Method and apparatus for dynamic control of radial uniformity using two-layered microwave cavity

Abstract

Methods and apparatus provide plasma generation for a semiconductor process chamber. In some embodiments, the plasma is generated by a system comprising: a process chamber having at least two upper microwave cavities separated from a lower microwave cavity by a metal plate having a plurality of radiation slots; at least one microwave input port connected to a first upper microwave cavity of the at least two upper microwave cavities; at least two microwave input ports connected to a second upper microwave cavity of the at least two upper microwave cavities; and a lower microwave cavity receiving radiation through the plurality of radiation slots in the metal plate from both of the at least two upper microwave cavities, the lower microwave cavity being configured to form an electric field that provides a uniform plasma distribution within the process volume of the process chamber.

Description

Technical Field

[0001] Embodiments of this principle generally relate to semiconductor processing. Background Technology

[0002] Semiconductor process chambers are used to deposit and etch materials onto substrates, typically using plasma to assist in the deposition and etching process. Microwave plasma systems use microwaves to generate and sustain plasma during semiconductor processes. The most commonly used plasma systems use 13.56 MHz radio frequency (RF) for excitation. However, microwave systems are typically excited at 2.450 GHz. Early microwave plasma systems suffered from frequency and power instability, making it difficult to excite the system with poor uniformity during production. Because microwave-based systems generate a much higher radical density compared to 13.56 MHz RF plasma systems, their use in the semiconductor industry remains desirable. However, plasma uniformity in microwave-based systems is a significant problem.

[0003] Therefore, the inventors have provided an improved method and apparatus for controlling the uniformity of plasma in a microwave-based semiconductor processing system. Summary of the Invention

[0004] This article provides methods and apparatus for generating plasmas for semiconductor processes.

[0005] In some embodiments, a system for generating plasma for semiconductor processes may include: a process chamber having at least two upper microwave cavities separated from a lower microwave cavity by a metal plate having a plurality of radiation slots; at least one microwave input port connected to a first upper microwave cavity of the at least two upper microwave cavities; at least two microwave input ports connected to a second upper microwave cavity of the at least two upper microwave cavities; and a lower microwave cavity receiving radiation through the plurality of radiation slots in the metal plate from both of the at least two upper microwave cavities, the lower microwave cavity being configured to form an electric field that provides a uniform plasma distribution within the process volume of the process chamber.

[0006] In some embodiments, the system may further include: a first upper microwave cavity in the at least two upper microwave cavities being a square cavity in at least two dimensions; wherein the first upper microwave cavity in the at least two upper microwave cavities is an air cavity; a tuner on the first upper microwave cavity in the at least two upper microwave cavities, the tuner being configured to adjust the microwave excitation in the first upper microwave cavity in the at least two upper microwave cavities and act as a bandpass filter for the frequency of the center high mode; wherein the first upper microwave cavity in the at least two upper microwave cavities is a coaxial air cavity; wherein the coaxial air cavity excites the m=0 mode; wherein the coaxial air cavity has two different circular dimensions; wherein the second upper microwave cavity in the at least two upper microwave cavities is a ring cavity; wherein the second upper microwave cavity in the at least two upper microwave cavities is an air cavity; and a tuner on the second upper microwave cavity in the at least two upper microwave cavities. On a lower microwave cavity, a tuner is configured to adjust microwave excitation in a second upper microwave cavity of the at least two upper microwave cavities and act as a bandpass filter for frequencies used for edge high modes; wherein a first upper microwave cavity of the at least two upper microwave cavities supports a center high mode of microwave excitation, and a second upper microwave cavity of the at least two upper microwave cavities supports an edge high mode of microwave excitation; wherein the at least two upper microwave cavities are configured to form an electric field in a lower microwave cavity, the electric field generating a uniform plasma by adjusting the power ratio of the center high mode to the edge high mode in the at least two upper microwave cavities; and / or at least one microwave monitor, the at least one microwave monitor interacting with at least one of the at least two upper microwave cavities or the lower microwave cavity to monitor a single frequency or multiple frequencies for each of the at least one microwave monitor, the at least one microwave monitor being configured to provide feedback to a system controller for adjusting microwave parameters.

[0007] In some embodiments, a system for generating plasma for semiconductor processes may include: a first upper microwave cavity that excites a central high mode; a second upper microwave cavity that excites an edge high mode, the second upper microwave cavity surrounding the first upper microwave cavity; a metal plate under the first and second upper microwave cavities, the metal plate having a plurality of radiation slots configured to radiate a central high mode from the first upper microwave cavity and an edge high mode from the second upper microwave cavity; and a lower microwave cavity that receives the central high mode radiated from the first upper microwave cavity and the edge high mode radiated from the second upper microwave cavity, the lower microwave cavity being configured to provide an electric field for uniform plasma distribution in a process chamber.

[0008] In some embodiments, the system may further include: a first upper microwave cavity and a second upper microwave cavity being air cavities, and a lower microwave cavity being a quartz cavity; wherein the quartz cavity has a plurality of holes passing through it; wherein the first upper microwave cavity is a square cavity in at least two dimensions, and the second upper microwave cavity is an annular cavity surrounding the square cavity; and / or a first tuner, the first tuner being on the first upper microwave cavity, the first tuner being configured to adjust the microwave excitation in the first upper microwave cavity and act as a bandpass filter for a frequency for a center high mode; and a second tuner, the second tuner being on the second upper microwave cavity, the second tuner being configured to adjust the microwave excitation in the second upper microwave cavity and act as a bandpass filter for a frequency for an edge high mode.

[0009] In some embodiments, a system for generating plasma for semiconductor processes may include: a first upper microwave cavity that excites a central high mode, the first upper microwave cavity being a square air cavity; a second upper microwave cavity that excites an edge high mode, the second upper microwave cavity being an annular air cavity surrounding the first upper microwave cavity; a metal plate under the first and second upper microwave cavities, the metal plate having a plurality of radiation slots configured to radiate the central high mode from the first upper microwave cavity and the edge high mode from the second upper microwave cavity; and a lower microwave cavity that receives the central high mode radiated from the first upper microwave cavity and the edge high mode radiated from the second upper microwave cavity, the lower microwave cavity being a cylindrical quartz cavity having a plurality of holes passing through the cylindrical quartz cavity, the cylindrical quartz cavity being configured to provide an electric field for uniform plasma distribution in a process chamber.

