Capacitive coupling plasma etching equipment and etching method

Abstract

The invention provides capacitive coupling plasma etching equipment and an etching method, the etching equipment comprises a reaction cavity, the top and the bottom of the reaction cavity are provided with a pair of upper electrode and lower electrode in parallel, the upper electrode comprises a gas spraying area used for spraying gas downwards and an edge area, a middle area and a lower area surrounding the gas spraying area, a plurality of electromagnetic coils which are uniformly distributed along the circumferential direction are arranged above the edge area, and the electromagnetic coils are circularly electrified according to a preset sequence so as to sequentially generate magnetic fields along the circumferential direction of the edge area according to the preset sequence. The magnetic field generated by the invention can simulate a magnetic field which moves circumferentially in the reaction cavity, and the magnetic field which moves circumferentially can deflect charged ions generated by capacitive coupling near the edge area of the upper electrode in the reaction cavity to assist dissociation of plasmas, so that plasmas with higher density can be excited at the edge of a wafer, and the plasma dissociation efficiency is improved. Therefore, the etching rate of the wafer edge is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of plasma etching, and in particular to a capacitively coupled plasma etching device and an etching method. Background Art

[0002] At present, the dry etching process using plasma for etching has become the mainstream etching process because it can effectively control the size of the etching opening. In existing plasma etching equipment, radio frequency signals are usually used to form plasma, and radio frequency signals are used to form a bias voltage on the substrate to be processed so that the plasma can bombard the substrate to be processed, thereby achieving etching of the substrate to be processed. Among them, capacitively coupled plasma (CCP) etching equipment has been widely used in the field of dry etching due to its simple structure and relatively low cost.

[0003] Figure 1 The reaction chamber of the existing capacitively coupled plasma etching equipment is shown, and a pair of flat upper electrodes 10' and lower electrodes 20' are arranged in parallel at the top and bottom of the reaction chamber. After the wafer to be etched is placed between the upper electrode and the lower electrode, at least one radio frequency source is connected to the lower electrode 20', and the upper electrode 10' is grounded, so that a radio frequency electric field can be generated to ionize the reaction gas entering the reaction chamber and generate plasma for etching. However, when etching the wafer, it is easy to cause the plasma density at the edge of the wafer to be relatively low, so that the processing rate on the center area of ​​the wafer is faster, while the processing rate on the edge area of ​​the wafer is slower, resulting in different performances of semiconductor devices formed in different areas on the wafer, so it is necessary to adjust the uniformity of plasma etching. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a capacitively coupled plasma etching device and an etching method to improve the uniformity of wafer etching.

[0005] In order to achieve the above purpose, the present invention adopts the above technical solution: In a first aspect, the present invention provides a capacitively coupled plasma etching device, comprising a reaction chamber, a pair of upper electrodes and a lower electrode being arranged in parallel at the top and bottom of the reaction chamber, the upper electrode comprising a gas spraying zone for spraying gas downward and an edge zone surrounding the gas spraying zone, a plurality of electromagnetic coils uniformly distributed along the circumferential direction are arranged above the edge zone, and each of the electromagnetic coils is energized in a preset sequence to sequentially generate a magnetic field along the circumference of the edge zone in the preset sequence.

[0006] Furthermore, the preset sequence is: taking one of the electromagnetic coils as the starting coil, energizing them one by one along a specified direction, and the specified direction is clockwise or counterclockwise.

[0007] Further, the plurality of electromagnetic coils are divided into at least two groups, and the electromagnetic coils in each group are spaced apart by a specified angle; The preset sequence is: taking one group of the electromagnetic coils as the starting group, energizing each group one by one along a specified direction, wherein the specified direction is a clockwise direction or a counterclockwise direction.

[0008] Furthermore, the number of the electromagnetic coils is n, wherein n / 2 is an integer greater than 2, or n / 4 is an integer greater than 2.

[0009] Furthermore, a mounting plate is provided above the edge area, and the electromagnetic coil is mounted on the mounting plate.

[0010] Furthermore, the etching device also includes a lifting mechanism, and the lifting mechanism drives the mounting plate to move up and down, thereby driving the electromagnetic coils to move up and down synchronously.

[0011] In a second aspect, the present invention provides a capacitively coupled plasma etching method for etching a wafer using a capacitively coupled plasma etching device, wherein the etching device comprises a reaction chamber, a pair of upper electrodes and a lower electrode are arranged in parallel at the top and bottom of the reaction chamber, and the upper electrode comprises a gas spraying area for spraying gas downward and an edge area surrounding the gas spraying area, wherein the etching method comprises: A plurality of electromagnetic coils are arranged above the edge area and are evenly distributed along the circumferential direction; placing a wafer between the upper electrode and the lower electrode; The etching parameters are set, and the etching gas is introduced into the reaction chamber through the gas spray area to etch the wafer according to the etching parameters. During the etching process, each of the electromagnetic coils is controlled to be energized in a preset sequence to generate a magnetic field in sequence along the circumference of the edge area according to the preset sequence.

