Ion filter and process chamber

Abstract

The present application discloses an ion filter and a process chamber. The ion filter comprises: a filter main body portion, wherein the filter main body portion is provided with a plurality of filter holes, the filter main body portion is provided with a first surface on which the outlet ends of the filter holes are located, and in the direction of the central axis of the filter main body portion, the center of the first surface protrudes from the plane where the edge of the filter main body portion is located. The ion filter of the present application can adjust the distribution density of free radicals and the distribution density of ions, thereby improving the etching quality of a wafer.

Description

Ion filters and process chambers Technical Field

[0001] This application relates to the field of processing equipment technology, specifically to an ion filter and a process chamber. Background Technology

[0002] With the rapid development of semiconductor device manufacturing processes, the requirements for the performance and integration of semiconductor devices are becoming increasingly stringent, leading to the widespread application of plasma technology. In systems that utilize plasma for etching or deposition, the distribution of plasma within the process chamber has a significant impact on the uniformity of the etching results.

[0003] In semiconductor processing equipment, the radio frequency (RF) power output from the RF power supply is applied to the coil through a matching converter. This RF power, coupled by the coil, generates plasma within the process chamber via a dielectric window. However, because the evacuation devices in most semiconductor processing equipment are offset from the axis of the process chamber, the gas flow rate at the wafer edge is faster than at the center. This results in shorter ion residence times at the wafer edge, leading to a higher ion density at the wafer center and a lower ion density at the edge. Consequently, the wafer edge etching is insufficient, resulting in a "footing" phenomenon that negatively impacts the wafer etching quality. Summary of the Invention

[0004] This application discloses an ion filter and a process chamber to improve the etching quality of wafers.

[0005] To achieve the above objectives, according to one aspect of this application, an ion filter is provided, comprising: a filter body portion having a plurality of filter holes;

[0006] The filter body has a first surface where the outlet ends of each of the filter holes are located, and the center of the first surface protrudes from the plane where the edge of the filter body is located along the central axis of the filter body.

[0007] In some embodiments, the first surface is conical.

[0008] In some embodiments, the filter body is plate-shaped, and the filter body also has a second surface facing away from the first surface, with the inlet end of each filter hole located on the second surface;

[0009] The second surface is conical.

[0010] In some embodiments, the acute angle β formed between the first surface and a plane perpendicular to the central axis of the filter body is greater than or equal to 5 degrees and less than or equal to 20 degrees.

[0011] In some embodiments, at least one connecting portion is connected to the edge of the filter body portion and extends along the edge of the filter body portion.

[0012] In some embodiments, there is one connecting portion connected end to end along the edge of the filter body portion, or there are multiple connecting portions, which are spaced apart along the edge of the filter body portion.

[0013] According to another aspect of this application, a process chamber is provided, comprising:

[0014] The cavity has a filter port;

[0015] The aforementioned ion filter element is located at the filter port.

[0016] In some embodiments, the cavity includes: a first reaction chamber and a second reaction chamber, wherein,

[0017] The second reaction chamber is equipped with a wafer carrier, and the top wall of the second reaction chamber is provided with the filter port;

[0018] The first reaction chamber is located above the second reaction chamber. One end of the first reaction chamber is connected to the second reaction chamber through the filter holes of the filter body. The other end of the first reaction chamber is used to connect to the air intake assembly. The first surface of the filter body is opposite to the bearing surface of the wafer carrier device.

[0019] In some embodiments, the filter body is coaxial with the wafer carrier.

[0020] In some embodiments, the ratio of the projected area of ​​the first surface on the wafer carrier to the area of ​​the carrier surface is greater than or equal to 0.3 and less than or equal to 0.6.

[0021] In some embodiments, the distance between the bearing surface of the wafer carrier and the lower surface of the top wall of the second reaction chamber is a first distance, the minimum distance between the bearing surface of the wafer carrier and the first surface is a second distance, and the ratio of the second distance to the first distance is greater than or equal to 0.1 and less than or equal to 0.15.

[0022] In some embodiments, the cavity is provided with a medium cylinder and a medium window, the medium cylinder forming the first reaction cavity, and the medium window serving as the top wall of the second reaction cavity.

[0023] In some embodiments, the process chamber further includes an upper electrode assembly, which includes a first coil group and a second coil group coaxially sleeved on the outside of the dielectric cylinder, wherein the maximum distance from the first coil group to the dielectric cylinder is less than the minimum distance from the second coil group to the dielectric cylinder.