[0010] In some embodiments, the system may further include: a first tuner located on a first upper microwave cavity, the first tuner being configured to adjust microwave excitation in the first upper microwave cavity and act as a bandpass filter for a frequency used for a center high mode; and a second tuner located on a second upper microwave cavity, the second tuner being configured to adjust microwave excitation in the second upper microwave cavity and act as a bandpass filter for a frequency used for an edge high mode; wherein the first upper microwave cavity and the second upper microwave cavity are configured to generate an electric field in a lower microwave cavity, and the electric field generates a uniform plasma by adjusting the power ratio of the center high mode to the edge high mode in the first upper microwave cavity and the second upper microwave cavity, respectively.

[0011] Other and further embodiments are disclosed below. Attached Figure Description

[0012] Embodiments of this principle can be understood by referring to the illustrative examples depicted in the accompanying drawings, which have been briefly summarized above and discussed in more detail below. However, the drawings illustrate only typical embodiments of this principle and should therefore not be considered as limiting the scope, as other equally effective embodiments are permissible.

[0013] Figure 1 An isometric view depicting a microwave input system with a two-story cavity according to some embodiments of this principle.

[0014] Figure 2 An isometric view is depicting a microwave input system with a two-layer cavity, having a small top radius R, according to some embodiments of this principle.

[0015] Figure 3 An isometric view is depicting a microwave input system with a two-layer cavity, having a square top cavity, according to some embodiments of this principle.

[0016] Figure 4 Describing some embodiments based on this principle Figure 3 A side view of a two-layer cavity microwave input system.

[0017] Figure 5 Depicting some embodiments based on this principle Figure 4 A top view of the microwave input system.

[0018] Figure 6 Depicting some embodiments based on this principle Figure 4 Electric field diagram of a side view of a microwave input system.

[0019] Figure 7 Depicting some embodiments based on this principle Figure 4 Electric field diagram of a top view of a microwave input system.

[0020] Figure 8A The illustration depicts a table of slowly rotating microwave signal inputs for a microwave cavity, illustrating some embodiments based on this principle.

[0021] Figure 8B The illustrations depict tables for rapidly rotating microwave signal inputs in microwave cavities, based on some embodiments of this principle.

[0022] Figure 9 Depicting some embodiments based on this principle Figure 4 A two-port variant of the microwave input system.

[0023] Figure 10An isometric view depicting a microwave input system with a separate top annular cavity according to some embodiments of this principle.

[0024] Figure 11 Illustrations depicting some embodiments based on this principle Figure 10 A top view of the pattern of the radiation slot of the microwave input system.

[0025] Figure 12 Electric field diagrams depicting the top annular air cavity according to some embodiments of this principle.

[0026] Figure 13 Electric field diagrams depicting the bottom cylindrical quartz cavity in some embodiments based on this principle.

[0027] Figure 14 An isometric view depicting a microwave input system with a movable top plate according to some embodiments of this principle.

[0028] Figure 15 A diagram of resonant frequencies according to some embodiments of this principle is depicted.

[0029] Figure 16 A top view depicting the electric field in the top annular air cavity of a microwave input system according to some embodiments of this principle.

[0030] Figure 17 A diagram depicting the resonant frequency and electric field effects of displacement of a wall-plunging tuner according to some embodiments of this principle.

[0031] Figure 18 A top view depicting a microwave input system according to some embodiments of this principle is shown.

[0032] Figure 19 An isometric view of a microwave input system according to some embodiments of this principle is depicted.

[0033] Figure 20 A top view depicting a microwave input system according to some embodiments of this principle is shown.

[0034] Figure 21 An isometric view of a microwave input system according to some embodiments of this principle is depicted.

[0035] Figure 22 Electric field diagrams depicting the power ratios of m=1 and m=3 modes according to some embodiments of this principle.

[0036] Figure 23 A top view depicting a variation of the input port orientation of a microwave input system according to some embodiments of this principle.

[0037] Figure 24Cross-sectional views of microwave input systems according to some embodiments of this principle are depicted.

[0038] Figure 25 Depicting some embodiments based on this principle Figure 24 A top view of the microwave input system.

[0039] Figure 26 Cross-sectional views of microwave input systems according to some embodiments of this principle are depicted.

[0040] Figure 27 Depicting some embodiments based on this principle Figure 26 A top view of the microwave input system.

[0041] Figure 28 Cross-sectional views of microwave input systems according to some embodiments of this principle are depicted.

[0042] Figure 29 Depicting some embodiments based on this principle Figure 28 A top view of the microwave input system.

[0043] Figure 30 A schematic diagram depicts a microwave input system with feedback according to some embodiments of this principle.

[0044] Figure 31 An isometric view of a microwave input system with a microwave monitor, according to some embodiments of this principle.

[0045] Figure 32 An isometric view of a microwave input system with a microwave monitor, according to some embodiments of this principle.

[0046] Figure 33 This is a schematic diagram of a plasma chamber having a microwave input for plasma generation, according to some embodiments of this principle.

[0047] To facilitate understanding, the same reference numerals have been used as much as possible to indicate common elements in the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be advantageously incorporated into other embodiments without further description. Detailed Implementation

[0048] A microwave cavity separated by a metal plate with a radiation slot is referred to herein as a two-layer microwave cavity. The inventors have discovered that two-layer microwave cavities are advantageous for exciting plasma under high voltage. In some embodiments, microwaves with a plasma mode near the edge of the accentuate substrate are combined with microwaves with a plasma mode near the center of the accentuate substrate to control plasma deposition uniformity. However, non-ideals in the top cavity of the two-layer microwave cavity must be addressed through mechanical tuning, which is difficult when simultaneously exciting two modes. The method and apparatus of this principle include embodiments that excite both center-high and edge-high eigenmodes in the bottom cavity of the two-layer microwave cavity without the problems encountered when simultaneously tuning two eigenmodes in the top cavity under normal conditions.

