Inductively coupled reactor and operating method thereof

Abstract

An inductively coupled reactor and operating method thereof include: a reaction chamber body; an inductively coupled radio frequency unit located above the reaction chamber body; the inductively coupled radio frequency unit comprising: a shielding cover; a reaction chamber dielectric tube located within the shielding cover, wherein the sidewalls of the reaction chamber dielectric tube are inclined and the top cross-section of the reaction chamber dielectric tube is smaller than the bottom cross-section; and a radio frequency antenna located within the shielding cover and distributed on the side of the reaction chamber dielectric tube, wherein the radio frequency antenna includes an effective radio frequency antenna with adjustable height. The inductively coupled reactor can enhance the control over plasma distribution.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and in particular to an inductively coupled reactor and a working method thereof. Background Art

[0002] Semiconductor manufacturing involves multiple processes, each of which is accomplished using specialized equipment and techniques. Etching, for example, is a crucial process in semiconductor manufacturing. Plasma etching utilizes energized reactive gases to generate plasma, which contains charged particles such as ions and electrons, as well as highly chemically active neutral atoms, molecules, and free radicals. This process etches the target through physical and chemical reactions.

[0003] However, during plasma etching, the etching conditions at the wafer edge differ significantly from those at the wafer center. These conditions include plasma density distribution, radio frequency electric field, and temperature distribution. Plasma density distribution is a crucial etching condition. For example, the plasma density at the center of the wafer is generally higher than that at the wafer edge, and this distribution is difficult to adjust.

[0004] Therefore, it is necessary to propose an inductively coupled reactor that can controllably adjust the plasma distribution to meet the needs. Summary of the Invention

[0005] The problem solved by the present invention is to provide an inductively coupled reactor and a working method thereof, which can enhance the control capability of plasma distribution.

[0006] In order to solve the above technical problems, the present invention provides an inductively coupled reactor, comprising: a reaction chamber body; an inductively coupled radio frequency unit located above the reaction chamber body; the inductively coupled radio frequency unit comprising: a shielding cover; a reaction chamber medium tube located inside the shielding cover, wherein the side walls of the reaction chamber medium tube are inclined and the top cross-section of the reaction chamber medium tube is smaller than the bottom cross-section; and a radio frequency antenna located inside the shielding cover and distributed on the side of the reaction chamber medium tube, wherein the radio frequency antenna comprises an effective radio frequency antenna, and the height of the effective radio frequency antenna is adjustable.

[0007] Optionally, the longitudinal cross-section of the reaction chamber medium tube is trapezoidal.

[0008] Optionally, the RF antenna is consistent with the effective RF antenna; the inductively coupled RF unit further includes: an antenna height adjuster located inside the shielding cover, the antenna height adjuster being suitable for adjusting the position of the RF antenna in the longitudinal direction.

[0009] Optionally, the RF antenna surrounds the reaction chamber medium tube and has a plurality of continuous turns of coil; the RF antenna has a first antenna terminal and a second antenna terminal; the inductively coupled RF unit also includes: an RF source; an RF matcher, one end of the RF matcher is connected to the RF source, and the other end of the RF matcher is connected to the first antenna terminal; a voltage balancing capacitor, one end of the voltage balancing capacitor is connected to the second antenna terminal, and the other end of the voltage balancing capacitor is grounded.

[0010] Optionally, the RF antenna surrounds the reaction chamber medium tube and has multiple turns of continuous coil; the RF antenna has a first antenna terminal and a second antenna terminal and multiple intermediate connection terminals located between the first antenna terminal and the second antenna terminal; the first antenna terminal is the input terminal of the effective RF antenna, and the second antenna terminal or any intermediate connection terminal is the output terminal of the effective RF antenna.

[0011] Optionally, the inductively coupled RF unit also includes: an RF source; an RF matcher, one end of the RF matcher is connected to the RF source, and the other end of the RF matcher is connected to the first antenna terminal; a voltage balancing capacitor, one end of the voltage balancing capacitor is connected to the second antenna terminal or to any one of the multiple intermediate connection terminals, and the other end of the voltage balancing capacitor is grounded.

[0012] Optionally, the first antenna terminal is higher than the second antenna terminal; or, the second antenna terminal is higher than the first antenna terminal.

[0013] Optionally, it also includes: a wafer clamping platform located at the bottom of the reaction chamber body; the effective RF antenna is used to generate plasma inside the reaction chamber medium tube, and the plasma is suitable for passing through the reaction chamber medium tube into between the wafer clamping platform and the reaction chamber medium tube.

