Multi-antenna unit for a large-area inductively coupled plasma processing device

Abstract

The embodiments of the present disclosure generally relate to a cover suitable for use in a semiconductor processing chamber. The cover comprises a plurality of dielectric windows coupled to a perforated faceplate. The cover also comprises a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows. The cover further comprises a plurality of inductive couplers. One or more of the inductive couplers comprise a first lower portion, a second lower portion, and a bridge. The bridge is positioned over at least one of the plurality of support members. The first lower portion is positioned on the first dielectric window among the plurality of dielectric windows. The second lower portion is positioned on the second dielectric window among the plurality of dielectric windows. The second dielectric window is adjacent to the first dielectric window.

Description

Technology Field

[0001] The embodiments of the present disclosure generally relate to process chambers, e.g., high-density plasma (HDP) chambers used in semiconductor manufacturing. More specifically, the embodiments of the present disclosure relate to antenna configurations for process chambers. Background Technology

[0002] In the manufacture of solar panels or flat panel displays, many processes are employed to form electronic devices on substrates by depositing thin films on substrates, such as semiconductor substrates, solar panel substrates, and liquid crystal display (LCD) and / or organic light-emitting diode (OLED) substrates. Deposition is generally achieved by introducing a precursor gas into a chamber having a substrate placed on a temperature-controlled substrate support. The precursor gas is typically directed through a gas distribution assembly placed on the substrate support. The precursor gas in the chamber is activated (e.g., excited) into a plasma by applying a single radio frequency (RF) antenna or an array of radio frequency antennas inductively coupled to the precursor gas to form a plasma. The excited gas reacts to form a layer of material on the surface of the substrate placed on the temperature-controlled substrate support.

[0003] The substrates for forming electronic devices have a surface area exceeding 1 square meter. Uniformity of film thickness across these substrates is difficult to achieve. The power applied to generate plasma within the process chamber can generate eddy currents that negatively affect plasma uniformity and consequently deposition uniformity, and can also generate other hardware problems, such as arcing and RF power loss (but not limited thereto).

[0004] Therefore, methods and devices are needed to generate more uniform plasmas and / or reduce other hardware problems.

[0005] The present disclosure generally relates to inductive coupler arrays for use in processing chambers, e.g., inductive coupler arrays suitable for use in semiconductor manufacturing. The present disclosure also generally relates to covers and processing chambers having inductive couplers.

[0006] In one example, the cover is suitable for use in a semiconductor processing chamber. The cover includes a plurality of dielectric windows coupled to a perforated faceplate. The cover also includes a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows. The cover further includes a plurality of inductive couplers comprising a first subset of inductive couplers and a second subset of inductive couplers. Each inductive coupler of the first subset of inductive couplers includes a first lower portion, a second lower portion, and a bridge. The bridge is positioned over at least one of the plurality of support members. The first lower portion is positioned on the first dielectric window among the plurality of dielectric windows. The second lower portion is positioned on the second dielectric window among the plurality of dielectric windows. The second dielectric window is adjacent to the first dielectric window.

[0007] In another example, the cover is suitable for use in a semiconductor processing chamber. The cover comprises a plurality of dielectric windows coupled to a perforated faceplate, and the plurality of dielectric windows have a first subset of dielectric windows and a second subset of dielectric windows. The cover further comprises a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows. The cover comprises a plurality of inductive couplers, comprising a first subset of inductive couplers and a second subset of inductive couplers. The first subset of inductive couplers is non-planar. The second subset of inductive couplers is planar. The first subset of dielectric windows has portions of two inductive couplers of the first subset of inductive couplers positioned thereon. The second subset of dielectric windows has portions of one inductive coupler of the first subset of inductive couplers and one inductive coupler of the second subset of inductive couplers positioned thereon.

