阅读说明：本技术 层形成方法和装置 (Layer forming method and apparatus ) 是由 J.弗鲁伊特 于 2020-04-14 设计创作，主要内容包括：提供了在衬底上沉积包含钼的层的方法和装置,做法是在反应室中向衬底供给包含二氯二氧化钼(VI)的前体及包含硼和氢的第一反应物以反应和形成钼层。包含硼和氢的第一反应物可为乙硼烷。(Methods and apparatus are provided for depositing a layer comprising molybdenum on a substrate by supplying a precursor comprising molybdenum (VI) dichloride dioxide and a first reactant comprising boron and hydrogen to the substrate in a reaction chamber to react and form a molybdenum layer. The first reactant comprising boron and hydrogen may be diborane.)

1. A method of depositing a layer comprising molybdenum on a substrate in a reaction chamber, the method comprising:

supplying a substrate comprising molybdenum (VI) dichloride dioxide (MoO) to the reaction chamber₂Cl₂) A precursor of (a); and the combination of (a) and (b),

supplying a first reactant to the substrate in the reaction chamber to react a portion of the precursor with the first reactant to form a molybdenum layer, wherein the first reactant comprises boron and hydrogen.

2. The method of claim 1, wherein the molybdenum layer is a seed layer.

3. The method of claim 2, wherein the method further comprises providing the seed layer with a bulk molybdenum layer by a method comprising:

supplying the substrate with the solution containing molybdenum (VI) dichloride dioxide (MoO) in the reaction chamber₂Cl₂) A precursor of (a); and the combination of (a) and (b),

supplying a second reactant comprising hydrogen to the substrate in the reaction chamber, wherein a portion of the precursor reacts with the reactant to form the bulk molybdenum layer.

4. The method of claim 3, wherein the second reactant comprises hydrogen (H)₂)。

5. The method of claim 1, wherein the precursor is fed into the reaction chamber in pulses and the pulses are between 0.1 and 10 seconds.

6. The method of claim 1, wherein the flow rate of the precursor into the reaction chamber is between 50 and 1000 seem.

7. The method of claim 1, wherein the flow rate of the first reactant stream into the reaction chamber is between 50 and 50000 seem.

8. The method of claim 1, wherein the pressure in the reaction chamber is between 0.1 and 100 torr.

9. The method of claim 1, wherein the process temperature is between 300 and 800 ℃.

10. The method of claim 1, wherein depositing the molybdenum layer comprises repeating an Atomic Layer Deposition (ALD) cycle comprising sequentially supplying the precursor and the first reactant to the substrate.

11. The method of claim 10, wherein the substrate is purged for 0.5 to 50 seconds between supplying the first precursor and the first reactant.

12. The method of claim 11, wherein the feeding of the first reactant into the reaction chamber takes between 0.5 and 50 seconds.

13. The method of claim 1, wherein the first reactant comprising boron and hydrogen is selected from formula B_nH_(n+x)Borane ofWherein n is an integer of 1 to 10, and x is an even number.

14. The method of claim 13, wherein the first reactant comprising boron and hydrogen is selected from formula B_nH_(n+4)The nest type borane.

15. The method of claim 13, wherein the first reactant comprising boron and hydrogen is selected from formula B_nH_(n+6)The cobweb borane.

16. The method of claim 13, wherein the first reactant comprising boron and hydrogen is selected from formula B_nH_(n+8)Is a net-open type borane.

17. The method of claim 13, wherein the first reactant comprising boron and hydrogen is diborane (B)₂H₆)。

18. The method of claim 1, wherein the first reactant comprising boron and hydrogen is selected from the group consisting of bis-borane, B_nH_mWherein n is an integer of 1 to 10, and m is an integer of 1 to 10 different from n.

19. The method of claim 1, wherein the first reactant comprising boron and hydrogen is provided in the reaction chamber to pre-process a surface of the substrate prior to providing the precursor to the reaction chamber.

20. The method of claim 1, wherein the substrate comprises one or more gaps created during fabrication of features on the substrate and the one or more gaps are at least partially filled by the method of depositing a layer comprising molybdenum on a substrate in a reaction chamber.

