Focusing ring, etching system

Abstract

The application relates to a focusing ring and an etching system, and relates to the technical field of semiconductors. When the focusing ring is used for semiconductor etching, the first film layer in the first groove has a plurality of protruding structures, and a first included angle is formed between two adjacent protruding structures. The first film layer can reflect and absorb the incoming plasma, thereby consuming the plasma, and the problem of focusing ring deviation and tilting caused by plasma aggregation is solved. Furthermore, since the focusing ring is not deviated and tilted, the generation of the bottom micro groove is avoided, and the yield of wafer etching is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor technology, in particular to a focusing ring and an etching system. BACKGROUND

[0002] In the existing semiconductor etching device, a wafer is placed on an electrostatic chuck (ESC), a focusing ring is arranged outside the electrostatic chuck, the focusing ring is used for limiting the wafer, and upper and lower electrodes are arranged on the upper and lower sides of the electrostatic chuck respectively. The electric field generated by the upper and lower electrodes can control the plasma bombarding the wafer between the upper and lower electrodes to achieve the purpose of etching the wafer.

[0003] However, when the wafer is etched by using the plasma, the bombardment of the plasma will inevitably cause the edge region of the focusing ring to deviate and tilt with the passage of time of radio frequency (RF). Due to the electric field, the edge region of the wafer will form a concentrated ion beam, which is more likely to cause the deviation and tilt of the focusing ring. If the focusing ring deviates and tilts, the plasma will be reflected to the same position at some positions of the focusing ring, so that some regions of the wafer are etched to form bottom microgrooves, thereby affecting the yield of wafer etching.

[0004] Therefore, how to improve the yield of wafer etching during etching has become a technical problem to be solved by those skilled in the art. SUMMARY

[0005] Therefore, it is necessary to provide a focusing ring and an etching system capable of improving the yield of wafer etching.

[0006] To achieve the above purpose, in one aspect, the present application provides a focusing ring, which comprises:

[0007] A first ring body, the first ring body comprises a ring structure and a first film layer;

[0008] In a first direction, one side of the ring structure has a first groove, and the first film layer covers the surface of the first groove; the first direction is perpendicular to the radial direction of the first ring body.

[0009] The first film layer comprises a plurality of protruding structures, and adjacent two protruding structures have a first included angle.

[0010] In one embodiment, the angle of the first included angle is θ1, wherein 0°< θ1< 180°.

[0011] In one embodiment, the inner wall of the first ring body and the radial direction of the first ring body have a second included angle, and the angle of the second included angle is θ2, wherein 0°< θ2< 90°.

[0012] In one of the embodiments, the first ring body has a second included angle between the inner wall of the first ring body and the radial direction of the first ring body, and the second included angle is θ2, where 90°<θ2<180°.

[0013] In one of the embodiments, the focusing ring further comprises:

[0014] a second ring body located outside the first ring body;

[0015] The height of the second ring body in the first direction is less than the height of the first ring body in the first direction.

[0016] In one of the embodiments, the first ring body further comprises a plurality of first sections arranged at intervals along the circumference of the first ring body, and the second ring body comprises a plurality of second sections arranged at intervals along the circumference of the second ring body;

[0017] The second sections are located on the side of the first sections away from the center of the focusing ring.

[0018] In one of the embodiments, the first ring body further comprises a plurality of first through holes extending along the first direction and arranged at intervals along the circumference of the first ring body, and the first through holes penetrate the first ring body;

[0019] The second ring body comprises a plurality of second through holes extending along the first direction and arranged at intervals along the circumference of the second ring body, and the second through holes penetrate the second ring body;

[0020] The second through holes are located on the side of the first through holes away from the center of the focusing ring.

[0021] In another aspect, the present application also provides an etching system, which comprises:

[0022] an electrostatic chuck for adsorbing a wafer to be etched;

[0023] a focusing ring surrounding the electrostatic chuck, and the focusing ring is any one of the above-mentioned focusing rings;

[0024] a first electrode and a second electrode oppositely arranged for generating an electric field to control the etching of the plasma on the wafer to be etched; and the electrostatic chuck and the focusing ring are located between the first electrode and the second electrode.

[0025] In one of the embodiments, the etching system further comprises:

[0026] a by-product monitoring device connected with the focusing ring for monitoring the by-products after the etching of the wafer to be etched to determine the etching uniformity of the wafer to be etched.

