Method for gap filling

Abstract

A gap filling method may include depositing a sacrificial Si layer in an opening of a feature and on a region of a substrate. Further, the method may include depositing a metal layer in the opening and on the region, where at least a portion of the sacrificial Si layer is replaced by the metal layer. The method may also include depositing a metal gap fill material in the opening and directly over the metal layer on the region, wherein the metal gap fill material completely fills the opening.

Description

Technical Field

[0001] Embodiments of the present invention generally relate to a method for gap filling for a semiconductor substrate. Background Art

[0002] When manufacturing semiconductor devices, the devices are formed with contacts to allow electrical connection to other devices or for external electrical connection to a chip or circuit. The contacts are made of a metal material that promotes electrical connection. The higher the connectivity, the lower the resistivity. The inventors have observed that current manufacturing techniques produce contacts with high resistivity, which reduces electrical connection and can cause thermal problems due to resistive heating in the contacts, resulting in poor performance and reduced reliability.

[0003] Accordingly, the inventors have provided an improved method for gap filling when forming with low resistivity and increased reliability. Summary of the Invention

[0004] Embodiments of the present invention relate to a method for gap filling features in a substrate. In an embodiment, a method for gap filling may include depositing a sacrificial Si layer in an opening of a feature and on a region of a substrate; depositing a metal layer in the opening and on the region, wherein at least a portion of the sacrificial Si layer is replaced by the metal layer; and depositing a metal gap filling material directly over the metal layer in the opening and on the region, wherein the metal gap filling material completely fills the opening.

[0005] In an embodiment, a method for gap filling may include depositing a sacrificial Si layer on top of a base metal layer in an opening of a feature and on a region of a substrate; performing an atomic layer deposition process on top of the sacrificial Si layer to replace Si atoms with metal atoms and create a metal layer in the opening and on top of the base metal layer on the region, wherein greater than or equal to about 95 wt% of the sacrificial Si layer is replaced by the metal layer; and depositing a metal gap filling material directly over the metal layer in the opening and on the region, wherein the metal gap filling material completely fills the opening. Other embodiments include corresponding computer systems, devices, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of this method. Brief Description of the Drawings

[0006] Embodiments of the invention briefly summarized above and discussed in detail below may be understood by reference to the illustrative embodiments of the invention depicted in the drawings. The drawings only depict typical embodiments of the invention and are therefore not to be considered limiting of the scope, as the invention may admit other equivalent embodiments.

[0007] Figure 1 A cross-sectional view depicting the formation of a feature in a substrate according to embodiments disclosed herein.

[0008] Figure 2 Depicts a cross-sectional view of a lower layer deposited on a feature and a substrate according to an embodiment disclosed herein.

[0009] Figure 3 Depicts a cross-sectional view of a base metal layer deposited on a feature and a substrate according to an embodiment disclosed herein.

[0010] Figure 4a depicts a cross-sectional view of a sacrificial Si layer deposited on a base metal layer according to an embodiment disclosed herein.

[0011] Figure 4b depicts a cross-sectional view of a metal layer deposited on the sacrificial Si layer and replacing the sacrificial Si layer according to an embodiment disclosed herein.

[0012] Figure 4c depicts a metal gap filling material deposited on a metal layer in a feature and on a substrate according to an embodiment disclosed herein.

[0013] Figure 5 Is a flow chart depicting a method for metal gap filling according to an embodiment disclosed herein.

[0014] Figure 6 Depicts an integration tool according to an embodiment disclosed herein. Detailed Description

[0015] The present method provides metal gap filling, wherein the metal gap filling material completely fills the opening of a feature of a substrate.

[0016] In an embodiment, a method for metal gap filling includes depositing a sacrificial Si layer in an opening of a feature and on a region of a substrate. Thereafter, a metal layer is deposited in the opening and on this region of the substrate, wherein at least a portion of the sacrificial Si layer is replaced by the metal layer. Then a metal gap filling material is deposited directly above the metal layer in the opening and on this region, such that the metal gap filling material completely fills the opening.

