, 1 to 300 times, 1 to 200 times, 1 to 50 times, 1 to 100 times, or 1 to 50 times.

In some implementations, the etch process of step 330 may include an ALE process comprising one or more etch sub-cycles, where the etch sub-cycles include:

contacting the substrate with a first vapor phase etch reactant;

If an excess amount of the first etch reactant and reaction by-product is present, removing the excess first etch reactant and reaction by-product from the substrate;

contacting the substrate with a first vapor phase etch reactant;

If excess second etch reactant and reaction by-product are present, removing the excess second etch reactant and reaction by-product from the substrate; and

Optionally repeating the contacting and removing steps to etch the deposited Al and N containing material to a desired extent, for example, until the deposited Al and N containing material is substantially completely removed from the second surface of the substrate.

In some implementations, the etch process of step 330 may include an ALE process comprising one or more etch sub-cycles, where the etch sub-cycles include:

contacting the substrate with a first vapor phase halide etch reactant, such as NF ₃ ;

If an excess amount of the first etch reactant and reaction by-product is present, removing the excess first etch reactant and reaction by-product from the substrate;

contacting the substrate with a second vapor phase etch reactant comprising Al, such as TMA;

If excess second etch reactant and reaction by-product are present, removing the excess second etch reactant and reaction by-product from the substrate; and

Optionally repeating the contacting and removing steps to etch the deposited Al and N containing material to a desired extent, for example, until the deposited Al and N containing material is substantially completely removed from the second surface of the substrate.

In some implementations, an etch sub-cycle can be repeated one or more times. Some embodiments have at least about 5 sub-cycles, at least about 10 sub-cycles, at least about 50 sub-cycles, at least about 100 sub-cycles, at least about 150 sub-cycles, at least about 200 sub-cycles, at least about 300 sub-cycles. -comprises repetition of a cycle, at least about 500 sub-cycles, or at least about 1000 sub-cycles. In some embodiments, the etch sub-cycle is such that substantially all of the deposited Al and N containing material is removed from the second surface of the substrate and substantially all of the deposited Al and N containing material is not removed from the first surface of the substrate. It can be repeated until

According to some embodiments, each sub-cycle has a temperature ranging from about 20 to about 1200°C, from about 50 to about 800°C, from about 75 to about 600°C, from about 300 to about 500°C, or from about 350 to about 450°C. It can be performed in In some embodiments, the temperature is greater than about 20°C, 50°C, or 100°C, but less than about 1000°C, 800°C, 600°C, or 500°C. In some embodiments, the cycle is performed at a temperature of about 450°C.

The pressure within the reaction chamber is generally from about 10 ^-9 torr to about 760 torr, or from about 0.001 torr to about 100 torr. However, in some cases the pressure may be higher or lower than these ranges, as can be determined by one of ordinary skill in the art given a particular situation. In some embodiments, pressures of less than 2 Torr are used.

In some embodiments, the etch reactant is contacted with the surface having the surface to be etched for about 0.01 seconds to about 60 seconds, about 0.05 seconds to about 30 seconds, about 0.05 seconds to about 5.0 seconds, about 0.1 seconds to about 3 seconds, or about 0.2 seconds. The contact lasts from seconds to about 1.0 seconds. In some embodiments, the etch reactant is in contact with the substrate surface to be etched for about 0.05 seconds to about 5.0 seconds, about 0.1 seconds to about 3 seconds, or about 0.2 seconds to about 1.0 seconds. In some embodiments, contact time can exceed about 60 seconds. However, depending on the reactor type, the material being etched, and other process conditions such as surface area and temperature, the contact time of the etch reactants may be even longer than about 10 seconds. In some implementations, contact time can be in minutes. The optimal contact time can be easily determined by one skilled in the art based on specific circumstances.

In some embodiments, excess reactants and reaction by-products, if present, can be removed from the substrate, such as by purging the reaction chamber with an inert purge gas. In some implementations, the reaction chamber can be purged by stopping the flow of etch reactants while continuing to flow a carrier gas or purge gas for a time sufficient to diffuse or purge excess reactants and reaction by-products from the reaction space. In some embodiments, excess etch reactants and reaction by-products are purged with an inert gas such as helium or argon. In some embodiments, the substrate can be moved from a reaction space containing the second reactant to another reaction space. In some implementations, pulses of purge gas can be from about 0.1 seconds to about 10 seconds, from about 0.1 seconds to about 4 seconds, or from about 0.1 seconds to about 0.5 seconds.