[0027] In one embodiment, the byproduct monitoring device comprises:

[0028] a first detection unit configured to detect byproducts of a first region of the wafer to be etched;

[0029] a second detection unit configured to detect byproducts of a second region of the wafer to be etched; the second region is located between the first region and the focus ring;

[0030] a judging unit configured to judge etching uniformity of the wafer to be etched based on the byproducts of the first region and the second region.

[0031] Compared with the prior art, the above technical solution has the following advantages:

[0032] The focus ring comprises a first ring body, the first ring body comprises a ring structure and a first film layer, the ring structure has a first groove on one side in a first direction, the first film layer covers a surface of the first groove, the first film layer has a plurality of protruding structures, and a first included angle is formed between two adjacent protruding structures.

[0033] When the focus ring is used for semiconductor etching, the first film layer in the first groove has a plurality of protruding structures, and a first included angle is formed between two adjacent protruding structures, so that the first film layer can reflect and absorb the incoming plasma, thereby consuming the plasma, and the problem of focus ring deviation and tilting caused by plasma accumulation is solved. Further, since the focus ring is not deviated and tilted, the generation of bottom micro trenches is avoided, so that the yield of wafer etching is increased. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0035] Figure 1 A top view structural schematic diagram of a focus ring provided by an embodiment of the present application;

[0036] Figure 2 A sectional view structural schematic diagram of a focus ring provided by an embodiment of the present application; Figure 1

[0037] Figure 3 A sectional view structural schematic diagram of a focus ring provided by an embodiment of the present application;

[0038] Figure 4 ​Another cross-sectional view of the focusing ring provided by the embodiment of the present application is shown in FIG. 1C.

[0039] Figure 5 Another cross-sectional view of the focusing ring provided by the embodiment of the present application is shown in FIG. 1C.

[0040] Figure 6 Another top view of the focusing ring provided by the embodiment of the present application is shown in FIG. 1D.

[0041] Figure 7 Provided is Figure 6 A cross-sectional view of the focusing ring provided by the embodiment of the present application is shown in FIG. 2A.

[0042] Figure 8 Provided is Figure 6 Another cross-sectional view of the focusing ring provided by the embodiment of the present application is shown in FIG. 2B.

[0043] Figure 9 Another top view of the focusing ring provided by the embodiment of the present application is shown in FIG. 2C.

[0044] Figure 10 A structure view of the etching system provided by the embodiment of the present application is shown in FIG. 3A.

[0045] Figure 11 Another structure view of the etching system provided by the embodiment of the present application is shown in FIG. 3B.

[0046] Figure 12 A partial top view of the etching system provided by the embodiment of the present application is shown in FIG. 3C.

[0047] Figure 13 A view of the byproduct proportion when etching uniformity is determined and adjusted provided by the embodiment of the present application is shown in FIG. 4.

[0048] Figure 14 A view of the through hole offset when the focusing ring is offset provided by the embodiment of the present application is shown in FIG. 5.

[0049] Legend: 01-first ring body; 02-ring structure; 03-first film layer; 04-protruding structure; 05-second ring body; 06-electrostatic chuck; 07-wafer to be etched; 08-focusing ring; 09-first electrode; 10-second electrode; 11-byproduct monitoring device; 12-first region; 13-second region; 01a-first section; 05a-second section; 01b-first through hole; 05b-second through hole. DETAILED DESCRIPTION

[0050] For the purposes of the present application, a more complete description of which will follow, reference will be made to the accompanying drawings referenced below. The drawings illustrate embodiments of the present application. However, the present application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. It is therefore necessary to set forth more than one embodiment.

[0051] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0052] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It should also be understood that the term "comprising" or "having" etc., specifies the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but does not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0053] Based on the content in the background art, the focus ring position of the existing photolithography process machine is fixed and cannot be flexibly adjusted. With the passage of radio frequency time, the edge of the focus ring will produce deviation and tilt. Due to the deviation and tilt of the edge of the focus ring, the etched plasma will be reflected to a certain position of the wafer to be etched, thereby causing the bottom micro groove at this position. However, the etching index of the existing photolithography process machine for etching the wafer is not easy to characterize, and the in-plane uniformity of the critical dimension of the photolithography process machine is not easy to monitor and adjust, and the state of the wafer etching cannot be judged and adjusted in time.

[0054] In addition, the polymer produced after etching may accumulate in a specific direction in the edge area when it is precipitated, thereby causing a defect problem of the wafer.

[0055] Based on this, the present application provides a focus ring and an etching system, wherein the focus ring comprises a first ring body, the first ring body comprises a ring structure having a first groove in a first direction, and a first film layer covering the surface of the first groove. Since the first film layer has a plurality of protruding structures and the first included angle between adjacent protruding structures can greatly absorb and reflect plasma, thereby consuming plasma, the problem of deviation and tilt of the edge of the focus ring is solved, and the problem of bottom micro groove is solved.

