KR20210068972A - Focus Ring and plasma device including the same - Google Patents

Abstract

The present invention relates to a focus ring and a plasma device including the same, and more particularly, to a focus ring which includes: a first ring including a first recess in a lower portion thereof, wherein the first recess is depressed toward the upper surface of the first ring from the lower surface of the first ring; and a second ring provided in the first recess. The first ring and the second ring include different materials. The first recess includes an inner side and an outer side facing each other. The second ring is spaced apart from at least one of the inner surface and the outer surface. A groove is defined between the second ring and the first recess. It is possible to provide a focus ring that has a low dielectric constant while improving a helium leakage problem.

Description

A focus ring and a plasma device including the same

The present invention relates to a focus ring and a plasma device including the same. More particularly, it relates to a focus ring used in a semiconductor plasma etching apparatus.

In general, a semiconductor device is completed by repeatedly performing a manufacturing process on a silicon wafer. The semiconductor manufacturing process includes oxidation, masking, photoresist application, etching, diffusion, and lamination processes for the wafer as a material. In addition, processes such as washing, drying and inspection should be performed auxiliary before and after the above processes. In particular, the etching process is an important process for substantially forming a pattern on the wafer. The etching process can be largely divided into wet etching and dry etching.

The dry etching process is a process for removing the exposed portion of the photoresist pattern formed after the photo process. An electric field is formed by applying high-frequency power to the upper and lower electrodes spaced apart from each other by a predetermined distance in the sealed inner space, and the reactive gas supplied into the enclosed space is activated with the electric field to make a plasma state, and then ions in the plasma state The wafer positioned on the lower electrode is etched.

Preferably, the plasma is focused on the entire area of the upper surface of the wafer. To this end, a focus ring is disposed to surround the periphery of the chuck body on the lower electrode.

The focus ring concentrates the region where the electric field is formed by applying high-frequency power formed on the chuck body to the region where the wafer is located.

Referring to Japanese Patent Laid-Open Publication No. 2002-246370 (Aug. 30, 2002), a focus ring made of different materials is disclosed. The focus ring of the document includes a focus ring body made of an insulating material such as quartz, and a silicon member inserted into the body. The above document aims to improve the abnormal discharge phenomenon occurring during plasma processing by using the focus ring as described above. However, there is no awareness of the problem of helium leakage caused by the focus ring during operation of the plasma apparatus.

An object of the present invention is to provide a focus ring capable of improving a helium leakage problem while having a low dielectric constant.

A focus ring according to an embodiment of the present invention includes a first ring including a first recess at a lower portion thereof, wherein the first recess is recessed from a lower surface of the first ring toward an upper surface of the first ring; and a second ring provided in the first recess. The first ring and the second ring include different materials, the first recess includes an inner surface and an outer surface facing each other, and the second ring includes at least one of the inner surface and the outer surface may be spaced apart from, and a groove may be defined between the second ring and the first recess.

A plasma apparatus according to another embodiment of the present invention includes: a substrate support having a ring-shaped protrusion; and a focus ring on the substrate support. The focus ring may include: a first ring including a recess in a lower portion thereof; and a second ring provided in the recess, wherein the first ring and the second ring contain different materials, and the focus ring has a groove defined between the first ring and the second ring. and the groove is a ring-shaped groove formed in the bottom of the focus ring, and the groove may be engaged with the protrusion.

The focus ring according to the present invention may have a low dielectric constant and a long service life by combining the first ring and the second ring having different materials. Furthermore, the focus ring according to the present invention can be easily aligned and mounted in a plasma apparatus, and a problem of helium (He) leaking between the focus ring and the electrostatic chuck during operation of the plasma apparatus can be prevented.

1 is a diagram schematically illustrating a plasma apparatus.
2A is a cross-sectional view of a substrate support.
FIG. 2B is an enlarged view of area A of FIG. 2A .
FIG. 2C is a cross-sectional view illustrating only the focus ring in FIG. 2B .
3A is an exploded perspective view of a focus ring;
FIG. 3B is an enlarged view of area B of FIG. 3A .
FIG. 4 is an enlarged view illustrating area A of FIG. 2A for explaining a focus ring according to a comparative example of the present invention.
FIG. 5 is an enlarged view illustrating area A of FIG. 2A for explaining a focus ring according to an embodiment of the present invention.
6 is a graph comparing the degree of helium leakage between a focus ring according to a comparative example of the present invention and a focus ring according to an embodiment of the present invention.
7, 8, 9, and 10 are each a cross-sectional view for explaining another embodiment of the focus ring of the present invention.