[0049] The inventors have discovered that by separating the top cavity of a two-layer microwave cavity for a center-high eigenmode (e.g., m=1) and an edge-high eigenmode (e.g., m=3), two eigenmodes can be generated without interfering with each other. Each of the separated top cavities allows resonance of only one desired mode. The method and apparatus of this principle enable the autotuner connected to each cavity to operate without frequency interference, thereby providing radial uniformity control in a systematic manner without relying on the operator's skill or experience. In some embodiments, the power ratio and / or field rotation of the two eigenmodes (e.g., m=1 and m=3) can be adjusted to advantageously provide control over the radial uniformity of the plasma generated in the bottom cavity of the two-layer microwave cavity. The top cavity can accept high power input and is advantageously an air cavity with low power loss and low cost. The inventors have discovered that the method and apparatus of this principle advantageously provide high uniformity at high pressures (e.g., greater than about 50 Torr). In some embodiments, uniformity can be achieved at pressures from about 50 Torr to about 100 Torr. In some embodiments, uniformity can be achieved at pressures ranging from about 50 Torr to about 200 Torr. In some embodiments, uniformity can be achieved at low pressures, such as from about 0.5 Torr to about 1.0 Torr. In some embodiments, the power ratio of the m=1 mode and the m=3 mode can be adjusted based on pressure to provide uniformity.

[0050] The two-layer microwave cavity has a radiating slot metal plate that separates the structure into a top cavity and a bottom cavity. The top cavity and the bottom cavity are weakly electrically connected via the radiating slot metal plate. Microwaves injected into the top cavity interfere with the two eigenmodes within the top cavity. However, in the bottom cavity, because the two eigenmodes are excited via the radiating slot metal plate with an optimized radiating slot pattern, field interference caused by the input microwaves is eliminated. As a result, the plasma excited by the two modes under the bottom cavity will have a theoretically ideal distribution (see "Microwave plasma generation by the fast and slow pulsation of resonant fields in a cylindrical cavity" by Y. Hasegawa et al., Journal of Applied Physics, Vol. 56, No. 046203 (2017); "Generation of slowly rotating microwave plasma by amplitude-modulated resonant cavity" by M. Hotta et al., Journal of Applied Physics, Vol. 56, No. 116002 (2017)). In reality, designing the theoretically calculated two-layer cavity is impossible. In such cases, non-idealities in the bottom cavity can be addressed by microwave frequency tuning, while non-idealities in the top cavity must be absorbed by a mechanical microwave tuner. Mechanical tuning can be easily implemented when only one eigenmode is excited in the structure. However, simultaneously activating both modes requires highly precise tuning, which is impractical for commercial products.

[0051] It is possible Figure 1-3 The diagram shows the separation of the top cavity for the center high mode (e.g., m=1). Figure 1 It is a microwave input system 100 with a two-layer cavity 160, the two-layer cavity 160 including a bottom cavity 102 with a bottom radius α 116, a metal plate 104 with a radiation slot 108, a top cavity 106 with a top radius R 114, and a frequency f r The waveguide 110 of the side power input port 112. In some embodiments, the bottom cavity 102 is filled with a dielectric material (e.g., quartz), while the top cavity is filled with air. Figure 1 The two-layered cavity 160 has a top radius R114 (R = α) equal to the bottom radius α116. Figure 2In the microwave input system 200, a two-layer cavity 260 (R < α) with a small top radius R 214 is shown. The top radius R 214 is reduced while maintaining the circular symmetry of the top cylindrical air cavity 206. The circular symmetry can be applied to any mode excited in the top cylindrical air cavity 206. The m = 1 (TE / TM) in any cylindrical cavity can be rotated by placing the two input ports at a 90-degree angle. 1XX ) and m = 3 (TE / TM) 3XX (See U.S. Patent Application Publication Serial No. 2018 / 0226230, entitled "Systems and Methods for Radial and Azimuthal Control of Plasma Uniformity," published August 9, 2019, and U.S. Patent Application Publication Serial No. 2019 / 0189399, entitled "Methods and Apparatus for Dynamic Control of Radial Uniformity in Microwave Chambers," published June 20, 2019). Figure 3 In the microwave input system 300, a two-layer cavity 360 is shown as having a top square cavity 306. A square cavity is defined as having at least two cavities of approximately equal size, and will also include a rectangular cavity with a longer third dimension. The top square cavity 306 is easier to manufacture and maintain compared to a cylindrical cavity. In other modes (e.g., m = 2TE / TM)... 2XX In the case of ), Figure 3 The rectangular or other polyhedral shape of the top square cavity 306 must be used in conjunction with the input angle calculated according to the previously described "SYSTEMS AND METHODS FOR RADIAL AND AZIMUTHAL CONTROL OF PLASM UNIFORMITY" (several options may be available for a single mode, e.g., 135 degrees for the m=2 mode). For illustrative purposes only, Figure 1-3 The two-layer cavity example shown has a component H installed to excite the magnetic field. z The waveguide can be any input configuration.

[0052] Figure 4 is based on Figure 3 Side view of a two-layer cavity 360 microwave input system 400. Figure 5 yes Figure 4 A top view 500 of a microwave input system 400. A top square air cavity 406, having a rectangular shape and filled with air, is connected to a bottom cylindrical quartz cavity 402 via at least one radiation slot 508 in a metal plate 404. For simplicity, but without any limitation, TE will be used in subsequent examples. 101 or TE 111 To replace m=1 (i.e. TE / TM) 1XX ), and use TM 310 or TE 311 To replace m=3 (i.e. TE / TM) 3XX ). Used at 2.417GHz Figure 4 When the microwave input system 400 is in place, the TE in the top square air cavity 406 101 High TE at the center is excited in the bottom cylindrical quartz cavity 402 via at least one radiation slot 508. 111 Patterns, such as Figure 6 Drawing 600 and Figure 7 As illustrated in drawing 700.