[0056] The etching system comprises an electrostatic chuck arranged between the first electrode and the second electrode, and a focusing ring surrounding the electrostatic chuck, the focusing ring being the focusing ring described above, and the focusing ring can solve the problems of edge deviation and tilt of the focusing ring, and further solve the problem of bottom microgroove, and the etching system adopting the focusing ring can increase the yield of wafer etching.

[0057] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0058] Please refer to Figure 1 , Figure 1 The top view structural schematic diagram of a focusing ring provided in an embodiment of the present application; refer to Figure 2 , Figure 2 For Figure 1 The cross-sectional structural schematic diagram of the focusing ring cut along AA' section; the focusing ring comprises:

[0059] The first ring body 01 comprises a ring structure 02 and a first film layer 03.

[0060] In the first direction M, one side of the ring structure 02 has a first groove, and the first film layer 03 covers the surface of the first groove; the first direction M is perpendicular to the radial direction of the first ring body 01.

[0061] The first film layer 03 comprises a plurality of protruding structures 04, and adjacent two protruding structures 04 have a first included angle.

[0062] Specifically, the first ring body 01 comprises the ring structure 02 and the first film layer 03, wherein the material of the ring structure 02 can be ceramic material or silicon carbide material, and the material of the first film layer 03 can be fluorocarbon polymer, which can reflect and absorb plasma, thereby protecting the first ring body 01, and the materials of the ring structure 02 and the first film layer 03 are not specifically limited. The first film layer 03 comprises a plurality of protruding structures 04, and it should be noted that the shapes of the ring structure 02 and the protruding structure 04 are not specifically limited, and the protruding structure 04 can also be an arc structure, a trapezoidal structure, etc. The first film layer 03 covers the surface of the first groove, and adjacent two protruding structures 04 have a first included angle, and the setting of the first groove and the first included angle can increase the scattering ability of the plasma on the first ring body 01, and more greatly consume the plasma, thereby protecting the first ring body 01.

[0063] Optionally, as shown in Figure 2 In another embodiment of the present application, the angle of the first included angle is θ1, wherein 0°< θ1< 180°.

[0064] Specifically, the first included angle θ1 is in the range of 0° to 180°, and the end values are not included. The first included angle θ1 can be 30°, 60°, 100°, etc., and is not specifically limited.

[0065] When the focusing ring is used for semiconductor etching, the first film layer 03 in the first groove has a plurality of protruding structures 04, and the first included angle is between two adjacent protruding structures 04. The arrangement of the first groove and the first included angle increases the scattering and absorption of the plasma on the first ring body 01, and the plasma is consumed to a greater extent. The problem of focusing ring deviation and tilting caused by plasma beam aggregation is solved. Further, since the focusing ring will not deviate and tilt, the yield of wafer etching is increased.

[0066] Optionally, with reference to Figure 3 , Figure 3 A cross-sectional view of a focusing ring provided in an embodiment of the present application; in another embodiment of the present application, the inner wall of the first ring body 01 and the radial direction of the first ring body 01 have a second included angle, and the angle of the second included angle is θ2, wherein 0°< θ2< 90°.

[0067] Specifically, the inner wall of the first ring body 01 and the radial direction of the first ring body 01 have a second included angle, which means that when the focusing ring is used for semiconductor etching, the included angle between the plane where the wafer to be etched is located and the inner wall of the first ring body 01 is also the second included angle. The value of the second included angle is in the range of 0° to 90°, and the end values are not included. The angle θ2 of the second included angle can be 30°, 60°, 80°, etc., and is not specifically limited.

[0068] Since the second included angle is less than 90° and greater than 0°, that is, it is inclined inward, the plasma can be blocked on the outer surface of the first ring body 01, that is, the plasma is blocked on the side of the first film layer 03 on the surface of the first groove. The first film layer 03 will reflect and absorb the incoming plasma, consume the plasma, thereby shielding the plasma beam directed to a certain position of the wafer to be etched, and avoiding the generation of a bottom micro groove.

[0069] Optionally, with reference to Figure 4 , Figure 4 Another cross-sectional view of a focusing ring provided in an embodiment of the present application; in another embodiment of the present application, the inner wall of the first ring body 01 and the radial direction of the first ring body 01 have a second included angle, and the angle of the second included angle is θ2, wherein 90°< θ2< 180°.