[0024] In some embodiments, the minimum distance from the first coil group to the dielectric window is greater than the minimum distance from the second coil group to the dielectric window.

[0025] In some embodiments, the ratio of the minimum distance from the end of the dielectric tube connected to the dielectric window to the first coil group to the length of the dielectric tube is greater than or equal to 0.33 and less than or equal to 0.67.

[0026] In some embodiments, the ratio of the outer diameter of the dielectric cylinder to the inner diameter of the first coil group is greater than or equal to 0.8 and less than 1.

[0027] In some embodiments, the ratio of the inner diameter of the first coil group to the inner diameter of the second coil group is greater than or equal to 0.2 and less than or equal to 0.5.

[0028] The ion filter disclosed in this application includes a filter body portion having a plurality of filter holes; the filter body portion has a first surface where the outlet end of each filter hole is located, and the center of the first surface protrudes from the plane where the edge of the filter body portion is located along the central axis of the filter body portion.

[0029] When plasma passes through the ion filter, most of the ions in the plasma are filtered out, while free radicals can pass through. In addition, since the center of the first surface protrudes from the plane containing the edge of the filter body along the central axis of the filter body, the discharge space of ions on the side of the filter body adjacent to the center of the first surface is compressed, thereby causing the ions to exhibit a distribution state of low density at the center and high density at the edge.

[0030] Because the filter body has a dense and uniformly distributed number of filter holes, high-energy ions will collide and lose energy when passing through the filter holes. Therefore, the filter holes are selective for ions. When plasma containing ions and free radicals passes through the ion filter, the ions will lose energy. Therefore, the main components of the plasma after passing through the ion filter are free radicals and residual reactive gases. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.

[0032] Figure 1 shows a schematic diagram of the structure of the process chamber in an optional embodiment of this application;

[0033] Figure 2 shows a schematic diagram of the positional relationship between the first coil group and the second coil group in Figure 1 and the dielectric cylinder;

[0034] Figure 3 shows a side view of the ion filter in Figure 1;

[0035] Figure 4 shows a perspective view of the ion filter element in Figure 1 from one angle;

[0036] Figure 5 shows a top view of the ion filter in Figure 1;

[0037] Figure 6 shows a schematic diagram of the sheath distribution during wafer processing in a process chamber according to an optional embodiment of this application;

[0038] Figure 7 shows a simulation diagram of the center-to-edge ion density distribution of a wafer in a process chamber according to an alternative embodiment of this application.

[0039] Explanation of key component symbols: 12, connecting hole; 20, upper electrode assembly; 21, first coil group; 211, first coil section; 212, First connecting post; 22, Second coil group; 221, Second coil section; 222, Second connecting post; 23, Upper RF power supply; 24, Upper matching unit; 241, Power divider network; 31, First reaction chamber; 32, Dielectric cylinder; 33, Dielectric window; 40, Second reaction chamber; 41, Filter port; 50, Ion filter element; 51, Filter body section; 511, Filter hole; 512, Edge of filter body section; 513, First surface; 514, Second surface; 52, Connecting part; 521, Mounting hole; 60, Wafer carrier; 61, Carrier surface; 70, Inlet assembly; 80, Lower electrode assembly; 81, Lower RF power supply; 82, Lower matching unit; 83, Coaxial feed structure; 84, Support ring; 90, Sheath layer; 100, Wafer. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] As one embodiment of the disclosure in this application, an ion filter is disclosed. As shown in Figures 1 and 3, the ion filter 50 includes a filter body 51 having a plurality of filter holes 511. The filter body 51 has a first surface 513 where the outlet end of each filter hole 511 is located. The center of the first surface 513 protrudes from the plane containing the edge of the filter body 51 along the central axis of the filter body 51 (i.e., the central axis O in Figure 3). The edge of the first surface 513 constitutes the edge 512 of the filter body 51.

[0042] When plasma passes through the filter holes 511 of the ion filter 50, most of the ions in the plasma are filtered out, while free radicals can pass through the filter holes 511 of the ion filter 50. In addition, since the center of the first surface 513 protrudes from the plane containing the edge of the filter body 51 along the central axis of the filter body 51, the discharge space of ions on the side of the filter body 51 adjacent to the center of the first surface 513 is compressed, thereby causing the ions to exhibit a distribution state with low center density and high edge density.

