Plasma processing system and method using radio frequency (RF) and microwave power

Abstract

In one embodiment, a plasma processing system comprises a vacuum system, a plasma processing chamber comprising a chamber cavity coupled to the vacuum system, a substrate holder comprising a surface disposed inside the chamber cavity, and a radio frequency (RF) source electrode coupled to an RF power source, wherein the RF source electrode is configured to ignite plasma in the chamber cavity. The system comprises a microwave source coupled to a microwave oscillator, and a conductive spatial uniformity component comprising a plurality of through-openings, wherein the conductive spatial uniformity component comprises a main surface electromagnetically coupled to the microwave source, and the main surface is configured to couple microwave power to the plasma in the chamber cavity.

Description

Technology Field

[0001] Cross-reference regarding related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 145,048 (filed February 3, 2021), which is incorporated herein by reference.

[0003] Technology field

[0004] The present invention generally relates to a system and method for a plasma process, and in a specific embodiment, to a system and method for plasma treatment of a semiconductor wafer using radio frequency (RF) and microwave power. Background Technology

[0005] Generally, semiconductor devices, such as integrated circuits (ICs), are manufactured by sequentially depositing and patterning layers of dielectric, conductive, and semiconductor materials on a substrate to form a network of electronic components and interconnect elements (e.g., transistors, resistors, capacitors, metal lines, contacts, and vias) integrated into a monolithic structure. A number of processing steps used to form the structural components of semiconductor devices are performed using plasma processing techniques, including sputtering, reactive ion etching (RIE), plasma-enhanced chemical vapor deposition (PECVD), and plasma-enhanced atomic layer etching (PEALE) and atomic layer deposition (PEALD).

[0006] At each successive technology node, the minimum feature size has shrunk, reducing costs by nearly doubling component packing density. Innovations in patterning techniques, such as immersion photolithography, multi-patterning, and 13.5 nm wavelength extreme ultraviolet (EUV) optical systems, have reduced the critical feature size to approximately 10 nanometers. Simultaneously, unconventional materials, such as organics, ferroelectrics, and chalcogenides, are being increasingly used in products. This scenario presents challenges for plasma technology in providing a platform for patterning features at the atomic scale, through precise sizing, fine placement, and tight control. Further innovation is required to address this challenge, along with the uniformity and repeatability requirements for mass IC fabrication.

[0007] A plasma processing system comprises a vacuum system; a plasma processing chamber comprising a chamber cavity coupled to the vacuum system and a substrate holder comprising a surface disposed inside the chamber cavity; and a radio frequency (RF) source electrode coupled to an RF power source, wherein the RF source electrode is configured to ignite plasma in the chamber cavity. The system comprises a microwave source coupled to a microwave oscillator and a conductive spatial uniformity component comprising a plurality of through-openings, wherein the conductive spatial uniformity component comprises a main surface electromagnetically coupled to the microwave source, and the main surface is configured to couple microwave power to the plasma in the chamber cavity.

[0008] A plasma processing system comprises: a plasma processing chamber; a radio frequency (RF) source electrode coupled to an RF power source and configured to ignite the plasma in the plasma processing chamber; a conductive spatial uniformity component coupled to the plasma by microwave power, comprising a plurality of through-openings and a main surface configured to couple the microwave power to the plasma in the plasma processing chamber; and a microwave power system comprising a microwave source coupled to a microwave oscillator; and a controller configured to execute commands to adjust the spatial uniformity metric of the electromagnetic (EM) power supplied to the plasma.

[0009] A method for plasma processing of a semiconductor wafer, the method comprises the steps of: loading a semiconductor wafer into a plasma processing chamber coupled to a radio frequency (RF) source electrode and a microwave power system comprising a conductive spatial uniformity component comprising a plurality of through-openings, wherein the conductive spatial uniformity component comprises a depth adjuster, a microwave oscillator, and a main surface coupled to a microwave source; igniting a plasma by coupling RF power from the RF source electrode to a gas in the plasma processing chamber; coupling microwave power from the microwave power system to the plasma ignited in the plasma processing chamber by coupling the microwave oscillator to the microwave source; and controlling coupled electromagnetic (EM) power supplied to the plasma by changing the uncharged depth of the plurality of through-openings by the depth adjuster component, wherein controlling the coupled EM power is adjusting the spatial uniformity metric of the EM power. Brief explanation of the drawing

[0010] For a more complete understanding of the present invention and the advantages of the present invention, we now refer to the following description together with the accompanying drawings. FIG. 1a is a cross-sectional view of an inductively coupled plasma (ICP) processing chamber having an electromagnetic (EM) metasurface in a substrate holder of an ICP chamber according to an embodiment; FIG. 1b is a perspective view of an EM metasurface according to an embodiment; FIG. 1c is a perspective view of an EM metasurface according to an embodiment; FIG. 2 is a cross-sectional view of an ICP processing chamber having an EM metasurface and a microwave waveguide in a substrate holder of an ICP chamber according to an embodiment; FIG. 3 is a cross-sectional view of a capacitively coupled plasma (CCP) processing chamber having an electromagnetic (EM) metasurface in a substrate holder of a capacitively coupled plasma (CCP) chamber according to an embodiment; FIG. 4 is a cross-sectional view of a CCP processing chamber having an EM metasurface and a microwave waveguide in a substrate holder of a CCP chamber according to an embodiment; FIG. 5 is a cross-sectional view of a CCP processing chamber having an EM metasurface below the upper electrode of the CCP chamber according to an embodiment; FIG. 6 is a cross-sectional view of a CCP processing chamber having a microwave waveguide on the top electrode and an EM metasurface below the top electrode of the CCP chamber, according to an embodiment; FIG. 7 is a cross-sectional view of an ICP processing chamber having a helical radio frequency (RF) coil on the side wall of the ICP chamber, a microwave waveguide on the top cover, and an EM metasurface under the top cover, according to an embodiment; and FIG. 8 is a flowchart illustrating a method for plasma treatment of a semiconductor wafer using RF power and microwave power according to an embodiment. Specific details for implementing the invention

[0011] The present disclosure describes embodiments of a plasma processing system and method for processing semiconductor wafers, wherein radio frequency (RF) power is supplemented by microwave power within the total electromagnetic (EM) power applied to ignite, sustain, and control the plasma in a plasma processing chamber. The spatial distribution of microwave power coupled to the plasma may differ from and be complementary to the spatial distribution of RF power coupled to the plasma. It is desirable to have a spatially uniform distribution of coupled EM power coupled to the plasma. In exemplary embodiments, while the plasma may be ignited and sustained using power from an RF power source, a microwave power system providing microwave power from a microwave source is used to adjust the spatial distribution of the total electromagnetic (EM) power supplied to the plasma. This adjustment may improve the spatial uniformity metric of the total EM power supplied to the plasma. By utilizing two independent sources of EM power, the system and method exemplified by the exemplary embodiments of the present disclosure provide the advantage of achieving a more uniform plasma, and thus the advantage of achieving spatially more uniform characteristics for the processed semiconductor wafer.