[0017] In an embodiment, depositing the metal layer includes atomic layer deposition, which includes contacting the sacrificial Si layer with a metal precursor according to Formula I;

[0018] MXa (I);

[0019] Wherein M is a Group 6 to Group 9 metal, X is fluorine or chlorine; and a is 2 to 6.

[0020] In an embodiment, the metal precursor includes tungsten hexafluoride.

[0021] In an embodiment, a metal layer is deposited using thermal atomic layer deposition or plasma enhanced atomic layer deposition. In an embodiment, a metal layer is deposited using thermal atomic layer deposition or plasma enhanced atomic layer deposition at a temperature greater than or equal to about 200°C.

[0022] In an embodiment, the metal layer has a thickness less than or equal to about 15 nm. In an embodiment, the metal layer is a conformal metal layer having a thickness of about 5 nm to about 10 nm.

[0023] In an embodiment, the metal layer comprises tungsten.

[0024] In an embodiment, a sacrificial Si layer is deposited over a base metal layer, the base metal layer comprising the same metal as the metal layer. In an embodiment, the base metal layer is deposited anisotropically by physical vapor deposition or chemical vapor deposition. In an embodiment, the base metal layer is deposited anisotropically by physical vapor deposition or chemical vapor deposition, followed by deposition of the sacrificial Si layer, and in an integrated process without breaking vacuum between the above steps.

[0025] In an embodiment, a sacrificial Si layer is deposited using plasma enhanced atomic layer deposition. In an embodiment, the sacrificial Si layer is a sacrificial conformal Si layer having a thickness less than or equal to about 4 nm.

[0026] In an embodiment, the metal gap filling material comprises the same metal as the metal layer. In an embodiment, the metal gap filling material is deposited by physical vapor deposition or chemical vapor deposition. In an embodiment, greater than or equal to about 95 wt% of the sacrificial Si layer is replaced by the metal layer.

[0027] In an embodiment, the method for metal gap filling is performed in an integration tool without breaking vacuum between deposition of the sacrificial Si layer, deposition of the metal layer, and deposition of the metal gap filling material.

[0028] In Figure 5 , a method (method 500) of depositing a metal gap filling according to some embodiments is depicted. During the discussion of method 500 reference is made to Figure 1 -4, which may be within the opening 103 of a feature of a substrate. As Figure 1 shown in view 100 of , the features of the substrate may include feature 104, which is in the form of an opening 103 having sides 106 and a bottom 108, feature 104 being formed on or within substrate 102. A representative feature 104 in this example is the opening 103 in region 110 of substrate 102. Feature 104 has a height 114 and a width 112.

[0029] In an embodiment, as Figure 2As shown, the feature 104 of the substrate 102 may further include a lower layer 202, and the lower layer 202 may be deposited using atomic layer deposition (ALD) processing, physical vapor deposition (PVD) processing, or chemical vapor deposition (CVD) processing. In an embodiment, the lower layer 202 is a conformal layer deposited by atomic layer deposition. In an embodiment, the lower layer may include, but is not limited to, titanium nitride, tungsten nitride, and / or tungsten carbonitride and the like. The material for the lower layer 202 is typically an oxide with a high resistivity, which reduces the connectivity of the contacts. By using a thin layer (i.e., less than about 10 microns), the resistivity of the lower layer 202 is significantly reduced. Metal depositions such as PVD tungsten and CVD tungsten have a resistivity of about 15 ohm-cm or less. However, tungsten nitride has a resistivity of about 200 to 500 ohm-cm. The reduction in the thickness 204 of the lower layer 202 (i.e., to less than about 10 microns) has a significant effect on the contact resistivity.