[0043] Since the filter body 51 is provided with a dense and uniformly distributed plurality of filter holes 511, high-energy ions will collide and lose energy when passing through the filter holes 511. Therefore, the filter holes 511 are selective for ions. When plasma containing ions and free radicals passes through the ion filter 50, the ions will lose energy. Therefore, the main components of the plasma after passing through the ion filter 50 are free radicals and residual reactive gases.

[0044] In some embodiments, as shown in Figures 3 to 5, the first surface 513 is tapered. That is, the orthographic projection size of the first surface 513 on a plane perpendicular to the central axis of the filter body 51 gradually decreases at different positions of its edge toward the center.

[0045] Furthermore, in some embodiments, the filter body 51 is plate-shaped, and the filter body 51 also has a second surface 514 facing away from the first surface 513, with the inlet end of each filter hole 511 located on the second surface 514; the second surface 514 is conical.

[0046] In some embodiments, the ion filter 50 further includes at least one connecting portion 52, which is connected to the edge of the filter body portion 51 and extends along the edge of the filter body portion 51. In embodiments where both the first surface 513 and the second surface 514 are tapered, the edges of the first surface 513 and the second surface 514 form the edge 512 of the filter body portion 51 and are connected to the connecting portion 52.

[0047] Furthermore, in some embodiments, there is a single connecting portion 52, which is connected end to end along the edge of the filter body portion 51. That is, the connecting portion 52 is in the form of a closed loop, which surrounds the circumference of the filter body portion 51 and is connected to the edge of the filter body portion 51.

[0048] In other embodiments, there are multiple connecting portions 52, which are spaced apart along the edge of the filter body portion 51. That is, multiple connecting portions 52 are spaced apart circumferentially along the filter body portion 51, and each connecting portion 52 is connected to the edge of the filter body portion 51. The specific structure of the connecting portions 52 is not specifically limited here and can be designed according to specific usage requirements.

[0049] As one embodiment of the content disclosed in this application, an embodiment of this application discloses a process chamber, as shown in Figure 1. Figure 1 is a structural schematic diagram of a process chamber disclosed in this application embodiment. The process chamber includes a cavity and the aforementioned ion filter 50. The cavity has a filter port 41; the ion filter 50 is located at the filter port 41. The ion filter 50 is positioned at the filter port 41 to filter ions in the gas passing through the filter port 41, allowing free radicals and residual reactive gases to pass through the filter port 41. This facilitates the adjustment of the distribution state of free radicals and ions within the cavity, which is beneficial for improving the etching quality of the wafer.

[0050] The cavity includes a first reaction chamber 31 and a second reaction chamber 40. A wafer carrier 60 is disposed within the second reaction chamber 40. A filter port 41 is disposed on the top wall of the second reaction chamber 40, located at the central reaction region of the second reaction chamber 40. Above the second reaction chamber 40, one end of the first reaction chamber 31 is connected to the second reaction chamber 40 through the filter port 41, and the other end of the first reaction chamber 31 is connected to the air intake assembly 70. The first surface 513 of the filter body 50 is opposite to the bearing surface 61 of the wafer carrier 60. The first plasma in the first reaction chamber 31 flows into the second reaction chamber 40 through the filter holes 511 of the ion filter element 50 at the filter port 41.

[0051] As shown in Figure 1, the ion filter 50 is located at the filter port 41. The ion filter 50 is configured to filter the gas flowing from the first reaction chamber 31 to the second reaction chamber 40, thereby filtering out ions from the plasma in the first reaction chamber 31 and allowing free radicals and residual reactive gas to flow into the second reaction chamber 40. Since the filter port 41 is located in the central reaction region of the second reaction chamber 40, free radicals enter the second reaction chamber 40 and concentrate in the central reaction region, resulting in a lower ion density in the central reaction region of the second reaction chamber 40 compared to the ion density in the edge reaction regions of the second reaction chamber 40. Since the thickness of the sheath is inversely proportional to the ion density, the sheath is thinner in areas with higher ion density. When the ion density in the central reaction region of the second reaction chamber 40 is lower than the ion density in the edge reaction region of the second reaction chamber 40, the sheath thickness at the edge of the wafer 100 is less than the sheath thickness at the center of the wafer 100. The direction of ion acceleration will be bent to the centripetal side, bombarding the footing on the centrifugal side of the edge, improving the effect of ion bombardment on the edge of the wafer 100, and reducing the footing phenomenon at the edge of the wafer 100.