[0012] Adjustment of EM power distribution is performed outside the plasma processing chamber using a controller that controls the microwave power coupled to the plasma, as described in more detail below. Accordingly, the embodiment provides the advantage of having plasma control parameters that can be used to adjust the distribution of EM power. Specific control parameter values ​​may be selected for a specific plasma process recipe and / or a specific set of values ​​may be selected for a specific periodic or multi-stage plasma process recipe, for example, for multi-stage plasma etching. The control parameter values ​​may be selected by a process control system as part of feedback or feedforward control in a process flow for semiconductor device manufacturing.

[0013] In the embodiments described in this disclosure, a fixed surface EM wave in the microwave frequency band is activated at an EM metasurface positioned in close proximity to the plasma inside a processing chamber to couple microwave power from a microwave source to the plasma. Generally, the EM metasurface represents a repetitive two-dimensional (2D) array of patterns of conductors and insulators having subwavelength features. In the embodiments of this disclosure, the EM metasurface is a conductor comprising a plurality of through-openings, referred to as a conductive spatial uniformity component. Incident EM radiation at the resonant frequency or near-resonant frequency of the repetitive unit of the 2D array can activate the surface EM wave. The repetitive unit pattern may be through-openings having various shapes in various embodiments, as described in more detail below. One example of an EM metasurface is a conductive spatial uniformity component having a wavy metal surface, which is an array of trench-shaped openings etched into a metal layer. When the quarter wavelength of the colliding EM radiation is significantly close to the depth of the groove, EM activation is observed propagating along the metal to the dielectric interface in a direction perpendicular to the groove. This surface EM activation is sometimes referred to as camouflage surface plasmon polaritons.

[0014] Surface plasmon polaritons (SPPs) are EM surface waves at the interface between a dielectric and a conductor activated through the coupling of an EM field to an electron plasma of a metal using a suitably designed coupler. Surface electromagnetic field oscillations on the dielectric side and plasma oscillations of free electrons on the metal side are localized and propagated at the interface with a minute electric field having a subwavelength decay length perpendicular to the direction of the wave. Typically, at lower frequencies (e.g., 10 13 At frequencies below Hz, most metals behave as ideal conductors, so the vibration frequency of the SPP is high (e.g., 1014 Hz to 10 15 Hz), this means that the frequency-dependent composite dielectric constant has a real part equal to zero. Nevertheless, in the microwave range (e.g., 10 9 Hz to 10 11 Artificial SPP modes at Hz have been demonstrated using EM metasurfaces that mimic the localization and dispersion characteristics of natural SPPs; thus, they are referred to as camouflage surface plasmon polaritons (SSPPs).

[0015] In the embodiments described in this disclosure, the microwave power system comprises a microwave source coupled to a microwave oscillator and a conductive spatial uniformity component having a main surface. The main surface is configured to receive microwave power from the microwave source and to couple the microwave power to the plasma. Surface EM activation similar to the SSPP activation described above is generated between two conductive zones: a conductive spatial uniformity component and a conductive charge-neutral zone of the plasma with high electron density. The dielectric between these two conductors includes a plasma sheath, which is a peripheral space-charge zone of the localized plasma where moving electrons are depleted. As mentioned above and described in more detail below, the EM metasurface has a main surface comprising a unit pattern repeated in a 2D array. In various embodiments, the main surface may have various patterns and arrangements. However, the main surface of this disclosure has one common feature. The main surface comprises an array of hollow through-openings extending through the conductive matrix of the conductive spatial uniformity component.

[0016] The depth dimension of the through-opening that affects the resonance frequency can be selected using a depth adjuster included in an embodiment of the plasma processing system and positioned in close proximity to the EM metasurface. As described in more detail below, a conductive protrusion from the depth adjuster extends to one end of each through-opening to partially fill the hollow opening. The length of the unfilled portion of the opening from the opposite end is a depth dimension (referred to as the unfilled depth). d It is. Uncharged depth ( d ) is set by moving the position of the tip of the protrusion inside the opening using the mechanical system of the depth adjuster. It is understood that the mechanical system may include electrical components, such as a precision motor, an electromagnet, and an electronic control network, configured to receive command instructions from a controller located outside the plasma processing chamber.

[0017] As explained above, ( d Adjusting ) adjusts the resonant frequency of the unit pattern of the main surface. Changing the resonant frequency changes the coupling between the microwave source and the main surface. As further explained below, this provides the plasma processing system with the advantage of controlling spatial distribution; thus, by adjusting the spatial uniformity metric of EM power, a more spatially uniform distribution of EM power coupled to the plasma is achieved.

[0018] FIG. 1a illustrates an exemplary embodiment of a plasma processing system (100) comprising a plasma processing chamber (150) comprising a substrate holder (112). In FIG. 1a, the plasma processing chamber (150) is an inductively coupled plasma (ICP) processing chamber illustrated in a cross-sectional view. An RF source electrode (108) having the shape of a flat coil disposed on a top cover comprising a dielectric window (126) is an RF source that provides RF power to ignite and sustain the plasma (106). The dielectric window (126) may comprise, for example, ceramic, such as quartz.

[0019] The microwave source of the plasma processing system (100) is a microwave antenna (110) shown as being placed on the side wall (124) of the plasma processing chamber (150). In this exemplary embodiment, the side wall (124) may comprise a conductive material, for example, aluminum or stainless steel coated with yttria. The microwave antenna (110) is coupled to a microwave oscillator (190) and configured to emit EM waves inside the plasma processing chamber (150) in the microwave range. The radiation emitted from the antenna has the same frequency as the output signal of the microwave oscillator (190) coupled to the antenna (110). f It will have ). The microwave frequency suitable for plasma treatment may be about 1 GHz to about 100 GHz in various embodiments and 2.45 GHz in one embodiment.

[0020] As illustrated in FIG. 1a, a semiconductor wafer (120) exposed to the internal environment of the chamber cavity (102) is loaded onto a substrate holder (112). The substrate holder (112) is generally an electrostatic chuck comprising a conductive pedestal, e.g., a conductive pedestal (118). A conductive spatial uniformity component (134) having a main surface (130) (a surface facing the chamber cavity (102)) is attached to the upper portion of the pedestal (118). The main surface (130) is electromagnetically coupled to the antenna (110) so that a portion of the emitted microwave power is received by the main surface (130) to activate EM surface waves or SSPP. The main surface (130) includes a pattern of hollow openings extending through a conductive matrix, as described in more detail below with reference to FIG. 1b and FIG. 1c.

[0021] The depth adjuster (114) is coupled to the lower side (the side opposite the main surface (130)) of the conductive spatial uniformity component (134). The coupling is made using a protrusion (132) supported by a conductive plate of the depth adjuster (114) that aligns with the patterned main surface (130) of the conductive spatial uniformity component (134), so that the conductive protrusion is aligned perpendicularly with the through opening. The protrusion (132) also contains a conductive material. The conductive plate may be supported by a vertical column of the depth adjuster (114) located opposite or adjacent to the conductive protrusion. A vertical column is shown that passes through the central section of the pedestal (118) and terminates at a surface connected to the back side (the side opposite the front) of the conductive plate.