Advantages and features of the present invention, and methods for achieving them, will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, 'comprises' and/or 'comprising' refers to the presence of one or more other components, steps, operations and/or devices mentioned. or addition is not excluded. Hereinafter, embodiments of the present invention will be described in detail.

1 is a diagram schematically illustrating a plasma apparatus.

Referring to FIG. 1 , the plasma apparatus 10 may include a chamber 100 , a shower head 200 , and a substrate support unit 300 .

A wafer W may be accommodated in the chamber 100 . An etching process may be performed in the chamber 100 .

An exhaust pipe 120 may be connected to the chamber 100 . The exhaust pipe 120 may be connected to a lower wall of the chamber 100 . The pressure inside the chamber 100 may be maintained as a process pressure by the exhaust pipe 120 . Through the exhaust pipe 120 , reaction by-products generated in the chamber 100 may be discharged. A vacuum pump (not shown) may be connected to the exhaust pipe 120 . A first valve 122 may be connected to the exhaust pipe 120 .

A gas supply pipe 140 may be connected to the chamber 100 . The gas supply pipe 140 may be connected to the upper wall of the chamber 100 . A process gas may be supplied into the chamber 100 through the gas supply pipe 140 . A second valve 142 may be connected to the gas supply pipe 140 .

A shower head 200 may be provided in the chamber 100 . By the shower head 200 , the gas supplied into the chamber 100 may be entirely sprayed onto the wafer W .

The shower head 200 may include a side plate 220 and a spray plate 240 . The side plate 220 may protrude from the upper wall of the chamber 100 . The side plate 220 may have a ring shape. The lower portion of the side plate 220 and the injection plate 240 may be connected. The injection plate 240 may have a disk shape. A buffer space 260 may be defined by the side plate 220 , the injection plate 240 , and the upper wall of the chamber 100 . A gas supply pipe 140 may be connected to the buffer space 260 , and gas may be supplied to the buffer space 260 . The spray plate 240 may include a plurality of spray openings 242 . Gas in the buffer space 260 may be injected toward the wafer W through the injection openings 242 .

A substrate support 300 may be provided in the chamber 100 . The substrate support 300 may face the shower head 200 . A substrate W may be provided on the substrate support 300 . A support 180 penetrating the lower wall of the chamber 100 may be provided. The support 180 may support the substrate support 300 .

The shower head 200 may function as an upper electrode. The substrate support 300 may function as a lower electrode. A power source 160 may be connected to each of the shower head 200 and the substrate support unit 300 . Plasma may be generated from the gas introduced into the chamber 100 by the power sources 160 .

2A is a cross-sectional view of a substrate support. FIG. 2B is an enlarged view of area A of FIG. 2A . FIG. 2C is a cross-sectional view illustrating only the focus ring in FIG. 2B . 3A is an exploded perspective view of a focus ring; FIG. 3B is an enlarged view of area B of FIG. 3A .

Referring first to FIG. 2A , the substrate support 300 may include an electrostatic chuck 310 and a covering 320 . A focus ring 330 may be provided on the substrate support 300 .

The electrostatic chuck 310 may hold the wafer W by electrostatic force. Instead of the electrostatic chuck 310 , a vacuum chuck for sucking the wafer W by vacuum may be provided. The electrostatic chuck 310 may include an upper portion 311 and a lower portion 312 . Each of the upper part 311 and the lower part 312 of the electrostatic chuck 310 may have a disk shape with a C-C' line as a central axis. A diameter of the upper portion 311 of the electrostatic chuck 310 may be smaller than a diameter of a lower portion of the electrostatic chuck 310 . A wafer W may be provided on the upper portion 311 of the electrostatic chuck 310 . For example, the electrostatic chuck 310 may include an aluminum body.