[0053] In the previously described “METHODS AND APPARATUS FOR DYNAMICAL CONTROL OF RADIALUNIFORMITY IN MICROWAVE CHAMBERS”, the system is configured to simultaneously rotate the center height (e.g., m=1 mode or TE / TM). 1XX ) and edge high (e.g., m=3 mode or TE / TM) 3XX The electric field distribution operates in two modes, resulting in high plasma homogeneity. Amplitude modulation is employed at a slow rotation frequency Ω. i The operating electrical parameters of the four ports P, Q, P', and Q' (see the same reference) in a rotating field from 1 Hz to 10,000 Hz are shown in [the table / reference]. Figure 8A In Table 800A. Furthermore, at the same rotation frequency as the carrier frequency (e.g., ω... i The rapid rotation at / 2π=2.45GHz was summarized in Figure 8B In Table 800B. Thereafter, for the sake of brevity without implying limitation, the following will be used. Figure 8A The slow rotation is defined in Table 800A. For rotation Figure 4 TE in the bottom cylindrical quartz cavity 402 111 ,like Figure 9 The diagram shows two orthogonal power inputs (port P 910 and port Q 912), with their electrical parameters set at... Figure 8AIn Form 800A. The inventor has already... Figure 9 During the modeling of the microwave input system 900, a perfect rotation at a rotation frequency of Ω / 2π was achieved.

[0054] It is possible Figure 10 The microwave input system 1000 shown has a separate top cavity for edge high modes (e.g., m=3). Figure 10 The diagram shows a combined cavity (top annular air cavity 1006 and bottom cylindrical quartz cavity 1002), which is connected via a radial slot 1108 in a metal plate 1004 (see...). Figure 11 The top view 1100) is used for connection. For illustrative purposes, input 1012 is used to connect to the component H that is installed to excite the magnetic field. r The waveguide 1010 can be used, but any configuration can be employed. This is because the top annular air cavity 1006 is designed to excite TM. 310 (See also) Figure 12 This height is independent of the cavity height, so the height of the top annular air cavity 1006 can be arbitrarily chosen, allowing for greater design flexibility. Figure 11 The pattern of the radial slot 1108 in the metal plate 1004 shown is an example. Other radial slot patterns may also be used. Figure 12 and Figure 13 This is the result using a 2.474 GHz input. TM is excited within the top annular air cavity 1006. 310 Pattern (e.g.) Figure 12 As shown in the electric field diagram 1200), its power is transmitted to the bottom cylindrical quartz cavity 1002 via the radiation slot 1108 in the metal plate 1004, thereby... Figure 13 The electric field diagram 1300 shows the excitation of TE in the bottom cylindrical quartz cavity 1002. 311 model.

[0055] When simultaneously exciting two modes in the bottom cavity, center-high (e.g., m=1) and edge-high (e.g., m=3) modes are introduced separately from the top square cavity and the top annular cavity, and fine tuning may be required if non-ideals exist relative to the theory. In the bottom cavity, frequency tuning can address non-ideals, while in the two top cavities, mechanical tuning should be employed. The two top cavities are designed such that each top cavity allows resonance for only one desired mode. For example, the square cavity should allow the excitation of the center-high mode at a frequency (e.g., 2.417 GHz, TE...). 101 Furthermore, the annular cavity should allow for the excitation of high-mode frequencies at the edges (e.g., 2.474 GHz TM). 310 ).

[0056] For center-high modes (e.g., m=1 modes), in some embodiments, tuning is as follows: Figure 14 The movable top plate 1420, similar to the plunger tuner, is shown in view 1400. When adjusting the height h 1422 with a fixed parameter for the width w 1424, TE... 101 The frequency shift of the resonant frequency is plotted on Figure 15 In Figure 1500, the available frequency range is determined when the parameter of width w 1424 is changed. For edge-high modes (m=3 modes), in some embodiments, tuning is as follows: Figure 16 The top view 1600 shows the sidewall plunger tuner 1630. Wall perturbation is used to precisely excite the TM in the top annular air cavity 1006. 310 (m=3) mode, thus ultimately exciting TE in the bottom cylindrical quartz cavity 1002. 311 The angle θ1640 between waveguide 1010 and sidewall plunger tuner 1630 is determined by multiplying an integer N by π and dividing by 4 (θ = N × (π / 4)). Figure 16 In the example, N = 3. The sidewall plunger tuner 1630 can be located at any angle satisfying θ = N × (π / 4).

[0057] When using two power inputs P and Q, such as Figure 20 As shown in View 2000, two identical plunger tuners (sidewall plunger tuner A 2040 and sidewall plunger tuner B 2042) can be implemented to maintain the same power input conditions. Sidewall plunger tuner A 2040 and sidewall plunger tuner B 2042 can also be applied to... Figure 14 The top square air cavity 406 in the middle is used for TE 101 (m=1) mode. Conversely, the concept of the movable top plate 1420 can be applied to... Figure 16 The top annular air cavity 1006 is used for m=3 modes, especially for exciting highly correlated modes (such as TM / TE) in the top annular cavity. 3x1 However, because the top annular air cavity 1006 is more... Figure 14 The top square air cavity 406 is much larger, so the movable top plate on the top annular air cavity 1006 would become bulky and difficult to control. Figure 17 In Figure 1700A, for a fixed width w, the frequency shift is plotted as a function of the disturbance wall displacement Δr. Figure 17 Figure 1700B illustrates the electric field distribution in the top air cavity (in Figure 16 The tuning effect occurs at point A (1632) in the diagram. In this example, the electric field near the plunger tuner is weakened, however, relative to the ideal TM. 310The distribution is not so strongly disturbed. Therefore, the slightly disturbed electric field in the top air cavity produces an ideal TE in the bottom cylindrical quartz cavity. 311 distributed.