[0052] It should be noted that the second reaction chamber 40 includes a wafer carrier device 60 for supporting the wafer 100. The wafer carrier device 60 has a carrier surface for supporting the wafer 100. The central reaction region of the second reaction chamber 40 refers to a columnar region formed with the perpendicular bisector of the carrier surface 61 as its central axis. The minimum distance from the orthographic projection of the boundary of the columnar region onto the carrier surface 61 to the center of the carrier surface 61 is less than or equal to half the minimum distance from the edge of the carrier surface 61 to the center of the carrier surface 61. In other words, the central axis of the second reaction chamber 40 is not necessarily coaxial with the central reaction region of the second reaction chamber 40, but the perpendicular bisector of the carrier surface 61 is coaxial with the central reaction region.

[0053] If the second reaction chamber 40 has multiple wafer carrier devices 60, then the second reaction chamber 40 has multiple central reaction regions.

[0054] In some embodiments, the reactant gas includes a fluorine-based gas. Of course, the reactant gas may also include other gaseous components, which are not specifically limited here.

[0055] In some embodiments, a medium cylinder 32 and a medium window 33 are provided inside the cavity. The medium cylinder 32 surrounds the first reaction cavity 31, and the medium window 33 serves as the top wall of the second reaction cavity 40. One end of the medium cylinder 32 is connected to the medium window 33, and the medium window 33 has a filter port 41. Both ends of the medium cylinder 32 are open structures, and the air intake assembly 70 is located at the end of the medium cylinder 32 away from the medium window 33. The reaction gas ejected from the air intake assembly 70 flows through the first reaction cavity 31 to the second reaction cavity 40.

[0056] In some embodiments, the medium cylinder 32 and the medium window 33 can be an integral structure or a separate structure; no specific limitation is made here.

[0057] In some embodiments, the dielectric cylinder 32 and the dielectric window 33 are made of ceramic. Of course, the materials of the dielectric cylinder 32 and the dielectric window 33 can be the same or different; there are no specific limitations here, and the design can be based on the reaction gas.

[0058] In some embodiments, the process chamber further includes an upper electrode assembly 20, a portion of which is located within the chamber. The upper electrode assembly 20 excites the reactive gases in the first reaction chamber 31 and the second reaction chamber 40 to generate plasma. The reactive gases flow from the first reaction chamber 31 into the second reaction chamber 40. Under the excitation of the upper electrode assembly 20, the reactive gases dissociate in the first reaction chamber 31 to generate a first plasma. Since the reactive gases are not fully dissociated in the first reaction chamber 31, and some reactive gases remain undissociated, the first plasma comprises free radicals, ions, and residual reactive gases. The remaining reactive gases can enter the second reaction chamber 40 and dissociate to generate a second plasma.

[0059] Since only free radicals and residual reactive gases in the first plasma can enter the second reaction chamber 40, free radical etching is achieved. The residual gas entering the second reaction chamber 40 is ionized by the upper electrode assembly 20 to generate a second plasma. Since the ion density in the second plasma is greater than the free radical density, ion etching is achieved. By adjusting the power distribution of the upper electrode assembly 20, the ratio of free radicals to ions can be adjusted, enabling precise etching of free radicals and ions simultaneously.

[0060] In some embodiments, the ion filter 50 and the media window 33 are an integral structure. In other embodiments, the ion filter 50 and the media window 33 are separate structures, and the ion filter 50 and the media window 33 are connected, for example, the ion filter 50 and the media window 33 are detachably connected.

[0061] In some embodiments, the ion filter element 50 is made of aluminum.

[0062] In some embodiments, as shown in Figures 1, 3 to 5, the ion filter 50 includes a filter body 51, which has a plurality of filter holes 511. The filter holes 511 are connected to the first reaction chamber 31 and the second reaction chamber 40. By providing a plurality of filter holes 511 on the filter body 51, not only can ions be filtered out, but the gas flowing from the first reaction chamber 31 into the second reaction chamber 40 can also be uniformly distributed to avoid excessive concentration of gas in the second reaction chamber 40 and to ensure the etching morphology of the wafer 100.