The electrostatic chuck 310 may further include a helium tube 313 therein. Through the helium tube 313 , helium (He) may be supplied between the electrostatic chuck 310 and the focus ring 330 . Helium (He) may control the temperature of the focus ring 330 during the operation of the plasma apparatus 10 . By controlling the temperature of the focus ring 330 through helium (He), the uniformity of the plasma may be controlled.

The covering 320 may planarly surround the electrostatic chuck 310 . The covering 320 may have a ring shape with the line C-C' as a central axis. The covering 320 may include a protrusion 321 vertically protruding from an upper surface thereof. The protrusion 321 may have a ring shape with the line C-C' as a central axis. For example, the covering 320 may include an insulator such as quartz.

The focus ring 330 may planarly surround the upper portion 311 of the electrostatic chuck 310 . The focus ring 330 may be provided on the lower portion 312 and the covering 320 of the electrostatic chuck 310 . The focus ring 330 may have a ring shape with a C-C' line as a central axis.

The focus ring 330 may be provided adjacent to the edge of the wafer W to prevent plasma diffusion during the etching process. In other words, the focus ring 330 may allow plasma to be concentrated on the wafer W during the etching process. The focus ring 330 may include a first ring 331 , a second ring 332 , and an adhesive layer 333 .

In the focus ring 330 , an empty space, that is, a groove GRV, may be defined between the first ring 331 and the second ring 332 . The groove GRV may be a groove formed in the bottom of the focus ring 330 . The groove GRV may be a groove having a ring shape with a C-C′ line as a central axis. The groove GRV may be engaged and inserted into the protrusion 321 of the covering 320 .

Referring to FIGS. 2B, 2C, 3A and 3B, the first ring 331 may have a ring shape with a C-C' line as a central axis. The first ring 331 may include a first recess RC1 . The first recess RC1 may be formed by recessing the lower surface 331b of the first ring 331 in the upper surface 331a direction. The space defined by the first recess RC1 may have a ring shape with the line C-C' as a central axis.

The first recess RC1 may include an upper surface RC11 , an inner surface RC12 , and an outer surface RC13 . The inner surface RC12 and the outer surface RC13 may face each other. The inner surface RC12 and the outer surface RC13 may be parallel to each other. The inner surface RC12 may be closer to the line C-C' (ie, the central axis) than the outer surface RC13 . The upper surface RC11 of the first recess RC1 may be a surface connecting the inner surface RC12 and the outer surface RC13.

The inner surface RC12 and the outer surface RC13 of the first recess RC1 may be perpendicular to the upper surface RC11 . In other words, the inner surface RC12 and the outer surface RC13 may be parallel to the line C-C′. The upper surface RC11 may be a surface perpendicular to the line C-C′.

The first recess RC1 may have a first width W1 . The first width W1 may be the width of the first recess RC1 in a direction perpendicular to the line C-C′. The first width W1 may be the width of the upper surface RC11 of the first recess RC1 . The first width W1 may be equal to the shortest distance between the inner surface RC12 and the outer surface RC13 of the first recess RC1 .

The upper surface 331a of the first ring 331 may include a first portion 331a1 and a second portion 331a2 . A portion of the first portion 331a1 may vertically overlap the first recess RC1 . The second portion 331a2 may not vertically overlap the first recess RC1 . The second portion 331a2 may be closer to the line C-C′ than the first portion 331a1 . A level of the first portion 331a1 may be higher than a level of the second portion 331a2 . A wafer W may be disposed on the second portion 331a2 . More specifically, an edge of the wafer W may be disposed on the second portion 331a2 .

The first ring 331 may have a first thickness T1 . The first thickness T1 may be a thickness of the first ring 331 in the C-C' line direction. The first thickness T1 may be the shortest distance from the lower surface 331b of the first ring 331 to the first portion 331a1 of the upper surface 331a.

The second ring 332 may have a ring shape with a C-C' line as a central axis. The second ring 332 may be provided in the first recess RC1 of the first ring 331 . The second ring 332 may fill a portion of the first recess RC1 of the first ring 331 .