[0070] Specifically, the first ring body 01 has a second included angle between the inner wall of the first ring body 01 and the radial direction of the first ring body 01, which means that when the focusing ring is used for semiconductor etching, the included angle between the plane where the wafer to be etched is located and the inner wall of the first ring body 01 is also the second included angle. The second included angle is in the range of 90° to 180°, and the end values are not included. The angle θ2 of the second included angle can be 100° or 120° or 160°, and is not specifically limited.

[0071] Since the second included angle is less than 180° and greater than 90°, that is, it is inclined outward, the plasma incident on the inner wall can be scattered, and the first film layer 03 can reflect and absorb the plasma beam at the edge, so that the plasma beam incident on a certain position of the wafer to be etched can be shielded, and the bottom micro groove is avoided.

[0072] It should be noted that when the second included angle is 90°, that is, as shown in Figure 2 , since the first film layer 03 can also reflect and absorb the plasma, the angle θ2 of the second included angle is not specifically limited, and can be set according to specific needs.

[0073] Reference Figure 5 , Figure 5 is another cross-sectional view of the focusing ring provided by the embodiment of the present application. It should be noted that the shape of the first ring body 01 is not specifically limited, and the shape of the first ring body 01 can also be as shown in Figure 5 , at this time, the inner wall of the first ring body 01 is in an arc shape, and the angle of the second included angle is different at different positions, for example Figure 5 , θ2 a is less than 180° and greater than 90°, and θ2 b is less than 90° and greater than 0°.

[0074] It should be noted that θ2 b inclined inward can block the plasma at the outer surface of the first ring body 01, and θ2 a inclined outward can scatter the plasma incident on the inner wall, and the first film layer 03 will reflect and absorb the incident plasma, consume the plasma, so as to shield the plasma beam incident on a certain position of the wafer to be etched, and avoid the generation of the bottom micro groove. It should be further noted that Figure 3 , Figure 4 , Figure 5 , the shape of the cross section of the first ring body 01 is only for illustration, and other shapes can be set according to specific needs.

[0075] Optionally, reference Figure 6 , Figure 6 is another top view of the focusing ring provided by the embodiment of the present application. ReferenceFigure 7 , Figure 7 For Figure 6 is a schematic diagram of a cross-section structure of cutting along the section BB' in FIG. 1; reference Figure 8 , Figure 8 For Figure 6 is another schematic diagram of a cross-section structure of cutting along the section BB' in FIG. 1; in another embodiment of the present application, the focusing ring further comprises:

[0076] A second ring body 05 is located outside the first ring body 01.

[0077] The height of the second ring body 05 in the first direction M is less than the height of the first ring body 01 in the first direction M.

[0078] Specifically, the material of the second ring body 05 can be ceramic material or silicon carbide material, etc., which is not specifically limited, and it should be noted that in the first direction M, the height of the second ring body 05 is h, and the height of the first ring body 01 is H, h

[0079] It should be noted that the shape of the second ring body 05 is not specifically limited, and the first ring body 01 and the second ring body 05 are arranged in close proximity, Figure 7 and Figure 8 are only for illustration, and of course can be adjusted as needed. In addition, the first ring body 01 and the second ring body 05 can be separately arranged, or can be the same whole, and for easier description, the first ring body 01 and the second ring body 05 are described in the form of the first ring body 01 and the second ring body 05, which is not specifically limited. In the present embodiment, the first ring body 01 and the second ring body 05 are described in the form of separate bodies.

[0080] Optionally, reference Figure 9 , Figure 9 is another schematic diagram of a top view structure of the focusing ring provided by the present application; in another embodiment of the present application, the first ring body 01 further comprises a plurality of first segments 01a arranged at intervals along the circumference of the first ring body 01, and the second ring body 05 comprises a plurality of second segments 05a arranged at intervals along the circumference of the second ring body 05.

[0081] The second segment 05a is located on the side of the first segment 01a away from the center of the focusing ring.

[0082] Specifically, the first ring body 01 includes multiple first segments 01a arranged at intervals along the circumference of the first ring body 01. It should be noted that if a problem occurs in a certain first segment 01a of the first ring body 01, it can be repaired or adjusted by adjusting or replacing that first segment 01a without adjusting the entire first ring body 01. In other words, the first ring body 01 is movable. Compared with a first ring body 01 without segments, a first ring body 01 with multiple first segments 01a can be adjusted more flexibly.