21. A deposition apparatus for depositing a layer comprising molybdenum on a substrate, the deposition apparatus comprising:

a reaction chamber provided with a substrate holder to hold a substrate;

a heating system constructed and arranged to control a temperature of the substrate;

a dispensing system comprising a valve that provides a precursor and at least a first reactant in the reaction chamber; and the combination of (a) and (b),

a sequence controller operably connected to the valve and programmed to enable deposition of molybdenum on the substrate in the reaction chamber with the precursor and the first reactant, wherein the dispensing system is provided with a precursor delivery apparatus ready to deliver molybdenum (VI) dichloride dioxide (MoO) and a first reactant delivery system₂Cl₂) A vapor, the first reactant delivery system constructed and arranged to deliver a vapor of a first reactant comprising boron and hydrogen.

Technical Field

The present disclosure relates generally to methods and apparatus for forming layers on a substrate. More particularly, the present disclosure relates to a method and apparatus for depositing a layer comprising molybdenum on a substrate in a reaction chamber.

The deposition method may include supplying a precursor including molybdenum oxychloride and a first reactant to a substrate in a reaction chamber to allow a portion of the precursor to react with the first reactant to form a molybdenum layer. Layers on a substrate may be used to fabricate semiconductor devices.

Background

In Atomic Layer Deposition (ALD) and Chemical Vapor Deposition (CVD), a substrate is subjected to a precursor and a first reactant, which are adapted to react into a desired layer on the substrate. A layer may be deposited in the gap created during fabrication of the feature on the substrate to fill the gap.

In ALD, the substrate is exposed to pulses of the precursor and a monolayer of the precursor may chemisorb on the surface of the substrate. The surface sites may be occupied by the entire precursor or fragments of the precursor. The reaction may be chemically self-limiting, in that the precursor may not adsorb or react with the portion of the precursor that has adsorbed on the substrate surface. Excess precursor is then purged from the reaction chamber, for example by providing an inert gas and/or removed from the reaction chamber with a pump. Subsequently, the substrate is exposed to a pulse of the first reactant, which chemically reacts with the adsorbed whole first precursor or fragments of the first precursor until the reaction is complete and the surface is covered by a single layer of the reaction product.

It has been found that there may be a need to improve the quality of the molybdenum layer deposition process.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form. These concepts are described in more detail below in the detailed description of example embodiments of the disclosure. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

There may be a need for an improved method of forming a deposited molybdenum layer on a substrate. Accordingly, in one embodiment, a method of depositing a layer comprising molybdenum on a substrate in a reaction chamber may be provided. The method can include supplying a substrate comprising molybdenum (VI) dichloroxide (MoO) to a reaction chamber₂Cl₂) A precursor of (2). The method may include supplying a first reactant to the substrate in the reaction chamber to allow a portion of the precursor to react with the first reactant to form the molybdenum layer. The first reactant may comprise boron and hydrogen.

The first reactant is reacted with a solution comprising molybdenum (VI) dichlorodioxide (MoO) by including boron and hydrogen in the first reactant₂Cl₂) The reactivity of the precursor of (a) can be improved. The deposition of the molybdenum layer can be improved. The quality of the overall layer may be improved and/or the speed of the deposition process may be improved.

In some other embodiments, a method for semiconductor processing is provided. The method includes depositing a metal layer into the gap of the substrate, thereby filling the gap.

According to yet another embodiment, there is provided a deposition apparatus for depositing a layer comprising molybdenum on a substrate, comprising:

a reaction chamber provided with a substrate holder to hold a substrate;

a heating system constructed and arranged to control a temperature of the substrate;

a dispensing system comprising a valve that provides a precursor and at least a first reactant in the reaction chamber; and the combination of (a) and (b),

a sequence controller operably connected to the valve and programmed to enable deposition of molybdenum on the substrate in the reaction chamber with the precursor and the first reactant, wherein the dispensing system is provided with a precursor delivery device to deliver molybdenum (VI) dichloride dioxide (MoO) and a first reactant delivery system₂Cl₂) A vapor, the first reactant delivery system constructed and arranged to deliver a vapor of a first reactant comprising boron and hydrogen.

Drawings

While the specification concludes with claims particularly pointing out and distinctly claiming what are regarded as embodiments of the present disclosure, the advantages of embodiments of the disclosure may be more readily ascertained from the description of certain examples of embodiments of the disclosure when read in conjunction with the accompanying drawings, in which:

fig. 1a and 1b show a flow chart illustrating a method of depositing a layer according to an embodiment.