The second ring 332 may have a first sidewall 332c and a second sidewall 332d that face each other. The first sidewall 332c of the second ring 332 may be in contact with the inner surface RC12 of the first recess RC1 . The upper surface 332a of the second ring 332 may be in contact with the upper surface RC11 of the first recess RC1 .

The second sidewall 332d of the second ring 332 may be spaced apart from the outer surface RC13 of the first recess RC1 . The aforementioned groove GRV may be defined between the second ring 332 and the outer surface RC13 of the first recess RC1 .

The groove GRV may have a third width W3 . The third width W3 may be the width of the groove GRV in a direction perpendicular to the line C-C′. A ratio W1/W3 of the first width W1 of the first recess RC1 to the third width W3 of the groove GRV may be 5 to 20. Preferably, the ratio W1/W3 of the first width W1 to the third width W3 may be 5.5 to 10.

The second ring 332 may have a second thickness T2 . A ratio (T1/T2) of the first thickness T1 of the first ring 331 to the second thickness T2 of the second ring 332 may be 1.5 to 4. Preferably, the ratio (T1/T2) of the first thickness T1 to the second thickness T2 may be 1.9 to 2.2.

The second ring 332 may include a second recess RC2 . The second recess RC2 may be formed by recessing the upper surface 332a of the second ring 332 in the lower surface 332b direction. The space defined by the second recess RC2 may have a ring shape with the line C-C' as a central axis.

The second recess RC2 may include a lower surface RC21 , an inner surface RC22 , and an outer surface RC23 . The inner surface RC22 and the outer surface RC23 may face each other. The inner surface RC22 and the outer surface RC23 may be parallel to each other. The inner surface RC22 may be closer to the line C-C' than the outer surface RC23. The lower surface RC21 of the second recess RC2 may be a surface connecting the inner surface RC22 and the outer surface RC23.

The inner surface RC22 and the outer surface RC23 of the second recess RC2 may be perpendicular to the lower surface RC21. In other words, the inner surface RC22 and the outer surface RC23 may be parallel to the line C-C′. The lower surface RC21 may be a surface perpendicular to the line C-C'.

The second recess RC2 may have a second width W2 . The second width W2 may be the width of the second recess RC2 in a direction perpendicular to the line C-C′. The second width W2 may be the width of the lower surface RC21 of the second recess RC2 . The second width W2 may be equal to the shortest distance between the inner surface RC22 and the outer surface RC23 of the second recess RC2 . A ratio W1/W2 of the first width W1 of the first recess RC1 to the second width W2 of the second recess RC2 may be 2 to 5. Preferably, the ratio W1/W2 of the first width W1 to the second width W2 may be 2 to 3.

The second ring 332 may include a material different from that of the first ring 331 . For example, the first ring 331 may include silicon carbide (SiC). The second ring 332 may include silicon (Si). When the first ring 331 includes silicon carbide (SiC), etching of the focus ring 330 by an etching process may be minimized. Accordingly, the lifespan of the focus ring 330 may be increased.

Referring to FIG. 2B , helium (He) may be supplied through the helium tube 313 so that the helium (He) may flow along the gap GAP between the second ring 332 and the electrostatic chuck 310 . When the second ring 332 includes silicon (Si), adhesion between the electrostatic chuck 310 and the second ring 332 is improved during the etching process, so that helium (He) leaks from the focus ring 330 . out can be prevented.

The adhesive layer 333 may have a ring shape with the line C-C' as a central axis. The adhesive layer 333 may be provided in the second recess RC2 of the second ring 332 . The adhesive layer 333 may completely fill the second recess RC2 of the second ring 332 . The adhesive layer 333 may be provided between the first ring 331 and the second ring 332 .

The first ring 331 and the second ring 332 may be adhered to each other by the adhesive layer 333 . The adhesive layer 333 may include a material capable of bonding the first ring 331 and the second ring 332 to each other. For example, the adhesive layer 333 may include aluminum oxide and a silicon compound (eg, siloxane).

In the focus ring 330 according to embodiments of the present invention, the dielectric constant according to the ratio between the first thickness T1 of the first ring 331 and the second thickness T2 of the second ring 332 is below. Table 1 shows.