[0063] In some embodiments, as shown in Figures 3 to 5, the ion filter 50 further includes at least one connecting portion 52. The connecting portion 52 is connected to the surface of the media window 33 facing the second reaction chamber 40, and the connecting portion 52 is connected to the edge of the filter body portion 51. The connecting portion 52 facilitates the connection between the ion filter 50 and the media window 33. In embodiments where both the first surface 513 and the second surface 514 are tapered, the edges of the first surface 513 and the second surface 514 form the edge 512 of the filter body portion 51 and are connected to the connecting portion 52.

[0064] In some embodiments, as shown in Figures 3 to 5, the connecting portion 52 is detachably connected to the medium window 33. For example, the connecting portion 52 has a mounting hole 521 through which an insulating fastener, such as a resin screw, passes and is connected to the medium window 33.

[0065] In some embodiments, as shown in Figures 3 to 5, the filter body 51 is plate-shaped, and both the first surface 513 and the second surface 514 are tapered. The edges of the first surface 513 and the second surface 514 form the edges 512 of the filter body 51. The edges 512 of the filter body 51 are connected to the connecting portion 52, and the filter body 51 is located on the side of the connecting portion 52 away from the media window 33. The edges 512 of the filter body 51 are integrally formed with the connecting portion 52. The filter body 51 extends from the connecting portion 52 to the side away from the media window 33, and the sharp corner of the filter body 51 (i.e., the center of the first surface 513) is furthest from the connecting portion 52, so that the sharp corner of the filter body 51 is closest to the center of the wafer 100.

[0066] In some embodiments, as shown in FIG1, the filter body 51 is coaxial with the wafer carrier 60. The wafer 100 is coaxially placed on the wafer carrier 60 such that the filter body 51 is coaxial with the wafer 100, and the sharp corner of the filter body 51 (i.e., the center of the first surface 513) is closest to the wafer 100, so that the discharge height below the filter hole 511 near the sharp corner in the filter body 51 is smaller, and the discharge space V1 corresponding to the filter hole 511 near the sharp corner is smaller, while the discharge height below the filter hole 511 away from the sharp corner is larger, and the discharge space V2 below the filter hole 511 away from the sharp corner is larger. Since the contact area S between the plasma and the ion filter 50 is considered to be the same, the S / V1 ratio of the filter hole 511 near the sharp corner is relatively large, resulting in more plasma surface loss and thus a lower ion density near the sharp corner. Conversely, the S / V2 ratio of the filter hole 511 away from the sharp corner is relatively small, resulting in less plasma surface loss and thus a higher ion density away from the sharp corner. This leads to a phenomenon where the ion density is low at the center of the wafer 100 and gradually increases from the center of the wafer 100 towards the edge, reducing the footing phenomenon at the edge of the wafer 100 and improving the etching morphology of the edge of the wafer 100.

[0067] In some embodiments, as shown in FIG1, the wafer carrier 60 has a carrier surface 61 for carrying the wafer 100, and the ratio of the projected area of ​​the orthographic projection of the first surface 513 of the filter body 51 on the wafer carrier 60 to the area of ​​the carrier surface 61 is greater than or equal to 0.3 and less than or equal to 0.6. This arrangement can further increase the ion density difference between the edge reaction region and the central reaction region of the second reaction chamber 40, which is beneficial to improving the etching effect on the edge of the wafer 100 and avoiding the generation of footing. For example, the ratio of the projected area of ​​the orthographic projection of the first surface 513 on the wafer carrier 60 to the area of ​​the carrier surface 61 is 0.4. The ratio of the projected area of ​​the orthographic projection of the first surface 513 on the wafer carrier 60 to the area of ​​the carrier surface 61 is 0.5.

[0068] In some embodiments, as shown in FIG1, the maximum distance between the wafer carrier 60 and the lower surface of the top wall (i.e., dielectric window 33) of the second reaction chamber 40 is a first distance H1, and the minimum distance between the wafer carrier 60 and the first surface 513 is a second distance H2. The ratio of the second distance H2 to the first distance H1 is greater than or equal to 0.1 and less than or equal to 0.15. This arrangement ensures that there is a certain ionization space between the ion filter 50 and the center of the wafer 100, ensuring that ions are generated at the center of the wafer 100, so that the ions can etch the center of the wafer 100, thereby ensuring the uniformity of the etching of the wafer 100.