Detailed Description

While certain embodiments and examples are disclosed below, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Therefore, it is intended that the scope of the present disclosure should not be limited by the particular disclosed embodiments described below.

The illustrations presented herein are not intended as actual views of any particular material, structure, or apparatus, but are merely idealized representations which are employed to describe embodiments of the present disclosure.

As used herein, the term "substrate" may refer to any underlying material or materials that may be used, or upon which a device, circuit, or film may be formed.

As used herein, the term "cyclic deposition" may refer to the sequential introduction of one or more precursors (reactants) into a reaction chamber to deposit a film over a substrate and includes deposition techniques such as atomic layer deposition and cyclic chemical vapor deposition.

As used herein, the term "cyclic chemical vapor deposition" may refer to any process in which a substrate is sequentially exposed to one or more volatile precursors that react and/or decompose on the substrate to produce a desired deposition.

As used herein, the term "Atomic Layer Deposition (ALD)" may refer to a vapor deposition process in which a deposition cycle, preferably a plurality of consecutive deposition cycles, is performed in a process chamber. Typically, during each cycle, the precursor is chemisorbed to a deposition surface (e.g., the substrate surface or a previously deposited underlying surface, such as material from a previous ALD cycle) forming a monolayer or sub-monolayer that is not readily reactive with the additional precursor (i.e., a self-limiting reaction). Thereafter, if necessary, a reactant (e.g., another precursor or a reactive gas) can then be introduced into the process chamber for converting the chemisorbed precursor to the desired material on the deposition surface. Typically, this reactant is capable of further reaction with the precursor. In addition, during each cycle, a purge step may also be utilized to remove excess precursor from the process chamber and/or excess reactants and/or reaction byproducts from the process chamber after conversion of the chemisorbed precursor. Furthermore, when performed using alternating pulses of precursor compositions, reactive gases, and purge (e.g., inert carrier) gases, the term "atomic layer deposition" as used herein is also intended to include processes specified by related terms such as "chemical vapor atomic layer deposition," "atomic layer epitaxy" (ALE), Molecular Beam Epitaxy (MBE), gas source MBE, or organometallic MBE and chemical beam epitaxy.

As used herein, the term "layer" may refer to any continuous or non-continuous structure and material formed by the methods disclosed herein. For example, a "layer" may comprise a 2D material, a nanolaminate, a nanorod, a nanotube, or a nanoparticle, or even a partial or complete molecular layer, or a partial or complete atomic layer, or a cluster of atoms and/or molecules. A "layer" may comprise a material or layer having pinholes, but is still at least partially continuous.

A molybdenum layer may be required as a conductive layer in a semiconductor device. A method of depositing a layer comprising molybdenum on a substrate in a reaction chamber may therefore be used. The method can include supplying a substrate comprising molybdenum (VI) dichloroxide (MoO) to a reaction chamber₂Cl₂) A precursor of (2). The precursor may comprise molybdenum oxyhalide other than molybdenum tetrachlorooxide (MoOCl)₄). The precursor may comprise molybdenum oxychloride, other than molybdenum tetrachloride oxide (MoOCl)₄). The precursor may have Mo-O and Mo-Cl bonds and is not molybdenum tetrachloride oxide (MoOCl)₄). The precursor may comprise a molybdenum oxyhalide having the same number of oxygen as chlorine atoms bonded to the molybdenum. The precursor may comprise a molybdenum oxyhalide having two oxygens and two chlorine atoms bonded to the molybdenum.

The method may further include supplying a first reactant including boron and hydrogen to the substrate in the reaction chamber to allow a portion of the precursor to react with the first reactant to form a molybdenum layer on the substrate. The first reactant comprising boron and hydrogen may be selected from formula B_nH_(n+x)Wherein n is an integer from 1 to 10 and x is an even number.

The first reactant comprising boron and hydrogen may, for example, be selected from formula B_nH_(n+4)The nest type borane.

The first reactant comprising boron and hydrogen may, for example, be selected from formula B_nH_(n+6)The cobweb borane.

The first reactant comprising boron and hydrogen may, for example, be selected from formula B_nH_(n+8)Is a net-open type borane.