First thickness (T1): second thickness (T2) dielectric constant (ε) Example 1 1.9:1 7.1 Example 2 2.1:1 4.6 Example 3 2.2:1 6.5 Example 4 2.3:1 14 Example 5 2.5:1 11

Referring to Table 1, when the ratio (T1/T2) of the first thickness (T1) to the second thickness (T2) is 2.1, the dielectric constant is the smallest, and then the first thickness ( As the ratio (T1/T2) of T1) increased, the dielectric constant increased. In other words, when the ratio (T1/T2) of the first thickness T1 to the second thickness T2 is 1.9 to 2.2 (Examples 1 to 3), the focus ring 330 will have a relatively low dielectric constant. It was confirmed that it is possible.

In the focus ring 330 according to embodiments of the present invention, the first width W1 of the first recess RC1 of the first ring 331 and the second recess RC2 of the second ring 332 are ), the thermal conductivity according to the ratio between the second widths W2 is shown in Table 2 below. The thermal conductivity is a value at a temperature (about 75° C. to 100° C.) in the chamber when the etching process is performed.

First Width W1: Second Width W2 Thermal Conductivity (W/m·K) Example 6 2:1 85 Example 7 2.2:1 78 Example 8 2.25:1 68 Example 9 2.5:1 50 Example 10 3 : 1 34

Referring to Table 2, when the ratio (W1/W2) of the first width W1 to the second width W2 is 2 to 3 (Examples 6 to 10), the focus ring 330 is a relatively good heat Conductivity can be confirmed. Here, the ratio W1/W2 of the first width W1 to the second width W2 may be similar to a ratio of the area of the first ring 331 to the area of the adhesive layer 333 . As the ratio (W1/W2) increases, the thermal conductivity tends to gradually decrease. In the case of Example 6, it was confirmed that the thermal conductivity of the focus ring made of silicon was most similar.

FIG. 4 is an enlarged view illustrating area A of FIG. 2A for explaining a focus ring according to a comparative example of the present invention.

Referring to FIG. 4 , in the focus ring 330 ′ according to the comparative example of the present invention, the groove between the first ring 331 and the second ring 332 may be omitted. For example, the first sidewall 332c of the second ring 332 may be in contact with the inner surface RC12 of the first recess RC1 . The second sidewall 332d of the second ring 332 may be in contact with the outer surface RC13 of the first recess RC1 .

During the operation of the plasma apparatus 10 , DC power may be applied to the electrostatic chuck 310 . When DC power is applied to the electrostatic chuck 310 , the aluminum body of the electrostatic chuck 310 is bent. As a result, the electrostatic chuck 310 and the covering 320 may be bent together.

Even if the electrostatic chuck 310 and the covering 320 are bent, the focus ring 330 ′ of the present comparative example may not be bent along the electrostatic chuck 310 because of its low flexibility. Accordingly, the gap GAP between the focus ring 330 ′ and the electrostatic chuck 310 may be increased. Accordingly, helium (He) may leak out of the focus ring 330 ′ due to the wide gap GAP.

FIG. 5 is an enlarged view illustrating area A of FIG. 2A for explaining a focus ring according to an embodiment of the present invention.

Referring to FIG. 5 , as described above, DC power is applied to the electrostatic chuck 310 so that the electrostatic chuck 310 and the covering 320 may be bent. Since the focus ring 330 according to the present exemplary embodiment includes the groove GRV, flexibility may be greater than that of the focus ring 330 ′ of the comparative example. In addition, the groove GRV and the protrusion 321 of the covering 320 may be fixed in close contact with each other. As a result, when the electrostatic chuck 310 and the covering 320 are bent, the focus ring 330 may also be bent together with them.

As the focus ring 330 is bent together with the electrostatic chuck 310 and the covering 320 , the gap GAP therebetween may be kept small. As a result, the problem of helium (He) leaking out of the focus ring 330 can be solved.

6 is a graph comparing the degree of helium leakage between a focus ring according to a comparative example of the present invention and a focus ring according to an embodiment of the present invention.

Hemium leakage measured during a plasma process by mounting the focus ring ( FIG. 4 ) according to the comparative example of the present invention and the focus ring ( FIG. 5 ) according to the embodiment of the present invention to the plasma apparatus 10 shown in FIG. 1 . The amount is shown in a graph. The x-axis of the graph represents the pressure Torr in the chamber 100 of the plasma apparatus 10 .