[0022] The opposing end of the vertical column can be joined to a component of the mechanical system (170), schematically illustrated in FIG. 1a. The mechanical system (170) has a specific depth dimension ( dTo achieve ), it may include a moving part and an actuator configured to move the conductive protrusion (132) inside the hollow opening of the main surface (130). The actuator may be, for example, an electric component, such as an electric motor and an electromagnet. Adjustment of the position of the conductive protrusion (132) may be achieved in various ways in various embodiments. For example, the tip of the conductive protrusion (132) may be raised or lowered by raising or lowering the depth adjuster plate and vertical column supporting the conductive protrusion (132). In some embodiments, the movement may be electrically actuated using, for example, an electric motor. In some other embodiments, a pneumatic actuator may be used. There may also be an additional moving part along the conductive depth adjuster plate and vertical column that mechanically transmits force from the actuator of the mechanical system (170) to the conductive protrusion (132). It may even be possible to place an actuator (e.g., a magnet and an electromagnet) adjacent to a conductive protrusion (132) that can be triggered remotely or wirelessly by an electrical signal. By receiving a command instruction from the controller (180) that commands the mechanical system (170) to the mechanical system, the tip of the conductive protrusion (132) is precisely positioned so that in various embodiments, there is a step of about 0.1 mm to about 5 mm ( d It may be configured to adjust the spatial uniformity metric of the electromagnetic (EM) power supplied to the plasma. The controller (180) may be configured to execute a command to adjust the spatial uniformity metric of the electromagnetic (EM) power supplied to the plasma. By executing the command, the controller (180) generates a command instruction according to the information provided in the plasma process recipe and, in some embodiments, may include additional information, such as feedback from a sensor used to monitor the characteristics of the plasma or feedforward information obtained from a previously executed process step.

[0023] The pedestal (118) serves as a conductive base to which an EM metasurface, comprising an array of through-openings, can be attached to the main surface (130). However, it should be noted that the conductive pedestal (118) may additionally be configured to function as an RF bias electrode, a DC bias electrode, a ground connection, or a combination of a DC bias electrode and an RF bias electrode. The conductor of the conductive spatial uniformity component (134), comprising the main surface (130), the depth adjuster (114), and the conductive pedestal (118), may include a metal, such as copper, aluminum, brass, and tungsten.

[0024] In an exemplary embodiment illustrated in FIG. 1a, the EM metasurface comprises a conductive spatial uniformity component (134), and the main surface (130) of the EM metasurface comprises an array of through-openings extending through the conductor of the conductive spatial uniformity component (134). To facilitate achieving spatially more uniform process characteristics for a semiconductor wafer (120), the main surface of the wafer (120) that may be exposed to plasma and the main surface of the EM metasurface, e.g., the main surface (130), are oriented parallel to each other, and the main surface (130) is located opposite the plasma sheath of the plasma (106). Openings of various shapes are possible: some exemplary patterns are described in more detail below with reference to FIG. 1b and FIG. 1c. The opening may be filled with an insulating gas (e.g., air or nitrogen) that can be insulated from the environment within the chamber cavity (102) by a separator (122) comprising a solid dielectric layer covering the main surface (130) of the conductive spatial uniformity component (134), the opening being hollow. This causes the insulating gas within the opening to be at a pressure (e.g., atmospheric pressure) much higher than the pressure in the chamber cavity (102), thereby helping to prevent the occurrence of incidental arcs, as in low-pressure gas exposed to a high electric field. Suitable materials for the separator (122) include quartz, alumina, and glass. The sides of the pedestal (118) are covered by any dielectric structure (116).

[0025] FIGS. 1B and FIGS. 1C illustrate perspective views of two exemplary conductive spatial uniformity components (134A and 134B) that can be used as EM metasurfaces in the plasma processing system (100) illustrated in FIG. 1A. FIG. 1B additionally illustrates a depth adjuster (114) and a separator (122) in an exploded view. Either of the main surface (130A) ( FIG. 1B) and the main surface (130B) ( FIG. 1C) may be the main surface (130) of the EM metasurface illustrated in FIG. 1A.

[0026] In FIG. 1b, the main surface (130A) comprises a spatial pattern formed by conductive lines spaced apart by a gas insulator and an array of long, narrow parallel lines. Although referred to as surface waves, the oscillating electromagnetic field of SSPP activation exists in the dielectric zone of the main surface (130A / 130B) as well as in the dielectric zone between the main surface (130A / 130B) and the plasma (106) (exemplified in FIG. 1a). Thus, the main surfaces (130A and 130B) include conductive sidewalls of hollow openings in addition to conductive surfaces covered by separators (122) on the sides facing the chamber cavity (102) (see FIG. 1a). Each hollow trench of the main surface (130A) has a nearly vertical conductive sidewall and is terminated at the bottom by a nearly flat conductive tip of one of the protrusions (132) on the front of the conductive plate of the depth adjuster (114). A portion of the conductive protrusion (132) extending into the hollow trench partially fills the through opening, leaving the remaining portion of the trench unfilled to a depth ( d All trenches of the array are filled with gas up to ) by using a mechanical system configured to slide the protrusion (132) along the side wall of the through opening, thereby placing the tip of the protrusion (132) inside the hollow opening, so that they are nearly identical ( d It can be terminated at ). The mechanical system receives a command from the controller and at the uncharged depth ( d It can be configured to adjust ). Using a mechanical system, the controller from outside the plasma processing chamber ( d ) can be adjusted to a desired value. The exploded view illustrated in FIG. 1b shows a separator (122) on the main surface (130A). The separator (122) is a solid dielectric layer used to cover the main surface (130) in FIG. 1a.

[0027] The main surface (130B) illustrated in FIG. 1c comprises a rectangular array of through holes of a prismatic shape extending through a conductor. The conductive sides of the prismatic holes are nearly vertical. Similar to the main surface (130A), the main surface (130B) also comprises conductive sidewalls of hollow prismatics in addition to the conductive surfaces between the prismatics on the sides facing the chamber cavity (102). As described above for the main surface (130A), each of the holes in the main surface (130B) will be partially filled by each conductive protrusion protruding from the conductive plate of each depth adjuster, e.g., the depth adjuster (114). The unfilled portion will be terminated at the bottom by the tip of the protrusion (132). The unfilled depth of the through opening within the main surface (130B) ( d ) is within the main surface (130A) ( d Similar to the mechanical system described above for adjusting ), it can be adjusted by a mechanical system using a controller. In the example illustrated in FIG. 1c, the through opening has a shape such as a square prism. However, it is understood that a prism with other shapes, such as a cylinder and a pyramid, may be used. In various embodiments, the through opening may be tapered instead of having a prism shape, and the sides may be curved instead of flat sides with edges.

[0028] The feature size of the patterned main surfaces (130A and 130B) of the conductive spatial uniformity components (134A and 134B) exemplified in FIG. 1b and 1c determines the resonance mode for the structure. As mentioned above, EM radiation incident at the resonance frequency can activate the respective SSPP modes on the main surface of the EM metasurface. As indicated by the wavy symbol with an arrow in FIG. 1b, microwave radiation can be coupled to the conductive spatial uniformity component (134A) at the edge of the main surface (130A). The SSPP mode activated by this can propagate microwave power from the edge of the main surface (130A) toward the central region. One condition for resonance for the main surfaces (130A and 130B) is that the aperture is at a depth substantially close to λ / 4 ( d It means that it has ), and λ is the wavelength of the incident EM radiation. d The condition = λ / 4 applies to the microwave frequency range mentioned above, 1 GHz < f For < 100 GHz, the depth of the openings on the main surfaces (130A and 130B) is 7.5 cm < d It implies that it should be in the range of < 0.75 mm. Generally, the size of various features on the main surface of the conductive spatial uniformity component used in various embodiments of the plasma processing system described in this disclosure may be nominally about 1 mm to about 10 cm. Nominal depth ( d The depth adjuster (114) can be adjusted to a small step by a controller that controls the mechanical system of the depth adjuster (114). The step size can be about 0.1 mm to about 5 mm.

