Wafer etching uniformity improving device
By using correction components in the wafer etching device to ensure concentric installation of the focus ring and the electrostatic suction cup, the problems of poor etch uniformity and low edge yield caused by difficult centering of the focus ring and the electrostatic suction cup are solved, and the problem of poor etch uniformity and low edge yield is achieved. Uniform plasma distribution and higher yield.
Patent Information
- Application Number
- CN202420141145.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-19
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2034-01-19
AI Technical Summary
In the prior art, the focus ring and the electrostatic suction cup are difficult to center, resulting in poor wafer etching uniformity, affecting yield, and due to the narrow gap, it is difficult to accurately observe the offset, resulting in a low yield on the wafer edge.
Design a wafer etching uniformity enhancement device, including an electrostatic suction cup, a focus ring and a correction assembly, the focus ring is surrounded by an electrostatic suction cup and forms an annular installation gap, and the correction assembly is arranged in the gap at intervals through multiple correction parts to ensure focus. The ring is concentric with the electrostatic suction cup and is inserted and removed with a calibrator of the same thickness to ensure uniformity of etching.
By correcting the use of the components, ensuring that the focus ring and the electrostatic suction cup are concentric, improving the etching uniformity, improving the wafer edge yield, and solving the problem of poor uniformity caused by the difficulty of centering the focus ring and the electrostatic suction cup.
Smart Images
Figure CN222168323U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of semiconductor integrated circuit manufacturing equipment, in particular to a wafer etching uniformity improvement device. Background Art
[0002] In semiconductor etching equipment (such as dry etching equipment), an electrostatic chuck (ESC) is usually used to adsorb and fix the wafer, and the whole is placed in the plasma formed between the upper and lower electrodes. High-energy ions are accelerated in the electric field to bombard the wafer and chemically react with the material to be removed to obtain the desired pattern on the wafer.
[0003] However, in the etching equipment chamber, the plasma concentration distribution is not uniform, so a focusing ring needs to be installed on the periphery of the electrostatic chuck to improve the uniformity of plasma distribution in the middle and edge of the wafer and improve the uniformity of wafer etching.
[0004] Taking into account the dimensional compatibility between the focusing ring and the electrostatic chuck, and the different deformation amounts caused by the temperature rise and fall of the process, it is necessary to leave necessary installation margin between the focusing ring and the electrostatic chuck. Therefore, the inner diameter of the focusing ring is usually designed to be slightly larger than the outer diameter of the electrostatic chuck, so that an installation gap will be formed between the inner side of the focusing ring and the outer side of the electrostatic chuck.
[0005] In order to ensure the uniformity of plasma distribution on the wafer during etching, the installation of the focus ring is required to be completely concentric with the electrostatic chuck. If the focus ring is offset from the center of the electrostatic chuck after installation, the wafer will have poor etching uniformity and affect the yield rate. If the two are not concentric, a large amount of plasma gas will easily accumulate in the part with a larger gap.
[0006] At present, the installation of the focus ring basically relies on manual visual inspection and the use of a gauge to complete the alignment confirmation between the focus ring and the electrostatic chuck. This method is not only time-consuming, but also after confirming the gap, due to the lack of positioning for the focus ring, it is easy for the focus ring to shift again due to uneven force during the fixing process. In addition, due to the narrow gap between the focus ring and the electrostatic chuck, it is difficult to accurately observe the occurrence of the shift, which cannot avoid the problem of low wafer edge yield due to poor etching uniformity. Utility Model Content
[0007] The utility model aims to provide a wafer etching uniformity improvement device to solve the existing problem of poor wafer etching uniformity and low wafer edge yield caused by difficulty in aligning a focusing ring and an electrostatic chuck.
[0008] In order to solve the above technical problems, the utility model provides a wafer etching uniformity improvement device, which comprises:
[0009] Electrostatic chuck;
[0010] A focusing ring, wherein the focusing ring surrounds the electrostatic chuck, and an annular installation gap is formed between the inner side of the focusing ring and the outer side of the electrostatic chuck;
[0011] A correction component, wherein the correction component comprises a plurality of correction parts, and the plurality of correction parts are arranged in the installation gap in sequence and at intervals, the inner side of the electrostatic suction cup and the outer side of the focusing ring are both in contact with the correction parts, and the radial dimensions of each correction part along the focusing ring are the same.
[0012] Optionally, a plurality of correction members are arranged in the installation gap at equal intervals along the circumference of the focusing ring.