In some implementations, the first vapor phase etch reactant can include a halide. In some embodiments, the first vapor phase etch reactant may include NF ₃ . In some embodiments, the first vapor phase reactant can include NbF ₅ . In some implementations, the first vapor phase etch reactant may not include plasma or excited reactants. In some implementations, the second vapor phase etch reactant can include aluminum. In some embodiments, the second vapor phase etch reactant may include one of tritertbutyl aluminum (TTBA), trimethyl aluminum (TMA), or triethylaluminum (TEA). In some implementations, the second vapor phase etch reactant may be the same as the vapor phase precursor of selective deposition step 320. In some embodiments, the second vapor phase etch reactant can include TMA. In some implementations, the second vapor phase etch reactant may not include plasma or excited reactants.

In some implementations, the etch step 330 is performed in the same reaction space as the selective deposition step 320. However, in some implementations, the etch step 330 may be performed in a different reaction space than the selective deposition step 320. In some embodiments, the selectively depositing AlN and etching the substrate steps may be optionally repeated in step 340 until a desired thickness of Al and N containing material is formed on the first surface of the substrate relative to the second surface. there is. That is, super-cycle 301 may be optionally repeated until a desired thickness of Al and N containing material is formed on the first surface of the substrate relative to the second surface. In some implementations, after the etch step 330, the substrate is not exposed to an atmospheric environment before starting another super-cycle 301. In some implementations, after the etch step 330, the substrate is not exposed to air before starting another super-cycle 301.

first precursor

A number of different first precursors may be used in the selective deposition process described herein as first precursors in a selective deposition cycle and/or selective deposition sub-cycle. In some embodiments, the first precursor is an organometallic compound comprising aluminum. In some embodiments, the first precursor is an alkyl aluminum compound. In some implementations, the first precursor does not include any other metals other than aluminum.

In some embodiments, the first precursor is a compound having the formula R ₃ Al, where R is an alkyl group. Each R may be independently selected from the list of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, and tertbutyl groups. Each R may preferably be independently selected from a methyl group, an ethyl group and a tertbutyl group. In some embodiments, each R can be independently selected from C ₁ -C ₄ alkyl groups.

In some embodiments, the first precursor includes Me ₃ Al, Et ₃ Al, or ^t Bu ₃ Al. In some embodiments, the first precursor is tritbutylaluminum (TTBA). As mentioned above, in some embodiments, the first precursor is trimethylaluminum (TMA).

In some embodiments, the first precursor is not a halide. In some embodiments, the first precursor includes a halogen in at least one, but not all, ligands. In some embodiments, the first precursor includes one chlorine ligand and at least two alkyl ligands. In some embodiments, the first precursor is AlCl ₃ .

In some embodiments, the first precursor may include hydrogen as at least one, but not all, ligands. In some embodiments, the first precursor can include at least one hydrogen ligand and at least one alkyl ligand.

In some embodiments, the first precursor does not include nitrogen. In some implementations, the first precursor does not include silicon. In some embodiments, the first precursor does not include oxygen. In some embodiments, the first precursor does not include nitrogen, silicon, or oxygen.

second precursor

In some embodiments, the second precursor includes nitrogen-hydrogen bonds. In some embodiments, the second precursor is ammonia (NH ₃ ). In some embodiments, the second precursor is molecular nitrogen. In some embodiments, the second precursor is a nitrogen-containing plasma. In some implementations, the second precursor is a nitrogen-containing plasma, such as a nitrogen- and hydrogen-containing plasma. In some embodiments, the second precursor comprises an activated or excited nitrogen species. In some implementations, the second precursor can be provided as a nitrogen-containing gas pulse, which can be a mixture of a nitrogen reactant and an inert gas, such as argon.

