Apparatus and method for conditioning ion and radical species in a plasma

Abstract

Embodiments disclosed herein include an apparatus for ion blocking. In embodiments, the apparatus includes a first plate, wherein a plurality of first holes pass through a thickness of the first plate; and a second plate, the second plate being above the first plate, wherein a plurality of second holes pass through a thickness of the second plate. In embodiments, a spacer is disposed between the first plate and the second plate.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Patent Application No. 18 / 405,726, filed January 5, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments relate to the field of semiconductor manufacturing, and more specifically, to apparatus and methods for regulating ions and free radicals in plasma.

[0004] Related technical descriptions

[0005] Integrated circuits are realized through processes that create complex patterned material layers on a substrate surface. Creating patterned material on a substrate requires controlled methods for removing exposed material. Chemical etching is used for a variety of purposes, including transferring patterns from photoresist to underlying layers, thinning layers, or thinning the lateral dimensions of features already present on a surface. Typically, an etching process is desired that etches one material faster than another to facilitate, for example, pattern transfer processes. This type of etching process is referred to as selective etching for a first material. Due to the diversity of materials, circuits, and processes, selective etching processes for multiple materials have been developed.

[0006] Some etching processes are characterized as "dry" processes. Dry processes typically involve a plasma used to ionize a gas fed into a chamber. The rate at which ions travel from the plasma to the substrate surface may at least partially determine the etching rate of a given process. Therefore, the ability to control ion flow is ideal for precisely controlling dry etching processes. Summary of the Invention

[0007] The embodiments disclosed herein include a device for ion blocking. In one embodiment, the device includes a first plate through which a plurality of first holes pass through the thickness of the first plate; and a second plate situated on top of the first plate, through which a plurality of second holes pass through the thickness of the second plate. In another embodiment, a spacer is disposed between the first plate and the second plate.

[0008] The embodiment further includes a method for plasma etching, the method comprising generating plasma in a chamber. In one embodiment, the chamber includes an ion barrier system between a cover of the chamber and a substrate. In another embodiment, the method further includes orienting the ion barrier system in a first configuration to allow ions from the plasma to pass through the ion barrier system at a first flow rate and reach the substrate; and orienting the ion barrier system in a second configuration to allow ions from the plasma to pass through the ion barrier system at a second flow rate and reach the substrate.

[0009] The embodiment further includes a tool comprising a chamber and a plasma source coupled to the chamber. In one embodiment, a base is disposed in the tool to support a substrate in the chamber. In another embodiment, an ion blocking system is disposed between the base and the plasma source. In yet another embodiment, the ion blocking system includes a first plate with a plurality of first holes passing through the thickness of the first plate; and a second plate situated above the first plate, with a plurality of second holes passing through the thickness of the second plate. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view of an ion blocking system according to an embodiment, which includes a first plate on top of a second plate.

[0011] Figure 2A This is a cross-sectional view of a portion of an ion barrier system according to an embodiment, the ion barrier system being configured to allow 100% overlap of the holes in the first plate and the second plate.

[0012] Figure 2B This is a cross-sectional view of a portion of an ion barrier system according to an embodiment, the ion barrier system being configured to allow the holes in the first plate and the second plate to overlap.

[0013] Figure 2C This is a cross-sectional view of a portion of an ion barrier system according to an embodiment, the ion barrier system being configured to allow the holes in the first plate and the second plate to not overlap.

[0014] Figure 3A This is a cross-sectional view of a portion of an ion blocking system according to an embodiment, the ion blocking system having actuators coupled to a first plate and a second plate.

[0015] Figure 3B This is a cross-sectional view of a portion of an ion blocking system according to an embodiment, the ion blocking system having a first actuator coupled to a first plate to provide lateral displacement, and a second actuator coupled to a second plate to provide vertical displacement.

[0016] Figure 4 This is a cross-sectional view of a portion of an ion blocking system according to an embodiment, the ion blocking system having a first plate having a first hole and a second plate having a second hole, the second hole having a diameter different from that of the first hole.

[0017] Figure 5A This is a cross-sectional view of a portion of an ion barrier system according to an embodiment, the ion barrier system having a first plate and a second plate that are electrically grounded.

[0018] Figure 5BThis is a cross-sectional view of a portion of an ion blocking system according to an embodiment, the ion blocking system having a first plate and a second plate electrically grounded.

[0019] Figure 5C This is a cross-sectional view of a portion of an ion blocking system according to an embodiment, the ion blocking system having a first plate held under a first voltage and a second plate held under a second voltage.

[0020] Figure 6A This is a plan view of a plate with slotted holes according to an embodiment.

[0021] Figure 6B This is a plan view of a plate with an annular hole according to an embodiment.

[0022] Figure 7 This is a cross-sectional view of a microwave plasma system including an ion blocking system according to an embodiment.

[0023] Figure 8A This is a cross-sectional view of a three-dimensional (3D) NAND structure during the manufacturing stage, according to an embodiment.