[0058] In addition to precisely tuning the top cavity to elicit the desired pattern in both the top and bottom cavities, the mechanical plunger tuner has additional functions. Figure 18 The top view of the microwave input system 1800 shows the arrangement of microwave components implemented on the two top cavities described above (top square air cavity 1808 for m=1 mode and top annular air cavity 1806 for m=3 mode). Plunger tuners 1820 and 1822 for m=1 and m=3 respectively are also implemented. Figure 18 The placement of the plunger tuner 1822 in the example does not imply any limitation. To prevent reflected waves from returning to the microwave generator in the 2.450 GHz band via waveguide / coaxial cables 1828, 1830, an automatic / manual stub tuner 1824 for m=1 mode and an automatic / manual stub tuner 1826 for m=3 can be implemented near each of them in the top cavity. Figure 15 As shown in Figure 1500, a microwave stub tuner typically controls a frequency band from 2.410 GHz to 2.490 GHz. If the m=1 mode at 2.417 GHz and the m=3 mode at 2.474 GHz are simultaneously excited, both frequencies are within the control band of the microwave stub tuner and cannot be distinguished from each other, leading to unintentional operation of the microwave stub tuner. However, as shown below, a top cavity with a mechanical plunger tuner can be used as a practical bandpass filter. Figure 15 In Figure 1500, the microwave stub tuner band is divided into two halves, with the first band 1502 and the second band 1504 assigned to the m=1 mode and m=3 mode, respectively. The square widths w and h of w1 are selected. min with h max When the plunger tuner is at an adjustable height, the top square air cavity is allowed to resonate only in the first frequency band 1502, where m=1 (TE). 101 )model.

[0059] In a similar way, Figure 17 In Figure 1700A, the width w of the wall plunger tuner at the selected w = w2 and the distance from Δr min to Δr max When the adjustable plunger tuner is shifted, m=3 (TM) in the annular air cavity 310 The resonant frequency of the mode is limited to Figure 15 Within the second band 1504 of the stub tuner band 1506 in Figure 1500. Figure 18 With these settings of the plunger tuners 1820 and 1822, two modes are simultaneously excited at m=1 (TE) at 2.417 GHz in the bottom quartz cavity (not visible in the top view). 111 ) and at 2.474 GHz m=3 (TM 311 When the top square air cavity 1808 and the top annular air cavity 1806 are in operation, only 2.417 GHz and 2.474 GHz are allowed to pass into the interior, respectively. Therefore, each automatic / manual stub tuner 1824, 1826 will operate only for its assigned frequency, thus avoiding frequency interference and associated malfunctions. The adjustability and bandwidth filtering of the microwave input system 1800 are extremely beneficial, reducing complexity, maintenance, and cost. To rotate the TE in the bottom cavity... 311 ,like Figure 19 and Figure 20 The diagram shows two orthogonal power inputs (port P 1902 and port Q 1904) with electrical parameters that are consistent with... Figure 8A The method is set in the same way as shown in Table 800A. The inventors found that the test results showed perfect rotation at a rotation frequency of Ω / 2π.

[0060] like Figure 21 The microwave input system 2100 shown will Figure 9 Microwave input system 900 and Figure 19 The microwave input system 1900 combination, center high mode (m=1, e.g., at 2.417 GHz TE) 111 ) and edge high mode (m=3, e.g., at 2.474 GHz TE) 311 ) can be with Figure 8A The electrical parameters defined in Table 800A rotate simultaneously within the bottom cylindrical quartz cavity 402. In some embodiments, the autotuner is mounted on four waveguides 2102-2108 for proper rotation. Because Figure 14 and Figure 16 The tuner is implemented in two top cavities, so the top square air cavity 406 and the top annular air cavity 1006 each allow only TE 111 and TE 311 Resonance. Therefore, even with an autotune having a bandwidth of 2.41-2.49 GHz, TE can be avoided on the autotune. 111 Pattern and TE 311 Frequency interference between modes is eliminated, thus providing near-perfect tuning. Figure 22 The drawing 2200 shows m=1 (at 2.417GHz TE). 111) and m=3 (at 2.474GHz TE 311 The power ratio α:β between the two components can alter the electric field distribution within a bottom cylindrical quartz cavity without field rotation. With a rotating electric field, an azimuth-symmetric distribution will be achieved as a time-averaged value, particularly for high rotation frequencies exceeding 1 kHz. A distribution with an approximate ratio α:β = 0.33:0.67 approaches optimized uniformity, thus generating uniform plasma in both the azimuth and radial directions. In some embodiments, to further stabilize and uniformly generate plasma, hundreds of holes can be formed throughout the entire bottom of the bottom cylindrical quartz cavity 402 (as described in "Multi-hollow plasma production along dielectric plate in microwave discharge" by S. Nakao and H. Sugai, Vol. 43, No. L1039, 2007, and "Control of microwave plasma with use of multi-hollow dielectric plate" by I. Liang et al., Vol. 3, No. 61, 2010, Industrial Application of Plasma Process), to facilitate easy plasma ignition and subsequent stabilization without exciting plasma surface waves. The hollow quartz stabilizes the plasma, particularly at high pressures (e.g., about 50 Torr to about 100 Torr).

[0061] Figure 23 The microwave input systems 2300A-2300C are shown in top views of three variations, in which top power input and side power input are used in some embodiments. In microwave input system 2300A, a second top annular air cavity 2308 for m=2 mode is implemented above a bottom cylindrical quartz cavity, between a first top cylindrical air cavity 2306 for m=3 mode and a third top cylindrical air cavity 2310 for m=1 mode. The first top cylindrical air cavity 2306 has a top input port P3 2320 and a top input port Q3 2322. The second top cylindrical air cavity 2308 has a top input port P2 2324 and a top input port Q2 2326. The third top cylindrical air cavity 2310 has a top input port P1 2328 and a top input port Q1 2330. The top input ports 2328 and 2330 in the third top cylindrical air cavity 2310 used for m=1 mode are respectively replaced Figure 2 microwave input system 200 and Figure 3 The side input of the microwave input system 300 is used to excite the magnetic field at the azimuth angle H. θ Components. To rotate the electric field, the microwave inputs for m=1 and m=3 modes are separated by 90 degrees, while the microwave inputs for m=2 mode are separated by 135 degrees, as determined according to the previously described "SYSTEMS AND METHODS FOR RADIAL AND AZIMUTHAL CONTROL OF PLASMA UNIFORMITY". Microwave input system 2300B is a variant of microwave input system 2300A. The microwave inputs for m=3 mode are changed to side input ports P3 2332 and Q32334 to excite the axial H of the magnetic field. z Components (for illustrative purposes only). In some embodiments, such as Figure 23 As shown in the microwave input system 2300C, the third top cylindrical air cavity 2310 of the microwave input system 2300A for the m=1 mode is replaced with a top square cavity 2336, and the top input port P1 2328 and top input port Q1 2330 are replaced with side input ports P1 2338 and Q1 2340. In some embodiments, any combination of cavity shape and microwave input orientation is permitted.