The first reactant comprising boron and hydrogen may, for example, be selected from formula B_nH_mTo a borane complex. In the above examples, n is an integer of 1 to 10, and m is an integer other than n of 1 to 10.

The first reactant comprising boron and hydrogen may be diborane (B)₂H₆). Diborane may have a structure with four terminal hydrogen atoms and two bridging hydrogen atoms. Between boron and terminal hydrogen atomsThe bond is a conventional covalent bond. The bonding between the boron atom and the bridging hydrogen atom can be different because two electrons have been used in the bonding with the terminal hydrogen atoms, each boron atom having one remaining valence electron to effect additional bonding. The bridging hydrogen atoms each provide one electron, and thus the boron atoms in diborane can be held together by four electrons. The length of the B-H bridge may be longer than the B-H terminal bond. This difference in the length of the bonds may reflect a difference in their strength. The B-H bridge of diborane may be relatively weak.

With diborane (B)₂H₆) Reduction of molybdenum dichloride dioxide (MoO)₂Cl₂) The following reaction pathways are possible: MoO₂Cl₂+1/2B₂H₆->Mo(s)+BOCl+HCl+H₂And O. For this reaction, it may be necessary to break the B-H bridge of diborane in order to cleave it in half. With MoO₂Cl₂+3H₂->Mo(s)+2HCl+2H₂The reaction pathway for O may involve fewer molecules than for O, which may also have weaker hydrogen bonds, which would favor MoO₂Cl₂And B₂H₆The reaction of (1). With diborane (B)₂H₆) Reduction of molybdenum tetrachloride oxide (MoOCl)₄) Will follow MoOCl₄+1/2B₂H₆->Mo(s) + BOCl +3HCl, which may cause higher etchant HCl concentrations in the reaction chamber, which may lead to undesirable etching and/or reduced deposition rates.

Diborane can be a highly reactive and versatile reactant. Diborane has been used in the semiconductor industry, for example, as a dopant. Thus, diborane can be readily used in industry as molybdenum (VI) dichlorodioxide (MoO)₂Cl₂) To deposit molybdenum.

The surface on which molybdenum may be deposited may comprise a deposition material. Alternatively, the surface may comprise different kinds of deposition materials. The surface may, for example, comprise aluminum oxide and/or titanium nitride. When, for example, a molybdenum conductive layer is desired, it can be difficult to deposit molybdenum on these different materials. The first layer, often referred to as a seed layer or nucleation layer, may be more difficult to deposit. It may therefore be preferred to use a reaction chamber with a gas flowSubstrate providing molybdenum (VI) dichlorodioxide (MoO)₂Cl₂) (ii) a And supplying a first reactant comprising boron and hydrogen to the substrate in the reaction chamber to allow a portion of the precursor to react with the first reactant to form a molybdenum seed layer on the substrate.

The gaps created during the fabrication of the features of the integrated circuit device may be filled with a metal layer, for example made of molybdenum. The gap may have a high aspect ratio because its depth is much greater than its width. The gap may extend vertically in a fabricated layer having a substantially horizontal top surface. The gap in the vertical direction and filled with metal may be used, for example, in a word line of a Dynamic Random Access Memory (DRAM) type memory integrated circuit. Gaps in the vertical direction and filled with metal may also be used, for example, in logic integrated circuits. For example, the metal-filled gap may be used as a gate fill in a p-type metal oxide semiconductor (PMOS) or Complementary Metal Oxide Semiconductor (CMOS) integrated circuit or source/drain trench contacts.

The gaps may also be arranged in the manufactured layer in a horizontal direction. Again, the gap may have a high aspect ratio, since its depth in the horizontal direction is now much larger than its width. The gap in the horizontal direction and filled with metal may be used, for example, in the word line of a 3d nand type memory integrated circuit. The gaps may also be arranged in a combination of vertical and horizontal directions.

The surface of the gap may include one type of deposition material. Alternatively, the surfaces of the gap may comprise different types of deposition materials. The surface of the gap may, for example, comprise aluminum oxide and/or titanium nitride. When a molybdenum conductive layer is desired, for example, in the gap, it may be difficult to deposit molybdenum on these different materials in the gap. It may be desirable that the molybdenum layer cover the entire surface of the gap and fill the entire gap. Furthermore, it may be desirable that the molybdenum layer may cover the entire surface of the interstices in which the packets comprise different kinds of materials.