[0024] Figure 8B This is a cross-sectional view of the 3D-NAND structure according to the implementation method during the subsequent manufacturing stage.

[0025] Figure 9 This is a process flow diagram of a process for controlling the ion flow rate through an ion barrier system according to an embodiment.

[0026] Figure 10 The diagram illustrates a block diagram of an exemplary computer system that can be used in conjunction with a processing tool according to an embodiment. Detailed Implementation

[0027] The system described herein includes a system for regulating the flow rate of ions from plasma to a substrate located below an ion-barrier system. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. It will be apparent to those skilled in the art that embodiments can be practiced without these specific details. In other instances, well-known aspects have not been described in detail to avoid unnecessarily obscuring the embodiments. Furthermore, it should be understood that the various embodiments shown in the accompanying drawings are illustrative representations and are not necessarily drawn to scale.

[0028] As mentioned above, controlling the flow of ions to the substrate surface is useful for controlling the etching parameters of a given etching process. Ion barrier systems have been used to control ion flow. In one case, a thin plate with pinholes is used. In an alternative approach, a thicker plate is used in conjunction with the pinholes. Typically, the diameter of the pinholes in these types of ion barrier systems is 1.0 mm or less, 500 μm or less, or 100 μm or less. In both designs, the goal is to maximize the probability of ions contacting the surface of the plate. Once in contact with the surface, the ions lose their charge and become neutral. This neutralization of the ions before they reach the underlying substrate is achieved.

[0029] Furthermore, plasma density is typically proportional to the plasma frequency. At low to medium frequencies (e.g., less than approximately 160 MHz), the plasma density is insufficient, and the small-diameter orifice is adequate to transfer a sufficient amount of plasma through the ion-blocking system. However, as the plasma density increases, the small orifice of the ion-blocking system becomes a choke point, limiting the effectiveness of high-density plasmas.

[0030] Therefore, the embodiments disclosed herein include an ion-blocking system that controls the ion flow rate while still allowing the use of high-density plasma. By providing an ion-blocking system adapted to high-density plasma, the system comprises a pair of plates with holes through each plate. Unlike previous solutions, the holes described herein are relatively large. For example, the holes may have a diameter of approximately 1.0 mm or larger, approximately 15 mm or larger, or approximately 25 mm or larger.

[0031] Larger apertures typically reduce the probability of ions contacting the plates when the apertures in the first and second plates are aligned. In other words, a high percentage overlap between apertures results in a high ion flow rate to the substrate. However, the embodiments disclosed herein include plates that can be configured to reduce aperture overlap. Depending on the desired ion flow rate, the aperture overlap between the first and second plates can be between 0% and 100%.

[0032] In some embodiments, the ion barrier system is configured with a desired overlap to process one or more substrates (e.g., via a dry etching process). The overlap percentage can be manually changed between processing cycles. In other embodiments, the ion barrier system may include one or more actuators that allow automatic adjustment of the overlap percentage. This implementation may be advantageous for some etching processes. For example, the first part of an etching process may need to be more aggressive (e.g., with a higher ion flow rate) compared to the second part of the etching process (e.g., with a lower ion flow rate). This variable etching process may be particularly advantageous for processing three-dimensional (3D) NAND structures.

[0033] Now refer to Figure 1 According to an embodiment, a perspective cross-sectional view of the ion blocking system 120 is shown. In this embodiment, the ion blocking system 120 can be useful as a shield between the plasma 110 and the substrate 105. As indicated by arrow 108, ions can pass from the plasma 110 through the ion blocking system 120 to reach the surface of the substrate 105.

[0034] In one embodiment, the ion barrier system 120 may include a first plate 121 and a second plate 122. The first plate 121 and the second plate 122 may be stacked. A spacer 125 may be disposed between the first plate 121 and the second plate 122. In the illustrated embodiment, the spacer 125 includes a plurality of gaskets 125A to 125C to provide a desired gap G between the first plate 121 and the second plate 122. In other embodiments, a single gasket 125A may be used for the spacer 125. The spacer 125 may comprise a conductive material or an electrically insulating material. The gap G may be approximately 0.5 mm or greater, approximately 5.0 mm or greater, approximately 10 mm or greater, or approximately 20 mm or greater. Increasing the gap G can achieve a higher ion transport rate. As used herein, “approximately” may refer to a range within ten percent of the stated value. For example, approximately 10 mm may refer to a range between 9 mm and 11 mm.

[0035] In some embodiments, the first plate 121 may include a plurality of first holes 127. In some embodiments, the first holes 127 may be circular. However, the first holes 127 may have any shape. The first holes 127 pass completely through the thickness of the first plate 121. In some embodiments, the first holes 127 may have a first diameter D1. The first diameter D1 may be approximately 1.0 mm or greater, approximately 15 mm or greater, or approximately 25 mm or greater. In some embodiments, the first diameter D1 may be equal to or greater than the thickness of the first plate 121.

