Device and method for realizing automatic centering of focusing ring

Abstract

The present invention discloses a device and method for achieving automatic centering of a focus ring. The device comprises: an elastic correction ring mounted on a base; an electrostatic chuck disposed on the surface of the base, the outer side of the electrostatic chuck being used to mount the focus ring; the correction ring being clamped onto the side of the electrostatic chuck, with the outer side of the correction ring equidistant from the side of the electrostatic chuck; the inner diameter of the correction ring being smaller than the outer diameter of the electrostatic chuck, and the outer diameter of the correction ring being larger than the inner diameter of the focus ring; and the focus ring being sleeved onto the outer side of the correction ring, so that the elastic force of the correction ring causes the focus ring to generate a lateral automatic centering motion relative to the electrostatic chuck, thereby achieving automatic centering of the focus ring. The present invention can obtain uniformly distributed plasma on a wafer, prevent etching process byproducts from entering the interior of the base, maintain the cleanliness of the interior of the base, thereby improving the uniformity of dry etching, and has the advantages of simple technology and significant effect.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuit manufacturing equipment, and in particular to a device and method for realizing automatic centering of a focus ring. Background Art

[0002] In semiconductor dry etching equipment, the wafer is usually placed on an electrostatic chuck (ESC) on a base and placed in a plasma formed between upper and lower electrodes. High-energy ions are accelerated in an 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, the plasma concentration distribution in the etching equipment chamber is not uniform; therefore, a focus ring (Focus ring / Top edge ring) is required around the electrostatic chuck to improve the uniformity of plasma distribution in the middle and on the edge of the wafer.

[0004] Considering the dimensional compatibility between the focus ring and the electrostatic chuck, and considering the different deformations caused by process temperature increases and decreases, it is necessary to leave a necessary installation margin between the focus ring and the electrostatic chuck. Therefore, the inner diameter of the focus ring is usually designed to be slightly larger than the outer diameter of the electrostatic chuck. As a result, there is inevitably a gap between the outer periphery of the electrostatic chuck and the inner periphery of the installed focus ring.

[0005] To ensure uniform plasma distribution on the wafer during etching, the focus ring must be installed completely concentrically with the electrostatic chuck. If the focus ring is offset from the center of the electrostatic chuck after installation, poor etching uniformity will result.

[0006] Moreover, the focusing ring is usually made of brittle materials such as silicon or quartz, and the gap between the focusing ring and the electrostatic chuck cannot be reduced by reducing the inner diameter to avoid the focusing ring from breaking due to thermal expansion and contraction when the electrostatic chuck is heated or cooled.

[0007] Currently, the installation of a focus ring relies primarily on manual visual inspection, supplemented by a gauge, to confirm the alignment between the focus ring and the electrostatic chuck. This method is not only time-consuming, but also lacks precise positioning of the focus ring after confirming the gap and before securing it to the base. This can easily lead to further shifting of the focus ring during the securing process due to uneven force. Furthermore, due to the relatively narrow gap, accurate observation of the shift is difficult, which can lead to poor etching uniformity and low wafer edge yield. Therefore, there is an urgent need to provide a method for accurately aligning the focus ring.

[0008] In addition, since there is an installation gap between the outer periphery of the electrostatic chuck and the inner periphery of the installed focusing ring, the by-products generated during the etching process can easily enter the interior of the base through the gap and are difficult to remove, which will also have an adverse effect on the uniformity of dry etching. Summary of the Invention

[0009] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a device and method for realizing automatic centering of a focus ring.

[0010] To achieve the above object, the technical solution of the present invention is as follows:

[0011] The present invention provides a device for realizing automatic centering of a focus ring, comprising:

[0012] an elastic correction ring provided on the base;

[0013] An electrostatic chuck is provided on the surface of the base, and an outer side of the electrostatic chuck is used for mounting a focusing ring;

[0014] The correction ring is clamped on the side of the electrostatic chuck, and the outer side of the correction ring is equidistant from the side of the electrostatic chuck; the inner diameter of the correction ring is smaller than the outer diameter of the electrostatic chuck, and the outer diameter of the correction ring is larger than the inner diameter of the focusing ring;

[0015] Among them, by sleeve-arranging the focusing ring on the outer surface of the correction ring, the focusing ring generates a lateral automatic centering movement relative to the electrostatic suction cup under the action of the elastic force of the correction ring, thereby realizing automatic centering of the focusing ring.