To fill the entire gap, a molybdenum seed layer may be deposited in the gap and a molybdenum bulk layer may be deposited on the molybdenum seed layer. The seed layer may be formed by sequentially repeating a pretreatment Atomic Layer Deposition (ALD) cycle. It may therefore be preferred to provide molybdenum (VI) dichloride dioxide (M) to the substrate in the reaction chamberoO₂Cl₂) (ii) a And supplying a first reactant comprising boron and hydrogen to the substrate in the reaction chamber to allow a portion of the precursor to react with the first reactant to form a molybdenum seed layer in the gap on the substrate.

Alternatively, the seed layer may be formed by a Chemical Vapor Deposition (CVD) process. The CVD process may be pulsed, wherein the first precursor is supplied to the substrate in pulses while the first reactant is continuously supplied to the substrate.

A bulk layer may be deposited on the seed layer by sequentially repeating the bulk ALD cycle. The substrate may be provided by supplying a substrate comprising molybdenum (VI) dichloroxide (MoO) in a reaction chamber₂Cl₂) And a second reactant comprising hydrogen, a bulk molybdenum layer may be provided on top of the molybdenum seed layer, wherein a portion of the precursor reacts with the second reactant to form the bulk molybdenum layer. The second reactant may comprise hydrogen (H)₂). The second reactant may not comprise boron. Hydrogen gas may be a relatively inexpensive and common reactant.

Alternatively, the bulk molybdenum layer may be deposited on the molybdenum seed layer by a CVD process. The CVD process may be pulsed, wherein the second precursor is supplied to the substrate in pulses while the second reactant is continuously supplied to the substrate.

Fig. 1a and 1b show a flow diagram illustrating a method of depositing a molybdenum layer according to an embodiment.

The molybdenum layer may be deposited as a seed layer. A molybdenum layer may be deposited in the gap. A molybdenum bulk layer may be deposited on the seed layer.

A first ALD cycle 1 for a molybdenum seed layer may be illustrated in fig. 1 a. A second ALD cycle 2 for a molybdenum bulk layer may be illustrated in fig. 1 b.

A substrate with a gap may be provided in the reaction chamber in step 3. The substrate may be supplied with a solution containing molybdenum (VI) dichlorodioxide (MoO) in step 5₂Cl₂) For a first supply period T1 (see fig. 1 a). Subsequently, the additional supply of the first precursor to the substrate may be stopped in step 7, for example by purging a portion of the first precursor from the reaction chamber for a first removal period R1.

Further, the first cycle may include applying a first voltage to the substrateThe first reactant is supplied 9 for a second supply period T2. The first reactant may comprise boron and hydrogen. The first reactant may comprise boron and hydrogen atoms in one molecule, for example it may be diborane (B)₂H₆). Hydrogen may be added to the gas stream of the first reactant. A portion of the first precursor and the first reactant may react to form at least a portion of a molybdenum seed layer on the substrate. Several (about 50) cycles may be required before starting the deposition of the seed layer. The additional supply of the first reactant to the substrate may be stopped in step 10, for example by purging a portion of the first reactant from the reaction chamber for a second removal period R1.

Optionally, the substrate can be cleaned using the first reactant prior to depositing the seed layer. Diborane reactants can be highly reactive and efficient in cleaning the surface of a substrate.

The first precursor and the first reactant may be selected to have the proper nucleation on the surfaces of the gap. The first ALD cycle 1 may be repeated N times to deposit a molybdenum seed layer, where N is selected between 100 and 1000, preferably between 200 and 800, more preferably between 300 and 600. The thickness of the seed layer may be between 1 and 20nm, preferably between 2 and 10nm, more preferably between 3 and 7 nm.

After repeating the first ALD cycle 1N times, the substrate may be supplied with a solution comprising molybdenum (VI) dichlorodioxide (MoO) in step 11 in a bulk ALD cycle 2₂Cl₂) For a third supply period T3 (see fig. 1 b). This may be performed in the same reaction chamber as the first ALD cycle 1 of fig. 1a or in a different reaction chamber.

While the temperature requirements of the first cycle may be different, it may be advantageous to perform a bulk ALD cycle in a different reaction chamber than the first ALD cycle. Substrate transfer may therefore be required.