[0014] Optionally, the inductively coupled radio frequency unit further includes: an air inlet channel located at the top of the reaction chamber dielectric tube, wherein the air inlet channel is suitable for introducing etching gas for etching the wafer into the reaction chamber dielectric tube.

[0015] Optionally, it further includes: a cooling device, which is located on the top of the shielding cover and is used to cool the radio frequency antenna and the reaction chamber medium pipe.

[0016] The present invention also provides a working method of an inductively coupled reactor, using any of the inductively coupled reactors described above, comprising: placing a wafer in the reaction chamber body; adjusting the position of the effective RF antenna in the shielding cover; after adjusting the position of the effective RF antenna in the shielding cover, the effective RF antenna generates plasma inside the reaction chamber medium tube, and the plasma enters the reaction chamber body to etch the wafer.

[0017] Optionally, the RF antenna is consistent with the effective RF antenna; the inductively coupled RF unit further includes: an antenna height adjuster located inside the shielding cover; the antenna height adjuster is used to longitudinally adjust the position of the effective RF antenna in the shielding cover.

[0018] Optionally, the RF antenna surrounds the reaction chamber medium tube and has multiple turns of continuous coil; the RF antenna has a first antenna terminal and a second antenna terminal and multiple intermediate connection terminals located between the first antenna terminal and the second antenna terminal; the first antenna terminal is the input terminal of the effective RF antenna, and the second antenna terminal or any intermediate connection terminal is the output terminal of the effective RF antenna; adjusting the position of the effective RF antenna in the shielding cover includes: selecting the second antenna terminal or any intermediate connection terminal as the output terminal of the effective RF antenna.

[0019] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0020] The inductively coupled reactor provided by the technical solution of the present invention has an effective radio frequency antenna for generating plasma in the reaction chamber dielectric tube. Because the sidewalls of the reaction chamber dielectric tube are inclined and the top cross-section of the reaction chamber dielectric tube is smaller than the bottom cross-section, and the height of the effective radio frequency antenna is adjustable, the plasma density distribution inside the reaction chamber dielectric tube can be adjusted by changing the position of the effective radio frequency antenna, thereby better controlling the distribution of the plasma after entering the reaction chamber body, and thus performing corresponding controllable etching on the wafer in the reaction chamber body. In summary, the inductively coupled reactor can enhance the ability to control plasma distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the cross-sectional structure of an inductively coupled reactor;

[0022] Figure 2 is a schematic cross-sectional structural diagram of an inductively coupled reactor in one embodiment of the present invention;

[0023] Figure 3 is a schematic cross-sectional structural diagram of an inductively coupled reactor in another embodiment of the present invention;

[0024] Figure 4 A working method of an inductively coupled reactor in another embodiment of the present invention;

[0025] Figure 5 2 is a schematic cross-sectional structural diagram of an inductively coupled reactor in another embodiment of the present invention. DETAILED DESCRIPTION

[0026] As described in the background art, it is difficult to controllably adjust the distribution of generated ions in existing inductively coupled reactors.

[0027] An inductively coupled reactor, reference Figure 1 , including an inductively coupled RF unit, the inductively coupled RF unit includes a shielding cover 1000, a reaction chamber medium tube 1001 located inside the shielding cover 1000, and a coil-shaped RF antenna 1002 located on the side wall of the reaction chamber medium tube 1001. The reaction chamber medium tube 1001 is cylindrical in shape, and the coil-shaped RF antenna 1002 surrounds the reaction chamber medium tube 1001, and the position of the coil-shaped RF antenna 1002 is fixed.

[0028] In the above-mentioned inductively coupled reactor, gas enters the reaction chamber medium tube 1001 from the air inlet pipe 1003 at the top of the reaction chamber medium tube 1001, and is mixed in the cylindrical reaction chamber medium tube 1001. The RF antenna 1002 generates plasma in the reaction chamber medium tube 1001, and the plasma then diffuses into the reaction chamber body. The wafer is located in the reaction chamber body and opposite to the inductively coupled RF unit. The plasma density distribution above the wafer is high in the middle and low at the edges, and cannot be controlled, resulting in uneven etching.

[0029] Secondly, a cooling fan 1004 is provided on the top of the shielding cover 1000. However, since the reaction chamber medium tube 1001 is cylindrical in shape, the cooling fan 1004 will not cool the top and side walls of the reaction chamber medium tube 1001 very evenly, resulting in uneven distribution of plasma density in the reaction chamber medium tube 1001, and further resulting in uneven distribution of plasma density above the wafer.