[0016] Furthermore, the inner diameter of the focusing ring is larger than the outer diameter of the electrostatic chuck. After the focusing ring is sleeved on the outer surface of the correction ring to form a center, a uniform installation gap is formed between the focusing ring and the electrostatic chuck.

[0017] Furthermore, when the correction ring is clamped on the side surface of the electrostatic chuck, the upward-facing surface of the correction ring is lower than the upper end of the installation gap.

[0018] Furthermore, a groove is provided on the side of the electrostatic suction cup along the circumferential direction, and the correction ring is embedded in the groove to form a snap connection with the side of the electrostatic suction cup and be positioned, and the outer side surface of the correction ring is exposed from the groove to form abutment with the focusing ring.

[0019] Furthermore, the exposed outer side surface of the correction ring includes an arc-shaped surface or a stepped surface.

[0020] Furthermore, the terrace side surface facing upward on the terrace-shaped surface includes a horizontal surface.

[0021] Furthermore, a mounting guide is provided between the step side and the step surface of the step facing the focusing ring.

[0022] Furthermore, an ejection mechanism is provided on the bottom surface of the groove.

[0023] Furthermore, the ejection mechanism includes an air hole or an air gap provided on the bottom surface of the groove, and an air channel connected to the inside of the electrostatic chuck.

[0024] Furthermore, the surface of the correction ring is fully covered with a protective layer.

[0025] The present invention also provides a method for realizing automatic centering of a focus ring, comprising:

[0026] Providing an etching chamber with a base inside, wherein an electrostatic chuck is provided on a surface of the base;

[0027] A correction ring having an inner diameter smaller than an outer diameter of the electrostatic chuck is mounted on a side surface of the electrostatic chuck, so that the correction ring is clamped on the side surface of the electrostatic chuck and an equidistant state is formed between the outer surface of the correction ring and the side surface of the electrostatic chuck;

[0028] A focus ring having an inner diameter smaller than an outer diameter of the correction ring is mounted on the outer surface of the correction ring, and the focus ring is automatically centered laterally relative to the electrostatic chuck by utilizing the uniform elastic force generated by the outer surface of the correction ring against the inner surface of the focus ring to achieve positioning;

[0029] The focus ring is mounted on the surface of the base according to the positioning state of the focus ring, and a mounting gap is formed between the focus ring and the electrostatic chuck, which is evenly isolated by the correction ring.

[0030] Furthermore, when the correction ring is clamped onto the side surface of the electrostatic chuck, the upward-facing surface of the correction ring is lower than the upper end of the installation gap.

[0031] Furthermore, by providing a groove along the circumferential direction on the side surface of the electrostatic suction cup, the correction ring is clamped in the groove, and the outer side surface of the correction ring is exposed from the groove to form an elastic abutment with the focusing ring; and / or, by providing the correction ring with a vertical side surface facing the focusing ring, a uniform lateral elastic force is applied to the focusing ring mounted thereon; and / or, by providing the correction ring with a flat surface facing upward, the thickness along the longitudinal direction of the correction ring is increased, thereby enhancing the ability to resist erosion from plasma from above; and / or, by providing a protective layer on the surface of the correction ring, the ability to resist erosion from plasma from above is improved.

[0032] Furthermore, it also includes: providing air holes or air gaps on the bottom surface of the groove, and providing air channels connected to the air holes or air gaps inside the electrostatic suction cup, so as to introduce high-pressure gas into the groove through the air channels to tighten the correction ring onto the focusing ring.