[0029] FIG. 2 illustrates a cross-sectional view of another plasma processing system (200) that uses both RF power and microwave power to process a semiconductor wafer (120) in a plasma processing chamber (150) composed of an ICP chamber. Similar to the plasma processing system (100) described above with reference to FIG. 1a, an RF source electrode (108) is placed over a dielectric window (126).

[0030] Also, similar to the plasma processing system (100), the EM metasurface of the plasma processing system (200) is attached to a substrate holder (112) and has an adjustable depth (214) that is adjusted by a depth adjuster (214). d It has a main surface (130) including a through opening. The opening of the main surface (130) is insulated from the environment within the chamber cavity (102) by a separator (122). Similar to the plasma processing system (100), the substrate holder (112) of the plasma processing system (200) includes a conductive pedestal (118). A vertical column supports the conductive plate of the depth adjuster (214) in the central area, and the sides of the pedestal (118) are covered by any dielectric structure (116). As described below with reference to FIG. 2, the vertical column functions as a microwave source that generates surface EM activation on the main surface (130).

[0031] In a plasma processing system (200), instead of using a microwave antenna, a microwave waveguide (210) may be used as a microwave source. Similar to a transmission line, the waveguide is used for point-to-point transmission of EM power. In the plasma processing system (200) illustrated in FIG. 2, the microwave waveguide (210), shown passing through the conductive pedestal (118) of the substrate holder (112), may be used to couple microwave power from a microwave oscillator to the main surface (130) of the EM metasurface.

[0032] In various embodiments of the plasma processing system described in the present disclosure, the depth adjuster comprises a conductive plate having a side having a conductive protrusion (132) extending into a through opening of the main surface (130), and the conductive plate is connected to a vertical column located opposite or adjacent to the conductive protrusion. The vertical column may include a conductive outer wall connected to the conductive plate on one end and a mechanical system (170) on the opposite end. The mechanical system (170) moves the protrusion along each side wall of the opening to achieve an unfilled depth of a target value ( d It can be configured to adjust to the target value ( d ) can be selected by a controller (180) that transmits command commands from outside the plasma processing chamber to operate the mechanical system (170) of the depth adjuster (e.g., the depth adjuster (114) of FIG. 1a and the depth adjuster (214) of FIG. 2).

[0033] The depth adjuster (214) of the plasma processing system (200) is similar to the depth adjuster (114), except that the vertical column connected to the conductive plate by a protrusion is twice the size of the microwave waveguide (210) as illustrated in FIG. 2. The waveguide (210) includes a conductive outer wall (204) surrounding the waveguide dielectric (202). The waveguide (210) may have a pipe-like shape with a rectangular cross-section. In this embodiment, the conductive plate of the depth adjuster (214) has an opening in the central region aligned with the end surface of the vertical column. As illustrated in FIG. 2, the hole in the conductive plate exposes a portion of the conductive spatial uniformity component (134) at the end of the waveguide, thereby allowing microwave power to be transmitted to the exposed EM metasurface by activating surface EM waves on the main surface (130) of the waveguide (210). Microwave power coupled from the waveguide (210) to the main surface (130) can be propagated toward the edge of the main surface (130) through an activated SSPP mode. The conductive outer wall (204) is connected to the side of a conductive plate opposite to or adjacent to the protrusion, as illustrated in the cross-sectional view of FIG. 2. The conductive outer wall (204) may comprise, for example, copper, and the waveguide dielectric (202) may comprise a gas (e.g., air). However, as is known to those skilled in the art, in various embodiments, the outer wall (204) may comprise other metals, such as copper-plated steel, aluminum, silver, or brass, and the waveguide dielectric (202) may comprise nitrogen gas or a solid dielectric, such as glass, silicon, or quartz. In some embodiments, the microwave waveguide may have a shape such as a cylindrical pipe.

[0034] As described above, a microwave waveguide (210), which is twice the size of the vertical column supporting the conductive plate of the depth adjuster (214), can be coupled to the moving part of the mechanical system (170). The mechanical system (170), controlled by the controller (180), moves the conductive protrusion of the depth adjuster (214) to a specific depth ( d ) can be achieved.

[0035] FIG. 3 illustrates an embodiment of a plasma processing system (300) similar to a plasma processing system (100) (exemplified in FIG. 1a), wherein a microwave source is a microwave antenna (110), a substrate holder (112) includes a conductive pedestal (118), a conductive spatial uniformity component (134) has a main surface (130) including a hollow opening attached to the upper portion of the pedestal (118), and a depth adjuster (114) includes a horizontal conductive plate having a protrusion extending vertically into the opening and a vertical column passing through the central portion of the pedestal (118). Unlike the plasma processing system (100), the plasma processing chamber (150) of the plasma processing system (300) is configured as a capacitive coupled plasma (CCP) chamber. Generally, in a CCP configuration, an RF source electrode has a substantially flat conductive surface (similar to the plate of a parallel plate capacitor) and is placed in the plasma processing chamber (150).

[0036] As illustrated in FIG. 3, the plasma processing system (300) includes a top electrode shaped like a conductive plate, referred to as a CCP electrode (302). A central portion of the CCP electrode (302) may extend through an opening in the top cover (304) of the plasma processing chamber (150). The opening may be part of a showerhead assembly used to flow gas into the chamber cavity (102). Gas may also be introduced into the chamber cavity (102) through a gas inlet in the sidewall (124). In some embodiments, the CCP electrode (302) may be an RF source electrode, and the conductive pedestal (118) may be configured as a bottom electrode configured to function as an RF bias electrode, a DC bias electrode or a ground connection, or a combination of a DC bias electrode and an RF bias electrode. In some other embodiments, the functions of the two electrodes may be reversed, and the CCP electrode (302) may be configured to function as an RF bias electrode, a DC bias electrode or a ground connection, or a combination of a DC bias electrode and an RF bias electrode, while the conductive pedestal (118) may be configured as an RF source electrode.

[0037] As mentioned above, the microwave source of the plasma processing system (300) is a microwave antenna (110) placed on the side wall (124) of the plasma processing chamber (150). Microwave radiation emitted from the microwave antenna (110) can be electromagnetically coupled to the EM metasurface at the edge of the main surface (130). As described above, microwave radiation at the resonant frequency or near resonant frequency of the EM metasurface can activate each SSPP mode, which allows microwave power to propagate from the edge of the main surface (130) toward the central zone.

[0038] The mechanical system (170) and controller (180) of the plasma treatment system (300) use a depth adjuster (114) to control the depth of the main surface (130), similar to the plasma treatment system (100). d ) can be adjusted.