[0030] As Figure 3 shown, in an embodiment, the feature 104 of the substrate 102 may further include a base metal layer 302, which in an embodiment is a non-conformal layer deposited on the bottom 108 of the feature 104 and on the region 110 of the substrate 102 using an anisotropic deposition process, as Figure 3 depicted in view 300 of. Because the deposition process is directional, the first thickness 304 of the base metal layer 302 may be approximately the same on the region 110 of the substrate 102 and on the bottom 108 of the feature 104. In some embodiments, the first thickness 304 may be about 30 microns to about 50 microns. In some embodiments, the first thickness 304 may be about 30 microns to about 40 microns. In some embodiments, the first thickness 304 may be about 32 microns to about 37 microns. As Figure 3 shown, due to the directionality of the deposition process, the second thickness 306 of the base metal layer 302 on the side 106 of the feature 104 may be negligible and may be discontinuous.

[0031] In some embodiments, PVD processing and similar processes may be used to deposit the base metal layer 302. In some embodiments, the PVD processing is self-biasing to provide a non-isotropic and non-conformal deposition of the base metal layer 302. In some embodiments, the PVD processing may use an applied bias to the substrate to further affect the PVD deposition. The base metal layer 302 is formed on the underlying layer 202 over the region 110 of the substrate 102 and on the underlying layer 202 at the bottom 108 of the feature 104. Any deposition of the base metal layer 302 on the underlying layer 202 on the sidewalls 106 of the feature 104 may be discontinuous and negligible in thickness. In some embodiments, the base metal layer 302 is formed of a metal material, such as but not limited to any Group 6 to Group 9 metal, or the base metal layer 302 may comprise the same metal as the metal layer 406 (see FIG. 4a) and the metal gap filling material 410 (see FIG. 4c) discussed herein. In some embodiments, the base metal layer 302 is formed of a Group 6 to Group 9 metal, or formed of tungsten and / or cobalt, and in an embodiment, the base metal layer 302 is formed of tungsten.

[0032] As also shown in Figure 5 FIG. 5, block 502, method 500 includes depositing a sacrificial Si layer 402 in the opening 103 of the feature 104 and over the region 110 of the substrate 102, as shown in FIG. 4a. In an embodiment, plasma enhanced atomic layer deposition is used to deposit the sacrificial Si layer 402. In an embodiment, plasma enhanced atomic layer deposition is used to deposit the sacrificial Si layer, and plasma enhanced atomic layer deposition uses silane as the Si layer precursor. In an embodiment, the sacrificial Si layer 402 is a conformal layer. In an embodiment, the sacrificial Si layer 402 has a thickness 404 that is less than or equal to about 4 nm. In an embodiment, the sacrificial Si layer 402 has a thickness 404 of about 0.5 nm to 3 nm or about 1 nm to about 2 nm.

[0033] As Figure 5 shown in FIG. 5, block 504, method 500 further includes depositing a metal layer 406 in the opening 103 of the feature 104 and over the region 110, where at least a portion of the sacrificial Si layer 402 is replaced by the metal layer 406, as shown in FIG. 4b.

[0034] In an embodiment, the metal layer 406 is deposited by atomic layer deposition, and includes contacting the sacrificial Si layer 402 with a metal precursor according to Formula I;

[0035] MXa (I);

[0036] where M is a Group 6 to Group 9 metal, X is fluorine or chlorine; and a is 2 to 6.

[0037] In an embodiment, the metal precursor comprises tungsten hexafluoride. The inventors have found that by using ALD with a metal halide such as tungsten hexafluoride, tungsten atoms replace Si atoms, creating a continuous tungsten seeding layer, according to the reaction: Si + WF a →W(m) + SiF a (g)↑.

[0038] In an embodiment, thermal atomic layer deposition is used to deposit the metal layer 406. In an embodiment, plasma enhanced atomic layer deposition is used to deposit the metal layer 406. In an embodiment, the metal layer 406 is deposited at a temperature greater than or equal to about 200°C, or greater than or equal to about 300°C.