[0033] It can be seen from the above technical solution that the present invention addresses the problem that the focusing ring is difficult to center during installation, resulting in poor etching uniformity and low wafer edge yield. By arranging an elastic correction ring around the side of the electrostatic chuck of the base, the correction ring is clamped on the side of the electrostatic chuck, and the outer side surface of the correction ring is equidistant from the side surface of the electrostatic chuck, and the inner diameter of the correction ring is smaller than the outer diameter of the electrostatic chuck, and the outer diameter of the correction ring is larger than the inner diameter of the focusing ring. Therefore, when the focusing ring is installed, the focusing ring can be tightly fitted on the outer side surface of the correction ring, and the focusing ring can generate a lateral automatic centering movement and positioning relative to the electrostatic chuck under the action of the lateral elastic force of the correction ring. Therefore, the focusing ring can be centered and installed on the surface of the base according to the positioning state of the focusing ring, and an installation gap evenly isolated by the correction ring is formed between the focusing ring and the electrostatic chuck. In this way, when the wafer is placed on the surface of the electrostatic chuck within the focusing ring for processing, a uniformly distributed plasma can be obtained on the wafer, thereby effectively improving the uniformity of dry etching and thereby improving the edge yield on the wafer. At the same time, by arranging a correction ring in the installation gap and using a ejection mechanism to push the correction ring tightly into the installation gap, the installation gap can also be effectively blocked, thereby preventing the by-products generated during the etching process from entering the base through the gap and accumulating, thereby further improving the uniformity of dry etching. In addition, by using an elastic correction ring to install the focusing ring, damage to the focusing ring of brittle materials can be avoided. The present invention effectively solves the problem of centering the focusing ring during installation, while keeping the inside of the base clean, and has the advantages of simple technology and obvious effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the structure of a device for realizing automatic centering of a focus ring according to a preferred embodiment of the present invention;

[0035] Figure 2 for Figure 1 A schematic diagram of the enlarged structure of the middle part A;

[0036] Figure 3-Figure 5 The figure is a schematic diagram of the cross-sectional structure of a correction ring according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the invention belongs. The words "including" and similar words used in this article mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0038] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] See also Figure 1 , Figure 1 FIG. 1 is a schematic structural diagram of a device for realizing automatic centering of a focus ring according to a preferred embodiment of the present invention. Figure 1 As shown, a device for realizing automatic centering of a focus ring according to the present invention includes an elastic correction ring 4 provided on a base 2 .

[0040] See also Figure 1 The base 2 can be arranged in the chamber 1 of the etching equipment. An electrostatic chuck 5 is provided on the surface of the base 2; the outer side of the electrostatic chuck 5 is used to install a focus ring 6.

[0041] Before installing the focusing ring 6, the correction ring 4 is firmly attached to the side of the electrostatic chuck 5 by means of a snap-fit ​​mechanism to maintain its position. Furthermore, the outer surface of the correction ring 4 is equidistant from the side of the electrostatic chuck 5, meaning that the outer periphery of the correction ring 4 and the outer periphery of the electrostatic chuck 5 remain concentric. Furthermore, the inner diameter of the correction ring 4 is smaller than the outer diameter of the electrostatic chuck 5, while the outer diameter of the correction ring 4 is larger than the inner diameter of the focusing ring 6, which in turn is larger than the outer diameter of the electrostatic chuck 5.

[0042] Correction ring 4 is elastic. When focus ring 6 is mounted on base 2, it is tightly fitted onto the outer surface of correction ring 4. This allows focus ring 6 to be subjected to a lateral elastic force from the outer surface of correction ring 4, and in its free state, it generates lateral self-centering motion relative to electrostatic chuck 5, thereby achieving automatic centering relative to electrostatic chuck 5 and ensuring lateral positioning. This creates a uniform gap 3 between focus ring 6 and electrostatic chuck 5, evenly separated by correction ring 4, when focus ring 6 is mounted and fixed to base 2. This ensures accurate centering of focus ring 6 and electrostatic chuck 5.

[0043] In this way, when the wafer is placed on the surface of the electrostatic chuck 5 within the focusing ring 6 for processing, a uniformly distributed plasma can be obtained on the wafer, thereby effectively improving the uniformity of dry etching and thereby improving the edge yield on the wafer.

[0044] In some embodiments, the correction ring 4 can be appropriately sized so that when the correction ring 4 is installed on the side of the electrostatic chuck 5, the outer diameter of the correction ring 4 is slightly larger than the inner diameter of the focusing ring 6 in a free state (i.e., the state when the focusing ring 6 has not yet been mounted on the correction ring 4) (interference fit).

[0045] Furthermore, the lateral thickness of the correction ring 4 protruding from the side of the electrostatic chuck 5 can be made greater than the size of the installation gap 3. In other words, the outer diameter (outer surface) of the installed correction ring 4 is slightly larger than the inner diameter of the focus ring 6. This allows the focus ring 6 to be fully elastically contacted and fitted with the correction ring 4 when it is fitted over the correction ring 4. This allows the correction ring 4 to exert a lateral elastic force on the focus ring 6, smoothly achieving automatic centering of the focus ring 6. At the same time, damage to the focus ring 6 caused by excessive squeezing pressure from the oversized correction ring 4 is avoided.

