A confinement ring and its manufacturing method, and plasma processing device

Abstract

The present invention provides a confinement ring, a method for manufacturing the same, and a plasma processing device. By providing a non-longitudinal bend in a gas channel, the probability of collision between the plasma and the gas channel is increased, the plasma is effectively confined within the processing area, the aspect ratio is greatly reduced, and thus the gas resistance is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of plasma processing devices, and in particular to the technical field of a plasma confinement ring in a plasma processing device. Background Art

[0002] Plasma processing devices utilize the operating principle of a vacuum reaction chamber to process semiconductor substrates. This principle involves introducing a reaction gas containing an appropriate etchant or deposition source gas into the vacuum chamber. RF energy is then applied to the chamber to activate the reaction gas, igniting and maintaining a plasma. This allows the material layer on the substrate surface to be etched or deposited, thereby processing the semiconductor substrate. For example, capacitive plasma reactors have been widely used to process semiconductor substrates. In capacitive plasma reactors, when RF power is applied to either the upper or lower electrode, a capacitive discharge is formed between the electrodes.

[0003] After the plasma is generated, most of the plasma will be in the processing area between the upper and lower electrodes. However, due to the diffusion of plasma, some plasma may fill the entire reaction chamber and reach the exhaust area. If the plasma reaches the non-processing area, such as the exhaust area, these areas may be corroded, eroded, or deposited by the plasma, resulting in particle contamination in the reaction chamber, reducing the working life of the parts in the reaction chamber and affecting the quality of semiconductor processing.

[0004] Therefore, it is necessary to confine the plasma in the processing area. In the prior art, confinement rings are generally used to confine the plasma in the processing area. Figure 1 In the embodiment, the confinement ring 200' is arranged between the processing area 201 and the exhaust area 202, and has multiple channels. The distance that the charged particles in the plasma move through the channels is greater than the mean free path of the charged particles. When the charged particles in the plasma P pass through the channels, they are annihilated due to collision with the side walls of the channels, which reduces the amount of leaked plasma P' and effectively confines the plasma within the processing area. However, such a design increases the depth and width of the channels in order to increase the probability of charged particles in the plasma colliding with the side walls of the channels, that is, the depth D of the channels is large. The large depth D leads to an increase in gas resistance, which increases the gas flow resistance of the exhaust pump 140 (as shown in the attached figure). Figure 2 ) brings about a great workload, which reduces the service life of the exhaust pump 140. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems, the present invention provides a confinement ring for a plasma processing device, which is arranged between a processing area and an exhaust area of the plasma processing device, and is characterized in that it includes: an annular body, the annular body having an upper surface and a lower surface opposite to the upper surface; the annular body including at least one gas channel, the gas channel extending through the upper surface and the lower surface; the gas channel including at least one non-longitudinal bend portion located between the upper surface and the lower surface.

[0006] Optionally, the angle between the gas channel located at the non-longitudinal bending portion and the upper surface or the lower surface is greater than or equal to 0° and less than 90°.

[0007] Optionally, the angle is 0°.

[0008] Optionally, the gas channel is annular and extends circumferentially along the annular body, and adjacent gas channels are isolated from each other.

[0009] Optionally, the gas channel also includes: a main channel, and at least two secondary channels communicating with the same main channel; wherein, the gas inlet of the main channel is located on the upper surface, the gas outlet of the secondary channel is located on the lower surface, and the non-longitudinal bending portion is located at the connection between the main channel and the secondary channel.

[0010] Optionally, the gas channel also includes: a main channel, and at least two secondary channels communicating with the same main channel; wherein, the gas outlet of the main channel is located on the lower surface, the gas inlet of the secondary channel is located on the upper surface, and the non-longitudinal bending portion is located at the connection between the main channel and the secondary channel.

[0011] Optionally, the restriction ring further includes a spacer; the secondary channels connected to the same main channel are separated by the spacer, and the main channel and the secondary channels are both annular and extend circumferentially along the annular body.

[0012] Optionally, the spacer has a non-longitudinal surface on the side facing the upper surface.

[0013] Optionally, the spacer has a non-longitudinal surface on the side facing the lower surface.

[0014] Optionally, the same secondary channel is separated by a connecting portion in the circumferential direction of the annular body, one end of the connecting portion is integrally connected to the separating portion, and the other end of the connecting portion is integrally connected to the side wall of the annular body.