Referring to FIG. 6 , it can be seen that the degree of helium leakage generated from the focus ring 330 ′ according to the comparative example is about three times greater than the degree of helium leakage generated from the focus ring 330 according to the embodiment. That is, it was confirmed that the focus ring 330 according to the embodiment of the present invention can significantly improve the helium leakage problem compared to the focus ring 330 ′ according to the comparative example.

The focus ring 330 according to embodiments of the present invention includes the protrusion 321 of the covering 320 through the empty space between the first ring 331 and the second ring 332 , that is, the groove GRV. can be mechanically engaged. Accordingly, when the focus ring 330 is mounted on the plasma apparatus 10 , the focus ring 330 can be easily aligned and mounted using the groove relationship between the groove GRV and the protrusion 321 .

In addition, the empty space between the first ring 331 and the second ring 332 may serve to lower the dielectric constant of the focus ring 330 , and thus the desired dielectric constant by adjusting the size of the groove GRV. A constant (eg, 1.9 to 2.2) can be achieved.

Furthermore, as described above with reference to FIGS. 4 to 6 , the groove GRV increases the flexibility of the focus ring 330 and improves the adhesion between the focus ring 330 and the electrostatic chuck 310 , so there is a problem of helium leakage. can be improved

7, 8, 9, and 10 are each a cross-sectional view for explaining another embodiment of the focus ring of the present invention. In the present embodiment, detailed descriptions of the same technical features as previously described with reference to FIGS. 2A, 2B, 2C, 3A and 3B will be omitted, and differences will be described in detail.

Referring to FIG. 7 , the second sidewall 332d of the second ring 332 may be spaced apart from the outer surface RC13 of the first recess RC1 . The first groove GRV1 described above may be defined between the second ring 332 and the outer surface RC13 of the first recess RC1 . The first sidewall 332c of the second ring 332 may be spaced apart from the inner surface RC12 of the first recess RC1 . A second groove GRV2 may be defined between the second ring 332 and the outer surface RC13 of the first recess RC1 .

Like the first groove GRV1 , the second groove GRV2 may be a groove formed in the bottom of the focus ring 330 . The second groove GRV2 may be a groove having a ring shape with the line C-C' as the central axis. The ring-shaped diameter of the second groove GRV2 may be smaller than the ring-shaped diameter of the first groove GRV1 . That is, the second groove GRV2 may be closer to the central axis C-C′ than the first groove GRV1 .

The first groove RV1 may have a third width W3 , and the second groove GRV2 may have a fourth width W4 . For example, the fourth width W4 may be smaller than the third width W3 . However, although not shown, as another example of the present invention, the fourth width W4 may be greater than the third width W3 .

A ratio W1/W4 of the first width W1 to the fourth width W4 may be 1 to 100. Preferably, the ratio (W1/W4) of the first width W1 to the fourth width W4 may be 20 to 70.

Referring to FIG. 8 , the second sidewall 332d of the second ring 332 may contact the outer surface RC13 of the first recess RC1 . The first sidewall 332c of the second ring 332 may be spaced apart from the inner surface RC12 of the first recess RC1 . A groove GRV may be defined between the second ring 332 and the outer surface RC13 of the first recess RC1 .

The groove GRV may have a fourth width W4 . A ratio W1/W4 of the first width W1 to the fourth width W4 may be 4 to 30. Preferably, the ratio (W1/W4) of the first width W1 to the fourth width W4 may be 5 to 10.

Referring to FIG. 9 , the second recess RC2 of the second ring 332 may have a curved shape. Specifically, the inner surface RC22 and the outer surface RC23 of the second recess RC2 may have an inclination with respect to the line C-C′.

Since the adhesive layer 333 fills the second recess RC2 , the cross-sectional shape of the adhesive layer 333 may be defined by the second recess RC2 . The thickness T3 of the adhesive layer 333 may gradually increase from the inner surface RC22 to the outer surface RC23 of the second recess RC2 and then decrease again.