[0036] In some embodiments, the second plate 122 may include a plurality of second holes 128. In some embodiments, the second holes 128 may be circular. However, the second holes 128 may have any shape. The second holes 128 pass entirely through the thickness of the second plate 122. In some embodiments, the second holes 128 may have a second diameter D2. The second diameter D2 may be approximately 1.0 mm or greater, approximately 15 mm or greater, or approximately 25 mm or greater. In some embodiments, the second diameter D2 may be equal to or greater than the thickness of the second plate 122.

[0037] In some embodiments, the first plate 121 may be substantially similar to the second plate 122. For example, the first diameter D1 may be substantially equal to the second diameter D2. Additionally, the placement of the first hole 127 may be aligned with the placement of the second hole 128. However, as will be described in more detail below, the first hole 127 may be different from the second hole 128. The first plate 121 and the second plate 122 may also comprise the same or multiple materials. In some embodiments, the first plate 121 and the second plate 122 may comprise one or more of alumina (Al2O3), aluminum nitride, or aluminum. In some embodiments, the metal core may be coated with a coating, such as a coating comprising nickel or yttrium oxide.

[0038] exist Figure 1 In the configuration shown, the first plate 121 and the second plate 122 are aligned such that the first aperture 127 and the second aperture 128 are aligned with each other. However, the ion flow rate can be adjusted by offsetting one or both of the first plate 121 and the second plate 122 to deviate the first aperture 127 from the second aperture 128. This offset or displacement can be done manually or automatically (e.g., by an actuator or the like).

[0039] Now refer to Figures 2A to 2C According to embodiments, a series of cross-sectional views depicting various portions of an ion-barrier system 220 in different configurations are shown. In the illustrated embodiments, for simplicity, only the first plate 221 and the second plate 222 are shown. However, embodiments may also include spacers, actuators, and / or other structures that may be described in more detail herein.

[0040] Now refer to Figure 2A A cross-sectional view of an ion barrier system 220 is shown according to an embodiment. The ion barrier system 220 may include a first plate 221 disposed on a second plate 222. The first plate 221 may include a first aperture 227, and the second plate 222 may include a second aperture 228. The first plate 221 may be aligned with the second plate 222 such that the first aperture 227 and the second aperture 228 completely overlap each other. In this configuration, a maximum ion flow rate through the ion barrier system 220 is provided. For example, almost all ions 208 that pass through the first aperture 227 can also pass through the second aperture 228.

[0041] Now refer to Figure 2BAccording to an embodiment, a cross-sectional view of an ion blocking system 220 in an alternative configuration is shown. The ion blocking system 220 may include a first plate 221 disposed on a second plate 222. The first plate 221 may include a first aperture 227, and the second plate 222 may include a second aperture 228. The first plate 221 may be offset from the second plate 222 such that the first aperture 227 and the second aperture 228 are not perfectly aligned with each other. For example, the centerline of the first aperture 227 may be offset from the centerline of the second aperture 228 (at least partially overlapping with the first aperture 227). The offset distance between the centerlines may be up to the diameter of either the first aperture 227 or the second aperture 228.

[0042] In this configuration, the ion flow rate through the ion blocking system 220 is reduced. The amount of reduction in ion flow rate (relative to) depends on the offset. Figure 2A (Compared to the configuration shown) the ion flow rate can be between 0% and 100%. In some embodiments, the ion flow rate can be reduced by between 25% and 75%. The reduction in ion flow rate can be proportional to the reduction in the overlap area between the first aperture 227 and the second aperture 228. For example, the change in ion flow rate can be directly related to the change in overlap area in a 1:1 relationship. In some cases, some ions 208 passing through the first aperture 227 may be blocked by the second plate 222, and some ions 208 passing through the first aperture 227 may pass through the second aperture 228.

[0043] Now refer to Figure 2C According to an embodiment, a cross-sectional view of an ion blocking system 220 in an alternative configuration is shown. The ion blocking system 220 may include a first plate 221 disposed on a second plate 222. The first plate 221 may include a first aperture 227, and the second plate 222 may include a second aperture 228. The first plate 221 may be offset from the second plate 222 such that the first aperture 227 does not overlap with any portion of the second aperture 228. Figure 2C In the configuration shown, the ion flow rate can be reduced to virtually 0% (compared to...). Figure 2A (Compared to the configuration shown). That is, ions 208 passing through the first hole 227 may be completely blocked by the second plate 222.

[0044] In relation to Figures 2A to 2C In the described embodiments, ions 208 are all illustrated as being oriented substantially orthogonal to the flat surfaces of the first plate 221 and the second plate 222. However, ions 208 may also pass through the ion blocking system 220 at other angles. Depending on the angle of the ions, different offsets of the orifices 227 and 228 may result in different ion flow rates. For example, even when the first orifice 227 is completely offset from the second orifice 228 (e.g., as shown in the diagram), the ions 208 may be oriented differently. Figure 2CAs shown, when ions 208 enter at a more extreme angle, ions 208 can still pass through the ion barrier system 220. Increasing the spacing between holes, increasing the thickness of plates 221 and / or 222, decreasing the spacing between plates 221 and 222, and / or other structural changes can be used to reduce and / or eliminate leakage of ions 208 through the ion barrier system 220.