[0046] In addition, by setting the correction ring 4 on the base 2, the installation gap 3 between the focusing ring 6 and the electrostatic chuck 5 can be blocked at the same time, preventing the by-products generated during the etching process from entering the base 2 through the gap and accumulating, thereby further ensuring the uniformity of dry etching.

[0047] Furthermore, the upward surface of the correction ring 4 after being clamped and installed is lower than the upper end of the installation gap 3 to avoid interference with the wafer subsequently placed on the surface of the electrostatic chuck 5.

[0048] In some embodiments, the correction ring 4 may have a circular, elliptical, polygonal or irregular cross-section.

[0049] See also Figure 2 , Figure 2 show Figure 1 Enlarged view of section A. In some embodiments, a groove 53 may be circumferentially formed on the side of the electrostatic chuck 5. The inner portion of the correction ring 4 is inserted into the groove 53, thereby engaging with the side of the electrostatic chuck 5 and securing the position. Furthermore, the outer surface (outer portion) of the correction ring 4 is exposed from the side of the electrostatic chuck 5, that is, from the end face of the groove 53, to form an interference fit with the inner diameter of the focus ring 6 and form a resilient abutment.

[0050] In some embodiments, the exposed outer side surface of the correction ring 4 may include an arcuate surface or a stepped surface with multiple transition surfaces, wherein one stepped side surface of the stepped surface facing upward may include a horizontal surface.

[0051] Furthermore, an installation guide may be provided between a step side facing upward and a step surface on the step-shaped surface facing the focus ring 6 to facilitate the sleeve connection of the focus ring 6 .

[0052] See also Figure 2 In conjunction with Figure 3-Figure 5 In some embodiments, the correction ring 4 may include a first mating portion 42 located on the inner ring side and a second mating portion 41 located on the outer ring side. The first mating portion 42 is embedded in the groove 53; the second mating portion 41 may be connected to the first mating portion 42 and located on the outer side of the first mating portion 42 away from the groove 53. The second mating portion 41 extends from the groove 53, and the outer side surface of the second mating portion 41 (the outer side surface of the correction ring 4) is configured to form an elastic abutment with the inner diameter surface of the focus ring 6.

[0053] In some embodiments, the first matching portion 42 may have a cross-sectional profile corresponding to the inner wall of the groove 53. For example, when the groove 53 has a rectangular cross-sectional structure, the first matching portion 42 may have a rectangular cross-sectional profile corresponding to the inner wall of the groove 53. However, the present invention is not limited thereto.

[0054] In some embodiments, the second mating portion 41 may have a horizontal upper surface 411. Because the plasma in the etching equipment chamber 1 etches upward, the upper portion of the correction ring 4 located in the installation gap 3 is etched first. By providing the second mating portion 411 of the correction ring 4 located in the installation gap 3 with a horizontal upper surface 411, the upper portion of the correction ring 4 exposed to the plasma can be made thicker, making it more resistant to plasma etching, thereby extending the service life of the correction ring 4.

[0055] In some embodiments, the second mating portion 41 may have a vertical outer surface 412. This enhances the sealing effect with the inner diameter of the focus ring 6, thereby effectively preventing process byproducts generated by etching from penetrating between the outer surface 412 of the second mating portion 41 and the inner diameter of the focus ring 6 and entering the interior of the susceptor 2 below, causing difficult-to-remove accumulation.

[0056] See also Figure 3 In some embodiments, the second mating portion 41 may have a first step-shaped cross-sectional structure. The first step-shaped structure includes a vertical first step-shaped surface 4112 facing the focus ring 6, and two first step-shaped side surfaces 4111 and 4113 located above and below the first step-shaped surface 4112. This forms the outer surface of the correction ring 4 with a step-shaped surface structure having multiple transition surfaces.

[0057] Furthermore, the two first platform side surfaces 4111 and 4113 may be oblique planes, and may be symmetrically located on the upper and lower sides of the first platform surface 4112 .

[0058] In other embodiments, the two first step side surfaces 4111 and 4113 may also be curved surfaces.

[0059] Furthermore, the first step surface 4112 may also be a curved surface, and may be connected to the two first step side surfaces 4111 and 4113 which are also curved surfaces, thereby forming the outer side surface of the correction ring 4 with an integral curved surface structure.