[0083] Similarly, the second ring body 05 includes multiple second segments 05a arranged at intervals along the circumference of the second ring body 05. It should be noted that if a problem occurs in a certain second segment 05a of the second ring body 05, it can be repaired or adjusted by adjusting or replacing that second segment 05a without adjusting the entire second ring body 05. In other words, the second ring body 05 is movable. Compared with a second ring body 05 without segments, a second ring body 05 with multiple second segments 05a can be adjusted more flexibly.

[0084] When setting up, the second section 05a is placed on the side of the first section 01a away from the center of the focusing ring. In other words, the second section 05a is set to correspond with the first section 01a, which facilitates the subsequent setup of the by-product precipitation system.

[0085] Furthermore, since each first segment 01a includes a first film layer 03, and the first included angle between two adjacent protrusions 04 on the first film layer 03 can be adjusted, the uniformity of wafer etching can be ensured by adjusting the angle of the first included angle during etching. At this time, setting multiple first segments 01a allows for segmental adjustment, which is more flexible and convenient than adjusting the focusing ring as a whole first ring body 01.

[0086] Optional, such as Figure 9 As shown, in another embodiment of this application, the first ring body 01 further includes a plurality of first through holes 01b extending along the first direction M and arranged at circumferential intervals along the first ring body 01, the first through holes 01b penetrating the first ring body 01.

[0087] The second ring body 05 includes a plurality of second through holes 05b extending along the first direction M and arranged at intervals along the circumference of the second ring body 05, the second through holes 05b penetrating the second ring body 05.

[0088] The second through hole 05b is located on the side of the first through hole 01b away from the center of the focusing ring.

[0089] Specifically, the by-product extraction positions provided on the existing focus ring are fixed positions, for example, only three by-product extraction points are provided at the 3 o'clock, 6 o'clock and 9 o'clock positions of the focus ring. As the etching time increases, the by-products produced will inevitably accumulate at these positions. In the embodiment, the first through holes 01b are arranged at intervals in the circumferential direction of the first ring body 01, and the second through holes 05b are arranged at intervals in the circumferential direction of the second ring body 05. The arrangement of the plurality of first through holes 01b and the plurality of second through holes 05b can increase the extraction efficiency. The second through holes 05b are arranged on the side of the first through holes 01b away from the center of the focus ring, that is, the second through holes 05b are arranged corresponding to the first through holes 01b. The by-products in the same direction can be extracted in the same direction, which facilitates the subsequent arrangement of the by-product extraction system.

[0090] When the first ring body 01 is provided with a plurality of first sections 01a and the second ring body 05 is provided with a plurality of second sections 05a, each first section 01a is provided with at least one first through hole 01b, and each second section 05a is provided with at least one second through hole 05b. This is not specifically limited, and can be arranged as needed.

[0091] Based on the above-mentioned focus ring, the application further provides an etching system, which refers to Figure 10 , Figure 10 a structural schematic diagram of an etching system provided by an embodiment of the application; the etching system comprises:

[0092] an electrostatic chuck 06, which is used to adsorb a wafer 07 to be etched.

[0093] a focus ring 08, which is arranged outside the electrostatic chuck 06 and is any one of the focus rings described above.

[0094] a first electrode 09 and a second electrode 10 arranged oppositely and used to generate an electric field to control the etching of the wafer 07 to be etched by plasma; the electrostatic chuck 06 and the focus ring 08 are located between the first electrode 09 and the second electrode 10.

[0095] Specifically, when etching the wafer 07 to be etched, the electrostatic chuck 06 first adsorbs the wafer 07 to be etched, and the focus ring 08 is arranged outside the electrostatic chuck 06 to limit the wafer 07 to be etched. A radio frequency voltage is applied to the first electrode 09 and the second electrode 10, and an electric field is generated between the first electrode 09 and the second electrode 10. The electric field can control the plasma between the wafer 07 to be etched and the first electrode 09 to bombard the wafer 07 to be etched, thereby achieving etching of the wafer 07 to be etched.

[0096] Since the focusing ring 08 is the focusing ring in the above embodiment, the first film layer 03 of the first groove surface of the focusing ring 08 has a plurality of protruding structures 04, and a first included angle is formed between two adjacent protruding structures 04. The first groove and the first included angle increase the ability of the plasma shot on the first ring body 01 to be scattered and absorbed, and the plasma is consumed to a greater extent, solving the problem of the focusing ring being deviated and tilted due to the aggregation of the plasma beam. Further, since the focusing ring will not be deviated and tilted, the yield of wafer etching is increased.