[0069] In some embodiments, as shown in FIG3, the acute angle β formed between the first surface 513 and the plane perpendicular to the central axis of the filter body portion 51 is greater than or equal to 5 degrees and less than or equal to 20 degrees. This arrangement, while ensuring the uniformity of etching the wafer 100, is beneficial to further increase the ion density in the edge reaction region and further reduce the ion density in the central reaction region, thereby further reducing the risk of footing at the edge of the wafer 100.

[0070] In some embodiments, the ratio of the ion density of the edge reaction region to the ion density of the central reaction region is greater than 1 to reduce the risk of footing at the edge of the wafer 100.

[0071] In some embodiments, the ion filter element 50 may be disposed inside the filter port 41 or on one side of the filter port 41, without any specific limitation.

[0072] In some embodiments, as shown in FIG2, the upper electrode assembly 20 includes a first coil group 21 and a second coil group 22 coaxially sleeved on the outside of the dielectric cylinder 32. The maximum distance from the first coil group 21 to the dielectric cylinder 32 is less than the minimum distance from the second coil group 22 to the dielectric cylinder 32. This arrangement allows the first coil group 21 of the upper electrode assembly 20 to ionize the reactive gas in the first reaction chamber 31 to generate a first plasma, while the second coil group 22 ionizes the reactive gas in the second reaction chamber 40 to generate a second plasma. This allows the second coil group 22 to ionize the reactive gas in the edge reaction region of the second reaction chamber 40 to generate a second plasma, which is beneficial to increasing the ion concentration in the edge reaction region of the second reaction chamber 40.

[0073] In some embodiments, as shown in FIG1, the minimum distance from the first coil group 21 to the dielectric window 33 is greater than the minimum distance from the second coil group 22 to the dielectric window 33. This arrangement allows the second coil group 22, located outside the first coil group 21, to be closer to the dielectric window 33. This facilitates the second coil group 22 in fully exciting the remaining reactive gas in the second reaction chamber 40 to ionize and generate the second plasma. At the same time, since the second coil group 22 is farther from the first reaction chamber 31, it helps to improve the ionization efficiency of the edge reaction region in the second reaction chamber 40 and increase the ion density in the edge reaction region.

[0074] In some embodiments, the ratio of the minimum distance from the end of the dielectric cylinder 32 connected to the dielectric window 33 to the first coil group 21 to the length of the dielectric cylinder 32 is greater than or equal to 0.33 and less than or equal to 0.67. Limiting this ratio within a reasonable range ensures that the electromagnetic field generated by the first coil group 21 covers the area of ​​the first reaction chamber 31, thereby ensuring the ionization efficiency of the reactant gas in the first reaction chamber 31.

[0075] In some embodiments, the ratio of the outer diameter of the dielectric cylinder 32 to the inner diameter of the first coil group 21 is greater than or equal to 0.8 and less than 1. This arrangement ensures that the electromagnetic field generated by the first coil group 21 covers the range of the first reaction chamber 31, thereby ensuring the ionization efficiency of the reaction gas in the first reaction chamber 31.

[0076] In some embodiments, the ratio of the inner diameter of the first coil group 21 to the inner diameter of the second coil group 22 is greater than or equal to 0.2 and less than or equal to 0.5. This arrangement ensures that the second coil group 22 is at a certain distance from the central reaction region of the second reaction cavity 40, and is closer to the edge reaction region of the second reaction cavity 40. This helps to increase the ion density in the edge reaction region of the second reaction cavity 40, reduce the ion density in the central reaction region, and reduce the footing phenomenon at the edge of the wafer 100.

[0077] In some embodiments, referring to FIG1, the upper electrode assembly 20 further includes an upper RF power supply 23 and an upper matching unit 24. The upper RF power supply 23 is connected to the upper matching unit 24 via a coaxial cable. The upper RF power supply 23 provides RF power to the first coil group 21 and the second coil group 22 through the upper matching unit 24, so that the first coil group 21 excites the reaction gas in the first reaction chamber 31 to generate a first plasma, and the second coil group 22 excites the reaction gas in the second reaction chamber 40 to generate a second plasma.

[0078] The upper matching unit 24 includes a power divider network 241, which can adjust the current output ratio of the first coil group and the second coil group through an internal capacitor.