Subsequently, the additional supply of the first precursor to the substrate may be stopped and the substrate removed from the reaction chamber. This can be done by: the exhaust pump of the reaction chamber is purged with a portion of the first precursor from the reaction chamber in step 13 for a third removal period R3.

In addition, the cycle may include supplying 15 the second reactant to the substrate for a fourth supply period T4. A portion of the first precursor and the second reactant may react to form at least a portion of the bulk molybdenum layer on the substrate. The additional supply of the second reactant to the substrate may be stopped in step 17, for example by purging a portion of the second reactant from the reaction chamber for a fourth removal period R4.

The first precursor and the second reactant may be selected to have appropriate electronic properties. For example, have a low resistivity. The resistivity of the molybdenum film may be less than 3000 μ Ω -cm, or less than 1000 μ Ω -cm, or less than 500 μ Ω -cm, or less than 200 μ Ω -cm, or less than 100 μ Ω -cm, or less than 50 μ Ω -cm, or less than 25 μ Ω -cm, or less than 15 μ Ω -cm or even less than 10 μ Ω -cm.

The second ALD cycle 2 of the bulk layer may be repeated M times, wherein M is selected between 200 and 2000, preferably between 400 and 1200, more preferably between 600 and 1000. The thickness of the bulk molybdenum layer may be between 1 and 100nm, preferably between 5 and 50nm, more preferably between 10 and 30 nm.

The process temperature during the first ALD cycle of the seed molybdenum layer may be between 300 and 800 ℃, preferably between 400 and 700 ℃, more preferably between 500 and 650 ℃. The vessel in which the first precursor is vaporized may be maintained at between 20 and 150 ℃, preferably between 30 and 120 ℃, more preferably between 40 and 110 ℃.

The process temperature during the second ALD cycle of the bulk molybdenum layer may be between 300 and 800 ℃, preferably between 400 and 700 ℃, more preferably between 500 and 650 ℃. The vessel in which the first precursor is vaporized may be maintained at between 20 and 150 ℃, preferably between 30 and 120 ℃, more preferably between 40 and 110 ℃.

The feeding of the first precursor into the reaction chamber may take a duration T1, T3 selected between 0.1 and 10 seconds, preferably between 0.5 and 5 seconds, more preferably between 0.8 and 2 seconds. For example, T1 may be 1 second and T3 may be 1.3 seconds. The flow rate of the first or second precursor into the reaction chamber may be selected between 50 and 1000sccm, preferably 100 and 500sccm, and more preferably 200 and 400 sccm. The pressure in the reaction chamber may be selected between 0.1 and 100 torr, preferably 1 and 50 torr, and more preferably 4 and 20 torr.

Supplying the first and/or second reactant into the reaction chamber over the duration T2, T4 may take between 0.5 and 50 seconds, preferably 1 and 10 seconds, and more preferably 2 and 8 seconds. The flow of the first or second reactant into the reaction chamber can be between 50 and 50000sccm, preferably 100 and 20000sccm, and more preferably 500 and 10000 sccm.

Silanes are also contemplated for the second reactant. The general formula of the silane is Si_xH_2(x+2)Wherein x is an integer of 1, 2, 3, 4 … …. Silane (SiH)₄) Disilane (Si)₂H₆) Or trisilane (Si)₃H₈) Suitable examples of second reactants having hydrogen atoms are possible.

The duration of purging a portion of at least one of the first precursor, the first reactant, and the second reactant from the reaction chamber, R1, R2, R3, or R4, may be selected between 0.5 to 50 seconds, preferably 1 to 10 seconds, more preferably 2 to 8 seconds.

May be after supplying the first precursor to the substrate; after supplying the first reactant to the substrate; and removing a portion of at least one of the first precursor, the first reactant, and the second reactant from the reaction chamber using a purge after supplying the second reactant to the reaction chamber for a duration of R1, R2, R3, or R4. Purging may be accomplished by pumping and/or by providing a purge gas. The purge gas may be an inert gas such as nitrogen.

The method may be used in single wafer or batch wafer ALD equipment.