[0039] In an embodiment, greater than or equal to about 95 wt% of the sacrificial Si layer 402 is replaced by the metal layer 406. In an embodiment, greater than or equal to about 99 wt%, or greater than or equal to about 99.5 wt% of the sacrificial Si layer 402 is replaced by the metal layer 406.

[0040] In an embodiment, the metal layer 406 has a thickness 408 less than or equal to about 15 nm.

[0041] In an embodiment, the metal layer 406 is a conformal layer. In an embodiment, the metal layer 406 is a conformal metal layer having a thickness of about 5 nm to about 10 nm. In an embodiment, the metal layer 406 comprises tungsten. In an embodiment, the metal layer 406 is tungsten or consists essentially of tungsten. In an embodiment, the base metal layer 302 comprises the same metal as the metal layer 406 or is the same metal as the metal layer 406.

[0042] As further shown in Figure 5 box 506, method 500 may include depositing a metal gap filling material 410 (FIG. 4c) directly over this region in the opening above the metal layer 406, wherein the metal gap filling material 410 completely fills the opening 103 of the feature 104.

[0043] In an embodiment, the metal gap fill material 410 completely fills the opening 103 of the feature 104 without voids. In an embodiment, the metal gap fill material 410 can be, but is not limited to, tungsten and / or cobalt and the like. In an embodiment, the metal gap fill material 410 includes tungsten. In an embodiment, the metal gap fill material 410 is tungsten or consists essentially of tungsten. In an embodiment, the base metal layer 302, the metal layer 406, and the metal gap fill material 410 are all the same metal. In an embodiment, each of the base metal layer 302, the metal layer 406, and the metal gap fill material 410 includes tungsten. In an embodiment, each of the base metal layer 302, the metal layer 406, and the metal gap fill material 410 is tungsten or consists essentially of tungsten. In an embodiment, the metal gap fill material 410 is deposited by physical vapor deposition or chemical vapor deposition. In an embodiment, the metal gap fill material 410 is deposited by chemical vapor deposition.

[0044] The inventors have found that the gap filling method according to an embodiment results in an internal structure of all-tungsten contacts without the high resistivity layers that would result when the sacrificial Si layer 402 is not used. Further, the chemically vapor deposited tungsten of the metal gap fill material 410 grown on the atomic layer deposited tungsten layer 406 has a low resistivity of less than about 5 micro-ohms / mm 2 . Moreover, the metal gap fill material 410 completely fills the feature 104 without forming voids.

[0045] The methods described herein can be performed in individual processing chambers, and the individual processing chambers can be provided as part of a stand-alone configuration or a cluster tool, such as the integration tool 600 (i.e., cluster tool) described later with respect to Figure 6 The integration tool 600 (i.e., cluster tool). In an embodiment, the method 500 according to one or more embodiments is performed in an integration tool without a vacuum break between the deposition of the sacrificial Si layer 402, the deposition of the metal layer 406, and the deposition of the metal gap fill material 410. The advantage of using the integration tool 600 is that there is no vacuum break between chambers and thus no degassing and pre-cleaning prior to processing in the chambers is required. For example, in some embodiments, the methods described above can be advantageously performed in an integration tool such that there is limited or no vacuum break between processes, limiting or preventing contamination of the substrate such as oxidation and the like. The integration tool 600 includes a vacuum-sealed processing platform 601, a factory interface 604, and a system controller 602. The processing platform 601 includes a plurality of processing chambers, such as 614A, 613B, 614C, 614D, 614E, and 614F, operably coupled to a vacuum substrate transfer chamber (transfer chambers 603A, 603B). The factory interface 604 is operably coupled through one or more load lock chambers (two load lock chambers, such as Figure 6shown as 606A and 606B) and coupled to the transfer chamber 603A.