[0045] Now refer to Figure 3A A cross-sectional view of an ion barrier system 320 is shown according to an embodiment. In this embodiment, the ion barrier system 320 may include a first plate 321 having a first aperture 327 and a second plate 322 having a second aperture 328. In this embodiment, the first plate 321 may be spaced apart from the second plate 322 by a gap G. In this embodiment, the first plate 321 may be displaced relative to the second plate 322. For example, arrows 331A and 331B indicate that the first plate 321 and the second plate 322 may be displaced along planes substantially parallel to each other. This displacement allows for a desired amount of overlap between the first aperture 327 and the second aperture 328. Thus, the ion flow rate through the ion barrier system 320 can be controlled.

[0046] In one embodiment, the first plate 321 can be displaced by a first actuator 330A, and the second plate 322 can be displaced by a second actuator 330B. The first actuator 330A and the second actuator 330B can include any suitable actuation mechanism, such as an electromechanical actuator, a hydraulic actuator, a pneumatic actuator, or a piezoelectric actuator. Although each plate 321 and 322 is shown to have a single actuator 330, it should be understood that multiple actuators 330 can be used to displace each plate 321 or 322. Furthermore, although both plates 321 and 322 are shown to be displaceable by actuators 330, in some embodiments, only one of the plates 321 or 322 includes an actuator. For example, the first plate 321 may be fixed, while the second plate 322 may be displaceable by one or more actuators 330.

[0047] Using an actuator allows for adjustment of the ion flow rate without manually opening the chamber housing the ion barrier system 320. This is advantageous because it allows for etching processes that include variable etching conditions. As will be described in more detail herein, this non-uniform etching process can be particularly beneficial for 3D-NAND manufacturing processes.

[0048] Now refer to Figure 3B According to an additional embodiment, a cross-sectional view of the ion blocking system 320 is shown. The ion blocking system 320 can be similar to... Figure 3AThe ion-blocking system 320 includes an added vertical actuator 335. In this embodiment, the vertical actuator 335 allows the first plate 321 to be raised or lowered relative to the second plate 322 (as indicated by arrow 336). Thus, in addition to changing the offset of the first aperture 327 and the second aperture 328 (by using the actuator 330), the gap G between the first plate 321 and the second plate 322 can also be modified. The actuator 335 can be any suitable actuator, such as an electromechanical actuator, a hydraulic actuator, a pneumatic actuator, or a piezoelectric actuator.

[0049] Now refer to Figure 4 According to an additional embodiment, a cross-sectional view of an ion blocking system 420 is shown. In this embodiment, the ion blocking system 420 may include a first plate 421 and a second plate 422. The first plate 421 may have a first hole 427 with a first diameter D1, and the second plate 422 may have a second hole 428 with a second diameter D2. The first diameter D1 may be different from the second diameter D2. For example, in Figure 4 In this embodiment, the second diameter D2 is smaller than the first diameter D1. However, in other embodiments, the second diameter D2 may be larger than the first diameter D1.

[0050] Now refer to Figures 5A to 5C According to embodiments, a series of cross-sectional views of various ion blocking systems 520 are shown. In embodiments, Figures 5A to 5C The ion barrier system 520 may include different electrical configurations. For example, one or more of the plates 521 and / or 522 may be electrically grounded, electrically floating, or held at a certain voltage.

[0051] Now refer to Figure 5A According to an embodiment, a cross-sectional view of an ion barrier system 520 is shown. In this embodiment, the ion barrier system 520 may include a first plate 521 having a first aperture 527 and a second plate 522 having a second aperture 528. The first plate 521 and the second plate 522 may be configured (manually or by using an actuator) such that the first aperture 527 and the second aperture 528 overlap to provide a desired ion flow rate through the ion barrier system 520.

[0052] In the illustrated embodiment, a spacer 525 is disposed between the first plate 521 and the second plate 522. In some embodiments, the spacer 525 is an electrically insulating material, such as ceramic, polymer, or the like. Thus, there may be no electrical coupling between the first plate 521 and the second plate 522. Therefore, both the first plate 521 and the second plate 522 can be electrically coupled to ground 538.

[0053] Now refer to Figure 5BAccording to an additional embodiment, a cross-sectional view of the ion blocking system 520 is shown. In this embodiment, Figure 5B The ion barrier system 520 in the middle can be similar to Figure 5A The ion barrier system 520 differs in that it has a spacer 525. The spacer 525 can be conductive, rather than insulating. Thus, the first plate 521 can be electrically coupled to the second plate 522 via the spacer 525. Therefore, when it is desired to ground the ion barrier system 520, only one of the plates 521 or 522 needs to be electrically coupled to ground 538. Figure 5B In the case shown, the first plate 521 is coupled to ground 538.