[0015] Optionally, the main channel width is equal to the sum of all secondary channel widths.

[0016] Optionally, the surface of the annular body is anodized.

[0017] Optionally, the surface of the annular body that contacts or is close to the plasma is coated with a material that is resistant to plasma corrosion.

[0018] Furthermore, the present invention also discloses a plasma processing device, including a reaction chamber surrounded by a chamber wall, the reaction chamber having a processing area and an exhaust area, and is characterized in that it also includes: a restriction ring as mentioned above, the restriction ring is arranged between the processing area and the exhaust area.

[0019] Furthermore, the present invention also discloses a method for manufacturing the above-mentioned restriction ring, which includes: integrated processing by mechanical processing.

[0020] Furthermore, the present invention also discloses a method for manufacturing the above-mentioned restriction ring, which includes: separately processing the annular body and the spacer, and assembling the annular body and the spacer.

[0021] Optionally, the assembling includes: assembling the annular body and the spacer by means of an annular frame provided on the lower surface of the annular body and the spacer.

[0022] The advantages of the present invention are: the present invention provides a confinement ring and a method for manufacturing the same, as well as a plasma processing device, which increases the probability of collision between the plasma and the gas channel by arranging a non-longitudinal bend portion in the gas channel, effectively confines the plasma within the processing area, greatly reduces the aspect ratio, and thus reduces gas resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of a confinement ring in the prior art is shown;

[0025] Figure 2 A schematic structural diagram of a capacitively coupled plasma (CCP) processing device is shown;

[0026] Figure 3 A top view of a confinement ring is shown;

[0027] Figure 4 Shown Figure 3 A cross-sectional view of the middle confinement ring along the x-x' direction;

[0028] Figure 5 shows the gas distribution diagram inside the gas channel S;

[0029] Figure 6 A partial bottom view of the secondary channel is shown;

[0030] Figure 7 Yet another embodiment is shown;

[0031] Figure 8 Yet another embodiment is shown. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 efforts shall fall within the scope of protection of the present invention.

[0033] Figure 2 A schematic structural diagram of a capacitively coupled plasma (CCP) processing device is shown. Figure 2 In the present invention, a capacitively coupled plasma processing apparatus is a device that generates plasma in a reaction chamber through capacitive coupling using an RF power source applied to an electrode plate, and is used for etching. It includes a vacuum reaction chamber 100, which includes a generally cylindrical reaction chamber wall 101 made of metal material. An opening 102 is provided in the reaction chamber wall for accommodating the entry and exit of substrates. A gas showerhead 120 and a base 110 disposed opposite the gas showerhead are disposed above the reaction chamber. The gas showerhead 120 is connected to a gas supply device 125 for supplying reaction gas to the vacuum reaction chamber and also serves as the upper electrode of the vacuum reaction chamber. An electrostatic chuck 112 is disposed above the base 110 and also serves as the lower electrode of the vacuum reaction chamber. A processing region 201 is formed between the upper and lower electrodes. At least one RF power source 150 is applied to either the upper or lower electrode via a matching network 152, generating an RF electric field between the upper and lower electrodes to dissociate the reactant gas into a plasma. The plasma contains a large number of active species, such as electrons, ions, excited atoms, molecules, and free radicals. These active species can undergo various physical and chemical reactions with the surface of the substrate W to be processed, changing the surface morphology of the substrate W and completing the etching process. An exhaust pump 140 is also provided below the vacuum reaction chamber 100 to remove reaction byproducts and maintain the vacuum environment.

[0034] An electrostatic electrode 113 is disposed within the electrostatic chuck 112 to generate an electrostatic attraction force to support and secure the substrate W being processed during the process. A heating device 114 is disposed below the electrostatic chuck to control the substrate temperature during the process. A focus ring 132 and an edge ring 134 are disposed around the susceptor 110. These focus rings and edge rings are used to adjust the electric field and temperature distribution around the substrate, improving substrate processing uniformity. A plasma confinement ring 200 is disposed around the edge ring. Confinement ring 200 is located between the processing region 201 and the exhaust region 202, confining the plasma to the processing region 201 between the upper and lower electrodes to prevent leakage into non-processing regions, such as the exhaust region 202, which could damage components in these regions. A middle ground ring 136 is disposed below the plasma confinement ring 200 to provide electric field shielding for the plasma confinement ring. A lower ground ring 137 is disposed below the middle ground ring. The middle and lower ground rings 136 and 137 are electrically connected to form a radio frequency ground loop within the reaction chamber. A shielding ring 138 is provided between the lower grounding ring and the base for shielding the radio frequency signal applied to the base within the base, thereby achieving electrical isolation between the base and the lower grounding ring.