[0046] In some embodiments, the factory interface 604 includes at least one docking station 607 and at least one factory interface robot 638 to facilitate the transfer of semiconductor substrates. The docking station 607 is configured to receive one or more front-opening unified pods (FOUPs). Four FOUPs, such as 605, 605B, 605C, and 605D are shown in Figure 6 the embodiment. The factory interface robot 638 is configured to transfer substrates from the factory interface 604 through load lock chambers (such as 606A and 606B) to the processing platform 601. Each of the load lock chambers 606A and 606B has a first port coupled to the factory interface 604 and a second port coupled to the transfer chamber 603A. The load lock chambers 606A and 606B are coupled to a pressure control system (not shown) that pumps the load lock chambers 606A and 606B back and evacuates them to facilitate the passage of substrates between the vacuum environment of the transfer chamber 603A and the substantially ambient (e.g., atmospheric pressure) environment of the factory interface 604. The transfer chambers 603A, 603B have vacuum robots 642A, 642B, disposed in the respective transfer chambers 603A, 603B. The vacuum robot 642A is capable of transferring the substrate 621 between the load lock chambers 606A, 606B, the processing chambers 614A and 614F, and the cooling station 640 or the pre-cleaning station 642. The vacuum robot 642B is capable of transferring the substrate 621 between the cooling station 640 or the pre-cleaning station 642 and the processing chambers 614B, 614C, 614D, and 614E.

[0047] In some embodiments, the processing chambers 614A, 614B, 614C, 614D, 614E, and 614F are coupled to the transfer chambers 603A, 603B. The processing chambers 614A, 614B, 614C, 614D, 614E, and 614F may include, for example, atomic layer deposition processing chambers, physical vapor deposition processing chambers, chemical vapor deposition chambers, annealing chambers, or the like. The chambers may include any chambers suitable to perform all or part of the methods described herein, as described above, in one or more ALD deposition chambers, non-conformal layer PVD deposition chambers, and CVD deposition chambers, and the like. In some embodiments, one or more optional service chambers (shown as 616A and 616B) may be coupled to the transfer chamber 603A. The service chambers 616A and 616B may be configured to perform other substrate processing, such as degassing, orientation, substrate measurement, cooling, and the like.

[0048] The system controller 602 controls the operation of the tool 600, either by directly controlling the processing chambers 614A, 614B, 614C, 614D, 614E, and 614F, or by controlling a computer (or controller) associated with the processing chambers 614A, 614B, 614C, 614D, 614E, and 614F and the tool 600. In operation, the system controller 602 is capable of collecting data and feedback from the individual chambers and the system to optimize the performance of the tool 600. The system controller 602 generally includes a central processing unit (CPU) 630, a memory 634, and support circuitry 632. The CPU 630 can be any form of general-purpose computer processor that can be used in an industrial setting. The support circuitry 632 is conventionally coupled to the CPU 630 and can include a cache, a clock circuit, an input / output subsystem, a power supply, and the like. Software routines (such as the methods described above) can be stored in the memory 634, and when implemented by the CPU 630, transform the CPU 630 into a special-purpose computer (system controller) 602. The software routines can also be stored and / or executed by a second controller (not shown) that is remote from the tool 600.

[0049] Embodiments in accordance with the present invention can be implemented in hardware, firmware, software, or any combination of the foregoing. Embodiments can also be implemented as instructions stored on one or more computer-readable media that can be read and executed by one or more processors. The computer-readable media can include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing platform or a "virtual machine" running on one or more computing platforms). For example, the computer-readable media can include any suitable form of volatile or non-volatile memory. In some embodiments, the computer-readable media can include non-transitory computer-readable media.

[0050] Embodiment

[0051] Accordingly, the present invention includes the following embodiments, particularly as set forth in the appended claims.

[0052] E1. A method for metal gap filling, comprising:

[0053] Depositing a sacrificial Si layer in an opening of a feature and on a region of a substrate;

[0054] Depositing a metal layer in the opening and on the region, wherein at least a portion of the sacrificial Si layer is replaced by the metal layer; and

[0055] Depositing a metal gap filling material directly over the metal layer in the opening and on the region, wherein the metal gap filling material completely fills the opening.