[0054] Now refer to Figure 5C According to an additional embodiment, a cross-sectional view of the ion blocking system 520 is shown. Figure 5C The ion barrier system 520 in the middle can be similar to Figure 5A The difference between the ion blocking system 520 and the ion blocking system 520 lies in the voltage maintained by the ion blocking system 520. For example, the first plate 521 can be maintained under a first voltage 539A, and the second plate 522 can be maintained under a second voltage 539B. The first voltage 539A can be different from the second voltage 539B. Furthermore, although in Figure 5C The diagram shows that the plates 521 and 522 are to be kept at a specific voltage, but one or both of them may be electrically floating (i.e., not directly coupled to the voltage potential or ground potential).

[0055] Now refer to Figure 6A and Figure 6B According to an embodiment, a pair of plan view illustrations of a plate 621 that can be used in an ion barrier system are shown. Plate 621 may be similar to the plate described in more detail herein, except for the shape of the aperture 627. Figure 6A In this configuration, orifices 627 can be a series of grooves extending across plate 621. The width and spacing of orifices 627 can be selected to provide the desired ion flow rate. Figure 6B In this embodiment, hole 627 may contain multiple rings. Each ring may have a different inner and outer diameter. The spacing between holes 627 may be uniform or variable.

[0056] Now refer to Figure 7According to one or more embodiments of this disclosure, a cross-sectional view of a processing tool 780 (e.g., a microwave plasma chamber) including component 770 is shown. Those skilled in the art will understand that while the disclosure refers to a microwave plasma chamber, any remote plasma source, inductively coupled plasma (ICP) source, capacitively coupled plasma (CCP) source, or microwave plasma source can be implemented in the disclosed process.

[0057] In some embodiments, the processing tool 780 includes a processing chamber 778 sealed by component 770. For example, component 770 may press against one or more O-rings 781 to provide a vacuum seal to the internal volume 783 of the processing chamber 778. In other embodiments, component 770 interfaces with the processing chamber 778. In other words, in some embodiments, component 770 may be part of a lid sealing the processing chamber 778. In some embodiments, a chuck 779, such as an electrostatic chuck, may support a workpiece 774 (e.g., a wafer, substrate, etc.).

[0058] In some embodiments, component 770 may include a monolithic source array 750, a housing 772, and a cover plate 776. The monolithic source array 750 may include a dielectric plate 760 and a plurality of protrusions 766 extending upward from the dielectric plate 760. Although the monolithic source array 750 is shown, it should be understood that the protrusions 766 may differ from the dielectric plate 760. The protrusions 766 may be insulating bodies seated on top of the dielectric plate 760. In some embodiments, there may be five or more protrusions 766, or ten or more protrusions 766. In some embodiments, there are nineteen protrusions 766.

[0059] The protrusion 766 may comprise any suitable material known to those skilled in the art. In some embodiments, the protrusion 766 comprises a dielectric material. In some embodiments, the protrusion 766 acts as a dielectric resonator to couple microwaves into the cavity volume 783. In some embodiments, as used herein, the protrusion 766 may be referred to as an "applier," a "plasma applier," or a "microwave applier."

[0060] In some embodiments, the housing 772 includes an opening sized to receive the protrusion 766. The housing 772 may be made of a conductive material. In some embodiments, the housing 772 is grounded. Figure 7In the illustrated embodiment, the housing 772 is directly supported by the dielectric plate 760; however, it should be understood that a thermal interface material or the like may separate the housing 772 from the dielectric plate 760. In some embodiments, the monopole antenna 768 may extend into a hole in the protrusion 766. In some embodiments, the hole in the protrusion 766 is larger than the monopole antenna 768 to allow thermal expansion, thereby preventing damage to the monolithic source array 750. In some embodiments, the monopole antenna 768 is connected via a cover plate 776 situated above the housing 772 and the protrusion 766. In one or more embodiments, each of the monopole antennas 768 is coupled to a different power source. Those skilled in the art will appreciate that the power source can have any suitable configuration.

[0061] The chamber volume 783 is adapted to ignite plasma 782. In other words, the chamber volume 783 can be a vacuum chamber. In some embodiments, a vacuum source can be fluidly coupled to the chamber volume 783. To ignite plasma 782, a process gas can flow into the chamber volume 783. The process gas can enter the assembly 770 through a gas line 718. The process gas then passes through a hole 714 through a cover plate 776 and enters a hole 745 in the housing 772. The hole 745 intersects with a gas distribution channel 740, which laterally distributes the process gas. Although shown as a plurality of discrete gas distribution channels 740, those skilled in the art will understand that the gas distribution channels 740 are... Figure 7 They are fluidly coupled to each other outside the plane.

[0062] The process gas exits the channel 740 through a group of 742 holes 747 in the cover above the channel 740. The process gas then enters the chamber volume 783 through a gas distribution hole 763 passing through the dielectric plate 760 of the monolithic source array 750.