[0062] The inventors have discovered that because m = 0 (e.g., TM), 011 The TM is circularly symmetric, so it is of particular interest for exciting m=0 modes. 011 No rotation is required to impart a high electric field at the center with circular symmetry. In some embodiments, such as Figure 24 As illustrated in the microwave input system 2400, a simplified implementation of the top cavity consists of a top coaxial air cavity 2404 and a top annular air cavity 2412 with a side plunger tuner 2414. A radiation slot 2424 in the metal plate 2416 transmits microwaves to a bottom cylindrical quartz cavity 2418, which generates plasma 2420 in the process volume 2422. The microwave input system 2400 also has a movable top plate 2402 for tuning on the top coaxial air cavity 2404. The tuning condition is determined by (n·λ) / 2, where n is an integer and λ is the wavelength of the top coaxial air cavity 2404. Because the m=0 mode does not require rotation, the m=0 center-high mode requires only one side input port 2406. And as... Figure 25As illustrated in the microwave input system 2500, the edge-high mode (e.g., m=3 mode) of the microwave input system 2400 requires two top input ports P 2408 and Q 2410 separated by 90 degrees, which inject microwaves into the top annular cavity 2412. In some embodiments, any configuration of side inputs and top inputs can be used for both m=0 and m=3 modes. The inventors have discovered that by using the m=0 mode, the number of input ports can be reduced, which means at least one less power generator and one less tuner, thereby reducing cost and operational complexity.

[0063] In some embodiments, methods for excitation of the m=0 mode and the m=3 mode are utilized. Figure 26 The microwave input system 2600 is... Figure 24 A variation of the microwave input system 2400. The top coaxial air cavity 2602 includes a first cylinder 2612 with a diameter d1 2604 and a second cylinder 2614 with a diameter d2 2606. The microwave input system 2400 includes a first sidewall plunger tuner 2610 for m=0 mode on the first cylinder 2612 and a second sidewall plunger tuner 2608 for m=3 mode on the top annular air cavity 2412. The top input port of the microwave input system 2400 for m=3 mode is changed to a side input port 2618, 2720 for use in the microwave input system 2600. In some embodiments, any combination of d1 2604 and d2 2606 (including d1 = d2) is allowed. In the case where d1 ≠ d2, a small disturbance caused by the sudden change in diameter from d1 to d2 near the connection portion 2616 of the two coaxial cavities will be used for Figure 26 The tuning height of the first cylinder 2612 and the second cylinder 2614 of the microwave input system 2600 combination is changed to ~(n·λ) / 2. Figure 27 The microwave input system 2700 is illustrated for use in Figure 26 An example port arrangement of the microwave input system 2600. The m=0 mode has a single side input port P1 2406, and the m=3 mode has side input ports P3 2720 and Q32618 to provide electric field rotation.

[0064] In some embodiments, the central high mode (i.e., m=0) can also be excited by using a top cylindrical air cavity 206 instead of the coaxial cavity in the microwave input system 2400 and microwave input system 2600. Figure 2 A variation of the microwave input system 200, and illustrated in Figure 28The microwave input system 2800 also includes a side input port 2406 and a movable top plate 2402 for m=0 mode. In some embodiments, a top input port or a wall disturbance tuner may also be used for m=0 mode. Figure 29 The microwave input system 2900 is illustrated for use in Figure 27 An example port arrangement of the microwave input system 2700. The m=0 mode has a single side input port P1 2406, and the m=3 mode has a top input port P3 2410 and a top input port Q3 2408 to provide electric field rotation.

[0065] exist Figure 30 The image illustrates a microwave input system 3000 with a feedback controller 3006 according to some embodiments. The microwave input system 3000 includes a user interface 3020, stub tuners 3028 and 3030, and a cylindrical cavity 3008. Microwave monitors 3002 and 3004 provide microwave signals to the feedback controller 3006, which then feeds the microwave signals to a microwave signal (phase and amplitude) generator 3010. The microwave signal (phase and amplitude) generator 3010 sends two seed signals 3012 and 3014 to two amplifiers 3016 and 3018 (e.g., solid-state amplifiers or tube amplifiers). These amplified microwave inputs are supplied to ports P and Q, which are spatially separated by 90 degrees. Figure 30 In the example system shown, two microwave monitors 3002 and 3004 are implemented together with the feedback controller 3006. If a precise digital controller, such as a high-frequency FPGA (Field Programmable Gate Array), is implemented inside the microwave signal (phase and amplitude) generator 3010, the microwave monitors 3002 and 3004 and the feedback controller 3006 can be removed from the microwave input system 3000.