[0056] E2. The method according to embodiment E1, wherein depositing the metal layer comprises atomic layer deposition, which comprises contacting a sacrificial Si layer with a metal precursor according to formula I;

[0057] MXa (I);

[0058] wherein M is a Group 6 to Group 9 metal;

[0059] wherein X is fluorine or chlorine; and

[0060] a is 2 to 6.

[0061] E3. The method according to embodiment E1 or E2, wherein the metal precursor comprises tungsten hexafluoride.

[0062] E4. The method according to any one of embodiments E1 to E3, wherein the metal layer is deposited at a temperature of greater than or equal to about 200 °C using thermal atomic layer deposition or plasma enhanced atomic layer deposition.

[0063] E5. The method according to any one of embodiments E1 to E4, wherein the metal layer has a thickness of less than or equal to about 15 nm.

[0064] E6. The method according to any one of embodiments E1 to E5, wherein the metal layer is a conformal metal layer having a thickness of about 5 nm to about 10 nm.

[0065] E7. The method according to any one of embodiments E1 to E6, wherein the metal layer comprises tungsten.

[0066] E8. The method according to any one of embodiments E1 to E7, wherein the sacrificial Si layer is deposited over a base metal layer, the base metal layer comprising the same metal as the metal layer.

[0067] E9. The method according to any one of embodiments E1 to E8, wherein the base metal layer is deposited by physical vapor deposition or chemical vapor deposition rather than isotropic deposition, followed by depositing the sacrificial Si layer, the above steps being in an integrated process and without a vacuum break between the above steps.

[0068] E10. The method according to any one of embodiments E1 to E9, wherein plasma enhanced atomic layer deposition is used to deposit the sacrificial Si layer.

[0069] E11. The method according to any one of embodiments E1 to E10, wherein the sacrificial Si layer is a sacrificial conformal Si layer having a thickness of less than or equal to about 4 nm.

[0070] E12. The method according to any one of embodiments E1 to E11, wherein the metal gap filling material comprises the same metal as the metal layer.

[0071] Method according to any one of embodiments E1 to E12, wherein a metal gap filling material is deposited by physical vapor deposition or chemical vapor deposition.

[0072] Method according to any one of embodiments E1 to E13, wherein greater than or equal to about 95 wt% of the sacrificial Si layer is replaced by a metal layer.

[0073] Method according to any one of embodiments E1 to E14, which is performed in an integration tool without breaking vacuum between deposition of the sacrificial Si layer, deposition of the metal layer, and deposition of the metal gap filling material.

[0074] A method for metal gap filling, comprising:

[0075] Depositing a sacrificial Si layer on top of a base metal layer on a region of a substrate in an opening of a feature;

[0076] Performing an atomic layer deposition process on top of the sacrificial Si layer to replace Si atoms with metal atoms and create a metal layer in the opening and on top of the base metal layer in this region, wherein greater than or equal to about 95 wt% of the sacrificial Si layer is replaced by the metal layer; and

[0077] Depositing a metal gap filling material directly above the metal layer in the opening and in this region, wherein the metal gap filling material completely fills the opening.

[0078] Method according to embodiment E16, wherein the base metal layer, the metal layer, and the metal gap filling material are all the same metal.

[0079] Method according to any one of embodiments E16 to E17, wherein each of the base metal layer, the metal layer, and the metal gap filling material comprises tungsten.

[0080] Method according to any one of embodiments E16 to E18, wherein each of the base metal layer, the metal layer, and the metal gap filling material is tungsten.

[0081] A non-transitory computer-readable medium having instructions stored thereon that, when executed, cause a method for metal gap filling according to any one of embodiments E1 to E19 to be performed.