[0013] Optionally, the correction piece is in sheet form.
[0014] Optionally, the correction piece is rectangular in a free state.
[0015] Optionally, a radial dimension of the correction member along the focusing ring is greater than or equal to 0.25 mm and less than or equal to 0.35 mm.
[0016] Optionally, a circumferential dimension of the correction member along the focusing ring is greater than or equal to 115 mm and less than or equal to 125 mm.
[0017] Optionally, the axial dimension of the correction member along the focusing ring is greater than or equal to 65 mm and less than or equal to 75 mm.
[0018] Optionally, the material of the correction piece is polyvinyl chloride.
[0019] Optionally, the focusing ring comprises a first annular portion and a second annular portion, and the second annular portion protrudes from the first annular portion and away from the electrostatic chuck along the axial direction of the focusing ring;
[0020] A gap between the inner side of the first annular portion and the outer side of the electrostatic chuck is the installation gap, and the inner side of the first annular portion is closer to the outer side of the electrostatic chuck than the inner side of the second annular portion in the radial direction of the focusing ring.
[0021] Optionally, in the axial direction of the focusing ring, an upper surface of the first annular portion is flush with an upper surface of the electrostatic chuck.
[0022] To summarize, in the wafer etching uniformity improvement device provided by the present invention, the device includes an electrostatic chuck, a focusing ring and a correction assembly, the focusing ring surrounds the electrostatic chuck, and an annular installation gap is formed between the inner side of the focusing ring and the outer side of the electrostatic chuck; the correction assembly includes a plurality of correction parts, and the plurality of correction parts are arranged in sequence in the installation gap, the inner side of the electrostatic chuck and the outer side of the focusing ring are both in contact with the correction parts, and the radial dimensions of each correction part along the focusing ring are the same. With such configuration, during the process of positioning and installing the focusing ring and the electrostatic chuck, a plurality of correction pieces of the same thickness are inserted into the installation gap, and the correction pieces abut against the outer side of the electrostatic chuck and the inner side of the focusing ring, so that after the correction pieces are inserted into the installation gap, the focusing ring and the electrostatic chuck are concentric, and then the correction pieces are removed. In this way, when the wafer is placed on the surface of the electrostatic chuck within the focusing ring for the etching process, a uniformly distributed plasma can be obtained on the wafer, thereby effectively improving the uniformity of etching, and thereby improving the edge yield on the wafer. The utility model solves the problem that the prior art is difficult to align the focusing ring and the electrostatic chuck, resulting in poor wafer etching uniformity and low wafer edge yield. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Those skilled in the art should understand that the drawings provided are for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.
[0024] Figure 1 is a schematic diagram of the wafer, electrostatic chuck, and focus ring;
[0025] Figure 2 This is an axial cross-sectional view of a device for improving wafer etching uniformity according to an embodiment of the utility model;
[0026] Figure 3 It is a top view of a device for improving wafer etching uniformity according to an embodiment of the utility model.
[0027] In the attached figure:
[0028] 10 - wafer; 20 - electrostatic chuck; 30 - focusing ring; 31 - first annular portion; 32 - second annular portion; 40 - calibration piece. DETAILED DESCRIPTION
[0029] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.
[0030] As used in the present invention, the singular forms "one", "an" and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the term "at least two" is usually used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "the proximal end" and "the distal end" generally refer to two corresponding parts, which not only include the endpoints, and the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in the present invention, an element disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements may be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, an element may be in any orientation such as inside, outside, above, below or on one side of another element, unless otherwise clearly indicated in the content. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0031] Figure 1 is a schematic diagram of the wafer, electrostatic chuck, and focus ring. Figure 1 In semiconductor etching equipment (such as dry etching equipment), an electrostatic chuck 20 (ESC) is usually used to adsorb and fix the wafer 10, and the whole is in the plasma formed between the upper and lower electrodes, and the high-energy ions are accelerated in the electric field to bombard the wafer 10 and react chemically with the material to be removed, so as to obtain the required pattern on the wafer 10. When the electrostatic chuck 20 adsorbs the wafer 10, the electrostatic chuck 20 and the wafer 10 are concentric. In order to improve the uniformity of etching the wafer 10, a focusing ring 30 is usually set on the periphery of the electrostatic chuck 20 so that the concentration of the plasma gas is evenly distributed in the middle and edge of the wafer 10.