[0035] Figure 3 Shown attached Figure 2 A top view of a specific embodiment of a confinement ring 200 is shown. Confinement ring 200 includes an annular body 210 and a spacer 240. Annular body 210 includes an upper surface 230 and a lower surface 231 opposite the upper surface. The upper surface 230 faces the processing region 201, while the lower surface 231 faces the exhaust region 202. Optionally, the upper surface 230 is parallel to the lower surface. Annular body 210 includes at least one gas channel S, which extends through both upper and lower surfaces 230 and 231. The gas channel S extends annularly along the circumference of annular body 210, with adjacent gas channels S isolated from each other. Each gas channel S is circumferentially parallel to each other, forming a plurality of concentric rings. In the longitudinal direction (i.e., perpendicular to the upper and lower surfaces), each gas channel S is substantially parallel to the longitudinal direction.

[0036] Figure 4 Shown Figure 3 The cross-sectional view of the confinement ring along the x-x' direction. Figure 4As shown, each gas channel S includes: a main channel S1, and a first sub-channel S2a and a second sub-channel S2b respectively connected to the same main channel S1; wherein, the gas inlet 220 of the main channel S1 is located on the upper surface 230, and the gas outlet 221 of the sub-channel is located on the lower surface 231; each gas channel S also includes two non-longitudinal bending portions. The left and right are distinguished by the orientation of the plane where the paper is located. The two non-longitudinal bending portions 260 are the non-longitudinal bending portion on the left and the non-longitudinal bending portion on the right. The non-longitudinal bending portion 260 is located at the connection between the main channel and the sub-channel; for one of the gas channels S, the first sub-channel S2a is connected to the main channel S1 through the non-longitudinal bending portion 260 on the left, and the second sub-channel S2b is connected to the main channel S1 through the non-longitudinal bending portion 260 on the right. The non-longitudinal bending portion 260 has a tendency to extend roughly in the transverse direction, wherein the transverse direction is a direction parallel to the upper surface and the lower surface. The angle between the gas channel located at the non-longitudinal bending portion and the upper surface or the lower surface is greater than or equal to 0° and less than 90°. Optionally, the angle is greater than or equal to 0° and less than or equal to 45°. Optionally, the angle is 0°, attached Figure 4 Only the case where the angle is 0° is shown.

[0037] Furthermore, by the Figure 4 It can be seen that gas G passes through S1 and, after passing through non-longitudinal bend 260, is split into two paths. At non-longitudinal bend 260, gas G is forced to flow in a generally transverse direction. Because charged particles in the plasma exhibit directionality and relatively high velocity in the electric field of processing region 201, the vast majority of charged particles contained in the spent reactant gas, when drawn by exhaust pump 140, collide with upper surface 230 of confinement ring 200 due to their directionality and velocity, preventing them from passing through. A small portion of charged particles that do not strike upper surface 230 flow toward gas channel S.

[0038] Attachment Figure 5FIG4 shows a gas distribution diagram inside a gas channel S. The confinement ring 200 includes an annular body 210 and a spacer 240. The annular body 210 includes a plurality of side walls 250. The gas channel S is composed of two opposing side walls 250 and a spacer 240. The spacer 240 is disposed between the two opposing side walls 250. The side walls 250 include an upper side wall 252, a side wall non-longitudinal surface 251, and a lower side wall 253, which are sequentially connected from top to bottom. The upper side wall 252 and the lower side wall 253 extend substantially in the longitudinal direction. The side wall non-longitudinal surface 251 forms an angle with the upper surface or the lower surface. The angle is greater than or equal to 0° and less than 90°. Optionally, the angle is greater than or equal to 0° and less than 45°. Optionally, the angle is 0°. The spacer 240 It includes a non-longitudinal surface 241 and two side surfaces 242, the side surfaces 242 basically extend in the longitudinal direction, the non-longitudinal surface 241 can be parallel to the upper and lower surfaces (that is, the angle is equal to 0°), and the non-longitudinal surface is connected to the side surfaces on both sides to form a wall shape; optionally, the non-longitudinal surface 241 is peak-shaped, and the slope of the peak is parallel to the non-longitudinal surface 251 of the side wall. At this time, the angle of the non-longitudinal bending portion is at an angle to the upper surface or the lower surface (that is, the angle is greater than 0° and less than 90°); optionally, the downward extension line of the upper side wall 252 intersects with the non-longitudinal surface 241 of the spacer 240.