[0039] FIG. 4 illustrates a cross-sectional view of an exemplary plasma processing system (400) that uses both RF power and microwave power to process a semiconductor wafer (120), wherein the microwave source is similar to the microwave source of the plasma processing system (200) (see FIG. 2) and the RF source is similar to the RF source of the plasma processing system (300) (see FIG. 3). Thus, microwave power to activate the SSPP mode on the main surface (130) is delivered by a microwave waveguide (210) (described above with reference to FIG. 2), and either the CCP electrode (302) or the conductive pedestal (118) (configured as the bottom electrode) can be configured as the RF source electrode, and the plasma processing chamber (150) is configured as a CCP chamber (described above with reference to FIG. 3). Similar to the plasma processing system (200), the main surface (130) of the EM metasurface and the depth adjuster (214) of the plasma processing system (400) are positioned in a substrate holder (112) as illustrated in FIG. 4. The waveguide (210) couples microwave power to the main surface (130) through the central opening of the conductive plate of the depth adjuster (214). Depth adjustment can be achieved by positioning the conductive protrusion (132) of the conductive plate using a controller (180) and a mechanical system (170) that control the operation of the mechanical system.

[0040] FIG. 5 illustrates a cross-sectional view of a plasma processing system (500) in which a plasma processing chamber (150) is configured as a CCP chamber, and a conductive spatial uniformity component (134) having a main surface (130) is attached to the lower side of a CCP electrode (302). In the plasma processing system (500), a microwave power source includes an antenna (110) coupled to a microwave oscillator (190).

[0041] As in other embodiments of the plasma processing system described in the present disclosure, the main surface (130) of the conductive spatial uniformity component (134) of the plasma processing system (500) includes an opening extending through a conductor. In the exemplary embodiment illustrated in FIG. 5, the main surface (130) faces a substrate holder (112). As illustrated in FIG. 5, the conductive spatial uniformity component (134) is coupled to a depth adjuster (114). The protrusion (132) of the depth adjuster (114) can be moved by a mechanical system (170) controlled by a controller (180).

[0042] The depth adjuster (114) of the plasma processing system (500) and the depth adjuster (114) of the plasma processing system (300) (described with reference to FIG. 3) are similar. However, because the main surface (130) of the plasma processing system (500) faces downward toward the chamber cavity (102) and the substrate holder (112), the orientation of the depth adjuster (114) of FIG. 5 is reversed compared to the orientation of the depth adjuster (114) of FIG. 3. As illustrated in FIG. 5, a protrusion (132) on one side of the conductive plate extends downward (instead of upward) into a through opening of the main surface (130), and a vertical column connected to the side of the conductive plate opposite to or adjacent to the side with the protrusion (132) leads upward through the central area of ​​the CCP electrode (302) (instead of downward through the pedestal (118)). The depth adjuster (114) includes a mechanical system (170) configured to receive a command from a controller (180) and move a protrusion (132) along the side wall of a through opening. By positioning the tip of the protrusion inside each opening, the mechanical system [adjusts] the unfilled depth of the through opening ( d Adjusts ). As explained above, ( d Changing ) changes the resonance frequency of the unit pattern of the main surface (130) of the EM metasurface.

[0043] As illustrated in FIG. 5, the main surface (130) of the conductive spatial uniformity component (134) of the plasma processing system (500) is insulated from the environment within the chamber cavity (102) by a separator (510). The separator (510) is depicted as extending across the chamber like a second ceiling, leaving a small space between the separator (510) and the top cover (304). Fixing the separator (510) to the side wall (124) provides the advantage of greater mechanical stability. However, in some other embodiments, the lateral length of the separator (510) may be small, leaving a gap between the separator (510) and the side wall (124). It is understood that the separator (510) may have various shapes in various embodiments.

[0044] Note that for the plasma processing system (500), the substrate holder (112) does not include any part of the microwave power system (unlike the substrate holder (112) of the plasma processing systems (100, 200, 300 and 400). Accordingly, in some embodiments, as with the plasma processing system (500), the semiconductor wafer (120) may be placed on the top surface of the conductive pedestal (119). However, as is known to those skilled in the art, in some embodiments, the substrate holder (112) may be an electrostatic chuck including a dielectric top surface on the conductive pedestal (119). Similar to the conductive pedestal (118), the conductive pedestal (119) may also be configured to function as an RF bias electrode, a DC bias electrode or a ground connection, or a combination of a DC bias electrode and an RF bias electrode.

[0045] FIG. 6 illustrates another exemplary plasma processing system (600), similar to the plasma processing system (500), in which a conductive spatial uniformity component (134) is attached to the side of a CCP electrode (302) over the plasma (106) in a plasma processing chamber (150) configured as a CCP chamber. As illustrated in the cross-sectional view of FIG. 6, the plasma processing system (600) and the plasma processing system (500) are similar except for their respective microwave sources used to activate the SSPP mode on the main surface (130) of the EM metasurface. In the plasma processing system (600), a microwave waveguide (210) is used to deliver microwave power to the central part of the main surface (130) exposed to the waveguide (210) through an opening in the conductive plate of the depth adjuster (214). The vertical column of the depth adjuster (214) passing through the central area of ​​the CCP electrode (302) is the waveguide (210).

[0046] Similar to other embodiments of the plasma processing system described above, the resonant frequency of the unit pattern of the through-opening of the main surface (130) of the plasma processing system (600) is adjusted by a controller using the mechanical system of the depth adjuster (214) to slide a conductive protrusion along the side wall of the opening to achieve a target unfilled depth of the opening ( d Note that in the plasma processing system (600), a microwave source (waveguide (210)), an EM metasurface with a main surface (main surface (130)), and a depth adjuster (depth adjuster (214)) are placed over the plasma (106) and substrate holder (112) of the plasma processing chamber (150).

[0047] FIG. 7 illustrates a cross-sectional view of a plasma processing system (700). The plasma processing system (700) is another exemplary embodiment in which, similar to the plasma processing system (600), a microwave source, an EM metasurface, and a depth adjuster are positioned over the plasma (106) and substrate holder (112) of the plasma processing chamber (150).

[0048] In the plasma processing system (700), the above-mentioned component of the microwave power system is in the plasma processing chamber (150) configured as an ICP chamber, and the RF source electrode (710) is an RF coil in the shape of a spiral extending around the outer side wall (720) of the plasma processing chamber (150). The side wall (720) includes a dielectric window adjacent to the RF source electrode (710) so that RF power is coupled to the gas in the chamber cavity (102) to ignite and maintain the plasma (106). Similar to the plasma processing systems (500 and 600), the substrate holder (112) of the plasma processing system (700) includes a conductive pedestal (119) as described above with reference to FIGS. 5 and 6.

[0049] As illustrated in FIG. 7, the waveguide (210) is twice the vertical column of the depth adjuster (214). The conductive outer wall (204) of the vertical column (which is also the waveguide (210)) is connected to the side opposite the side having the conductive protrusion (132) or to the side of an adjacent conductive plate, as illustrated in FIG. 7, and is similar to the depth adjuster (214) of FIG. 6. However, unlike FIG. 6, in FIG. 7, the conductive spatial uniformity component (134) having the main surface (130) is attached to the side of the top cover (702) of the plasma processing chamber (150) opposite the substrate holder (112). Accordingly, similar to the plasma processing system (600) illustrated in FIG. 6, in the plasma processing system (700) illustrated in FIG. 7, the main surface (130) of the conductive spatial uniformity component (134) faces the chamber cavity (102) and the substrate holder (112). A vertical column (and waveguide (210)) passes through the central area of ​​the top cover (702). Similar to the depth adjuster (214) of the plasma processing system (600), the depth adjuster (214) of the plasma processing system (700) is the depth of the hollow opening of the main surface (130). d It includes a mechanical system (170) used to adjust the depth. The mechanical system (170) may be configured to receive command instructions from a controller (180) to achieve a specific depth adjustment with precision.