[0082] A non-transitory computer-readable medium having instructions stored thereon that, when executed, cause a method for metal gap filling to be performed, the method comprising:

[0083] Depositing a sacrificial Si layer in an opening of a feature and on a region of a substrate;

[0084] Deposit a metal layer in the opening over this region, where at least a portion of the sacrificial Si layer is replaced by the metal layer; and

[0085] Deposit a metal gap filling material directly over the metal layer in the opening, where the metal gap filling material completely fills the opening.

[0086] Although the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be conceived without departing from the basic scope of the invention.

Claims

1. A method for metal gap filling, the method comprising: Depositing a sacrificial Si layer in an opening of a feature and on a region of a substrate; Depositing a metal layer in the opening and on the region, wherein at least a portion of the sacrificial Si layer is replaced by the metal layer; and Depositing a metal gap filling material directly above the metal layer in the opening and on the region, wherein the metal gap filling material completely fills the opening.

2. The method of claim 1, wherein depositing the metal layer comprises atomic layer deposition, and the atomic layer deposition comprises contacting the sacrificial Si layer with a metal precursor according to Formula I; MX a (I); wherein M is a metal of Group 6 to Group 9; wherein X is fluorine or chlorine; and a is 2 to 6.

3. The method of claim 2, wherein the metal precursor comprises tungsten hexafluoride.

4. The method of claim 1, wherein the metal layer is deposited using thermal atomic layer deposition or plasma enhanced atomic layer deposition at a temperature greater than or equal to about 200 °C.

5. The method of claim 1, wherein the metal layer has a thickness less than or equal to about 15 nm.

6. The method of claim 1, wherein the metal layer is a conformal metal layer having a thickness of about 5 nm to about 10 nm.

7. The method of claim 1, wherein the metal layer comprises tungsten.

8. The method of any one of claims 1 to 7, wherein the sacrificial Si layer is deposited above a base metal layer, and the base metal layer comprises the same metal as the metal layer.

9. The method of claim 8, wherein the base metal layer is anisotropically deposited by physical vapor deposition or chemical vapor deposition, followed by depositing the sacrificial Si layer, and the above steps are performed in an integration process without a vacuum break between these steps.

10. The method of any one of claims 1 to 7, wherein the sacrificial Si layer is deposited using plasma enhanced atomic layer deposition.

11. The method of any one of claims 1 to 7, wherein the sacrificial Si layer is a sacrificial conformal Si layer having a thickness less than or equal to about 4 nm.

12. The method of any one of claims 1 to 7, wherein the metal gap filling material comprises the same metal as the metal layer.

13. The method of any one of claims 1 to 7, wherein the metal gap filling material is deposited by physical vapor deposition or chemical vapor deposition.

14. The method of any one of claims 1 to 7, wherein greater than or equal to about 95 wt% of the sacrificial Si layer is replaced by the metal layer.

15. The method of any one of claims 1 to 7, wherein the method is performed in an integration tool without a vacuum break between the steps of depositing the sacrificial Si layer, depositing the metal layer, and depositing the metal gap filling material.

16. The method of claim 1, wherein: A base metal layer is disposed in the opening of the feature and the sacrificial Si layer is deposited on top of the base metal layer; Depositing the metal layer in the opening and on the region includes: performing an atomic layer deposition process on top of the sacrificial Si layer to replace Si atoms with metal atoms and create the metal layer on top of the base metal layer in the opening and on the region, wherein greater than or equal to about 95 wt% of the sacrificial Si layer is replaced by the metal layer.

17. The method of claim 16, wherein: the base metal layer, the metal layer, and the metal gap filling material are all the same metal; each of the base metal layer, the metal layer, and the metal gap filling material comprises tungsten; or each of the base metal layer, the metal layer, and the metal gap filling material is tungsten.

18. A non-transitory computer-readable medium having stored therein a plurality of instructions that, when executed, cause a method for metal gap filling to be performed, the method being the method of any one of claims 1 to 7 or 16 to 17.

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