[0030] In order to solve the above technical problems, an embodiment of the present invention provides an inductively coupled reactor, referring to Figure 2 and Figure 3 ,include:

[0031] Reaction chamber body 10;

[0032] an inductively coupled radio frequency unit 20 located above the reaction chamber body 10;

[0033] The inductively coupled RF unit 20 includes: a shielding cover 201; a reaction chamber medium tube 202 located inside the shielding cover 201, wherein the side wall of the reaction chamber medium tube 202 is inclined and the top cross-section of the reaction chamber medium tube 202 is smaller than the bottom cross-section; an RF antenna 203 located inside the shielding cover 201 and distributed on the side of the reaction chamber medium tube 202, wherein the RF antenna 203 includes an effective RF antenna, and the height of the effective RF antenna is adjustable.

[0034] In this embodiment, the longitudinal cross-section of the reaction chamber medium tube 202 is trapezoidal.

[0035] In other embodiments, the reaction chamber medium tube 202 may also be tapered.

[0036] In this embodiment, the radio frequency antenna 203 is consistent with the effective radio frequency antenna, that is, the entire radio frequency antenna 203 constitutes an effective radio frequency antenna.

[0037] In this embodiment, the inductively coupled RF unit 20 further includes an antenna height adjuster 204 located inside the shielding cover 201 , and the antenna height adjuster 204 is adapted to adjust the position of the RF antenna 203 in the longitudinal direction.

[0038] In this embodiment, the shape of the radio frequency antenna 203 is a coil shape.

[0039] In this embodiment, the radio frequency antenna 203 surrounds the reaction chamber medium pipe 202 and has multiple turns of continuous coils, with each turn of the coil being equidistant from the reaction chamber medium pipe 202 .

[0040] In this embodiment, the RF antenna 203 has a first antenna terminal 2031 and a second antenna terminal 2032 .

[0041] In this embodiment, the inductively coupled RF unit 20 further includes: an RF source 205; an RF matcher 206, one end of the RF matcher 206 being connected to the RF source 205, and the other end of the RF matcher 206 being connected to the first antenna terminal 2031; and a voltage balancing capacitor 207, one end of the voltage balancing capacitor 207 being connected to the second antenna terminal 2032, and the other end of the voltage balancing capacitor 207 being grounded.

[0042] The voltage balancing capacitor 207 has the following functions: maintaining a certain voltage at the second antenna terminal 2032 , minimizing the voltage difference between the first antenna terminal 2031 and the second antenna terminal 2032 , and reducing the collision of plasma with the side wall of the reaction chamber medium tube 202 .

[0043] In this embodiment, the second antenna terminal 2032 is higher than the first antenna terminal 2031. In other embodiments, the first antenna terminal is higher than the second antenna terminal.

[0044] In this embodiment, the device further comprises: a wafer holding platform 103 located at the bottom of the reaction chamber body 10 .

[0045] In this embodiment, the effective RF antenna is used to generate plasma inside the reaction chamber dielectric tube 202 , and the plasma is suitable for passing through the reaction chamber dielectric tube 202 into between the wafer clamping platform 103 and the reaction chamber dielectric tube 202 .

[0046] In this embodiment, the inductively coupled RF unit 20 further includes an air inlet channel 208 located at the top of the reaction chamber medium tube 202 , and the air inlet channel 208 is suitable for introducing etching gas for etching wafers into the reaction chamber medium tube 202 .

[0047] In this embodiment, the present invention further includes a cooling device 209 . The cooling device 209 is located on the top of the shielding cover 201 . The cooling device 209 is used to cool the radio frequency antenna 203 and the reaction chamber medium pipe 202 .

[0048] Figure 2 It is the state when the height adjuster 204 adjusts the position of the radio frequency antenna 203 to the upper limit, Figure 3 This is the state when the height adjuster 204 adjusts the position of the radio frequency antenna 203 to the lower limit. It should be noted that the height adjuster 204 can also adjust the position of the radio frequency antenna 203 to other positions according to actual needs.

[0049] The height adjuster 204 includes a spring.