[0079] As shown in Figure 2, the first coil group 21 includes a first coil section 211 and a plurality of first connecting posts 212. One end of the first connecting post 212 is connected to the first coil section 211, and the other end of the first connecting post 212 is connected to the upper matching unit 24. The power provided by the upper matching unit 24 is fed into the first coil section 211 through the plurality of first connecting posts 212.

[0080] As shown in Figure 2, the second coil group 22 includes a second coil section 221 and a plurality of second connecting posts 222. One end of the second connecting post 222 is connected to the second coil section 221, and the other end of the second connecting post 222 is connected to the upper matching unit 24. The power provided by the upper matching unit 24 is fed into the second coil section 221 through the plurality of second connecting posts 222.

[0081] In some embodiments, referring to FIG1, the process chamber further includes a lower electrode assembly 80, which includes a wafer carrier 60, a lower RF power supply 81, a lower matching device 82, a coaxial feed structure 83, and a support ring 84. The lower RF power supply 81 is connected to the lower matching device 82 via a coaxial cable, and the lower matching device 82 is fed to the wafer carrier 60 via the coaxial feed structure 83, thereby enabling the wafer carrier 60 to...

[0082] In some embodiments, the bottom wall of the process chamber has at least one connection hole 12, the support ring 84 is located in the second reaction chamber 40 and is connected to the bottom wall of the process chamber, the support ring 84 is coaxial with the connection hole 12, and the wafer carrier device 60 is disposed on the support ring 84 and covers the central hole of the support ring 84, and the coaxial power supply structure 83 passes through the central hole and the support ring 84 and is connected to the wafer carrier device 60.

[0083] Theoretically, the ion movement trajectory is perpendicular to the sheath layer 90. In order to avoid footing on the edge side of the wafer 100, the ideal distribution trend of the sheath layer 90 should be that the edge sheath layer 90 is thinner and the center sheath layer 90 is thicker. This can avoid the footing phenomenon. The sheath layer is usually uniformly distributed above the wafer 100, and the shell layer distribution cannot be effectively adjusted.

[0084] However, the thickness of the sheath 90 is proportional to the Debye length, and the thickness s of the sheath and the Debye length λ D The calculation formula is as follows:

[0085] In the above formula, s is the thickness of the sheath, in mm; λ D φ is the Debye length in mm; e is the charge in coulombs (C); φ0 is the electric potential in volts (V); Te is the electron temperature in electron volts (eV); ne is the ion density in cm³. 3 ε0 is the vacuum permittivity, specifically 8.854187817 × 10⁻⁶. -12 F / m.

[0086] That is, the thickness of the sheath layer 90 is inversely proportional to the ion density. The higher the ion density, the thinner the sheath layer 90. In other words, since the ion density is inversely proportional to the thickness of the sheath layer 90, and the ion density is low at the center of the wafer 100 and high at the edge of the wafer 100 in this application, the sheath layer 90 on the wafer 100 in this application is thick at the center and thin at the edge, forming an ideal sheath layer distribution trend. The distribution trend of the sheath layer 90 is shown in Figure 6.

[0087] Furthermore, in Figure 6, the direction of the arrow is the trajectory of the ion. The angle between the trajectory of the ion and the X-axis is denoted as θ. The magnitude of this value can characterize the magnitude of the electric field in the X-axis component. The closer θ is to 0, the greater the force on the ion in the X-axis direction, and the more obvious the etching effect on the footing. In this application, the intensity of ion etching at the edge of wafer 100 is controlled by adjusting the ion density at the edge and center of wafer 100.

[0088] The simulation data of the ion density distribution from the center to the edge of wafer 100 is shown in Figure 7. As can be seen from Figure 7, the ion density at the edge of wafer 100 is higher than that at the center. When the power of the upper electrode increases, the ion density at the edge of wafer 100 increases significantly, while the increase at the center is smaller. According to the sheath theory, a very thin sheath will form at the edge of wafer 100, while the sheath at the center of wafer 100, due to the lower plasma density, will be thicker. The direction of ion acceleration will be bent towards the centripetal side, bombarding the footing on the centrifugal side of the edge. The magnitude of the bombardment force can be controlled by the current ratio and the power of the upper electrode. By adjusting the current ratio and the power of the upper electrode, the ratio of the ion density at the edge to that at the center of wafer 100 can be changed, allowing for targeted treatment of different footing morphologies.