[0008] In another example, the cover is suitable for use in a semiconductor processing chamber. The cover comprises a plurality of dielectric windows coupled to a perforated faceplate, wherein the plurality of dielectric windows comprises a first subset of dielectric windows and a second subset of dielectric windows. The cover further comprises a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows. The cover comprises a first subset of inductive couplers, wherein the inductive couplers comprise a first lower portion, a second lower portion, and a bridge. The cover further comprises a second subset of inductive couplers, wherein the second subset of inductive couplers is planar. Each of the first subset of dielectric windows has a portion of two inductive couplers of the first subset of inductive couplers positioned thereon. Each of the second subset of dielectric windows has a portion of one inductive coupler of the first subset of inductive couplers and one inductive coupler of the second subset of inductive couplers positioned thereon. The bridge is positioned over at least one of the plurality of support members. Brief explanation of the drawing

[0009] In order to enable a detailed understanding of the features of the present disclosure mentioned above, a more specific description of the present disclosure, briefly summarized above, may be made with reference to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that since the present disclosure may allow for other equally effective embodiments, the accompanying drawings are merely illustrative of exemplary embodiments and should not be construed as limiting the scope. FIG. 1 is a schematic front cross-sectional view of a chamber according to an embodiment. FIG. 2 is a perspective cross-sectional view of a part of a cover assembly according to an embodiment. FIGS. 3a and 3b illustrate a schematic plan view of an inductive coupler arrangement of a cover according to one embodiment. FIG. 4 illustrates a schematic plan view of an inductive coupler arrangement of a cover according to another embodiment. FIG. 5 illustrates a schematic plan view of an inductive coupler arrangement of a cover according to another embodiment. FIG. 6 illustrates a schematic plan view of an inductive coupler arrangement of a cover according to another embodiment. For ease of understanding, the same reference numbers have been used to denote identical elements common to the drawings where possible. It is considered that the elements and features of one embodiment may be advantageously incorporated into other embodiments without further mention. Specific details for implementing the invention

[0010] The present disclosure generally relates to inductive coupler arrays for use in processing chambers, e.g., inductive coupler arrays suitable for use in semiconductor manufacturing. The present disclosure also generally relates to covers and processing chambers having inductive couplers. The inductive couplers of the present disclosure are arranged relative to one another such that eddy currents generated by adjacent inductive couplers are reduced, thereby improving plasma uniformity.

[0011] In one example, a cover suitable for use in a semiconductor processing chamber comprises a plurality of dielectric windows, a plurality of support members positioned between adjacent dielectric windows, and a plurality of inductive couplers positioned adjacent to the dielectric windows. Each dielectric window among the plurality of dielectric windows has at least a portion of two of the plurality of inductive couplers positioned thereon.

[0012] FIG. 1 is a schematic side cross-sectional view of a processing chamber (100) according to one embodiment of the present disclosure. An exemplary substrate (102) is shown on a substrate surface (120) within a chamber body (104). The substrate (102) may be, for example, a large-area substrate having a surface area greater than 1 square meter. The processing chamber (100) also includes a cover assembly (106), a bottom (118) positioned opposite the cover assembly (106), and a pedestal or substrate support assembly (108) positioned between the cover assembly (106) and the bottom (118). The cover assembly (106) is positioned at the upper end of the chamber body (104), and the substrate support assembly (108) is positioned at least partially within the chamber body (104). The substrate support assembly (108) is coupled to a shaft (110). The shaft (110) is coupled to a drive unit (112) that moves the substrate support assembly (108) vertically (in the Z direction) within the chamber body (104). The substrate support assembly (108) of the processing chamber (100) shown in FIG. 1 is in a processing position. However, the substrate support assembly (108) can be lowered in the Z direction to a position adjacent to the transfer port (114).

[0013] The cover assembly (106) includes a backing plate (122) placed on the chamber body (104). The cover assembly (106) also includes a gas distribution assembly or a showerhead (124). The showerhead (124) delivers process gases from a gas source to a processing area (126) between the showerhead (124) and the substrate (102). The showerhead (124) is also coupled to a cleaning gas source that provides cleaning gases, such as fluorine, chlorine, or oxygen-containing gases, to the processing area (126).