[0032] Taking into account the dimensional compatibility between the focusing ring 30 and the electrostatic chuck 20, and the different deformation amounts caused by the temperature rise and fall during the process, it is necessary to leave necessary installation margins between the focusing ring 30 and the electrostatic chuck 20. Therefore, the inner diameter of the focusing ring 30 is usually designed to be appropriately larger than the outer diameter of the electrostatic chuck 20, so that an installation gap is formed between the inner side of the focusing ring 30 and the outer side of the electrostatic chuck 20.
[0033] In order to ensure the uniformity of plasma distribution on the wafer 10 during the etching process, the installation of the focus ring 30 is required to be completely concentric with the electrostatic chuck 20. If the focus ring 30 is offset from the electrostatic chuck 20 in the center after installation, the wafer 10 will have poor etching uniformity and affect the yield rate. If the two are not concentric, a large amount of plasma gas is likely to accumulate in the part with a larger gap.
[0034] At present, the installation of the focus ring 30 is basically completed manually by visual inspection and the aid of a gauge to confirm the alignment between the focus ring 30 and the electrostatic chuck 20. This method is not only time-consuming, but also after confirming the gap, due to the lack of positioning for the focus ring 30, it is easy to cause the focus ring 30 to shift again during the fixing process due to uneven force. In addition, since the gap between the focus ring 30 and the electrostatic chuck 20 is relatively narrow, it is difficult to accurately observe the occurrence of the shift, thereby failing to avoid the problem of low edge yield of the wafer 10 due to poor etching uniformity.
[0035] In view of this, an embodiment of the present invention provides a wafer etching uniformity improvement device to solve the existing problem that the wafer 10 has poor etching uniformity and low edge yield due to the difficulty in aligning the focusing ring 30 and the electrostatic chuck 20.
[0036] Figure 2 This is an axial cross-sectional view of a device for improving wafer etching uniformity according to an embodiment of the utility model. Figure 3 1 is a top view of a wafer etching uniformity improvement device according to an embodiment of the present invention. Figure 2 and Figure 3The wafer etching uniformity improvement device includes a correction component, the electrostatic chuck 20 and the focusing ring 30. The focusing ring 30 is made of quartz. The layout requirements of the focusing ring 30 and the electrostatic chuck 20 remain unchanged, that is, the focusing ring 30 is arranged around the outer periphery of the electrostatic chuck 20, and a ring-shaped installation gap is formed between the inner side of the focusing ring 30 and the outer side of the electrostatic chuck 20. The axial direction of the focusing ring 30 is perpendicular to the electrostatic chuck 20. The correction component includes a plurality of correction pieces 40. The correction piece 40 is made of polyvinyl chloride. The plurality of correction pieces 40 are arranged in the installation gap in sequence and at intervals. The inner side of the electrostatic chuck 20 and the outer side of the focusing ring 30 are both in contact with the correction piece 40. The radial dimensions of each correction piece 40 along the focusing ring 30 are the same, that is, the thickness of each correction piece 40 is the same. Preferably, the plurality of correction pieces 40 are arranged in the installation gap equidistantly along the circumference of the focusing ring 30. In one embodiment, the correction component includes four correction pieces 40, and the four correction pieces 40 are inserted into the installation gap in sequence.
[0037] With such configuration, during the process of positioning and installing the focusing ring 30 and the electrostatic chuck 20, a plurality of correction pieces 40 of the same thickness are sequentially inserted into the installation gap along the axial direction of the focusing ring 30. After being inserted into the installation gap, the correction pieces 40 abut against the outer side of the electrostatic chuck 20 and the inner side of the focusing ring 30, thereby ensuring that after the correction pieces 40 are inserted into the installation gap, the focusing ring 30 and the electrostatic chuck 20 are concentric, and then the correction pieces 40 are removed. In this way, when the wafer 10 is placed on the surface of the electrostatic chuck 20 within the focusing ring 30 for etching, a uniformly distributed plasma can be obtained on the wafer 10, thereby effectively improving the uniformity of etching, and thereby improving the edge yield on the wafer 10. The utility model solves the problem that the etching uniformity of the wafer 10 is poor and the edge yield of the wafer 10 is low due to the difficulty in centering the focusing ring 30 and the electrostatic chuck 20.
[0038] In one embodiment, the correction member 40 is in the form of a sheet. The correction member 40 is rectangular in a free state, that is, when the correction member 40 is not constrained by the installation gap, it can be considered that the correction member 40 is in the form of a straight sheet. When the correction member 40 is constrained in the installation gap, the correction member 40 is in the form of a rectangular sheet.