Integration

The Al and N containing materials of the present disclosure can be used in a variety of semiconductor applications. For example, Al and N containing materials can be particularly useful as etch stop layers, such as contact etch stop layers, in self-aligned contact formation processes. Self-aligned source/drain contacts can be used to provide misalignment margin for contact lithography. However, standard self-aligned contact processes require additional process steps, such as multiple metal recess steps, SiN filling steps, and SiN polishing steps using chemical-mechanical planarization.

Additionally, the need for additional scaling of the SiN sidewall spacers and etch stop layers in standard self-aligned contact processes due to further minimization of the device may introduce the risk of shorting between the contacts and the metal gate due to overetching of the spacers or etch stop layers. You can.

In some implementations, the Al and N containing materials of this disclosure can be used as an etch stop layer in self-aligned contact processes that do not include metal recesses. In some embodiments, the Al and N containing materials of the present disclosure are etch resistant. FIG. 4 illustrates a process flow for a self-aligned contact process including Al and N containing material protective layers, capping layers, or etch stop layers according to some implementations. In some implementations, the process for forming self-aligned contact 400 proceeds as follows:

At step 401, a semiconductor substrate is provided including a first surface overlying source/drain regions and a second, different surface;

At step 402, an Al and N containing protective layer or etch stop layer, such as AlN, is selectively deposited on the first surface of the substrate relative to the second surface;

In step 403, the second surface is removed, such as using a wet etch process;

At step 404, a contact is formed on the source/drain region of the substrate to replace the removed second surface.

According to some implementations, in step 401, a substrate comprising a semiconductor is provided. A semiconductor substrate includes a first surface and a different second surface. In some implementations, the first surface includes a conductive surface. In some implementations, the first surface includes one or more metal nitrides. In some implementations, the first surface can include a surface of a conductive gate and/or a surface of a spacer. For example, in some implementations, the first surface can include a TiN gate and a SiN spacer. The second surface is preferably a dielectric surface. In some embodiments, the dielectric includes SiO ₂ . In some implementations, the second surface is a dummy contact overlying the source/drain regions. In some implementations, a SiO ₂ dummy contact is placed over the source/drain regions.

In some implementations, the semiconductor substrate undergoes a standard process through gate polishing. That is, the semiconductor substrate can undergo a standard alternative metal gate process flow to form the source, gate and drain as is well known in the art. In some implementations, the semiconductor substrate may undergo a chemical-mechanical planarization process.

At step 402, an Al and N containing protective layer or etch stop layer is selectively deposited on the first surface of the substrate relative to the second surface. In some implementations, Al and N containing protective materials are formed on the TiN gate and SiN spacer. In some implementations, the Al and N containing protective materials are formed directly on the TiN gate and SiN spacer.

In some embodiments, the Al and N containing protective layers are deposited by the ALD process described herein. In some embodiments, the substrate is sequentially contacted alternately with a first precursor comprising Al and a second precursor comprising N. In some embodiments, the Al and N containing protective layer includes AlN. In some embodiments, the Al and N containing protective layer includes an AlN thin film.

In some embodiments, the deposition of the Al and N containing protective layer on the first surface of the substrate relative to the second surface of the substrate is at least about 90% selective, at least about 95% selective, at least about 96%, 97%, 98%. Or more than 99% selective. In some embodiments, deposition of Al and N containing materials occurs only on the first surface and not on the second surface. In some implementations, deposition on the first surface of the substrate relative to the second surface of the substrate is at least about 80% selective or at least about 50% selective.

In some implementations, an Al and N containing protective layer or etch stop layer is deposited on the first surface of the substrate to have a particular thickness. A suitable thickness may be about 0.1 nm or more and about 10 nm or less. In some embodiments, the thickness will be from about 0.1 nm to about 5 nm. In some embodiments, the thickness will be from about 1 nm to about 5 nm. In some embodiments, the thickness will be about 1 nm to about 3 nm. In some embodiments, the thickness will be about 2 nm to about 3 nm. A suitable thickness may be about 0.1 nm or more and about 10 nm or less. In some implementations, a suitable thickness will be one that forms a complete layer on the substrate surface (i.e., a thickness that leaves no gaps). Therefore, the actual thickness of the complete layer may vary depending on the types of precursors used to obtain the Al and N containing materials.