[0066] In some embodiments, feedback can be used to control the two-layer microwave cavity. Figure 30 This is an example of a microwave input system where feedback control of phase and amplitude is performed by two microwave monitors 3002 and 3004 and a feedback controller 3006. Typically, the two microwave monitors 3002 and 3004 are placed in paired orthogonal positions for m=1 and m=3 modes. Figure 30 In the microwave input system 3000, a cylindrical cavity 3008 is assumed for illustrative purposes only. Some embodiments can have any shape and can be made of any material, including square and / or annular cavities. Several embodiments have been described herein, including three cavity types: a bottom cylindrical quartz cavity, a top square air cavity, and a top annular air cavity. As a result, it is possible to... Figure 31The microwave input system 3100, as shown, utilizes at least one of six different monitor locations. The microwave input system 3100 has a first input port P3110 and a first input port Q3112 for an m=1 frequency (e.g., 2.417 GHz) and a second input port P3114 and a second input port Q3116 for an m=3 frequency (e.g., 2.474 GHz). Because of the m=1 and m=3 modes, each pair of microwave monitors 3102-3108 is arranged in orthogonal positions paired with each other. Any type of microwave monitor can be selected, such as a pickup coil detector and / or a crystal microwave monitor, etc. In some embodiments, the first set of microwave monitors 3102 detects microwaves in the top square air cavity 406 for the m=1 mode. In some embodiments, the second set of microwave monitors 3108 detects microwaves in the top annular air cavity 3120 for the m=3 mode. In some embodiments, within the bottom cylindrical quartz cavity 3118, two frequencies can be measured using a single microwave monitor (see, for example, a third set of microwave monitors 3106 detecting microwaves in the bottom cylindrical quartz cavity 3118). In the case of a single microwave monitor, two frequency processing is performed for each microwave monitor (e.g., for the m=1 mode frequency and m=3 mode frequency for the third set of microwave monitors 3106). In some embodiments, alternatively, for example... Figure 32 Each microwave monitor illustrated in the microwave input system 3200 (see, for example, monitors 3202, 3204) processes a single frequency. In some embodiments, the number and location of the microwave monitors can be varied.

[0067] Figure 33 This is a schematic diagram 3300 of a process chamber 3302 having a plasma chamber 3320 for plasma generation and a microwave input, according to some embodiments. The process chamber 3302 has interfaces with a microwave source 3304, a vacuum source 3310, a gas source 3312, a power supply 3314, and a substrate interface 3316. A microwave controller 3306 interfaces with the microwave source 3304 to control edge high microwave mode input and center high microwave mode input to control plasma homogeneity in the plasma chamber 3320. The microwave controller 3306 may also interface with the process chamber 3302 or the plasma chamber 3320 to receive feedback from the microwave input and / or from processed result parameters (e.g., film homogeneity, etc.). The microwave controller 3306 may communicate with or even be part of a system controller 3322 (described below).

[0068] The microwave controller 3306 can also interface with external devices and / or processes to receive external feedback 3318 regarding the uniformity of the process in the plasma chamber 3320. The microwave controller 3306 may also have a user interface 3308 to receive input regarding parameters or other processing changes regarding microwave input. The microwave controller 3306 can also compensate for power ratio changes over time in the process chamber 3302 due to different process, gas, pressure, and / or physical changes (deposit accumulation, etc.). The microwave controller 3306 can also adjust the power ratio to compensate for the performance of components involved in delivering microwave input (such as tuners, amplifiers, transmission lines, waveguides, and / or power combiners, etc.). The microwave controller 3306 can be manually operated using operator input and / or automatically operated based on settings or feedback. The substrate interface 3316 allows the loading of substrates / wafers into and out of the plasma chamber 3320. When needed during processing, the vacuum source 3310 allows the extraction of process gases and allows for pressure reduction. Gas source 3312 provides process gases and other gases for processing or cleaning / venting plasma chamber 3320. Power supply 3314 may include radio frequency (RF) bias power supplies, etc., depending on process requirements.

[0069] Process chamber 3302 may also include a system controller 3322. System controller 3322 includes a programmable central processing unit (CPU) 3328 operable with memory 3324 and mass storage devices, an input control unit, and a display unit (not shown), as well as various components coupled to the processing system to facilitate control of the board processing, such as power supplies, clocks, caches, input / output (I / O) circuitry, and pads. To facilitate control of the aforementioned process chamber 3302, CPU 3328 may be one of any form of general-purpose computer processor (such as a programmable logic controller (PLC)) usable in an industrial environment for controlling the various chambers and subprocessors. Memory 3324 is coupled to CPU 3328, and memory 3324 is non-transitory and may be one or more of random access memory (RAM), read-only memory (ROM), floppy disk drive, hard disk, or any other form of local or remote digital storage. Support circuitry 3326 is coupled to CPU 3328 to support the processor. Applications or programs used for the generation, heating, and other processes of charged materials are typically stored in memory 3324 (generally as software routines). Software routines may also be stored and / or executed by a second CPU (not shown), which is located remotely relative to the process chamber 3302 controlled by CPU 3328.

[0070] Memory 3324 is in the form of a computer-readable storage medium containing instructions that, when executed by CPU 3328, facilitate the operation of process chamber 3302. The instructions in memory 3324 are in the form of a program product (such as a program implementing the methods of this disclosure). Program code may conform to any of a variety of different programming languages. In one example, this disclosure may be implemented as a program product stored on a computer-readable storage medium for use with a computer system. The program(s) of the program product define the functionality of aspects (including the methods described herein). Illustrative computer-readable storage media include, but are not limited to: non-writable storage media on which information can be permanently stored (e.g., read-only memory devices within a computer, such as CD-ROM discs readable by a CD-ROM drive, flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory); and writable storage media on which changeable information is stored (e.g., floppy disks within a disk drive, or hard disk drives, or any type of solid-state random access semiconductor memory). Such computer-readable storage media are aspects of this disclosure when carrying computer-readable instructions that direct the functionality of the methods described herein.

[0071] Embodiments based on this principle may be implemented in hardware, firmware, software, or any combination thereof. Embodiments may also be implemented as instructions stored using one or more computer-readable media, which may be read and executed by one or more processors (such as microwave controller 3306). The computer-readable medium may include any means for storing or transmitting information in a machine-readable form (e.g., a computing platform or a “virtual machine” running on one or more computing platforms). For example, the computer-readable medium may include any suitable form of volatile or non-volatile memory. In some embodiments, the computer-readable medium may include a non-transitory computer-readable medium.

[0072] While the foregoing describes embodiments of this principle, other and further embodiments of this principle may be designed without departing from its basic scope.