[0060] The inclined surface or arc surface structure of a first step side surface 4111 facing upward on the first step shape can be used to form a first installation guide for matching installation with the focus ring 6.

[0061] See also Figure 4 In some embodiments, the second mating portion 41 may have a second step-shaped cross-section structure having a vertical second step-shaped platform 4112 facing the focus ring 6 and two second step-shaped side surfaces 4111 and 4113 located on the upper and lower sides of the second step-shaped platform 4112 .

[0062] Furthermore, a second terrace side surface 4111 facing upward on the second terrace shape may include a horizontal surface (the horizontal upper surface 411 of the second matching portion 41 ) to maximize the thickness of the second matching portion 41 in the longitudinal direction.

[0063] Furthermore, a second installation guide 4114 may be provided between a second terrace side surface 4111 facing upward and a second terrace surface 4112 on the second terrace shape for cooperating with the focus ring 6 for installation. Specifically, the second installation guide 4114 may be an arcuate surface, such as Figure 4 shown.

[0064] In other embodiments, the second mounting guide 4114 may also be a slope, etc.

[0065] Furthermore, the other second terrace side surface 4113 facing downward on the second terrace shape may be an inclined surface or a curved surface.

[0066] In some embodiments, the longitudinal height of the second terrace surface 4112 may be 0.9-1.1 mm; for example, the longitudinal height of the second terrace surface 4112 may be 1 mm.

[0067] See also Figure 5 In some embodiments, the longitudinal thickness of the second mating portion 41 at the connection point can be smaller than the longitudinal thickness of the first mating portion 42, thereby forming shoulder structures 43 on the upper and lower sides of the correction ring 4. In this way, when the second mating portion 41 and the focus ring 6 contract due to the reverse force from the focus ring 6, the formed shoulder structure 43 can be used to absorb the longitudinal volume expansion caused by the lateral contraction, thereby reducing the squeezing force on the focus ring 6, thereby preventing the focus ring 6 from being damaged by excessive squeezing force.

[0068] In some embodiments, the inner diameter of the correction ring 4 may be 48-52 mm, for example, the inner diameter may be 50 mm; the longitudinal height of the cross section of the correction ring 4 may be 2.9-3.1 mm, for example, the longitudinal height may be 3 mm.

[0069] In some embodiments, the transverse thickness of the first matching portion 42 on the cross section of the correction ring 4 may be 0.85-0.95 mm; for example, the transverse thickness of the first matching portion 42 may be 0.9 mm.

[0070] In some embodiments, the transverse thickness of the second fitting portion 41 on the cross section of the correction ring 4 may be 0.1-0.2 mm; for example, the transverse thickness of the second fitting portion 41 may be 0.15 mm.

[0071] In some embodiments, the surface of the correction ring 4 may be fully covered with a protective layer, so as to improve the ability of the correction ring 4 to resist erosion from plasma above the installation gap 3 .

[0072] In some embodiments, the correction ring 4 may be provided with a continuous rubber layer surrounding the sides of the electrostatic chuck 5. The continuous rubber layer may form the main body of the correction ring 4. A protective layer may be provided on the surface of the rubber correction ring 4. The high elasticity and excellent elasticity of the rubber material can effectively self-center the focus ring 6, and the protective layer can also provide good protection for the inner rubber correction ring 4.

[0073] In some embodiments, the protective layer may include a polymer material layer.

[0074] Furthermore, the protective layer may include a combination of one or more of a PTFE (polytetrafluoroethylene) layer, a PFA (tetrafluoroethylene-perfluoroalkoxy ether copolymer) layer, and a Parylene layer. These polymer materials offer properties such as temperature resistance (e.g., -120°C to 450°C), chemical and plasma resistance, and a very low coefficient of friction, effectively resisting the effects of harsh operating environments (e.g., temperature, corrosion, and friction). This protects the inner rubber correction ring 4, extending its service life and extending its maintenance cycle.

[0075] In some embodiments, the correction ring 4 body may be in the form of a rubber sealing ring, and the surface may be fully covered with a polymer material protective layer.

[0076] In some embodiments, the protective layer can be formed on the rubber sealing ring material by spraying, baking, or coating.

[0077] Also can adopt extrusion molding, form the composite layer structure with inner rubber layer and outer polymer material layer.Perhaps, also can adopt sleeve pipe method, rubber strip is penetrated polymer material outer membrane, and is welded and formed into correction ring 4 at the joint.