[0097] In addition, the focusing ring 08 can also be provided with a second included angle. By changing the second included angle, the problem of generating a bottom micro groove is further solved. For example, the inward tilt can block the plasma on the outer surface of the first ring body 01; the outward tilt can scatter the plasma shot on the inner wall, and the first film layer 03 will reflect and absorb the incoming plasma, consume the plasma, thereby shielding the plasma beam shot at a certain position of the wafer to be etched, avoiding the generation of a bottom micro groove, and improving the yield of etching wafer.

[0098] Optionally, referring to Figure 11 , Figure 11 Another etching system structure schematic diagram provided by the embodiment of the application; in another embodiment of the application, the etching system further comprises:

[0099] The by-product monitoring device 11 is connected with the focusing ring 08, and is used for monitoring the by-products after the wafer to be etched 07 is etched, so as to judge the etching uniformity of the wafer to be etched 07.

[0100] Specifically, the by-product exhaust port of the by-product monitoring device 11 is connected with the first through hole 01b of the first ring body 01 and the second through hole 05b of the second ring body 05 of the focusing ring 08, and is used for extracting by-products.

[0101] The by-product monitoring device 11 can detect the output and precipitation of by-products in different regions of the wafer to be etched 07 through wavelength detection, so as to judge the etching uniformity of the wafer to be etched 07 by comparing the output and precipitation of by-products in different regions. The detection is described below.

[0102] Optionally, referring to Figure 12 , Figure 12 A partial top view structure schematic diagram of an etching system provided by the embodiment of the application; in another embodiment of the application, the by-product monitoring device 11 comprises:

[0103] The first detection unit is used for detecting the by-products of the first region 12 of the wafer to be etched 07.

[0104] The second detection unit is configured to detect by-products of the second region 13 of the wafer 07 to be etched, and the second region 13 is located between the first region 12 and the focus ring 08.

[0105] The judging unit is configured to judge the etching uniformity of the wafer 07 to be etched based on the by-products of the first region 12 and the second region 13.

[0106] Specifically, the first detection unit is installed in the first region 12 of the wafer 07 to be etched, that is, the middle region in the dashed line, Figure 12 The second detection unit is installed in the second region 13 of the wafer 07 to be etched, that is, the edge region of the wafer 07 to be etched, and the second region 13 is located between the first region 12 and the focus ring 08.

[0107] The first detection unit can detect all by-products generated and separated from the first region 12. The first detection unit includes a wavelength recognition module, which can detect the type of by-products in the first region 12 by wavelength, and a by-product output detection module and a by-product separation detection module for detecting the by-product output and the by-product separation in the first region 12. When the by-products generated by etching the first region 12 are to be separated from the first region 12 to the second region 13, they must pass through the detection of the first detection unit, so as to obtain the detection result of the by-products of the first region 12.

[0108] The second detection unit can detect by-products generated and separated from the through hole. That is, the second detection unit first detects all by-products generated and separated from the first region 12 and the second region 13. Since the first detection unit only detects the first region 12, the generation and separation of the by-products in the second region 13 can be obtained by subtracting the detection result of the first detection unit from the detection result of the second detection unit.

[0109] The second detection unit includes a wavelength recognition module, which can detect the type of by-products separated from the through hole by wavelength, and a by-product output detection module and a by-product separation detection module for detecting the by-product output and the by-product separation in the second region 13.

[0110] The judging unit can judge the etching uniformity of the wafer 07 to be etched based on the generation and separation of the by-products of the first region 12 and the generation and separation of the by-products of the second region 13. When it is judged that the etching is not uniform, the etching of the plasma can be adjusted by adjusting the first angle and the second angle of the focus ring 08 to ensure uniform etching of the wafer to be etched.

[0111] Reference Figure 13 , Figure 13A segment curve, because the by-product extraction of the etching system is extracted through the through hole close to the second area 13, so in the early stage of etching, the by-product of the first area 12 is always more than that of the second area 13, at this time, because the etching just started, the by-product is accumulated rapidly in the whole process, so the extraction of the by-product is not accumulated fast, so the by-product output of the first area 12 and the second area 13 is larger than the precipitation.

[0112] B segment curve is the balance period of by-product production and precipitation, at this time, the etching has been carried out for a period of time, the by-product accumulation is not so fast, at this time, the extraction of the by-product in the whole etching system can reach the balance state with the production, but the etching of the first area 12 and the second area 13 of the etching wafer 07 has not balanced, the line in this stage is not a completely horizontal line, but a relatively slow rising process, the by-product amount on the etching wafer 07 is still relatively large, and the requirement of good wafer uniformity has not been reached.