Claims

1. A system for generating plasma for semiconductor processes, the system comprising: A process chamber having at least two upper microwave cavities, the at least two upper microwave cavities being separated from the lower microwave cavity by a metal plate having multiple radiation slots; At least one microwave input port, the at least one microwave input port being connected to a first upper microwave cavity in the at least two upper microwave cavities; At least two microwave input ports, the at least two microwave input ports being connected to a second upper microwave cavity in the at least two upper microwave cavities; as well as The lower microwave cavity receives radiation from two of the at least two upper microwave cavities through the plurality of radiation slots in the metal plate, and the lower microwave cavity is configured to form an electric field that provides a uniform plasma distribution within the process volume of the process chamber. The first upper microwave cavity in the at least two upper microwave cavities excites a high mode at the center, and the second upper microwave cavity in the at least two upper microwave cavities excites a high mode at the edge.

2. The system of claim 1, wherein the first upper microwave cavity of the at least two upper microwave cavities is a square cavity in at least two dimensions.

3. The system of claim 1, wherein the first upper microwave cavity of the at least two upper microwave cavities is an air cavity.

4. The system of claim 1, further comprising: A tuner, located in the first upper microwave cavity of the at least two upper microwave cavities, is configured to adjust the microwave excitation in the first upper microwave cavity of the at least two upper microwave cavities and act as a bandpass filter for the frequency of the center high mode.

5. The system of claim 1, wherein the first upper microwave cavity of the at least two upper microwave cavities is a coaxial air cavity.

6. The system of claim 5, wherein the coaxial air cavity excites the m=0 mode.

7. The system of claim 5, wherein the coaxial air cavity has two different circular dimensions.

8. The system of claim 1, wherein the second upper microwave cavity of the at least two upper microwave cavities is an annular cavity.

9. The system of claim 1, wherein the second upper microwave cavity of the at least two upper microwave cavities is an air cavity.

10. The system of claim 1, further comprising: A tuner, located in the second upper microwave cavity of the at least two upper microwave cavities, is configured to adjust the microwave excitation in the second upper microwave cavity of the at least two upper microwave cavities and act as a bandpass filter for frequencies used in edge high modes.

11. The system of claim 1, wherein the first upper microwave cavity of the at least two upper microwave cavities supports a center high mode of microwave excitation, and the second upper microwave cavity of the at least two upper microwave cavities supports an edge high mode of microwave excitation.

12. The system of claim 11, wherein the at least two upper microwave cavities are configured to form an electric field in the lower microwave cavity, and the electric field generates a uniform plasma by adjusting the power ratio of the center high mode to the edge high mode in the at least two upper microwave cavities.

13. The system of claim 1, further comprising: At least one microwave monitor is configured to interact with at least one of the at least two upper microwave cavities or the lower microwave cavity to monitor a single frequency or multiple frequencies for each of the at least one microwave monitor, and the at least one microwave monitor is configured to provide feedback to a system controller for adjusting microwave parameters.

14. A system for generating plasma for semiconductor processes, the system comprising: The first upper microwave cavity, the first upper microwave cavity excites the high mode at the center; The second upper microwave cavity, the second upper microwave cavity excites edge high modes, and the second upper microwave cavity surrounds the first upper microwave cavity; A metal plate located beneath a first upper microwave cavity and a second upper microwave cavity, the metal plate having a plurality of radiation slots configured to radiate a high-center mode from the first upper microwave cavity and a high-edge mode from the second upper microwave cavity; as well as A lower microwave cavity receives a center high mode radiated from a first upper microwave cavity and an edge high mode radiated from a second upper microwave cavity. The lower microwave cavity is configured to provide an electric field for uniform plasma distribution in the process chamber.

15. The system of claim 14, wherein the first upper microwave cavity and the second upper microwave cavity are air cavities, and the lower microwave cavity is a quartz cavity.

16. The system of claim 15, wherein the quartz cavity has a plurality of holes passing through the quartz cavity.

17. The system of claim 15, wherein the first upper microwave cavity is a square cavity in at least two dimensions, and the second upper microwave cavity is an annular cavity surrounding the square cavity.

18. The system of claim 15, further comprising: A first tuner, located on the first upper microwave cavity, is configured to adjust the microwave excitation in the first upper microwave cavity and act as a bandpass filter for the frequency of the center high mode. as well as A second tuner, located on the second upper microwave cavity, is configured to adjust the microwave excitation in the second upper microwave cavity and act as a bandpass filter for frequencies used in edge high modes.

19. A system for generating plasma for semiconductor processes, the system comprising: The first upper microwave cavity, the first upper microwave cavity excites the high mode at the center, and the first upper microwave cavity is a square air cavity; The second upper microwave cavity, the second upper microwave cavity excites edge high modes, and the second upper microwave cavity is an annular air cavity surrounding the first upper microwave cavity; A metal plate located beneath a first upper microwave cavity and a second upper microwave cavity, the metal plate having a plurality of radiation slots configured to radiate a high-center mode from the first upper microwave cavity and a high-edge mode from the second upper microwave cavity; as well as A lower microwave cavity receives a center high mode radiated from a first upper microwave cavity and an edge high mode radiated from a second upper microwave cavity. The lower microwave cavity is a cylindrical quartz cavity having a plurality of holes passing through it. The cylindrical quartz cavity is configured to provide an electric field for uniform plasma distribution in the process chamber.

20. The system of claim 19, further comprising: A first tuner, located on the first upper microwave cavity, is configured to adjust the microwave excitation in the first upper microwave cavity and act as a bandpass filter for the frequency of the center high mode. as well as A second tuner, located on the second upper microwave cavity, is configured to adjust the microwave excitation in the second upper microwave cavity and act as a bandpass filter for frequencies used in edge high modes. The first upper microwave cavity and the second upper microwave cavity are configured to generate an electric field in the lower microwave cavity. By adjusting the power ratio of the center high mode to the edge high mode in the first upper microwave cavity and the second upper microwave cavity, respectively, the electric field generates a uniform plasma.

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