In step 403 the second surface of the substrate is removed, such as using a wet etch process. In some implementations, the second surface of the substrate is removed by etching using dHF. For example, in some implementations, the first and second surfaces of the substrate are exposed to dHF and removed while an Al and N containing protective layer protects the underlying gate and spacer from etching. The Al and N containing protective layer can function as an etch stop layer because the Al and N containing protective layer has a lower wet etch rate than the wet etch rate of the second dielectric surface described herein.

Continuing to refer to Figure 4, at step 404 a contact may be formed on the source/drain region in place of the now removed second surface. In some implementations, contacts can be formed directly over the source/drain regions. In some implementations, the contact includes a silicide material or a titanium containing material, such as Ti or TiN. According to some implementations, the contacts may be formed according to any method known in the art or methods developed in the future. For example, a Ti contact may be formed by physical vapor deposition (PVD) or a TiN contact may be formed by atomic layer deposition (ALD).

In some implementations, after formation of the contact or contacts, the substrate may optionally undergo additional processing or processing steps.

In some implementations, the Al and N containing materials of this disclosure can be used as an etch stop layer in self-aligned contact processes that do not include metal recesses. FIG. 5 illustrates a process flow for a self-aligned contact process including an Al and N containing material protective layer or etch stop layer according to some embodiments. In some implementations, the process for forming self-aligned contact 500 proceeds as follows:

At step 501, a semiconductor substrate is provided including a first surface overlying source/drain regions and a second, different surface;

At step 502, a portion of the first surface is removed to create a recess therein;

At step 503, an Al and N containing protective layer or etch stop layer, such as AlN, is selectively deposited on the first surface of the substrate relative to the second surface;

At step 504, the second surface is removed, such as using a wet etch process, and a contact is formed on the source/drain region of the substrate to replace the removed second surface.

According to some implementations, in step 501, a substrate comprising a semiconductor is provided. A semiconductor substrate includes a first surface and a different second surface. In some implementations, the first surface includes a conductive surface. In some implementations, the first surface includes one or more metal nitrides. In some implementations, the first surface can include a surface of a conductive gate and/or a surface of a spacer. For example, in some implementations, the first surface can include a TiN gate and a SiN spacer. The second surface is preferably a dielectric surface. In some embodiments, the dielectric includes SiO ₂ . In some implementations, the second surface is a dummy contact overlying the source/drain regions. In some implementations, a SiO ₂ dummy contact is placed over the source/drain regions.

In some implementations, the semiconductor substrate undergoes a standard process through gate polishing. That is, the semiconductor substrate can undergo a standard alternative metal gate process flow to form the source, gate and drain as is well known in the art. In some implementations, the semiconductor substrate may undergo a chemical-mechanical planarization process.

According to some implementations, in step 502, a portion of the first surface is removed to create a recess therein. In some implementations, the portion of first surface removed is metal nitride. In some implementations, the portion of first surface removed is SiN. In some implementations, the portion of the first surface removed can include a spacer, such as a SiN spacer. In some embodiments, about 0.1 nm to about 30 nm of a portion of the first surface is removed to create a recess having a depth of about 0.1 nm to about 30 nm. In some embodiments, about 0.1 nm to about 20 nm of a portion of the first surface is removed to create a recess having a depth of about 0.1 nm to about 20 nm. In some embodiments, about 1 nm to about 10 nm of a portion of the first surface is removed to create a recess having a depth of about 1 nm to about 10 nm.

At step 503, an Al and N containing protective layer or etch stop layer is then selectively deposited on the first surface of the substrate relative to the second surface. In some implementations, Al and N containing protective materials are formed on the TiN gate and SiN spacer. In some implementations, the Al and N containing protective materials are formed directly on the TiN gate and SiN spacer.

In some embodiments, the Al and N containing protective layers are deposited by the ALD process described herein. In some embodiments, the substrate is sequentially contacted alternately with a first precursor comprising Al and a second precursor comprising N. In some embodiments, the Al and N containing protective layer includes AlN. In some embodiments, the Al and N containing protective layer includes an AlN thin film.