[0113] At this time, the first angle and the second angle of the focusing ring 08 are adjusted at Q point, C segment curve etching system is in the late etching stage, at this time, the production of by-product is less than the precipitation of by-product, but because it is judged that the by-product of the first area 12 is still more than that of the second area 13, at this time, because the first angle and the second angle of the focusing ring are adjusted, the precipitation of the first area 12 and the second area 13 is close, until the precipitation of the first area 12 and the second area 13 is balanced. Because the etching has been carried out to the middle and late stage, the by-product production is not so fast, the extraction rate of the by-product is unchanged, and the production of the by-product is less than the precipitation of the by-product.

[0114] D segment curve is in the late etching stage, the by-product production is not much, and the extraction rate of the by-product extraction system remains unchanged, at this time, the by-product of the first area 12 and the second area 13 has reached balance, at this time, the etching uniformity reaches the expectation.

[0115] The in-plane flatness of the etching wafer 07 is detected by the by-product monitoring device 11, when it is not uniform, the focusing ring is adjusted, so that the percentage of by-product reaches balance, so as to increase the etching yield of the etching wafer 07. When adjusting, the first area and the second area can be further divided, for example, the first area can be divided into a central area and a middle area, the second area can be divided into an edge area and an edge area, etc., so as to make the adjustment more accurate. The adjustment of the focusing ring is realized by adjusting the first angle and the second angle of the focusing ring, the adjustment of the first angle and the second angle can be calculated by the following function, so as to determine the angle of the first angle and the second angle.

[0116] First, the wafer 07 to be etched contains n chips arranged in an array, where n ≥ 2 and n is a positive integer. After etching, n vias will be etched onto each chip. This application determines the adjustment function by the offset of the etched vias on the wafer after the focus ring is shifted, referring to... Figure 14 , Figure 14 This is a schematic diagram of the offset of etched vias on a wafer when the focusing ring is offset, provided in an embodiment of this application; with no offset of the focusing ring as the reference, when the focusing ring is not offset, the position offset p of the etched vias on the wafer is 0, and the angle offset α is 0.

[0117] When the focusing ring shifts, the etched vias on the chip become tilted after wafer etching. In this case, each etched via can be divided into n segments for integration calculation. During segmentation, the segmentation planes of each segment do not need to be parallel, thereby obtaining the positional offset and offset angle at different locations, increasing sampling diversity. The positional offset of each etched via segment is pi, and the angular offset of each etched via segment is αi, where i ≤ n, and i is a positive integer. For example... Figure 14 In the process, the etched vias are divided into 4 segments, with positional offsets including p1, p2, p3 and p4, and angular offsets including α1, α2, α3 and α4.

[0118] The analysis yielded the index function UE(α, p) for etching unevenness. zone for:

[0119] Formula 1

[0120] Among them, T angle (α) represents the offset angle function of an etched via. T represents the integral of the angular offset from the first segment to the nth segment after dividing an etched via into n segments; location (p) represents a via offset position function. This represents the integral of the positional offset from the first segment to the nth segment after dividing an etched via into n segments; This represents the summation of n etched vias on a chip. This represents the summation of n chips on a single wafer.

[0121] We set multiple θ values ​​and calculated the index function UE(α, p) for the above etching unevenness at different θ values. zone Integrating over the corresponding interval yields multiple discrete data points (θ, UE(θ)). zone ), further obtaining UE(θ) zone Mass function as θ changes:

[0122] Formula 2

[0123] wherein fit(θ) is the UE(θ) zone and the least square fitting function of θ, θ can be the first angle θ1 or the second angle θ2.

[0124] When the angle θ1 of the first angle is to be adjusted, the adjustment function minY1 of the angle θ1 of the first angle is:

[0125] Formula 3

[0126] wherein X represents the position of etching unevenness or the position of generating bottom micro trenches, and ∞ represents the center point position of the wafer to be etched; std represents the relative standard deviation.

[0127] When the angle θ2 of the second angle is to be adjusted, the adjustment function minY2 of the angle θ2 of the second angle is:

[0128] Formula 4

[0129] wherein X represents the position of etching unevenness or the position of generating bottom micro trenches, X1 represents the position of the average value of etching of the wafer to be etched; std represents the relative standard deviation. The adjustment function of the first angle can also be used as a supplementary adjustment function of the second angle.