[0050] FIG. 8 is a flowchart illustrating a method (800) for processing a semiconductor wafer by performing a plasma process using a plasma processing system such as an exemplary embodiment of the plasma processing system (100, 200, 300, 400, 500, 600, and 700) described above with reference to FIG. 1a through 7. In this plasma processing system, microwave power supplements RF power to provide some of the advantages mentioned above, such as the advantage of achieving a spatially more uniform plasma, and thus, the advantage of achieving spatially more uniform characteristics for the processed semiconductor wafer. A method (800) for plasma processing is described below with reference to FIG. 1a through 8.

[0051] As indicated by the box (810) in FIG. 8, a semiconductor wafer (120) can be loaded onto a substrate holder (112) in the chamber cavity (102) of a plasma processing chamber (150). An RF power source can be coupled to an RF source electrode to provide RF power to the plasma processing chamber (150) using a suitable configuration. For example, in an ICP configuration (Fig. 1a, FIG. 2 and FIG. 7), an RF coil can be used as the RF source electrode, whereas in a CCP configuration (Fig. 3 to FIG. 6), a CCP electrode (302) or a bottom electrode (pedestal (118 and 119)) can be used as the RF source electrode. A gas mixture of process gas and carrier gas can flow through the chamber cavity (102) at a specific flow rate, and the gas mixture can be maintained at a low pressure, for example, controlled by a vacuum system coupled to the chamber cavity (102). As shown in the box (820) of FIG. 8, RF power from the RF source electrode is coupled to the gas mixture to ignite and maintain the plasma (106) in the chamber cavity (102).

[0052] As shown in the box (830) of FIG. 8, in addition to RF power, microwave power can be coupled to the plasma (106).

[0053] In a plasma processing system (100, 300 and 500), a microwave antenna (110) placed on the side wall (124) of a plasma processing chamber (150) may be a microwave source when coupled to a microwave oscillator (190). Coupled to the microwave antenna (110) can emit microwaves into the chamber cavity (102). The emitted microwave power can be electromagnetically coupled to the main surface (130) of the EM metasurface and propagate from near the edge of the main surface (130) toward the center.

[0054] In plasma processing systems (200, 400, 600 and 700), a microwave waveguide (210) coupled to a microwave oscillator is a microwave source that transmits microwave power to a conductive spatial uniformity component (134) (EM metasurface). The waveguide (210) is twice the vertical column of a depth adjuster (214) connected to a conductive plate, where a conductive protrusion (132) protrudes into a hollow opening in the main surface (130) of the conductive spatial uniformity component (134). When the waveguide (210) is coupled to the microwave oscillator, microwave power is transmitted through the waveguide (210). The waveguide (210) terminates at a surface connected to the back surface of the conductive plate of the depth adjuster (214). Microwave power through the waveguide can be coupled to the central area of ​​the main surface (130) through the opening in the central area of ​​the conductive plate of the depth adjuster (214). Microwave power from the waveguide (210) can activate EM surface waves on the main surface (130) and propagate microwave power from the central area toward the edge of the main surface (130).

[0055] The frequency of the microwave oscillator can be selected to be the resonant frequency of a repeating unit pattern on the main surface (130) of the conductive spatial uniformity component (134) of each plasma processing system, or to be the near-resonant frequency. As described above, microwave radiation at the resonant frequency or near-resonant frequency of a repeating pattern on the main surface can activate the SSPP mode on the main surface. Surface microwave SSPP activation generates a minute electric field within the plasma sheath. Thus, activating the surface EM wave using microwave power received from the antenna (110) or waveguide (210) involves coupling microwave power from the microwave source to the plasma (106).

[0056] The spatial distribution of RF power and microwave power can be complementary. A plasma powered by EM radiation at a higher microwave frequency (e.g., 2.45 GHz) can generate a high-density plasma having a different radial distribution than a plasma maintained from much lower RF frequencies (e.g., 13.56 Hz and 27.15 Hz). For example, without a microwave source, the plasma power density may be higher near the edge of the semiconductor wafer (120) compared to the center, indicating that there is stronger coupling of RF power to the plasma closer to the edge. Microwave power may be more strongly coupled closer to the center region; thus, a more uniform plasma power density can be achieved by supplementing microwave power. Furthermore, the spatial distribution depends on various other plasma process parameters, such as chamber pressure and plasma species. For this reason, it is advantageous to adjust the spatial distribution of EM power to improve process uniformity and process control.

[0057] As described below with reference to box (840), the spatial distribution of the coupled EM power coupled to the plasma (106) can be controlled by using method (800). In the plasma processing system described above, a command instruction is transmitted from a controller (180) outside the chamber cavity (102) to a mechanical system (170) of a depth adjuster (e.g., depth adjuster (114) and depth adjuster (214)) to an uncharged depth (as described above). d By adjusting ), the resonance frequency of the unit pattern of the main surface (130) can be adjusted. As described above, this adjustment can be utilized to adjust the spatial uniformity metric of the EM power supplied to the plasma, for example, the spatially localized magnitude of the EM power supplying the plasma.

[0058] The microwave power delivered to the plasma processing chamber (150) may be less than the RF power delivered by the RF source electrode. In various embodiments, the microwave power may be 10% to 50% of the combined EM power supplied to the RF source electrode and the microwave source. If the microwave power is too small, to the extent of a fraction of the total EM power, it may not be effective in adjusting the spatial distribution of the total EM power combined in the plasma (106). Meanwhile, regarding the fixed total EM power specified for plasma processing, if the microwave power is the primary source of EM power, each RF power may be insufficient to ignite and sustain the plasma (106), whereas in the embodiments described in this disclosure, this is the RF power used to ignite and sustain the plasma (106).

[0059] As indicated by the box (840) in FIG. 8, microwave power can be used to adjust the distribution of coupled EM power supplied to the plasma (106). The microwave power coupled to SSPP activation depends on the frequency of the EM radiation striking the main surface of the EM metasurface. The coupling will be strongest when the resonant frequency of the unit pattern of the main surface (130) matches the frequency of the microwave radiation. The coupling of microwave power to the EM metasurface decreases rapidly as the frequency mismatch between the frequency of the microwave source and the resonant frequency increases. Furthermore, the attenuation of activation by distance depends on the frequency mismatch. Therefore, adjusting the distribution of EM power may involve adjusting the resonant frequency of the unit pattern of the main surface (130). As described above, the resonant frequency is adjusted using a depth adjuster (e.g., depth adjuster (114) and depth adjuster (214)) to adjust the depth of the opening of the main surface (130). d It can be adjusted by adjusting ).

[0060] depth( d ) can be selected using a depth adjuster according to a command received from a controller (180) for a mechanical system (170) of a depth adjuster (e.g., depth adjuster (114) and depth adjuster (214)) in a plasma processing system (100, 200, 300, 400, 500, 600 and 700). The controller (180) executes a command, for example, a command coded in a process recipe that instructs the controller (180) to transmit a command to the mechanical system (170) of the depth adjuster (e.g., depth adjuster (114) and depth adjuster (214)), thereby selecting the target depth of the opening ( d It can be configured to adjust the distribution of EM power supplied to the plasma by selecting ).