[0039] Due to the presence of the non-longitudinal bend 260, charged particles entering the gas channel S are likely to collide with the non-longitudinal surface 241 of the partition 240. A small number of charged particles that do not collide with the non-longitudinal surface 241 will collide with the lower sidewall 253 due to the deflection of the gas flow. These collisions neutralize the charge on the charged particles, resulting in neutral particles exiting the gas channel S after the collisions. Therefore, the number of charged particles in the non-processing area is greatly reduced, and the exhausted gas does not cause plasma discharge to extend to the non-processing area, eliminating discharge in the non-processing area and preventing corrosion of the reaction chamber. Furthermore, particles in the exhaust area are blocked by the non-longitudinal sidewall 251 when they surge upward, thus preventing the upward surge of particles in the exhaust area from affecting semiconductor process quality.

[0040] Attachment Figure 6A partial bottom view of the secondary channels is shown. At least one of the first and second secondary channels S2a, S2b is discontinuous in the circumferential direction and separated by a connecting portion 270. One end of the connecting portion 270 is integrally connected to the spacer 240, and the other end of the connecting portion 270 is integrally connected to the sidewall 250. For example, a second secondary channel S2b is circumferentially separated by connecting portions 270. There is at least one connecting portion 270, and optionally, three or four connecting portions 270, with the multiple connecting portions 270 evenly spaced in the circumferential direction. The provision of connecting portions 270 facilitates the integrated molding of the restriction ring 200. Specifically, the integrated manufacturing method is machined to facilitate production and enhances the strength of the resulting restriction ring.

[0041] Alternatively, see Appendix Figure 5 The width of the main channel S1 is uniform, W1. The widths of the secondary channels S2a and S2b are also uniform, with the width of secondary channel S2a being W2 and the width of secondary channel S2b being W2'. Optionally, W1 = W2 + W2', or W2 = W2'. Of course, W2 may not be equal to W2'. This has the advantage of reducing gas resistance because the gas inlet and outlet ports are the same.

[0042] The above embodiment only illustrates the case where there are two secondary channels. Of course, there can also be only one secondary channel, in which case the main channel is connected to the secondary channel via a non-longitudinal bend; optionally, in this case, to ensure that air resistance is as low as possible, the width of the main channel and the secondary channel are the same.

[0043] Other embodiments are possible. The number of secondary channels can also be two or more. For example, a gas channel can also be provided on the spacer 240, the gas channel penetrating the non-longitudinal surface 241 and the lower surface, and including a main channel and one or two secondary channels connected by a non-longitudinal bend. Optionally, to ensure that air resistance is as low as possible, the width of the main channel is equal to the sum of the widths of all secondary channels.

[0044] Attachment Figure 7Another embodiment of the present application is shown. The figure shows a case with four non-longitudinal bends, and of course there can be more non-longitudinal bends. For the sake of clarity and brevity, the same parts as above are described using the same reference numerals. In this embodiment, the only difference from the above embodiment is that there are four non-longitudinal bends. The main channel is connected to one of the secondary channels through two non-longitudinal bends. In this embodiment, the spacer 40 has three non-longitudinal surfaces 241, which greatly increases the possibility of charged particles colliding; optionally, the extension line of the upper side wall extending downward intersects with the non-longitudinal surface 241. In this embodiment, in order to ensure that the air resistance is as low as possible, the width of the main channel is equal to the sum of the widths of all secondary channels. In addition, the secondary channels are not limited to two, but also include one or more secondary channels as described above.

[0045] Attachment Figure 8 Another embodiment of the present application is shown. The only difference between this embodiment and the above embodiments is that the main channel and the secondary channel are reversed, that is, the gas outlet of the main channel of the gas channel is located on the lower surface, the gas inlet of the secondary channel is located on the upper surface, and the non-longitudinal bend is located at the connection between the main channel and the secondary channel; for details, see the attached Figure 8 The gas enters through the two secondary channels S1a and S1b, and then flows to the main channel S2' through the non-longitudinal bend. In this embodiment, the charged particles tend to collide with the non-longitudinal surface of the side wall and the lower side wall; optionally, the extension line of the side of the partition 240 extending downward intersects with the non-longitudinal surface of the side wall.