[0078] In some embodiments, the thickness of the protective layer may be 0.1 to 100 μm; for example, the thickness of the protective layer may be 1 μm.

[0079] In some embodiments, since only the second mating portion 41 of the correction ring 4 is exposed in the installation gap 3 , the protective layer may have different thickness distributions on the surface of the correction ring 4 . For example, the protective layer may have a thinner thickness on the surface of the first mating portion 42 of the correction ring 4 located in the groove 53 , such as a thickness of 0.1 to 0.9 μm, while the protective layer may have a thicker thickness on the surface of the second mating portion 41 of the correction ring 4 exposed outside the groove 53 , such as a thickness of 0.9 to 100 μm. Furthermore, a protective layer with a smooth thickness transition may be formed between the surfaces of the first mating portion 42 and the second mating portion 41 . In one example, the protective layer may have a thickness of 0.5 μm on the surface of the first mating portion 42 and a thickness of 1 μm on the surface of the second mating portion 41 , forming a smooth transition from 0.5 μm to 1 μm between the surfaces of the first mating portion 42 and the second mating portion 41 .

[0080] In other embodiments, since only the second mating portion 41 of the correction ring 4 is exposed in the installation gap 3, the protective layer may be provided only on the surface of the second mating portion 41. The protective layer may not be provided on the surface of the first mating portion 42. In other words, the protective layer only covers the surface of the portion of the correction ring 4 exposed in the installation gap 3.

[0081] See also Figure 2 In some embodiments, an ejection mechanism may be further provided on the bottom surface of the groove 53 .

[0082] Furthermore, the ejection mechanism may include a plurality of air holes 521 uniformly arranged along the circumference of the electrostatic chuck 5 on the bottom surface of the groove 53, or air slits 522 arranged along the circumference of the electrostatic chuck 5 on the bottom surface of the groove 53, and an air channel 51 connected to the air holes 521 or air slits 522 and disposed within the electrostatic chuck 5. In this manner, after the focus ring 6 is installed, high-pressure gas can be introduced into the groove 53 through the air channels 51 via the air holes 521 or air slits 522, thereby tightening the correction ring 4 against the focus ring 6, thereby achieving a better seal.

[0083] A method for realizing automatic centering of a focus ring according to the present invention will be further described in detail below through specific implementations and in conjunction with the accompanying drawings.

[0084] See also Figure 1-Figure 2A method for realizing automatic centering of a focus ring according to the present invention can be realized by using the device for realizing automatic centering of a focus ring according to the present invention, and can include the following steps:

[0085] An etching chamber 1 is provided, wherein a base 2 is provided inside the chamber 1, and an electrostatic chuck 5 is provided on the surface of the base 2;

[0086] A correction ring 4 having an inner diameter smaller than an outer diameter of the electrostatic chuck 5 is mounted on the side of the electrostatic chuck 5 so that the correction ring 4 is clamped to the side of the electrostatic chuck 5 and an equal distance is formed between the outer side of the correction ring 4 and the side of the electrostatic chuck 5.

[0087] A focusing ring 6, whose inner diameter is smaller than the outer diameter of the correction ring 4, is mounted on the outer surface of the correction ring 4. The uniform elastic force exerted by the outer surface of the correction ring 4 on the inner surface of the focusing ring 6 causes the focusing ring 6 to automatically move laterally relative to the electrostatic chuck 5 and to be positioned. This achieves automatic centering of the focusing ring 6.

[0088] According to the positioning state of the focusing ring 6 , the focusing ring 6 is mounted on the surface of the base 2 , and a mounting gap 3 is formed between the focusing ring 6 and the electrostatic chuck 5 , which is evenly isolated by the correction ring 4 .

[0089] In this way, when the wafer is placed on the surface of the electrostatic chuck 5 within the focusing ring 6 for processing, a uniformly distributed plasma can be obtained on the wafer, thereby improving the uniformity of dry etching and increasing the edge yield of the wafer.

[0090] In some embodiments, when the correction ring 4 is mounted and clamped on the side of the electrostatic chuck 5 , the outer diameter of the correction ring 4 can be larger than the inner diameter of the focusing ring 6 in a free state.