The method can include providing a substrate in a reaction chamber and a first ALD cycle in the reaction chamber can include: supplying a first precursor to a substrate in a reaction chamber; purging a portion of the first precursor from the reaction chamber; supplying a first reactant to a substrate in a reaction chamber; and purging a portion of the first reactant from the reaction chamber.

Further, the method may include providing a substrate in a reaction chamber and a bulk ALD cycle in the reaction chamber may include: supplying a second precursor to the substrate in the reaction chamber; purging a portion of the second precursor from the reaction chamber; supplying a second reactant to the substrate in the reaction chamber; and purging a portion of the second reactant from the reaction chamber.

Specially designed for carrying out ALExemplary Single wafer reactor for Process D is available under the trade name Andcommercially available from ASM International NV (Armeler, Netherlands). The process may also be carried out in a batch wafer reactor, such as a vertical furnace. For example, the deposition method may also be carried out at A400 available from ASM International N.V.^TMOr A412^TMIn a vertical furnace. The furnace may have a process chamber that can accommodate a load of more than 100 semiconductor substrates or wafers 200 or 300mm in diameter.

The wafer reactor may have a controller and memory that may control the reactor. The memory can be programmed to supply the precursor and the reactant in the reaction chamber according to embodiments of the present disclosure when executed on the controller.

The gap that can be filled with molybdenum using the methods of the present disclosure can have a high aspect ratio because the vertical and/or horizontal depth is much greater than the width. For example, the aspect ratio of the gap (gap depth/gap width) may be greater than about 2, greater than about 5, greater than about 10, greater than about 20, greater than about 50, greater than about 75, or in some cases even greater than about 100 or greater than about 150 or greater than about 200. The aspect ratio may be less than 1000.

It may be noted that it may be difficult to determine the aspect ratio for the gap, but in this case the aspect ratio may be replaced by a surface enhancement ratio, which may be the ratio of the total surface area of the gap in the wafer or portion of the wafer relative to the planar surface of the wafer or portion of the wafer. The surface enhancement ratio of the gap (surface gap/surface wafer) may be greater than about 2, greater than about 5, greater than about 10, greater than about 20, greater than about 50, greater than about 75, or in some cases even greater than about 100, or greater than about 150, or greater than about 200. The surface enhancement ratio may be less than 1000.

The surfaces of the gaps may contain different types of deposition materials. The surface may, for example, comprise Al₂O₃Or TiN.

A conformal molybdenum metal layer can be deposited on the surfaces of the gaps by depositing a seed layer by repeating a first ALD cycle with a first precursor and a first reactant in sequence. Further, by repeating a second ALD cycle with a first precursor and a second reactant in sequence, a conformal molybdenum bulk layer can be deposited over the seed layer.

Details of the method used are shown in figures 1 and 1b and the associated description. In some embodiments, the step coverage of the deposited film comprising Mo may be greater than about 50%, greater than about 80%, greater than about 90%, greater than about 95%, greater than about 98%, greater than about 99%.

The method may be performed in an atomic layer deposition apparatus. For example, a deposition apparatus for depositing a layer comprising molybdenum on a substrate may comprise:

a reaction chamber provided with a substrate holder to hold a substrate;

a heating system constructed and arranged to control a temperature of the substrate;

a dispensing system comprising a valve that provides a precursor and at least a first reactant in the reaction chamber; and the combination of (a) and (b),

a sequence controller operably connected to the valve and programmed to enable deposition of molybdenum on a substrate in a reaction chamber with a precursor and a first reactant.

The dispensing system may be provided with a precursor delivery apparatus constructed and arranged to deliver molybdenum (VI) dichloroxide (MoO) and a first reactant delivery system₂Cl₂) A vapor, a first reactant delivery system constructed and arranged to deliver a vapor of a first reactant comprising boron and hydrogen, such as diborane.

The first reactant may be diborane and may be supplied to the reaction chamber for a duration T2, T4 of 5 seconds at a flow rate of between 50 and 50000sccm, for example 495 sccm. After supplying the first precursor; after supplying the first precursor and after supplying the first reactant; a nitrogen purge gas may be used for a duration of 5 seconds R1, R2, R3, or R4.

During the pretreatment and bulk ALD cycles, the process temperature may be, for example, about 550 ℃ and the pressure may be about 10 torr. The vessel in which the first precursor may be vaporized may be about 70 ℃.