Selectivity can be given as a percentage calculated by [(deposition on first surface)-(deposition on second surface)]/(deposition on first surface). Deposition can be measured in one of a variety of ways. In some implementations, deposition can be provided as a measured thickness of deposited material. In some implementations, deposition may be provided as a measured amount of material deposited. In some embodiments, the deposition of the Al and N containing protective layer on the first surface of the substrate relative to the second surface of the substrate is at least about 90% selective, at least about 95% selective, at least about 96%, 97%, 98%. Or more than 99% selective. In some embodiments, deposition of Al and N containing materials occurs only on the first surface and not on the second surface. In some implementations, deposition on the first surface of the substrate relative to the second surface of the substrate is at least about 80% selective or at least about 50% selective.

In some implementations, an Al and N containing protective layer or etch stop layer is deposited on the first surface of the substrate to have a particular thickness. A suitable thickness may be greater than 0.1 nm and less than or equal to about 10 nm. In some embodiments, the thickness will be from about 0.1 nm to about 5 nm. In some embodiments, the thickness will be from about 1 nm to about 5 nm. In some embodiments, the thickness will be about 1 nm to about 3 nm. In some embodiments, the thickness will be about 2 nm to about 3 nm. A suitable thickness may be about 0.1 nm or more and about 10 nm or less. In some implementations, a suitable thickness will be one that forms a complete layer on the substrate surface (i.e., a thickness that leaves no gaps). Therefore, the actual thickness of the complete layer may vary depending on the types of precursors used to obtain the Al and N containing materials.

At step 504 the second surface of the substrate is removed, such as using a wet etch process. In some implementations, the second surface of the substrate is removed by etching using dHF. For example, in some implementations, the first and second surfaces of the substrate are exposed to dHF and removed while an Al and N containing protective layer protects the underlying gate and spacer from etching. The Al and N containing protective layer can function as an etch stop layer because the Al and N containing protective layer has a lower wet etch rate than the wet etch rate of the second dielectric surface described herein. A contact is then formed on the source/drain region of the substrate to replace the now removed second surface. In some implementations, contacts can be formed directly over the source/drain regions. In some implementations, the contact includes a silicide material or a titanium containing material, such as Ti or TiN. According to some implementations, the contacts may be formed according to any method known in the art or methods developed in the future. For example, a Ti contact may be formed by physical vapor deposition (PVD) or a TiN contact may be formed by atomic layer deposition (ALD).

In some implementations, after formation of the contact or contacts, the substrate may optionally undergo additional processing or processing steps.

Example 1

In this example, AlN was selectively deposited on a first surface of the substrate relative to a second, different surface of the substrate. In this example, the first surface of the substrate comprised TiN deposited by ALD and the second surface of the substrate comprised SiO ₂ deposited by plasma enhanced vapor deposition (PEALD). Sample AlN films were selectively deposited by an ALD process using trimethyl aluminum (TMA) as a first precursor and NH ₃ as a second precursor. Each deposition cycle was performed at a temperature of 375° C. and a reaction chamber pressure of 2 Torr. Each deposition cycle included a 0.5 second first precursor pulse and a 2 second second precursor pulse. After each TMA pulse, the reaction chamber was purged for 3 seconds, and after each NH ₃ pulse, the reaction chamber was purged for 2 seconds.

Samples were deposited using an ALD process consisting of 30 to 70 deposition cycles. As shown in Figure 6, the thickness of the material deposited on the first TiN surface was measured and compared to the thickness of the material deposited on the second SiO ₂ surface. The ratio of the thickness of the material deposited on the first TiN surface to the second SiO ₂ surface defines the selectivity of the deposition process. Figure 6 shows that the ratio of AlN deposited on the first surface to the second surface is about 8.5:1 (indicating a selectivity of about 89%) in an ALD process consisting of 70 deposition cycles.