[0014] The showerhead (124) also functions as a plasma source. To function as a plasma source, the showerhead (124) includes one or more inductively coupled plasma generating components, or inductive couplers (130a, 130b) (e.g., antennas or coils). Each of the one or more inductive couplers (130a, 130b) is coupled across a power source and ground (133). FIG. 1 illustrates each of the inductive couplers (130a, 130b) connected in parallel to the power source and ground (133) to facilitate control and tunability, but series connection is also considered. In some embodiments, the ground (133) is a capacitor or grounded through a capacitor. The showerhead (124) also includes a faceplate (132) comprising a plurality of discontinuous perforated tiles (134). The power source includes a matching circuit or tunable capability for tuning the electrical characteristics of the inductive couplers.

[0015] Each of the perforated tiles (134) is supported by a plurality of support members (136). Each of one or more inductive couplers (130a, 130b) or portions of one or more inductive couplers are positioned on or above each dielectric window (138). A plurality of gas volumes (140) (three are shown) are defined by the surfaces of the dielectric windows (138), perforated tiles (134), and support members (136). Each of the one or more inductive couplers (130a, b) is configured to generate an electromagnetic field that activates process gases into plasma when gas flows through adjacent perforated tiles (134) into the gas volumes (140) and into the chamber volume below. In some embodiments that may be combined with other embodiments, process gases from a gas source are supplied to each of the gas volumes (140) through conduits of the support members (136). The volume or flow rate of gas(s) entering and exiting the showerhead is controlled in different zones of the showerhead (124). Zone control of the treatment gases is provided by a plurality of flow controllers, e.g., mass flow controllers (142, 143, and 144) illustrated in FIG. 1. When chamber cleaning is required, cleaning gases from a cleaning gas source flow into each of the gas volumes (140), then flow into the treatment volume (140), and within the treatment volume, the cleaning gases are activated into ions, radicals, or both. The activated cleaning gases flow through the perforated tiles (134) and into the treatment area (126) to clean the chamber components.

[0016] FIG. 2 is an enlarged side cross-sectional view of a portion of the cover assembly (106) of FIG. 1. The perforated tiles (134) include a plurality of openings (218) extending therethrough. Each of the plurality of openings (218) allows gases to flow from gas volumes (140) into the processing area (126) at predetermined flow rates due to the diameter of the openings (218). A mounting portion (225) surrounds the sides of adjacent perforated tiles (134) at the interface of adjacent perforated tiles (134). The mounting portion (225) includes a leg or shelf that supports a portion of the edge or perimeter of the perforated tiles (134). The mounting portion (225) is fastened to the support members (136) by fasteners, such as bolts or screws. Each support member (136) includes a leg or shelf that supports the edge or perimeter portion of the dielectric window (138).

[0017] The use of multiple dielectric windows (138) provides a physical barrier between the gas volume (140) and the processing area (126) without applying large stresses to the windows that would otherwise have occurred if smaller / larger dielectric windows were utilized. In some embodiments, during processing, the gas volumes (140) have a pressure of about 10 mTorr to about 3 Torr.

[0018] The materials for the showerhead (124) are selected based on one or more of electrical properties, strength, and chemical stability. Inductive couplers are made of electrically conductive materials, such as copper or aluminum. The backing plate (122) and support members (136) are made of a material capable of supporting the weight and atmospheric pressure load of the supported components, which may include metal or other similar materials, such as aluminum or an aluminum alloy, or steel. The backing plate (122) and support members (136) may be made of a non-magnetic material (e.g., a non-magnetic or non-ferromagnetic material), such as aluminum or an alloy thereof. The perforated tiles (134) are made of a ceramic material, such as quartz, alumina, or other similar material. The dielectric windows (138) are made of quartz, alumina, or sapphire. In some embodiments that can be combined with other embodiments, the dielectric windows (138) include copper, silver, aluminum, tungsten, molybdenum, titanium, combinations thereof, or alloys thereof.