[0063] In one embodiment, an ion blocking system 720 is disposed within a chamber 778 between component 770 and chuck 779. The ion blocking system 720 may be supported on a lug 775 or any other internal support structure (e.g., an edge ring, etc.) within the chamber 778. The ion blocking system 720 may be similar to any of the ion blocking systems described in more detail herein. For example, the ion blocking system 720 may include a first plate 721 having a first aperture 727 and a second plate 722 having a second aperture 728. A spacer 725 separates the first plate 721 from the second plate 722. The first plate 721 and the second plate 722 may be configured such that the first aperture 727 and the second aperture 728 are between 0% and 100% overlap to control the ion flow rate through the ion blocking system 720. In one embodiment, the first plate 721 and the second plate 722 are manually positioned. In other embodiments, the first plate 721 and the second plate 722 can be shifted about each other by using one or more actuators (such as those described in more detail herein).

[0064] In some implementations, etching processes with non-uniform processing conditions are desirable. For example, 3D-NAND architectures can benefit from such processes. In some cases, the first duration of the etching process may include aggressive etching (e.g., with a high ion flow rate) to remove the native oxide layer on top of the material to be etched, and the second duration of the etching process may include less aggressive etching (e.g., with a lower ion flow rate) to protect exposed oxide layers that are not intended to be etched. Figure 8A and Figure 8B An example of this etching process is shown in the figure. Figure 8A This is a cross-sectional view of a portion of a 3D-NAND structure, which has alternating silicon oxide and silicon nitride layers. Figure 8B It is after selective etching of the silicon nitride layer. Figure 8A A cross-sectional illustration of a portion of a 3D-NAND structure.

[0065] In one or more embodiments, the method described herein is implemented on a 3D structure 800. For example, the 3D structure 800 may be a structure for a 3D-NAND device. The 3D structure 800 includes a substrate 801, such as a polysilicon substrate, wherein polysilicon pillars 802 extend upward from the substrate 801. In one or more embodiments, each pillar 802 is made of silicon oxide (e.g., SiO2). X 803 and silicon nitride (e.g., Si) X N Y Alternating layers of silicon nitride layer 804 are used as lining. The sidewalls of silicon nitride layer 804 and silicon oxide layer 803 can be exposed through trenches 806 between the layers of pillars 802.

[0066] In some embodiments, the silicon nitride layer 804 is a sacrificial layer. In embodiments where the silicon nitride layer 804 is a sacrificial layer, the silicon nitride layer 804 is etched away, such as... Figure 8B As shown. Initially, the etching process may include a high ion flow rate to remove any native oxide on the silicon nitride layer 804. After the native oxide is removed, the ion flow rate may be reduced to minimize damage to the silicon oxide layer 803. Variable ion flow rates can be achieved by using any of the ion blocking systems similar to those described in more detail herein. Removal of the silicon nitride layer 804 results in the formation of grooves 805 between the silicon oxide layers 803. In some embodiments, the grooves 805 are subsequently filled with a conductive layer (not shown) containing any suitable conductive material known to those skilled in the art, such as tungsten (W).

[0067] Advantageously, embodiments of this disclosure utilize etch chemicals that provide high etch selectivity to the silicon nitride layer 804 relative to the silicon oxide layer 803. Embodiments of this disclosure advantageously increase the etch rate of silicon nitride and thereby reduce the time required to etch the silicon nitride layer 804. Embodiments of this disclosure include using a plasma source (such as a modular microwave source) to generate microwave plasma containing a fluorine precursor and a gas mixture as an etch chemical, and using a plasma source (such as a modular microwave source) to generate microwave plasma containing a sulfur precursor and a gas mixture as a passivation chemical.

[0068] exist Figure 8A and Figure 8B In this document, structure 800 is shown as suitable for a 3D-NAND device. The etching process described herein is particularly advantageous for use in 3D-NAND devices. It has been advantageously found that in highly scaled 3D-NAND devices, such as structures with high aspect ratios and numerous silicon nitride layers 804 and silicon oxide layers 803, etching uniformity is substantially uniform at the top and bottom of the structure. Furthermore, the etching process of one or more embodiments provides complete removal of the silicon nitride layer 804 without significantly damaging the silicon oxide layer 803. In some embodiments, in addition to using a sulfur-containing precursor / gas mixture chemical substance to form a passivation layer over the exposed portions of the silicon oxide layer 803, variable ion flow rate control allows for improved protection of the silicon oxide layer 803. As used herein, the sulfur-containing precursor / gas mixture chemical substance may be referred to as a "passivation chemical substance." In certain embodiments, the etching process of one or more embodiments provides complete removal of the silicon nitride layer 804 without damaging the silicon oxide layer 803 on which the passivation layer is applied.