[0091] In some embodiments, when the correction ring 4 is mounted and clamped on the side of the electrostatic chuck 5 , the lateral thickness of the correction ring 4 protruding from the side of the electrostatic chuck 5 can be greater than the size of the installation gap 3 .

[0092] In some embodiments, when the correction ring 4 is mounted and clamped on the side of the electrostatic chuck 5 , the upward surface of the correction ring 4 can be lower than the upper end of the installation gap 3 .

[0093] In some embodiments, a groove 53 is provided on the side of the electrostatic chuck 5 , and the correction ring 4 is clamped in the groove 53 to be positioned, and the outer side of the correction ring 4 is exposed from the groove 53 to form an elastic abutment with the focus ring 6 .

[0094] Furthermore, by making the correction ring 4 have a vertical side surface facing the focus ring 6 , a uniform transverse elastic force is formed on the focus ring 6 sleeved thereon.

[0095] Furthermore, by providing the correction ring 4 with a flat surface facing upward, the longitudinal thickness of the correction ring 4 at the portion located in the installation gap 3 is increased, thereby enhancing the ability of the correction ring 4 to resist erosion by plasma from above.

[0096] Furthermore, by providing a protective layer on the surface of the correction ring 4 , the ability of the correction ring 4 to resist erosion by plasma from above is improved.

[0097] Furthermore, by arranging air holes 521 or air gaps 522 on the bottom surface of the groove 53, and arranging an air channel 51 connecting the air holes 521 or air gaps 522 inside the electrostatic suction cup 5, high-pressure gas is introduced into the groove 53 through the air channel 51, and the correction ring 4 is pressed tightly against the focusing ring 6 to achieve a better sealing effect. This can effectively prevent the process by-products generated by etching from passing through the outer surface of the correction ring 4 and the inner diameter of the focusing ring 6, and entering the interior of the base 2 below to cause accumulation that is difficult to remove, thereby further ensuring the uniformity of the dry etching.

[0098] In summary, the present invention addresses the problem that the focus ring is difficult to center during installation, resulting in poor etching uniformity and low wafer edge yield. By arranging an elastic correction ring 4 around the side surface of the electrostatic chuck 5 of the base 2, the correction ring 4 is clamped on the side surface of the electrostatic chuck 5, and the outer side surface of the correction ring 4 is equidistant from the side surface of the electrostatic chuck 5, and the inner diameter of the correction ring 4 is smaller than the outer diameter of the electrostatic chuck 5, and the outer diameter of the correction ring 4 is larger than the inner diameter of the focus ring 6, when the focus ring 6 is installed, the focus ring 6 can be tightly fitted on the outer side surface of the correction ring 4, and the focus ring 6 can generate a lateral automatic centering movement and positioning relative to the electrostatic chuck 5 under the action of the lateral elastic force of the correction ring 4, thereby realizing automatic centering of the focus ring 6. Therefore, the focus ring 6 can be centered and installed on the surface of the base 2 according to the positioning state of the focus ring 6, and an installation gap 3 evenly isolated by the correction ring 4 is formed between the focus ring 6 and the electrostatic chuck 5. In this way, when the wafer is placed on the surface of the electrostatic chuck 5 within the focusing ring 6 for processing, a uniformly distributed plasma can be obtained on the wafer, thereby effectively improving the uniformity of dry etching and thereby improving the edge yield on the wafer. At the same time, by arranging the correction ring 4 in the installation gap 3 and using a ejection mechanism to push the correction ring 4 tightly into the installation gap 3, it can also play a role in effectively blocking the installation gap 3, thereby preventing the by-products generated during the etching process from entering the base 2 through the gap and accumulating, thereby further improving the uniformity of dry etching. In addition, by using an elastic correction ring 4 to install the focusing ring 6, damage to the focusing ring 6 made of brittle material can be avoided. The present invention effectively solves the problem of centering the focusing ring 6 during installation, while keeping the interior of the base 2 clean, and has the advantages of simple technology and obvious effects.

[0099] While the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.

Claims

1. A device for realizing automatic centering of a focus ring, characterized in that: include: an elastic correction ring provided on the base; An electrostatic chuck is provided on the surface of the base, and an outer side of the electrostatic chuck is used for mounting a focusing ring; The correction ring is clamped on the side of the electrostatic chuck, and the outer side of the correction ring is equidistant from the side of the electrostatic chuck; the inner diameter of the correction ring is smaller than the outer diameter of the electrostatic chuck, and the outer diameter of the correction ring is larger than the inner diameter of the focusing ring; Among them, by sleeve-arranging the focusing ring on the outer surface of the correction ring, the focusing ring generates a lateral automatic centering movement relative to the electrostatic suction cup under the action of the elastic force of the correction ring, thereby realizing automatic centering of the focusing ring.