[0019] The cover assembly (106) includes two different inductive couplers (130a and 130b). The inductive couplers (130a) are planar coils (e.g., helical coils placed in a plane) and are positioned over a single dielectric window (138). The inductive couplers (130b) are bridge-type coils (e.g., non-planar coils) comprising a lower portion (280) and a bridge (281). The bridge (281) is positioned over each support member (136) so that the inductive coupler (130b) is positioned over adjacent dielectric windows (138). In one example, the footprint of the inductive coupler (130a) is about half the footprint of the inductive coupler (130b), for example, about 70 percent to about 30 percent, for example, about 60 percent to about 40 percent, or about 55 percent to about 45 percent. In other embodiments that may be combined with the embodiments of the present invention, it is considered that the inductive coupler (130a) may have a bridge-type configuration similar to the inductive coupler (130b) even if the inductive coupler (130a) does not span across the support member (136). In such a configuration, the inductive coupler (130a) still has a reduced footprint compared to the inductive coupler (130b).

[0020] FIGS. 3a and 3b illustrate a schematic plan view of an inductive coupler array of a cover (106) according to one embodiment. The cover (106) comprises a plurality of dielectric windows (138) (six shown) in a 2x3 array, and a plurality of inductive couplers (130a) (four shown) and inductive couplers (130b) (four shown). For ease of explanation, the inductive couplers (130a) are individually labeled 130a1–130a4 (collectively referred to as 130a), and similarly, the inductive couplers (130b) are individually labeled 130b1–130b4 (collectively referred to as 130b).

[0021] Each of the inductive couplers (130a) is positioned adjacent to the lateral outer edges of the cover (106) and completely over each individual dielectric window (138). Each of the inductive couplers (130b) is positioned inside the inductive couplers (130a). Each inductive coupler (130b) is positioned over two dielectric windows. In the illustrated configuration, each inductive coupler (130a) also (partially) shares the dielectric window (138) with the inductive coupler (130b). Similarly, each inductive coupler (130b) also shares the dielectric window with the other inductive coupler (130b).

[0022] Referring to both FIG. 3a and 3b, the inductive couplers (130a) and the inductive couplers (130b) are positioned so that adjacent inductive couplers generate magnetic fields in opposite directions. For example, the inductive couplers (130a1, 130b2, 130b3, and 130a4) all generate magnetic fields extending in the z-direction (e.g., out of the plane of the page and indicated by the symbol (195)), whereas the inductive couplers (130b1, 130a2, 130a3, and 130b4) all generate magnetic fields extending in the negative z-direction (e.g., into the page and indicated by the symbol (196)). The arrows (190) of each inductive coupler (130a, 130b) are illustrated to show the direction of current flow during processing that generates the corresponding magnetic field according to the "right-hand rule".

[0023] As a result of the current supplied to each inductive coupler (130a, 130b) and the magnetic field generated thereby, eddy currents indicated by arrows (192) are generated in the cover (106) of the process chamber. In conventional systems, the generated eddy currents cause plasma non-uniformities, particularly at the edges of the cover (106) and / or at the center of the cover (106), due to the arrangement of inductive couplers to each support member (136) of each dielectric window (138) (which tends to accumulate eddy currents). However, the arrangement of inductive couplers of the present disclosure effectively reduces eddy currents within the cover due to the positioning of the cover (106) to the support members (136) around the dielectric window (138). In particular, inductive couplers (130a, 130b) are positioned such that eddy currents generated around each dielectric window (138) (and supporting members (136) surrounding each dielectric window (138)) are in opposite directions and thus substantially cancel each other out. To achieve this, each dielectric window includes at least portions of a plurality (e.g., two) of inductive couplers that generate magnetic fields in opposite directions. The generation of magnetic fields in opposite directions results in eddy currents in opposite directions that cancel each other out. Because the eddy currents cancel each other out, the eddy current effects on the plasma are reduced, and thus the plasma uniformity is increased.