[0069] Those skilled in the art will understand that embodiments of this disclosure are not limited to etching of 3D-NAND structures. For example, a similar etching process can be used in any situation where selective etching of a silicon nitride structure relative to a silicon oxide layer is required. For instance, a silicon nitride layer can be disposed above a silicon oxide layer, wherein the disclosed etching process etches through the silicon nitride layer and stops at the oxide layer. In this embodiment, the silicon oxide layer can be considered an etch-stopping layer.

[0070] While specific examples of semiconductor device architectures have been provided that benefit from the use of plasma sources (such as modular microwave sources) to generate microwave plasmas of fluorine-containing precursor and gas mixtures as etching chemicals and sulfur-containing precursor and gas mixtures as passivation chemicals, those skilled in the art will understand that the examples provided are non-limiting and that many different applications and architectures may benefit from fluorine-containing precursor / gas mixture etching chemicals and sulfur-containing precursor / gas mixture passivation chemicals according to one or more embodiments herein.

[0071] Now refer to Figure 9 According to an embodiment, a process flow diagram of a process 990 for controlling the ion flow rate in a chamber is shown. In process 990, the chamber may be similar to any of the chambers and / or tools described in more detail herein. Additionally, the ion barrier system may be similar to any of the ion barrier systems described in more detail herein.

[0072] In one embodiment, process 990 may begin with operation 991, which includes generating plasma in a chamber. In another embodiment, the chamber includes an ion barrier system located between a cover of the chamber and a substrate within the chamber. In yet another embodiment, the ion barrier system may include a first plate having a first aperture and a second plate having a second aperture. The plasma can be generated using any plasma source, such as a microwave plasma source, an ICP source, or a CCP source.

[0073] In one embodiment, process 990 may proceed to operation 992, which includes orienting the ion barrier system to a first configuration to allow ions from the plasma to pass through the ion barrier system at a first flow rate and reach the substrate. In one embodiment, the first configuration may include an overlap of up to approximately 100% of the aperture area between the first and second apertures. In other embodiments, the first configuration may include at least 50% or at least 75% overlap. However, a smaller overlap percentage may also be used in some embodiments.

[0074] In one embodiment, process 990 may proceed to operation 993, which includes orienting the ion barrier system to a second configuration to allow ions from the plasma to pass through the ion barrier system at a second flow rate and reach the substrate. In one embodiment, the second configuration may include an overlap percentage between the first and second holes that is less than the overlap percentage in operation 992. In one embodiment, the overlap percentage of the second configuration may be as high as 75% of the hole area. In other embodiments, the second configuration may include an overlap between 0% and 75% or between 25% and 75%. However, larger overlap percentages may also be used in some embodiments.

[0075] Now refer to Figure 10 A block diagram of an exemplary computer system 1000 of a processing tool is illustrated according to an embodiment. In this embodiment, the computer system 1000 is coupled to and controls processing within the processing tool. The computer system 1000 may be connected to other machines in a Local Area Network (LAN), intranet, extranet, or the Internet. The computer system 1000 may operate as a server or client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. The computer system 1000 may be a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), cellular phone, network device, server, network router, switch, or bridge, or any machine capable of executing (sequentially or otherwise) a set of instructions specifying actions to be taken by another machine. Furthermore, although only a single machine is shown for computer system 1000, the term "machine" should also be considered as any collection of machines (e.g., computers) that individually or jointly execute a set (or more) of instructions to perform any or more of the methods described herein.

[0076] Computer system 1000 may include computer program product or software 1022 having a non-transitory machine-readable medium thereon storing instructions which can be used to program computer system 1000 (or other electronic components) to perform a process according to an embodiment. Machine-readable medium includes any mechanism for storing or transmitting information in a machine-readable (e.g., computer-readable) form. For example, machine-readable (e.g., computer-readable) media include machine-readable (e.g., computer-readable) storage media (e.g., read-only memory ("ROM"), random access memory ("RAM"), disk storage media, optical storage media, flash memory elements, etc.), machine-readable (e.g., computer-readable) transmission media (electrical, optical, acoustic, or other forms of propagated signals (e.g., infrared signals, digital signals, etc.)), and so on.

[0077] In one embodiment, the computer system 1000 includes a system processor 1002, main memory 1004 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) (such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM)), static memory 1006 (e.g., flash memory, static random access memory (SRAM)), and secondary memory 1018 (e.g., a data storage device), which communicate with each other via a bus 1030.

[0078] System processor 1002 represents one or more general-purpose processing devices, such as microsystem processors, central processing units, or the like. More specifically, the system processor may be a complex instruction set computing (CISC) microsystem processor, a reduced instruction set computing (RISC) microsystem processor, a very long instruction word (VLIW) microsystem processor, a system processor implementing other instruction sets, or a system processor implementing a combination of instruction sets. System processor 1002 may also be one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal system processors (DSPs), network system processors, or the like. System processor 1002 is configured to execute processing logic 1026 to perform the operations described herein.