[0061] The embodiments of the plasma processing system described in the present disclosure provide the advantage of achieving a more uniform plasma and having plasma control parameters that can be used to adjust the distribution of EM power.

[0062] Exemplary embodiments discussed in this application are summarized herein. Other embodiments may also be understood from the entire scope of the claims as well as the specification submitted herein.

[0063] Example 1. A plasma processing system comprising: a vacuum system; a plasma processing chamber comprising a chamber cavity (e.g., 102) coupled to the vacuum system and a substrate holder (e.g., 112) comprising a surface disposed inside the chamber cavity; a radio frequency (RF) source electrode (e.g., 108) coupled to an RF power source and configured to ignite a plasma in the chamber cavity; a microwave source (e.g., 110) coupled to a microwave oscillator (e.g., 190); and a conductive spatial uniformity component (e.g., 134) comprising a plurality of through-openings and a main surface (e.g., 130, 230, 430, or 530) electromagnetically coupled to the microwave source and configured to couple microwave power to the plasma in the chamber cavity.

[0064] Example 2. A system in Example 1, wherein the main surface is sealed from the chamber cavity by a separator (e.g., 122) comprising a solid dielectric covering the main surface.

[0065] Example 3. The system of Example 1 or Example 2, further comprising a plurality of conductive protrusions configured to move relative to a conductive spatial uniformity component such that the depth distance from the main surface to the conductive protrusion within a plurality of through-openings is adjustable.

[0066] Example 4. A system in any one of Examples 1 to 3, wherein each of the plurality of through openings has a shape like a line, and the line has a length dimension greater than the width dimension.

[0067] Example 5. A system in any one of Examples 1 to 4, wherein each of the plurality of through openings has a shape like a prism having the same or similar transverse dimensions.

[0068] Example 6. A system comprising: a depth adjuster component comprising a conductive plate supporting a plurality of conductive protrusions in any one of Examples 1 to 5, wherein the depth adjuster component is aligned with a conductive spatial uniformity component so that the conductive protrusions are aligned perpendicularly with a through opening; and a vertical column located opposite or adjacent to the conductive protrusions.

[0069] Example 7. In any one of Examples 1 to 6, the system further comprises a mechanical system configured to move a depth adjuster plate so that a plurality of conductive protrusions move within a plurality of through openings, wherein the mechanical system is configured to receive a command instruction from a controller configured to adjust the depth from outside the plasma processing chamber.

[0070] Example 8. A system in any one of Examples 1 to 7, wherein the controller is configured to adjust the depth to a step difference of 0.1 mm to 5 mm.

[0071] Example 9. A system in any one of Examples 1 to 8, wherein the substrate holder comprises an electrically conductive pedestal, a conductive spatial uniformity component is attached to the pedestal, the main surface of the conductive spatial uniformity component faces the chamber cavity, and the main surface is insulated from the surrounding environment within the chamber cavity by a separator comprising a solid dielectric layer covering the main surface.

[0072] Example 10. In any one of Examples 1 to 9, the vertical column of the depth adjuster comprises a microwave waveguide, one end of the waveguide is the end surface of the vertical column, the vertical column comprises a core comprising a dielectric core of the waveguide, and the conductive outer wall of the column is the conductive wall of the waveguide; a portion of the conductive spatial uniformity component is exposed to the end of the waveguide through a hole in the conductive plate, and the hole is aligned with the end surface of the vertical column; and the microwave source comprises a microwave waveguide, and the waveguide is configured to deliver microwave power to the main surface.

[0073] Example 11. A system in any one of Examples 1 to 10, wherein the substrate holder comprises an electrically conductive pedestal, a conductive spatial uniformity component is attached to a portion of the pedestal where the main surface faces the chamber cavity, and the main surface is sealed from the chamber cavity by a separator comprising a solid dielectric layer covering the main surface.

[0074] Example 12. A system in any one of Examples 1 to 11, wherein the plasma processing chamber is an inductively coupled plasma (ICP) chamber, the ICP chamber has a dielectric window, the dielectric window is part of the sidewall of the ICP chamber, the RF source electrode is an RF coil having a spiral shape, the RF coil is disposed outside the chamber cavity adjacent to the dielectric window, a conductive spatial uniformity component is attached to the lower side of the top cover where the main surface faces the substrate holder, and the main surface is sealed from the chamber cavity by a separator comprising a solid dielectric layer covering the main surface.

[0075] Example 13. In any one of Examples 1 to 12, the plasma processing chamber is a capacitive coupled plasma (CCP) chamber, the CCP chamber has a plate-like CCP electrode disposed opposite a substrate holder, and the CCP electrode includes a portion disposed inside a chamber cavity; a conductive spatial uniformity component is attached to the CCP electrode, the main surface of which faces the substrate holder, and the main surface is sealed from the chamber cavity by a separator comprising a solid dielectric layer covering the main surface.

[0076] Example 14. A plasma processing system comprises: a plasma processing chamber; a radio frequency (RF) source electrode coupled to an RF power source and configured to ignite a plasma in the plasma processing chamber; a conductive spatial uniformity component coupled to the plasma by microwave power, comprising a plurality of through-openings and configured to couple microwave power to the plasma in the plasma processing chamber, and a main surface; a microwave power system comprising a microwave source coupled to a microwave oscillator; and a controller configured to execute commands to adjust the spatial uniformity metric of the electromagnetic (EM) power supplied to the plasma.

[0077] Example 15. The system of Example 14, wherein the microwave source comprises a microwave waveguide configured to activate surface EM waves on a main surface.

[0078] Example 16. The system of Example 14 or Example 15, further comprising a depth adjuster component coupled to a plurality of through openings, wherein the depth adjuster component is a conductive surface comprising a plurality of protrusions extending to one end of the plurality of through openings, wherein the tip of each of the plurality of protrusions is located inside each of the plurality of through openings at a depth from the opposite end; and a mechanical system configured to change the depth of the openings by sliding the protrusions along the sidewalls of the openings and configured to move the plurality of protrusions by receiving a command from a controller.

[0079] Example 17. A method for plasma processing of a semiconductor wafer, comprising the steps of: loading a semiconductor wafer into a plasma processing chamber coupled to a radio frequency (RF) source electrode and a microwave power system comprising a conductive spatial uniformity component including a plurality of through-openings, wherein the conductive spatial uniformity component comprises a depth adjuster, a microwave oscillator, and a main surface coupled to a microwave source; igniting a plasma by coupling RF power from the RF source electrode to a gas in the plasma processing chamber; coupling microwave power from the microwave power system to the plasma ignited in the plasma processing chamber by coupling the microwave oscillator to the microwave source; and controlling the coupled electromagnetic (EM) power supplied to the plasma by changing the uncharged depth of the plurality of through-openings by the depth adjuster component, wherein controlling the coupled EM power involves adjusting the spatial uniformity metric of the EM power.

[0080] Example 18. The method of Example 17, wherein coupling a microwave oscillator to a microwave source provides 10% to 50% of the microwave power of the coupled EM power supplied to the RF source electrode and the microwave source.

[0081] Example 19. The method of Example 17 or Example 18, further comprising the step of activating surface EM waves on a main surface by means of a microwave source.