Referring to FIG. 10 , the adhesive layer 333 may partially fill the second recess RC2 instead of completely filling it. Specifically, the adhesive layer 333 may be spaced apart from at least one of the inner surface RC22 and the outer surface RC23 of the second recess RC2 . Accordingly, an empty space that the adhesive layer 333 cannot fill in the second recess RC2 may be defined.

The adhesive layer 333 may have a fifth width W5 . A ratio W5/W2 of the fifth width W5 to the second width W2 may be 0.5 to 0.9. Preferably, a ratio (W5/W2) of the fifth width W5 to the second width W2 may be 0.8 to 0.9.

The adhesive layer 333 has a maximum thickness T3 at its center. The thickness of the first end 333a of the adhesive layer 333 adjacent to the inner surface RC22 of the second recess RC2 may decrease as it approaches the inner surface RC22. The thickness of the second end 333b of the adhesive layer 333 adjacent to the outer surface RC23 of the second recess RC2 may decrease as it approaches the outer surface RC23.

As mentioned above, although embodiments of the present invention have been described with reference to the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can practice the present invention in other specific forms without changing its technical spirit or essential features. You will understand that there is Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (18)

a first ring including a first recess at a lower portion thereof, the first recess being recessed from a lower surface of the first ring toward an upper surface of the first ring; and
a second ring provided within the first recess;
The first ring and the second ring include different materials,
The first recess includes an inner side and an outer side facing each other,
and the second ring is spaced apart from at least one of the inner surface and the outer surface to define a groove between the second ring and the first recess.
According to claim 1,
and the second ring is spaced apart from the outer surface of the first recess, and the groove is defined therebetween.
According to claim 1,
The groove is:
a first groove between the second ring and the outer surface of the first recess; and
a second groove between the second ring and the inner surface of the first recess;
A width of the second groove is smaller than a width of the first groove.
According to claim 1,
A ratio of a width of the first recess to a width of the groove is 5 to 20.
According to claim 1,
The groove is a focus ring that is a ring-shaped groove having the same central axis as the central axis of the second ring.
According to claim 1,
A ratio of a thickness of the first ring to a thickness of the second ring is 1.5 to 4.
According to claim 1,
Further comprising an adhesive layer interposed between the first ring and the second ring,
the second ring comprising a second recess in its upper portion;
The second recess is recessed from the upper surface of the second ring toward the lower surface of the second ring,
and the adhesive layer is provided in the second recess.
8. The method of claim 7,
A ratio of a width of the first recess to a width of the second recess is 2 to 5.
8. The method of claim 7,
The thickness of the adhesive layer gradually increases from the inner surface to the outer surface of the second recess and then decreases again.
According to claim 1,
The second ring is a focus ring in contact with the inner surface of the first recess.
According to claim 1,
An upper surface of the first ring includes a first portion vertically overlapping with the first recess and a second portion not vertically overlapping with the first recess,
the level of the second portion is lower than the level of the first portion,
The second portion is a focus ring where the wafer is placed.
According to claim 1,
The first ring comprises silicon carbide (SiC),
The second ring is a focus ring including silicon (Si).
According to claim 1,
The central axis of the first ring is the same as the central axis of the second ring.
a substrate support having a ring-shaped protrusion; and
a focus ring on the substrate support;
The focus ring is:
a first ring comprising a recess in its lower portion; and
a second ring provided in the recess;
The first ring and the second ring include different materials,
the focus ring has a groove defined between the first ring and the second ring, wherein the groove is a ring-shaped groove formed in a bottom of the focus ring;
The groove is engaged with the protrusion.
15. The method of claim 14,
The substrate support includes an electrostatic chuck and a covering,
The covering is a plasma device having the protrusion protruding from an upper surface thereof.
15. The method of claim 14,
The electrostatic chuck further includes a helium tube for supplying helium to a gap between the focus ring and the electrostatic chuck.
15. The method of claim 14,
The upper surface of the first ring includes a first portion vertically overlapping with the recess and a second portion not vertically overlapping with the recess,
the level of the second portion is lower than the level of the first portion,
The second portion is a region in which a wafer is placed.
15. The method of claim 14,
A central axis of the protrusion having a ring shape is the same as a central axis of the groove having a ring shape.

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