[0039] In one embodiment, the radial dimension of the correction member 40 along the focus ring 30 (that is, the thickness of the correction member 40) is greater than or equal to 0.25 mm and less than or equal to 0.35 mm, for example, the thickness is 0.3 mm. The circumferential dimension of the correction member 40 along the focus ring 30 is greater than or equal to 115 mm and less than or equal to 125 mm. It is understandable that the circumferential dimension of the correction member 40 along the focus ring 30 refers to the arc length of the correction member 40 after the correction member 40 is inserted into the installation gap. Of course, the arc length here is equal to the length of the correction member 40 when it is in a free state. The circumferential dimension of the correction member 40 along the focus ring 30 is, for example, 120 mm. The axial dimension of the correction member 40 along the focus ring 30 (that is, the width of the correction member 40) is greater than or equal to 65 mm and less than or equal to 75 mm, for example, the width is 70 mm.
[0040] Further, the focus ring 30 includes a first annular portion 31 and a second annular portion 32, the second annular portion 32 protrudes from the first annular portion 31 and away from the electrostatic chuck 20 along the axial direction of the focus ring 30; the gap between the inner side of the first annular portion 31 and the outer side of the electrostatic chuck 20 is the installation gap, and the inner side of the first annular portion 31 is closer to the outer side of the electrostatic chuck 20 than the inner side of the second annular portion 32 in the radial direction of the focus ring 30. Further, in the axial direction of the focus ring 30, the upper surface of the first annular portion 31 is flush with the upper surface of the electrostatic chuck 20, where the upper surface of the first annular portion 31 refers to the side of the first annular portion 31 facing the wafer 10, and the upper surface of the electrostatic chuck 20 refers to the side of the electrostatic chuck 20 facing the wafer 10.
[0041] Although the utility model is disclosed as above with preferred embodiments, the above embodiments are not intended to limit the utility model. For any technician familiar with the art, without departing from the scope of the technical solution of the utility model, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the utility model, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.
Claims
1. A wafer etching uniformity improvement device, characterized in that: include: Electrostatic chuck; A focusing ring, wherein the focusing ring surrounds the electrostatic chuck, and an annular installation gap is formed between the inner side of the focusing ring and the outer side of the electrostatic chuck; A correction component, wherein the correction component comprises a plurality of correction parts, and the plurality of correction parts are arranged in the installation gap in sequence and at intervals, the inner side of the electrostatic suction cup and the outer side of the focusing ring are both in contact with the correction parts, and the radial dimensions of each correction part along the focusing ring are the same.
2. The wafer etching uniformity improvement device according to claim 1, characterized in that: A plurality of correction members are arranged in the installation gap at equal intervals along the circumference of the focus ring.
3. The wafer etching uniformity improvement device according to claim 1, characterized in that: The correction piece is in the form of a sheet.
4. The wafer etching uniformity improvement device according to claim 3, characterized in that: The correction piece is rectangular in a free state.
5. The wafer etching uniformity improvement device according to claim 1, characterized in that: The radial dimension of the correction member along the focusing ring is greater than or equal to 0.25 mm and less than or equal to 0.35 mm.
6. The wafer etching uniformity improvement device according to claim 1, characterized in that: The circumferential dimension of the correction member along the focusing ring is greater than or equal to 115 mm and less than or equal to 125 mm.
7. The wafer etching uniformity improvement device according to claim 1, characterized in that: The axial dimension of the correction member along the focusing ring is greater than or equal to 65 mm and less than or equal to 75 mm.
8. The wafer etching uniformity improvement device according to claim 1, characterized in that: The material of the calibration piece is polyvinyl chloride.
9. The wafer etching uniformity improvement device according to claim 1, characterized in that: The focusing ring comprises a first annular portion and a second annular portion, wherein the second annular portion protrudes from the first annular portion and away from the electrostatic chuck along the axial direction of the focusing ring; A gap between the inner side of the first annular portion and the outer side of the electrostatic chuck is the installation gap, and the inner side of the first annular portion is closer to the outer side of the electrostatic chuck than the inner side of the second annular portion in the radial direction of the focusing ring.
10. The wafer etching uniformity improving device according to claim 9, characterized in that: In the axial direction of the focus ring, an upper surface of the first annular portion is flush with an upper surface of the electrostatic chuck.