[0082] Example 20. A method in any one of Examples 17 to 19, wherein adjusting the spatial uniformity metric of the EM power comprises transmitting a command command from a controller to a microwave power system to adjust the uncharged depth of a plurality of through-openings on a main surface.

[0083] Although the present invention has been described with reference to exemplary embodiments, this description is not intended to be interpreted in a limiting sense. By referring to the description, various modifications and combinations of other embodiments as well as the exemplary embodiments of the present invention will become apparent to those skilled in the art. Accordingly, the appended claims are intended to include any such modifications or embodiments.

Claims

Claim 1 A plasma processing system comprising: a vacuum system; a plasma processing chamber comprising a chamber cavity coupled to the vacuum system; and a substrate holder comprising a surface disposed inside the chamber cavity; a radio frequency (RF) source electrode coupled to an RF power source, configured to ignite a plasma in the chamber cavity; a microwave source coupled to a microwave oscillator; a conductive spatial uniformity component comprising a plurality of through-openings, wherein the conductive spatial uniformity component comprises a main surface electromagnetically coupled to the microwave source, and the main surface is configured to couple microwave power to the plasma in the chamber cavity; and a conductive protrusion comprising a plurality of conductive protrusions, wherein the plurality of conductive protrusions are configured to move relative to the conductive spatial uniformity component such that the depth distance from the main surface to the conductive protrusions within the plurality of through-openings is adjustable. Claim 2 A system according to claim 1, wherein the main surface is sealed from the chamber cavity by a separator comprising a solid dielectric covering the main surface. Claim 3 delete Claim 4 A system according to claim 1, wherein each of the plurality of through openings has a shape like a line, and the line has a length dimension greater than the width dimension. Claim 5 A system according to claim 1, wherein each of the plurality of through openings has a shape like a prism having the same or similar transverse dimensions. Claim 6 A system according to claim 1, comprising a depth adjuster component including a conductive plate supporting a plurality of conductive protrusions, wherein the depth adjuster component is aligned with the conductive spatial uniformity component so that the conductive protrusions are aligned vertically with the through opening; and further comprising a vertical column located opposite or adjacent to the conductive protrusions. Claim 7 A system according to claim 6, further comprising a mechanical system configured to move a conductive plate of a depth adjuster component so that the plurality of conductive protrusions move within the plurality of through openings, wherein the mechanical system is configured to receive a command from a controller configured to adjust the depth from outside the plasma processing chamber. Claim 8 In claim 7, the system is configured such that the controller adjusts the depth to a step difference of 0.1 mm to 5 mm. Claim 9 A system according to claim 6, wherein the substrate holder comprises an electrically conductive pedestal, the conductive spatial uniformity component is attached to the pedestal, the main surface of the conductive spatial uniformity component faces the chamber cavity, and the main surface is insulated from the surrounding environment within the chamber cavity by a separator comprising a solid dielectric layer covering the main surface. Claim 10 In claim 6, the vertical column of the depth adjuster component comprises a microwave waveguide, one end of the waveguide is the end surface of the vertical column, the vertical column comprises a core comprising a dielectric core of the waveguide, and the conductive outer wall of the vertical column is the conductive wall of the waveguide; a portion of the conductive spatial uniformity component is exposed to the end of the waveguide through a hole in the conductive plate, the hole is aligned with the end surface of the vertical column; and the microwave source comprises the microwave waveguide, and the waveguide is configured to deliver microwave power to the main surface, a system. Claim 11 A system according to claim 10, wherein the substrate holder comprises an electrically conductive pedestal, the conductive spatial uniformity component is attached to the portion of the pedestal where the main surface faces the chamber cavity, and the main surface is sealed from the chamber cavity by a separator comprising a solid dielectric layer covering the main surface. Claim 12 In claim 10, the plasma processing chamber is an inductively coupled plasma (ICP) chamber, the ICP chamber has a dielectric window, the dielectric window is part of the sidewall of the ICP chamber, the RF source electrode is an RF coil having a spiral shape, the RF coil is disposed outside the chamber cavity adjacent to the dielectric window, the conductive spatial uniformity component is attached to the lower side of the top cover where the main surface faces the substrate holder, and the main surface is sealed from the chamber cavity by a separator comprising a solid dielectric layer covering the main surface. Claim 13 In claim 10, the plasma processing chamber is a capacitively coupled plasma (CCP) chamber, the CCP chamber has a CCP electrode having the shape of a plate disposed opposite the substrate holder, the CCP electrode includes a portion disposed inside the chamber cavity; the conductive spatial uniformity component is attached to the CCP electrode, the main surface of which faces the substrate holder, and the main surface is sealed from the chamber cavity by a separator comprising a solid dielectric layer covering the main surface. Claim 14 A plasma processing system comprising: a plasma processing chamber; a radio frequency (RF) source electrode coupled to an RF power source, configured to ignite a plasma in the plasma processing chamber; a microwave power system coupled to the plasma by microwave power, comprising a conductive spatial uniformity component including a plurality of through-openings, comprising a main surface configured to couple microwave power to the plasma in the plasma processing chamber; a microwave power system comprising a microwave source coupled to a microwave oscillator; a controller configured to execute commands to adjust a spatial uniformity metric of electromagnetic (EM) power supplied to the plasma; and a depth adjuster component coupled to the plurality of through-openings, wherein the depth adjuster component is a conductive surface comprising a plurality of protrusions extending to one end of the plurality of through-openings, wherein the tip of each of the plurality of protrusions is located inside each of the plurality of through-openings at a depth from the opposing end. A mechanical system configured to change the depth of the through opening by sliding the protrusion along the side wall of the through opening, and comprising a mechanical system configured to move the plurality of protrusions by receiving a command from the controller. Claim 15 In claim 14, the system comprises a microwave waveguide configured to activate surface EM waves on the main surface, wherein the microwave source comprises a microwave waveguide. Claim 16 delete Claim 17 A method for plasma processing of a semiconductor wafer, comprising the steps of: loading the semiconductor wafer into a plasma processing chamber coupled to a radio frequency (RF) source electrode and a microwave power system comprising a conductive spatial uniformity component including a plurality of through-openings, wherein the conductive spatial uniformity component comprises a depth adjuster, a microwave oscillator, and a main surface coupled to a microwave source; igniting the plasma in the plasma processing chamber by coupling RF power from the RF source electrode to a gas; coupling microwave power from the microwave power system to the plasma ignited in the plasma processing chamber by coupling the microwave oscillator to the microwave source; and controlling the coupled electromagnetic (EM) power supplied to the plasma by changing the uncharged depth of the plurality of through-openings by the depth adjuster, wherein controlling the coupled EM power involves adjusting the spatial uniformity metric of the EM power. Claim 18 A method according to claim 17, wherein coupling the microwave oscillator to the microwave source comprises providing 10% to 50% of the microwave power of the coupled EM power supplied to the RF source electrode and the microwave source. Claim 19 A method according to claim 17, further comprising the step of activating surface EM waves on the main surface by means of the microwave source. Claim 20 A method according to claim 17, wherein adjusting the spatial uniformity metric of the combined EM power comprises transmitting a command instruction from a controller to the microwave power system to adjust the uncharged depth of the plurality of through openings on the main surface.

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