[0046] In summary, since the depth design of the confinement ring 200 of the present invention does not need to consider that the distance that the charged particles of the plasma move through the gas channel must be greater than the mean free path of the charged particles, the depth of the confinement ring of the present invention will be smaller than the depth of the confinement ring 200' in the prior art. The reduction in depth greatly reduces the aspect ratio, thereby reducing gas resistance and reducing the load on the pump.

[0047] Regarding the selection of materials for the above-mentioned embodiments, the confinement rings are made of metals such as aluminum, stainless steel, or tungsten. To protect the confinement rings, each surface is first anodized. The surface facing the processing area is then coated with a material that prevents plasma corrosion, such as a layer of Y2O3, to further prevent plasma corrosion.

[0048] As for the manufacturing method of the restriction ring, the integrated processing method has been mentioned above, that is, the integrated processing is achieved through mechanical processing.

[0049] Optionally, the limiting ring may also be manufactured by a separate processing method. First, the annular body and the spacer are processed separately, and then the annular body and the spacer are assembled. The assembling step includes assembling the two by means of an annular frame arranged on the lower surface of the annular body and the spacer. Optionally, the assembling step may also include assembling the annular body and the spacer together using the above-mentioned connecting part. The connecting part in this method is separate and is not manufactured integrally with the spacer and the annular body.

[0050] The confinement ring disclosed in the present invention is not limited to the above-mentioned plasma processing apparatus, but can also be applied to other plasma processing apparatuses, which will not be described in detail here.

[0051] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A confinement ring for a plasma processing apparatus, disposed between a processing region and an exhaust region of the plasma processing apparatus, characterized in that: include: an annular body having an upper surface and a lower surface opposite to the upper surface; The annular body includes at least one gas channel, the gas channel passing through the upper surface and the lower surface; the gas channel includes at least one non-longitudinal bending portion located between the upper surface and the lower surface; The gas channel further comprises: a main channel, and at least two secondary channels communicating with the same main channel; Wherein, the non-longitudinal bending portion is located at the connection between the main channel and the secondary channel; The restriction ring further includes a spacer; the secondary channels communicating with the same primary channel are separated by the spacer, and the spacer has a non-longitudinal surface on a side facing the primary channel; The width of the main channel is equal to the sum of the widths of all the secondary channels; The angle between the gas channel located at the non-longitudinal bending portion and the upper surface or the lower surface is greater than or equal to 0° and less than 90°.

2. The confinement ring according to claim 1, wherein: The angle is 0°.

3. The confinement ring according to claim 1, wherein: The gas channels are annular and extend circumferentially along the annular body, and adjacent gas channels are isolated from each other.

4. The confinement ring according to claim 3, wherein: The gas inlet of the main channel is located on the upper surface, and the gas outlet of the secondary channel is located on the lower surface.

5. The confinement ring according to claim 3, wherein: The gas outlet of the main channel is located on the lower surface, and the gas inlet of the secondary channel is located on the upper surface.

6. The confinement ring according to claim 4 or 5, wherein: The same secondary channel is partitioned by a connecting portion in the circumferential direction of the annular body. One end of the connecting portion is integrally connected to the partition portion, and the other end of the connecting portion is integrally connected to the side wall of the annular body.

7. The confinement ring according to any one of claims 1 to 5, wherein: The surface of the annular body is anodized.

8. The confinement ring according to any one of claims 1 to 5, wherein: The surface of the annular body that contacts or is close to the plasma is coated with a material that resists plasma corrosion.

9. A plasma processing apparatus comprising a reaction chamber surrounded by a chamber wall, the reaction chamber having a processing area and an exhaust area, characterized in that: Also includes: The confinement ring according to any one of claims 1 to 8, wherein the confinement ring is arranged between the processing area and the exhaust area.

10. The method for manufacturing a confinement ring according to any one of claims 1 to 8, comprising: Integrated processing through mechanical processing.

11. The method for manufacturing a confinement ring according to any one of claims 1 to 8, comprising: processing the annular body and the spacer separately; The annular body and the spacer are assembled.

12. The method for manufacturing a confinement ring according to claim 11, wherein the assembling comprises: The annular body and the spacer are assembled by an annular frame arranged on the lower surfaces of the annular body and the spacer.

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