[0050] Figure 2 and Figure 3The inductively coupled reactor has the following working principle: the RF power provided by the RF source 205 is fed into the first antenna terminal 2031 of the RF antenna 203 through the RF matcher 206, the height of the RF antenna 203 is freely adjusted by the antenna height adjuster 204, and the voltage distribution on the second antenna terminal 2032 of the RF antenna 203 is distributed and controlled by the voltage balancing capacitor 207. The RF current in the RF antenna 203 generates an alternating magnetic field H perpendicular to the current plane in the trapezoidal reaction chamber medium tube 202. The alternating magnetic field H will induce an angular electric field E parallel to the direction of the coil current in the reaction chamber medium tube 202; the reaction gas generates high-density plasma under the action of the angular electric field E, and the radial density distribution of the plasma can be controlled by moving the RF antenna 203 up and down; the regulated plasma is gradually accelerated by the bias voltage applied to the wafer clamping platform 103 to reach the wafer surface, completing the etching process of the wafer. Obviously, when the adjustable antenna is at the upper limit of the position ( Figure 2 ), the plasma distribution shows high density in the middle and low density at the edge; when the adjustable antenna is at the lower limit of the position ( Figure 3 ), the plasma distribution appears to be approximately uniform in the middle and at the edge.

[0051] The present invention also provides a working method of an inductively coupled reactor. Figure 4 , including the following steps:

[0052] S01: placing a wafer in the reaction chamber body 10;

[0053] S02: adjusting the position of the effective radio frequency antenna in the shielding cover 201;

[0054] S03: After adjusting the position of the effective RF antenna in the shielding cover 201, the effective RF antenna generates plasma inside the reaction chamber medium tube 202, and the plasma enters the reaction chamber body 10 to etch the wafer.

[0055] In this embodiment, the radio frequency antenna and the effective radio frequency antenna are consistent with each other, and the antenna height adjuster is used to longitudinally adjust the position of the effective radio frequency antenna in the shielding cover.

[0056] Specifically, the wafer is placed on the wafer clamping plate 103, and the antenna height adjuster is used to adjust the position of the effective RF antenna in the shielding cover 201. The RF power provided by the RF source 205 is fed into the first antenna terminal 2031 of the RF antenna 203 through the RF matcher 206. The RF antenna 203 will generate high-density plasma in the reaction chamber medium tube 202, and the radial density distribution of the plasma can be controlled by moving the RF antenna 203 up and down.

[0057] Another embodiment of the present invention provides an inductively coupled reactor, referring to Figure 5 The inductively coupled reactor in this embodiment differs from the inductively coupled reactor in the previous embodiment in that the RF antenna 203a has a first antenna terminal 2031a and a second antenna terminal 2032a, and multiple intermediate connection terminals 2033a and 2033b located between the first antenna terminal 2031a and the second antenna terminal 2032a; the first antenna terminal 2031a is the input terminal of the effective RF antenna, and the second antenna terminal 2032a or any of the intermediate connection terminals 2033a and 2033b is the output terminal of the effective RF antenna.

[0058] refer to Figure 5 The inductively coupled RF unit 20a further includes: an RF source 205a; an RF matching device 206a, wherein one end of the RF matching device 206a is connected to the RF source 205a, and the other end of the RF matching device 206a is connected to the first antenna terminal 2031a; and a voltage balancing capacitor 207a, wherein one end of the voltage balancing capacitor 207a is connected to the second antenna terminal 2032a or to any one of the multiple intermediate connection terminals 2033a and 2033b, and the other end of the voltage balancing capacitor 207a is grounded.

[0059] In this embodiment, the first antenna terminal 2031a is higher than the second antenna terminal 2032a.

[0060] In other embodiments, the second antenna terminal is taller than the first antenna terminal.

[0061] The same contents in this embodiment as in the previous embodiment will not be described in detail.

[0062] In this embodiment, when the voltage balancing capacitor 207a is connected to the second antenna terminal 2032a, the second antenna terminal 2032a extends to the RF antenna 203a of the first antenna terminal 2031a and serves as an effective RF antenna. When the voltage balancing capacitor 207a is connected to any of the plurality of intermediate connecting terminals 2033a and 2033b, the intermediate connecting terminal connected to the voltage balancing capacitor 207a extends to the RF antenna 203a of the first antenna terminal 2031a and serves as an effective RF antenna.

[0063] In this embodiment, the RF antenna surrounds the reaction chamber medium tube and has a plurality of continuous turns of coil. By controlling the effective number of turns of the RF antenna 203a, the effective position of the RF antenna is controlled.