[0079] The computer system 1000 may further include a system network interface device 1008 for communicating with other devices or machines. The computer system 1000 may also include a video display unit 1010 (e.g., a liquid crystal display (LCD), a light emitting diode display (LED), or a cathode ray tube (CRT)), a digit input device 1012 (e.g., a keyboard), a cursor control device 1014 (e.g., a mouse), and a signal generation device 1016 (e.g., a speaker).

[0080] Secondary memory 1018 may include machine-accessible storage medium 1032 (or more specifically, computer-readable storage medium) storing one or more sets of instructions (e.g., software 1022) embodying any or more of the methods or functions described herein. Software 1022 may also reside wholly or at least partially within main memory 1004 and / or system processor 1002 during execution via computer system 1000, both of which also constitute machine-readable storage media. Software 1022 may be transmitted or received on network 1060 via system network interface device 1008. In embodiments, network interface device 1008 may operate using RF coupling, optical coupling, acoustic coupling, or inductive coupling.

[0081] Although the machine-accessible storage medium 1032 is shown as a single medium in the exemplary embodiment, the term "machine-readable storage medium" should be understood to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of instructions. The term "machine-readable storage medium" should also be understood to include any medium capable of storing or encoding a set of instructions for execution by a machine and causing the machine to perform any one or more methods. Therefore, the term "machine-readable storage medium" should be understood to include, but is not limited to, solid-state memory, as well as optical and magnetic media.

[0082] Specific exemplary embodiments have been described in the foregoing description. It is obvious that various modifications can be made thereto without departing from the scope of the following claims. Therefore, the description and drawings should be viewed in an illustrative rather than restrictive manner.

Claims

1. An apparatus comprising: A first plate, wherein a plurality of first holes pass through the thickness of the first plate; A second plate, situated above the first plate, wherein a plurality of second holes pass through the thickness of the second plate; and A spacer is located between the first plate and the second plate.

2. The device of claim 1, further comprising: An actuator coupled to the first plate, wherein the actuator is configured to displace the first plate along a plane substantially parallel to the top surface of the second plate.

3. The device of claim 1, further comprising: An actuator coupled to the first plate, wherein the actuator is configured to displace the first plate to change the gap between the first plate and the second plate.

4. The device of claim 3, wherein the actuator is part of the spacer.

5. The device of claim 1, wherein the first hole has a diameter equal to or greater than the thickness of the first plate.

6. The device of claim 1, wherein the first hole has a diameter of approximately 1.0 cm or greater.

7. The device of claim 1, wherein the first hole has a first diameter and the second hole has a second diameter substantially equal to the first diameter.

8. The device of claim 1, wherein the spacer is electrically insulating.

9. The device of claim 8, wherein the first plate is configured to be held at a first voltage, and wherein the second plate is configured to be held at a second voltage, the second voltage being different from the first voltage.

10. The device of claim 1, wherein the first plate and the second plate comprise one or more of alumina, aluminum nitride, or aluminum.

11. The device of claim 10, wherein the coating is disposed on the first plate and the second plate, and wherein the coating comprises nickel or yttrium oxide.

12. A method for plasma etching, the method comprising: Plasma is generated in a chamber, wherein the chamber includes an ion barrier system located between a cover and a substrate of the chamber; Orienting the ion barrier system to a first configuration to allow ions from the plasma to pass through the ion barrier system at a first flow rate and reach the substrate; and The ion blocking system is oriented to a second configuration to allow ions from the plasma to pass through the ion blocking system at a second flow rate and reach the substrate.

13. The method of claim 12, wherein the ion barrier system comprises: A first plate, wherein a plurality of first holes pass through the thickness of the first plate; and A second plate, which is positioned above the first plate, wherein a plurality of second holes pass through the thickness of the second plate.

14. The method of claim 13, wherein the first configuration includes aligning the plurality of first holes with the plurality of second holes to allow at least 75% overlap between the first holes and the second holes, and wherein the second configuration includes aligning the plurality of first holes with the plurality of second holes such that there is less than 75% overlap between the first holes and the second holes.

15. The method of claim 12, wherein the first flow rate of the ions is higher than the second flow rate of the ions.

16. The method of claim 12, wherein the plasma is generated by a microwave plasma source.

17. The method of claim 12, wherein the plasma etching is an operation in the formation of a three-dimensional (3D)-NAND element on the substrate.

18. A tool comprising: Chamber; A plasma source, the plasma source being coupled to the chamber; A base for supporting a substrate within the chamber; and An ion blocking system is provided between the base and the plasma source, wherein the ion blocking system comprises: A first plate, wherein a plurality of first holes pass through the thickness of the first plate; and A second plate, which is positioned above the first plate, wherein a plurality of second holes pass through the thickness of the second plate.

19. The tool of claim 18, wherein the plasma source comprises a microwave plasma source, an inductively coupled plasma (ICP) source, or a capacitively coupled plasma (CCP) source.

20. The tool of claim 18, wherein the first plate and the second plate are displaceable relative to each other.

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