[0089] In summary, the process chamber in this application can not only meet the requirements of free radical etching in BVR process, but also precisely control ion etching. At the same time, the dominant element of etching can be adjusted by the upper electrode assembly 20, reducing footing and improving the etching morphology of the edge of wafer 100.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The above embodiments are merely illustrative of several implementation methods described in detail, but they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this specification, and these all fall within the scope of protection of this specification. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An ion filter, characterized by, Comprising: a filter body portion having a plurality of filter holes; the filter body portion has a first surface where the outlet ends of the filter holes are located, the center of the first surface is convex to the plane where the edge of the filter body portion is located along the direction of the central axis of the filter body portion.

2. The ion filter of claim 1, wherein, The first surface is conical.

3. The ion filter of claim 2, wherein, The filter body portion is plate-shaped, and the filter body portion further has a second surface facing away from the first surface, the inlet ends of the filter holes are located on the second surface; The second surface is conical.

4. The ion filter of claim 1, wherein, The acute angle β formed between the first surface and the plane perpendicular to the central axis of the filter body portion is greater than or equal to 5 degrees and less than or equal to 20 degrees.

5. The ion filter of claim 1, wherein, Further comprising: at least one connecting portion connected with the edge of the filter body portion, and the connecting portion extends along the edge of the filter body portion.

6. The ion filter of claim 5, wherein, The connecting portion is one, and the connecting portion is connected end to end along the edge of the filter body portion, or the connecting portion is multiple, and multiple connecting portions are arranged at intervals along the edge of the filter body portion.

7. A process chamber, comprising: Comprising: a cavity having a filter port; the ion filter of any one of claims 1 to 6 is located at the filter port.

8. The process chamber of claim 7, wherein, The cavity comprises: a first reaction cavity and a second reaction cavity, wherein, the second reaction cavity is provided with a wafer carrying device, and the top wall of the second reaction cavity is provided with the filter port; the first reaction cavity is located above the second reaction cavity, one end of the first reaction cavity communicates with the second reaction cavity through the filter holes of the filter body portion, and the other end of the first reaction cavity is used to communicate with a gas inlet assembly; the first surface of the filter body portion is opposite to the carrying surface of the wafer carrying device.

9. The process chamber of claim 7 or 8, wherein, The filter body portion is coaxial with the wafer carrying device.

10. The process chamber of claim 8, wherein, The ratio of the projection area of the normal projection of the first surface on the wafer carrying device to the area of the carrying surface is greater than or equal to 0.3 and less than or equal to 0.

6.

11. The process chamber of claim 8, wherein, The distance between the carrying surface of the wafer carrying device and the lower surface of the top wall of the second reaction cavity is a first distance, the minimum distance between the carrying surface of the wafer carrying device and the first surface is a second distance, and the ratio of the second distance to the first distance is greater than or equal to 0.1 and less than or equal to 0.

15.

12. The process chamber of claim 8 or 11, wherein, The cavity is provided with a medium cylinder and a medium window, the medium cylinder surrounds the first reaction cavity, and the medium window serves as the top wall of the second reaction cavity.

13. The process chamber of claim 12, wherein, The process chamber further comprises an upper electrode assembly, the upper electrode assembly comprises a first coil group and a second coil group coaxially sleeved outside the medium cylinder, and the maximum distance from the first coil group to the medium cylinder is less than the minimum distance from the second coil group to the medium cylinder.

14. The process chamber of claim 13, wherein, The minimum distance from the first coil group to the medium window is greater than the minimum distance from the second coil group to the medium window.

15. The process chamber of claim 13, wherein, The ratio of the minimum distance from the end of the medium cylinder connected with the medium window to the first coil group to the length of the medium cylinder is greater than or equal to 0.33 and less than or equal to 0.

67.

16. The process chamber of claim 13, wherein, The ratio of the outer diameter of the medium cylinder to the inner diameter of the first coil group is greater than or equal to 0.8 and less than 1.

17. The process chamber of claim 13, wherein, The ratio of the inner diameter of the first coil set to the inner diameter of the second coil set is greater than or equal to 0.2 and less than or equal to 0.

5. The ratio of the inner diameter of the first coil set to the inner diameter of the second coil set is greater than or equal to 0.2 and less than or equal to 0.5.

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