Example 2

In this example, AlN was selectively deposited on a first surface of the substrate relative to a second, different surface of the substrate. In this example, the first surface of the substrate comprised TiN deposited by ALD and the second surface of the substrate comprised SiO ₂ deposited by PEALD. Additional samples were prepared where AlN was selectively deposited on a first surface comprising TiN deposited by ALD relative to a second surface comprising native silicon oxide. Sample AlN films were selectively deposited by an ALD process using trimethyl aluminum (TMA) as a first precursor and NH ₃ as a second precursor. Each deposition cycle was performed at a temperature of 375° C. and a reaction chamber pressure of 2 Torr. Each deposition cycle included a 0.5 second first precursor pulse and a 1 second second precursor pulse. After each TMA pulse, the reaction chamber was purged for 3 seconds, and after each NH ₃ pulse, the reaction chamber was purged for 2 seconds.

Samples were deposited using an ALD process consisting of 70 to 150 deposition cycles. As shown in Figure 7, the thickness of the material deposited on the first TiN surface was measured and compared to the thickness of the material deposited on the second SiO ₂ and native oxide surfaces. Figure 7 shows that the ratio of AlN deposited on the first surface to the second PEALD SiO ₂ surface in an ALD process consisting of 130 deposition cycles is about 43:1 (indicating a selectivity of about 98%). It is shown that the ratio of AlN deposited on the first surface to the second native oxide surface is about 3:1 (indicating a selectivity of about 75%) in an ALD process consisting of 110 deposition cycles.

Example 3

In this example, AlN was selectively deposited on a first surface of the substrate relative to a second, different surface of the substrate. The first surface of the substrate comprised TiN deposited by ALD and the second surface of the substrate comprised native silicon oxide. Prior to deposition of AlN, the substrate underwent a plasma treatment process. The substrate was exposed to direct plasma generated at a power of 50 W for 10 seconds. The plasma was generated from O ₂ .

A sample AlN film was selectively deposited by an ALD process using trimethyl aluminum (TMA) as a first precursor and NH ₃ as a second precursor. Each deposition cycle was performed at a temperature of 375° C. and a reaction chamber pressure of 2 Torr. Each deposition cycle included a 0.5 second first precursor pulse and a 1 second second precursor pulse. After each TMA pulse, the reaction chamber was purged for 3 seconds, and after each NH ₃ pulse, the reaction chamber was purged for 2 seconds. The sample was deposited using an ALD process consisting of 110 deposition cycles.

Referring to Figure 8, the thickness of the material deposited on the first plasma treated TiN surface was measured and compared to the thickness of the material deposited on the second plasma treated native oxide surface. Figure 8 also shows data obtained from samples in Example 2. The thickness of the material deposited on the first TiN surface after 110 deposition cycles was compared to the thickness of the material deposited on the first plasma treated TiN surface after 110 deposition cycles. No significant changes in AlN thickness are observed. However, significant changes in AlN thickness are observed when comparing the thickness of the material deposited on the second native oxide surface to that of the material deposited on the second plasma treated native oxide surface after 110 deposition cycles. After plasma treatment, essentially no deposition is observed on the second surface relative to the first surface. For an ALD process consisting of 110 deposition cycles, the ratio of AlN deposited on the first plasma treated TiN surface to the second plasma treated native oxide surface is approximately 33:1, which is equivalent to the same selective deposition without plasma treatment. The selectivity improvement exceeds 10x when compared to the process.

Additional samples were prepared where the first surface of the substrate comprised TiN deposited by ALD and the second surface of the substrate comprised native silicon oxide. Prior to deposition of AlN, the substrates underwent a plasma treatment process. The substrates were exposed to direct plasma generated at an output of 50W to 300W for 3 to 10 seconds. The plasma was generated from O ₂ . The thickness of AlN deposited on the first surface of each substrate was compared to the thickness of the material deposited on the second surface and the selectivity was calculated for each sample. The results appear in Table 1 below.

Selectivity of AlN deposited by ALD when changing direct plasma processing conditions O2 plasma power (watts) O2 direct plasma exposure time (seconds) number of cycles Thickness of AlN deposited on TiN (nm) Thickness of AlN deposited on native oxide (nm) selectivity 50 10 110 5.21 0.16 32.6 300 10 110 4.36 0.2 21.8 300 3 110 4.40 0.43 10.2

From these results, it was observed that the selectivity of AlN decreased as the direct plasma pretreatment output increased, while the selectivity increased as the direct plasma exposure time increased.