[0024] FIG. 4 illustrates a schematic plan view of an inductive coupler arrangement of a cover (406) according to another embodiment. The cover (406) is similar to the cover (106) but includes four dielectric windows (138). Each dielectric window (138) places two (or parts thereof) inductive couplers over it, each of which generates magnetic fields in opposite directions. For example, each dielectric window (138) includes not only the inductive coupler (130a) over it but also a part of the inductive coupler (130b) over it. The magnetic field directions of each inductive coupler (130a, 130b) are illustrated by symbols (195, 196). The magnetic field directions indicated by the symbols (195, 196) result in a reduction of eddy currents and improve plasma uniformity.

[0025] FIG. 5 illustrates a schematic plan view of an array of inductive couplers of a cover (506) according to another embodiment. The cover (506) is similar to the cover (406) but includes 15 dielectric windows (138) in a 3x5 array. Each dielectric window (138) places two (or parts thereof) inductive couplers on it, each of which generates magnetic fields in opposite directions. For example, each dielectric window (138) includes not only the inductive coupler (130a) on it but also a part of the inductive coupler (130b) on it. The magnetic field directions of each inductive coupler (130a, 130b) are illustrated by symbols (195, 196). The magnetic field directions indicated by the symbols (195, 196) result in a reduction of eddy currents and improve plasma uniformity. As exemplified by the cover (506), the inductive couplers (130a, 130b) can be arranged in different orientations and scaled to accommodate arrays of desired dimensions.

[0026] FIG. 6 illustrates a schematic plan view of an array of inductive couplers of a cover (606) according to another embodiment. The cover (606) is similar to the cover (506) but includes 30 dielectric windows (138) in a 5x6 array. Each dielectric window (138) places two (or parts thereof) inductive couplers over it, each of which generates magnetic fields in opposite directions. For example, each dielectric window (138) along the lateral outer edges includes a portion of the inductive coupler (130a) over it as well as a portion of the inductive coupler (130b) over it. The inner dielectric windows (138) include a portion of the first inductive coupler (130b) and a portion of the second inductive coupler (130b) over it. The magnetic field directions of each inductive coupler (130a, 130b) are illustrated by symbols (195, 196). The magnetic field directions indicated by the symbols (195, 196) result in a reduction of eddy currents and improve plasma uniformity. As exemplified by the cover (606), the inductive couplers (130a, 130b) can be arranged in different orientations and scaled to accommodate arrays of desired dimensions.

[0027] Aspects of the present disclosure provide reduced eddy current effects during processing, and thus, because the influence of eddy currents on the plasma is reduced, plasma uniformity is improved and average plasma density is increased. Additionally, the reduction of eddy currents provided by the disclosed embodiments also reduces unwanted and / or negative effects on chamber components that would otherwise have occurred in conventional ICP chambers. For example, the reduction of eddy currents in support members surrounding dielectric windows—particularly those adjacent to chamber components such as chamber walls or bodies—reduces the likelihood of arcing occurring between the support members and adjacent chamber components. The reduction in arcing improves hardware lifespan and reduces particle contamination. Furthermore, the reduction of eddy currents facilitates improvements in RF power loss and temperature uniformity within the process chamber (thus promoting process uniformity), and also reduces the cooling requirements of the process chamber. For example, due to reduced eddy currents in the support members, resistive heating of the support members is reduced, lowering the cooling requirements of the process chamber and facilitating temperature uniformity.

[0028] Although the foregoing describes embodiments of the present disclosure, other and additional embodiments of the present disclosure may be devised without departing from the basic scope thereof, the scope thereof is determined by the subsequent claims.