[0064] This embodiment also provides a working method of an inductively coupled reactor, which includes placing a wafer in the reaction chamber body 10; adjusting the position of the effective RF antenna in the shielding cover 201; after adjusting the position of the effective RF antenna in the shielding cover 201, the effective RF antenna generates plasma inside the reaction chamber medium tube 202, and the plasma enters the reaction chamber body 10 to etch the wafer.

[0065] In this embodiment, adjusting the position of the effective RF antenna within the shielding cover 201 includes selecting the second antenna terminal 2032a or any of the intermediate connection terminals 2033a and 2033b as the output terminal of the effective RF antenna. Specifically, one end of the voltage balancing capacitor 207a is connected to the second antenna terminal 2032a or any of the intermediate connection terminals 2033a and 2033b.

[0066] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. An inductively coupled reactor, characterized in that: include: reaction chamber body; an inductively coupled radio frequency unit located above the reaction chamber body; The inductively coupled radio frequency unit includes: a shielding cover; a reaction chamber medium tube located inside the shielding cover, wherein the sidewall of the reaction chamber medium tube is inclined and the top cross-section of the reaction chamber medium tube is smaller than the bottom cross-section; a radio frequency antenna located inside the shielding cover and distributed on the side of the reaction chamber medium tube, wherein the radio frequency antenna is a coil having multiple continuous turns of an incense stick, and the radio frequency antenna surrounds the reaction chamber medium tube, and the radio frequency antenna includes an effective radio frequency antenna, wherein the height of the effective radio frequency antenna is adjustable, so that the plasma density distribution inside the reaction chamber medium tube can be adjusted by changing the position of the effective radio frequency antenna; An air inlet channel located at the top of the reaction chamber medium tube, the air inlet channel being suitable for introducing etching gas for etching wafers into the reaction chamber medium tube; The radio frequency antenna is consistent with the effective radio frequency antenna; the inductively coupled radio frequency unit further comprises: an antenna height adjuster located inside the shielding cover, the antenna height adjuster being adapted to adjust the position of the radio frequency antenna in the longitudinal direction; The radio frequency antenna surrounds the reaction chamber medium tube and has a plurality of continuous turns of coil; the radio frequency antenna has a first antenna terminal and a second antenna terminal; The inductively coupled RF unit further includes: a RF source; a RF matcher, one end of the RF matcher being connected to the RF source, and the other end of the RF matcher being connected to the first antenna terminal; a voltage balancing capacitor, one end of the voltage balancing capacitor being connected to the second antenna terminal, and the other end of the voltage balancing capacitor being grounded; The RF antenna has a first antenna terminal, a second antenna terminal, and multiple intermediate connection terminals located between the first antenna terminal and the second antenna terminal; the first antenna terminal is the input terminal of the effective RF antenna, and the second antenna terminal or any intermediate connection terminal is the output terminal of the effective RF antenna.

2. The inductively coupled reactor according to claim 1, wherein The longitudinal cross-section of the reaction chamber medium tube is trapezoidal.

3. The inductively coupled reactor according to claim 1, wherein: The inductively coupled RF unit also includes: an RF source; an RF matcher, one end of the RF matcher is connected to the RF source, and the other end of the RF matcher is connected to the first antenna terminal; a voltage balancing capacitor, one end of the voltage balancing capacitor is connected to the second antenna terminal or to any one of the multiple intermediate connection terminals, and the other end of the voltage balancing capacitor is grounded.

4. The inductively coupled reactor according to claim 1, wherein: The first antenna terminal is higher than the second antenna terminal; or the second antenna terminal is higher than the first antenna terminal.

5. The inductively coupled reactor according to claim 1, wherein: Also includes: a wafer holding platform located at the bottom of the reaction chamber body; The effective radio frequency antenna is used to generate plasma inside the reaction chamber dielectric tube, and the plasma is suitable for passing through the reaction chamber dielectric tube and entering between the wafer clamping platform and the reaction chamber dielectric tube.

6. The inductively coupled reactor according to claim 1, characterized in that Also includes: A cooling device is located on the top of the shielding cover and is used to cool the radio frequency antenna and the reaction chamber medium pipe.

7. A method for operating an inductively coupled reactor, using the inductively coupled reactor according to any one of claims 1 to 6, characterized in that: include: placing a wafer in the reaction chamber body; adjusting the position of the effective radio frequency antenna in the shielding cover; After the position of the effective RF antenna in the shielding cover is adjusted, the effective RF antenna generates plasma inside the reaction chamber medium tube, and the plasma enters the reaction chamber body to etch the wafer.

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