Example 4

In this example, AlN was selectively deposited on a first surface of the substrate relative to a second, different surface of the substrate. In this example, the first surface of the substrate comprised TiN deposited by ALD and the second surface of the substrate comprised SiO ₂ deposited by PEALD. Additional samples were prepared where AlN was selectively deposited on a first surface comprising TiN deposited by ALD relative to a second surface comprising SiO ₂ deposited by PEALD. Sample AlN films were selectively deposited by an ALD process using trimethyl aluminum (TMA) as a first precursor and NH ₃ as a second precursor. Each deposition cycle was performed at a temperature of 390° C. and a reaction chamber pressure of 2 Torr. Each deposition cycle included a 0.5 second first precursor pulse and a 1 second second precursor pulse. After each TMA pulse, the reaction chamber was purged for 5 seconds, and after each NH ₃ pulse, the reaction chamber was also purged for 5 seconds.

Samples were deposited using an ALD process consisting of 70 to 100 deposition cycles. As shown in Figure 9, the thickness of the material deposited on the first TiN and W surfaces was measured and compared to the thickness of the material deposited on the second SiO ₂ surface. Figure 9 shows that AlN deposition on the first surface containing either W or TiN had a very high selectivity compared to the SiO ₂ surface.

Example 5

In this example, AlN was selectively formed on a first surface of the same substrate relative to a second, different surface of the substrate. In this embodiment, the substrate included a W/SiO ₂ pattern, where the first surface of the substrate included W metal lines formed on a silicon wafer. The second surface of the substrate comprised SiO ₂ deposited by plasma enhanced chemical vapor deposition (PECVD). Sample AlN films were formed on a first surface of a substrate by a process described herein, e.g., with reference to FIG. 3, a process comprising a super-cycle, which includes pretreating the substrate, a second surface, selectively depositing AlN on the first surface relative to the first surface, and etching the deposited AlN such that substantially all of the deposited AlN is removed from the second surface and substantially all of the deposited AlN is not removed from the first surface. Includes. The process included four super-cycles.

According to some implementations and as described herein, the pretreatment step included exposing the substrate to a plasma generated from H ₂ at a temperature of 250°C. The selective deposition step included an ALD process comprising a plurality of sub-cycles, the plurality of sub-cycles comprising a first vapor phase precursor comprising TMA and NH ₃ according to some embodiments and as described herein. It included the step of sequentially contacting the second vapor phase precursor and the substrate alternately at a temperature of 375°C. The etching step includes an ALE process including a plurality of sub-cycles, wherein the first vapor phase etch reactant including NF ₃ and the second vapor phase etch reactant including TMA and the substrate are heated at 300° C. It includes the step of contacting each other alternately and sequentially at a temperature of . The sub-cycles were repeated until substantially all of the deposited AlN was removed from the second surface and substantially all of the deposited AlN was not removed from the first surface.

Figure 10a shows a scanning electron microscope (SEM) image of the deposited AlN film. It was observed that about 15 nm of AlN formed on the first surface comprising W, but no observable AlN formed on the second surface comprising SiO ₂ . Figure 10b is a partial detailed view of the board, showing one W wire. The AlN film can be clearly observed on the W surface, but AlN is not observed on the adjacent SiO ₂ surface.

As used herein, the language of degree, such as the terms “approximately,” “about,” and “substantially,” refers to still performing a desired function or achieving a desired result. Indicates a value, quantity, or characteristic that is close to a given value, quantity, or characteristic. For example, the terms “approximately,” “about,” “generally,” and “substantially” mean within 10% or less of, within 5% or less, within 1% or less, within 0.1% or less, and within 0.01% or less of the stated amount. It can refer to the amount within. If the stated quantity is 0 (e.g., none, does not have), then the range stated above may be a specific range and not within a specific percentage of this value. For example, within 10 wt./vol.% of the stated value, within 5 wt./vol.% of the stated value, within 1 wt./vol.% of the stated value, within 1 wt./vol.% of the stated value. Within 0.1 wt./vol.% or less, within 0.01 wt./vol.% or less of the stated value.