Claims

Claim 1 A cover for use in a semiconductor processing chamber, comprising: a plurality of dielectric windows coupled to a perforated faceplate; a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows; and a plurality of inductive couplers positioned adjacent to the dielectric windows; wherein each dielectric window among the plurality of dielectric windows has at least a portion of two inductive couplers among the plurality of inductive couplers positioned thereon, and the plurality of inductive couplers include a first subset of inductive couplers and a second subset of inductive couplers, and each inductive coupler of the first subset of inductive couplers comprises: a first lower portion; a second lower portion; and a bridge. Claim 2 A cover according to claim 1, wherein at least a first portion of two inductive couplers among the inductive couplers is configured to generate a magnetic field in a first direction, and at least a second portion of two inductive couplers among the inductive couplers is configured to generate a magnetic field in a second direction opposite to the first direction. Claim 3 delete Claim 4 In claim 1, the bridge is a cover disposed on at least one of the plurality of support members. Claim 5 In paragraph 1, each inductive coupler of the second subset of the inductive couplers is a flat cover. Claim 6 A cover according to claim 1, further comprising a power source and a ground, wherein each of the plurality of inductive couplers is connected to the power source and the ground. Claim 7 A cover for use in a semiconductor processing chamber, comprising: a plurality of dielectric windows coupled to a perforated faceplate; a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows; and a plurality of inductive couplers comprising a first subset of inductive couplers and a second subset of inductive couplers; wherein each inductive coupler of the first subset of inductive couplers comprises: a first lower portion; a second lower portion; and a bridge; wherein the bridge is positioned over at least one of the plurality of support members, the first lower portion is positioned on a first dielectric window among the plurality of dielectric windows, the second lower portion is positioned on a second dielectric window among the plurality of dielectric windows, and the second dielectric window is adjacent to the first dielectric window. Claim 8 In paragraph 7, each inductive coupler of the second subset of the inductive couplers is a flat cover. Claim 9 In paragraph 8, each inductive coupler of the second subset of the inductive couplers is a cover that is positioned entirely over each dielectric window of the plurality of dielectric windows. Claim 10 In paragraph 8, each inductive coupler of the second subset of the inductive couplers is a cover that is a coiled electrode. Claim 11 In claim 8, the second subset of the inductive couplers is a cover positioned laterally adjacent to the outer edge of the cover. Claim 12 In claim 7, each dielectric window among the plurality of dielectric windows is a cover connected to one inductive coupler of a first subset of inductive couplers and one inductive coupler of a second subset of inductive couplers. Claim 13 A cover according to claim 12, wherein one inductive coupler of a first subset of the inductive couplers is configured to generate a magnetic field in a first direction, and one inductive coupler of a second subset of the inductive couplers is configured to generate a magnetic field in a second direction opposite to the first direction. Claim 14 delete Claim 15 In claim 7, a cover further comprising a power source and a ground, wherein each of the plurality of inductive couplers is connected to the power source and the ground. Claim 16 A cover for use in a semiconductor processing chamber, comprising: a plurality of dielectric windows coupled to a perforated faceplate, wherein the plurality of dielectric windows comprises a first subset of dielectric windows and a second subset of dielectric windows; a plurality of support members coupled to the perforated faceplate and positioned between adjacent dielectric windows; and a plurality of inductive couplers comprising a first subset of inductive couplers and a second subset of inductive couplers, wherein the first subset of inductive couplers is non-planar and the second subset of inductive couplers is planar, wherein the first subset of dielectric windows has portions of two inductive couplers of the first subset of inductive couplers positioned thereon, and the second subset of dielectric windows has portions of one inductive coupler of the first subset of inductive couplers and one inductive coupler of the second subset of inductive couplers positioned thereon. Claim 17 In paragraph 16, the second subset of the genome windows is a cover located laterally adjacent to the outer edge of the cover. Claim 18 In paragraph 16, the first subset of the inductive couplers comprises: a first lower portion; a second lower portion; and a bridge, each comprising a cover. Claim 19 In paragraph 18, the bridge is a cover disposed on at least one of the plurality of support members. Claim 20 In paragraph 16, the portion of the two inductive couplers located on the first subset of the dielectric windows generates magnetic fields in opposite directions; and the portion of one inductive coupler of the first subset of the inductive couplers and one inductive coupler of the second subset of the inductive couplers located on the second subset of the dielectric windows generate magnetic fields in opposite directions, a cover.

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