[0130] In the above process of adjusting the first angle and the second angle, the set of the first angle and the second angle is:

[0131] Formula 5

[0132] wherein 0°<α<180°, G(θ)≤0 represents that the percentage of by-products generated by the second area 13 is always less than the first area 12, F(θ1)≥0 represents that the first angle is effectively adjusted, that is, the range of θ1 and θ2 belongs to 0°-180°, at the same time, the percentage of by-products generated by the second area 13 is always less than the first area 12 in the range of θ1 and θ2, and wherein the adjustment function F(θ1) of the effective adjustment of the first angle is:

[0133] Formula 6

[0134] When the first angle is effectively adjusted, the adjustment range of θ2 belongs to F(θ1)≥0.

[0135] Through the formulas 1-6, the angles of the first angle and the second angle of the focus ring when the etching is uniform can be obtained, and adjusting the angles of the focus ring can increase the in-plane uniformity of the wafer to be etched, thereby improving the yield of the etched wafer.

[0136] It should be noted that the adjustment of θ can be an adjustment of only the first included angle, or an adjustment of only the second included angle, or an adjustment of the first included angle and the second included angle respectively. When the first included angle and the second included angle are adjusted respectively, one of the included angles can be fixed first and then the other included angle is adjusted. For example, the first included angle can be adjusted first to reduce the influence of the focusing ring on the offset of the etching via, and then the second included angle is adjusted, at this time the adjustment range of the angle θ2 of the second included angle belongs to F(θ1)≥0.

[0137] It should also be noted that in some embodiments, the adjustment of the first ring body can be adjusted by a mechanical hand, etc., and is not specifically limited.

[0138] In the description of the present specification, the description referring to the terms "some embodiments", "another embodiment", and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0139] The technical features of the above-described embodiments can be combined arbitrarily, and in order to make the description simple, all possible combinations of the technical features of the above-described embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present specification.

[0140] The above-described embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as a limitation on the patent application scope. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A focus ring characterized by, The focusing ring comprises: a first ring body comprising a ring structure and a first film layer; in a first direction, one side of the ring structure has a first groove, and the first film layer covers the surface of the first groove; the first direction is perpendicular to the plane where the first ring body is located; the first film layer comprises a plurality of protruding structures, and each two adjacent protruding structures have a first included angle, and the material of the first film layer is used for reflecting and absorbing plasma.

2. The focus ring of claim 1, wherein, The angle of the first included angle is θ1, wherein 0° < θ1 < 180°.

3. The focus ring of claim 1, wherein, The inner wall of the first ring body and the radial direction of the first ring body have a second included angle, and the angle of the second included angle is θ2, wherein 0° < θ2 < 90°.

4. The focus ring of claim 1, wherein, The inner wall of the first ring body and the radial direction of the first ring body have a second included angle, and the angle of the second included angle is θ2, wherein 90° < θ2 < 180°.

5. The focus ring of claim 1, wherein, The focusing ring further comprises: a second ring body located outside the first ring body; the height of the second ring body in the first direction is less than the height of the first ring body in the first direction.

6. The focus ring of claim 5, wherein, The first ring body further comprises a plurality of first segments arranged at intervals along the circumference of the first ring body, and the second ring body comprises a plurality of second segments arranged at intervals along the circumference of the second ring body; The second segment is located on the side of the first segment away from the center of the focusing ring.

7. The focus ring of claim 5, wherein, The first ring body further comprises a plurality of first through holes extending in the first direction and arranged at intervals along the circumference of the first ring body, and the first through holes penetrate the first ring body; The second ring body comprises a plurality of second through holes extending in the first direction and arranged at intervals along the circumference of the second ring body, and the second through holes penetrate the second ring body; The second through hole is located on the side of the first through hole away from the center of the focusing ring.

8. An etching system, comprising: The etching system comprises: an electrostatic chuck for adsorbing a wafer to be etched; a focusing ring surrounding the electrostatic chuck, wherein the focusing ring is the focusing ring according to any one of claims 1-6; first and second electrodes oppositely arranged to generate an electric field for controlling plasma to etch the wafer to be etched; the electrostatic chuck and the focusing ring are located between the first and second electrodes.

9. The etching system of claim 8, wherein, The etching system further comprises: a byproduct monitoring device connected to the focusing ring, for monitoring byproducts after etching the wafer to be etched, to judge the etching uniformity of the wafer to be etched.

10. The etching system of claim 9, wherein, The byproduct monitoring device comprises: a first detection unit for detecting byproducts of a first region of the wafer to be etched; a second detection unit for detecting byproducts of a second region of the wafer to be etched; the second region is located between the first region and the focusing ring; a judging unit for judging the etching uniformity of the wafer to be etched based on the byproducts of the first and second regions.

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