2. The device for realizing automatic centering of a focus ring according to claim 1, characterized in that: The inner diameter of the focusing ring is larger than the outer diameter of the electrostatic chuck. After the focusing ring is sleeved on the outer surface of the correction ring to form a center, a uniform installation gap is formed between the focusing ring and the electrostatic chuck.

3. The device for realizing automatic centering of a focus ring according to claim 2, characterized in that: When the correction ring is clamped on the side surface of the electrostatic chuck, the upward surface of the correction ring is lower than the upper end of the installation gap.

4. The device for realizing automatic centering of a focus ring according to claim 1, wherein: A groove is provided on the side of the electrostatic suction cup along the circumferential direction. The correction ring is embedded in the groove to form a clamping connection with the side of the electrostatic suction cup and be positioned. The outer side surface of the correction ring is exposed from the groove to form abutment with the focusing ring.

5. The device for realizing automatic centering of a focus ring according to claim 4, characterized in that: The exposed outer side surface of the correction ring includes an arc-shaped surface or a stepped surface.

6. The device for realizing automatic centering of a focus ring according to claim 5, characterized in that: The terrace side surface facing upward on the terrace-shaped surface includes a horizontal surface.

7. The device for realizing automatic centering of a focus ring according to claim 6, characterized in that: A mounting guide is provided between the step side and the step surface of the step facing the focusing ring.

8. The device for realizing automatic centering of a focus ring according to claim 4, characterized in that: An ejection mechanism is provided on the bottom surface of the groove.

9. The device for realizing automatic centering of a focus ring according to claim 8, characterized in that: The ejection mechanism includes an air hole or an air gap provided on the bottom surface of the groove, and an air channel connected to the interior of the electrostatic chuck.

10. The device for realizing automatic centering of a focus ring according to claim 1, wherein: The surface of the correction ring is fully covered with a protective layer.

11. A method for realizing automatic centering of a focus ring, characterized in that: include: Providing an etching chamber with a base inside, wherein an electrostatic chuck is provided on a surface of the base; A correction ring having an inner diameter smaller than an outer diameter of the electrostatic chuck is mounted on a side surface of the electrostatic chuck, so that the correction ring is clamped on the side surface of the electrostatic chuck and an equidistant state is formed between the outer surface of the correction ring and the side surface of the electrostatic chuck; A focus ring having an inner diameter smaller than an outer diameter of the correction ring is mounted on the outer surface of the correction ring, and the focus ring is automatically centered laterally relative to the electrostatic chuck by utilizing the uniform elastic force generated by the outer surface of the correction ring against the inner surface of the focus ring to achieve positioning; The focus ring is mounted on the surface of the base according to the positioning state of the focus ring, and a mounting gap is formed between the focus ring and the electrostatic chuck, which is evenly isolated by the correction ring.

12. The method for realizing automatic centering of a focus ring according to claim 11, wherein: When the correction ring is clamped onto the side surface of the electrostatic chuck, the upward-facing surface of the correction ring is lower than the upper end of the installation gap.

13. The method for realizing automatic centering of a focus ring according to claim 11, wherein: A groove is provided along a circumferential direction on a side surface of the electrostatic chuck, the correction ring is clamped in the groove, and the outer side surface of the correction ring is exposed from the groove to form an elastic abutment with the focus ring; and / or the correction ring has a vertical side surface facing the focus ring to apply a uniform lateral elastic force to the focus ring mounted thereon; And / or, by providing the correction ring with a flat surface facing upward, the thickness along the longitudinal direction of the correction ring is increased, thereby enhancing the ability to resist erosion from plasma from above; and / or, by providing a protective layer on the surface of the correction ring, the ability to resist erosion from plasma from above is improved.

14. The method for realizing automatic centering of a focus ring according to claim 13, wherein: Also includes: By arranging air holes or air gaps on the bottom surface of the groove and arranging air passages connecting the air holes or air gaps inside the electrostatic suction cup, high-pressure gas is introduced into the groove through the air passages to tighten the correction ring onto the focusing ring.

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