The terms “film” and “thin film” are used herein for simplicity. “Film” and “thin film” refer to any continuous or non-continuous structure and material deposited by the methods disclosed herein. For example, “films” and “thin films” may include 2D materials, nanorods, nanotubes or nanoparticles or even single portions or entire molecular layers or partial or entire atomic layers or clusters of atoms and/or molecules. “Film” and “thin film” may include a material or layer containing pinholes but still be at least partially continuous.

Those skilled in the art will appreciate that many and various modifications may be made without departing from the spirit of the invention. The shapes, structures, features and precursors described may be combined in any suitable manner. Accordingly, it should be clearly understood that the forms of the invention are illustrative only and are not intended to limit the scope of the invention. All modifications and variations are intended to fall within the scope of the invention as defined by the appended claims.

Claims (20)

1. A method for selectively forming a material comprising aluminum and nitrogen on a first surface of a substrate compared to a second other surface of the substrate, the method comprising one or more super-cycles, The above super-cycles are:
one or more selective deposition sub-cycles comprising selectively depositing the material comprising aluminum and nitrogen on the first surface of the substrate compared to the second other surface of the substrate; and
comprising one or more atomic layer etch sub-cycles comprising etching the deposited material comprising the aluminum and nitrogen,
The method of claim 1, wherein the one or more atomic layer etch sub-cycles include contacting the substrate with a first vapor phase etch reactant comprising aluminum. 2. The method of claim 1, wherein the material comprising aluminum and nitrogen is selectively formed with a selectivity greater than 99% on the first surface of the substrate compared to the second other surface of the substrate. . 2. The method of claim 1, wherein the material comprising aluminum and nitrogen is deposited by 5% on the first surface of the substrate compared to the second other surface of the substrate within the one or more selective deposition sub-cycles. A method deposited with a selectivity exceeding . The method of claim 1, wherein the one or more super-cycles further comprise exposing the substrate to a pretreatment reactant. 5. The method of claim 4, wherein the substrate is exposed to the pretreatment reactant prior to the one or more selective deposition sub-cycles. 6. The method of claim 5, wherein the pretreatment reactant comprises plasma. 7. The method of claim 6, wherein the plasma is generated from a gas comprising _H2 . 2. The method of claim 1, wherein the one or more selective deposition sub-cycles:
contacting the substrate with a first vapor phase precursor containing aluminum; and
A method comprising contacting the substrate with a second vapor phase precursor comprising nitrogen. 9. The method of claim 8, wherein the one or more selective deposition sub-cycles are repeated until the one or more selective deposition sub-cycles are no longer selective. 9. The method of claim 8, wherein the first vapor phase precursor comprising aluminum comprises tritertbutylaluminum (TTBA), trimethylaluminum (TMA), or triethylaluminum (TEA). 9. The method of claim 8, wherein the second vapor phase precursor comprising nitrogen comprises NH ₃ . 2. The method of claim 1, wherein the one or more atomic layer etch sub-cycles:
The method further comprising contacting the substrate with a second vapor phase halide etch reactant. 13. The method of claim 12, wherein the second gaseous halide etch reactant comprises NF ₃ or NbF ₅ . The method of claim 1, wherein the first vapor phase etch reactant containing aluminum includes trimethyl aluminum (TMA) or triethylaluminum (TEA). 13. The method of claim 12, wherein the one or more atomic layer etch sub-cycles are performed at a process temperature of 300°C. 2. The method of claim 1, wherein the first surface is a conductive surface and the second other surface is a dielectric surface. 2. The method of claim 1, wherein the first surface comprises W and the second surface comprises SiO ₂ . The method of claim 1, wherein the first surface comprises TiN and the second surface comprises SiO ₂ . The method of claim 1, wherein the one or more selective deposition sub-cycles are repeated 1 to 300 times;
The method wherein the one or more atomic layer etch sub-cycles are repeated 1 to 150 times. 2. The method of claim 1, wherein the one or more selective deposition sub-cycles comprise contacting the substrate with a first vapor phase precursor comprising trimethylaluminum (TMA) and contacting the substrate with a second vapor phase precursor comprising NH ₃ . Includes steps,
The method of claim 1 , wherein the one or more atomic layer etch sub-cycles include contacting the substrate with a first vapor phase etch reactant comprising TMA and a second vapor phase halide etch reactant comprising NH ₃ .