The method may also be used in a spatial atomic layer deposition apparatus. In spatial ALD, precursors and reactants are supplied sequentially in different physical zones and the substrate is moved between the zones. At least two sections may be provided in which the half-reaction may be carried out in the presence of a substrate. If a substrate is present in such a semi-reactive zone, a monolayer may be formed from the first or second precursor. The substrate is then moved to a second half-reaction zone where the ALD cycle is completed by the first or second reactant to form one ALD monolayer. Alternatively, the substrate position may be fixed and the gas supply movable, or some combination of the two. This procedure can be repeated to obtain thicker films.

According to one embodiment of a spatial ALD apparatus, a method includes:

placing a substrate in a reaction chamber comprising a plurality of sections, each section separated from an adjacent zone section by a gas curtain;

supplying a first precursor, e.g., molybdenum (VI) dichloride dioxide, to the substrate in a first section of the reaction chamber;

moving the substrate surface relative to the reaction chamber (e.g., laterally) through the gas curtain to a second section of the reaction chamber;

supplying a first reactant comprising boron and hydrogen (e.g., diborane) to the substrate in a second section of the reaction chamber to form a molybdenum seed layer;

moving the substrate surface (e.g., laterally) relative to the reaction chamber through a gas curtain; and

the supplying of the first precursor and the reactant is repeated, including moving the substrate surface (e.g., laterally) relative to the reaction chamber to form a molybdenum seed layer.

To form the bulk layer, the method may further comprise:

placing a substrate in a reaction chamber comprising a plurality of sections, each section separated from an adjacent section by a gas curtain;

supplying a first precursor, e.g., molybdenum (VI) dichloride dioxide, to the substrate in a first section of the reaction chamber;

moving the substrate surface relative to the reaction chamber (e.g., laterally) through the gas curtain to a second section of the reaction chamber;

supplying a second reactant, such as hydrogen (H), to the substrate in a second section of the reaction chamber₂) To form a molybdenum body layer;

moving the substrate surface (e.g., laterally) relative to the reaction chamber through a gas curtain; and the combination of (a) and (b),

the first precursor and the second reactant are repeatedly supplied, including moving the substrate surface (e.g., laterally) relative to the reaction chamber to form a molybdenum bulk layer.

The first reactant may comprise hydrogen and boron, such as diborane. The second reactant may be hydrogen (H)₂)。

In further embodiments, the seed or bulk molybdenum layer may comprise less than about 40 atomic%, less than about 30 atomic%, less than about 20 atomic%, less than about 10 atomic%, less than about 5 atomic%, or even less than about 2 atomic% oxygen. In further embodiments, the seed or bulk layer may comprise less than about 30 atomic%, less than about 20 atomic%, less than about 10 atomic%, or less than about 5 atomic%, or less than about 2 atomic%, or even less than about 1 atomic% hydrogen.

In some embodiments, the seed or bulk molybdenum layer may comprise less than about 10 atomic%, or less than about 5 atomic%, less than about 1 atomic%, or even less than about 0.5 atomic% of halogen or chlorine. In still further embodiments, the seed or bulk molybdenum layer may comprise less than about 10 atomic%, or less than about 5 atomic%, or less than about 2 atomic%, or less than about 1 atomic%, or even less than about 0.5 atomic% carbon. In the examples outlined herein, the atomic percent (at.%) concentration of an element can be determined using Rutherford Backscattering (RBS).

In some embodiments of the present disclosure, forming a semiconductor device structure, such as a semiconductor device structure, may include forming a gate electrode structure including a molybdenum film having an effective work function greater than about 4.9eV, or greater than about 5.0eV, or greater than about 5.1eV, or greater than about 5.2eV, or greater than about 5.3eV, or even greater than about 5.4 eV. In some embodiments, electrode structures comprising a molybdenum layer having a thickness of less than about 100 angstroms, or less than about 50 angstroms, or less than about 40 angstroms, or even less than about 30 angstroms, may exhibit the effective work function values given above.

It will be understood by those skilled in the art that various omissions, additions and modifications may be made to the methods and structures described above without departing from the scope of the invention. It is contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the described scope. Various features and aspects of the disclosed embodiments can be combined with or substituted for one another in a sequential order. All such modifications and variations are intended to be within the scope of the present invention, as defined by the appended claims.