[0012] Furthermore, the preset sequence is: taking one of the electromagnetic coils as the starting coil, energizing them one by one along a specified direction, and the specified direction is clockwise or counterclockwise.

[0013] Further, the plurality of electromagnetic coils are divided into a plurality of groups, and the electromagnetic coils in each group are spaced apart by a specified angle; The preset sequence is: taking one group of the electromagnetic coils as the starting group, energizing each group one by one along a specified direction, wherein the specified direction is a clockwise direction or a counterclockwise direction.

[0014] Furthermore, the etching method further includes: arranging a lifting mechanism above the upper electrode for driving the electromagnetic coils to move synchronously, and the etching parameters include a target lifting height of the electromagnetic coils.

[0015] By adopting the above technical solution, the present invention has the following beneficial effects: The present invention arranges a plurality of electromagnetic coils evenly distributed along the circumferential direction above the edge region of the upper electrode. The magnetic field generated by the electromagnetic coils after being energized can enter the interior of the reaction chamber. By controlling the electromagnetic coils to be energized in a preset sequence in a cycle, the magnetic field is sequentially generated along the circumference of the edge region in the preset sequence, thereby simulating the circumferential movement of the magnetic field, so that the magnetic field can deflect the charged ions generated by capacitive coupling near the edge region of the upper electrode in the reaction chamber to assist in the dissociation of plasma, thereby exciting a higher density plasma at the edge of the wafer, thereby improving the etching rate of the edge of the wafer, and further improving the uniformity of etching in the center area and the edge of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of a conventional capacitively coupled plasma etching device; Figure 2 It is a schematic structural diagram of a plasma etching device according to Embodiment 1 of the present invention; Figure 3 A schematic diagram of the layout of the electromagnetic coil in Example 1 of the present invention; Figure 4 is another schematic diagram of the layout of the electromagnetic coil in Example 1 of the present invention; Figure 5 This is a schematic diagram of the layout of the electromagnetic coil in Example 2 of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. 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.

[0018] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "the" and "the" used in the present disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0019] As mentioned above, when using existing capacitively coupled plasma (CCP) etching equipment to etch wafers, it is easy to cause the problem of relatively low plasma density at the edge of the wafer, which will make the processing rate in the center area of ​​the wafer faster and the processing rate in the edge area of ​​the wafer slower, resulting in different performance of semiconductor devices formed in different areas of the wafer.

[0020] Based on this, the present invention provides an improved capacitively coupled plasma etching device and etching method to increase the etching rate of the wafer edge, thereby improving the uniformity of wafer etching.

[0021] Example 1 This embodiment provides a capacitively coupled plasma etching device, such as Figure 2 As shown, the etching device includes a reaction chamber, and a pair of upper electrodes 10 and lower electrodes 20 are arranged in parallel at the top and bottom of the reaction chamber. The upper electrode 10 and the lower electrode 20 are both circular electrode plates, and the two are coaxially arranged in the reaction chamber. When etching is performed, the wafer 30 is coaxially arranged above the lower electrode 20.

[0022] See also Figure 2-Figure 4 As shown, the upper electrode 10 in this embodiment includes a circular gas spraying area S1 located in the central area thereof and an annular edge area S2 surrounding the gas spraying area S1, wherein the gas spraying area S1 is used for spraying gas downward.

[0023] Different from traditional CCP etching equipment, Figures 2~4 As shown, in this embodiment, a plurality of electromagnetic coils 40 are evenly distributed along the circumferential direction above the edge region of the upper electrode 10, and the electromagnetic coils 40 are used to generate a magnetic field after being energized. It should be understood that the generated magnetic field can pass through the edge region of the upper electrode 10 into the interior of the reaction chamber, and the intensity near the edge region will be the strongest.

[0024] Preferably, the electromagnetic coil 40 is substantially square, and its length or width direction may extend along the radial direction of the upper electrode 10 (eg Figure 3 As shown), it is also possible not to extend along the radial direction of the upper electrode 10 (i.e., to form a certain angle with the radial direction, such as Figure 4 As shown). The number n of the electromagnetic coils 40 is an even number, and n / 2 is preferably an integer greater than 2, or n / 4 is preferably an integer greater than 2, so as to facilitate subsequent grouping. Of course, in addition to being roughly square, the electromagnetic coils 40 can also be configured in any other suitable shape (such as a circle, etc.), and this embodiment does not impose any specific limitation on this.

[0025] In this embodiment, each electromagnetic coil 40 is configured to be energized cyclically in a preset sequence (it should be understood that when the rear electromagnetic coil 40 is energized in sequence, the front energized electromagnetic coil 40 should be deenergized) to generate a magnetic field in sequence along the circumference of the edge area in the preset sequence, thereby simulating the circumferential movement of the magnetic field, so that the magnetic field can deflect the charged ions generated by capacitive coupling near the edge area of ​​the upper electrode inside the reaction chamber to assist in the dissociation of the plasma, thereby being able to excite a higher density plasma at the edge of the wafer, thereby improving the etching rate at the edge of the wafer, and further improving the uniformity of etching in the center area and edge of the wafer.

[0026] In an optional embodiment, the preset sequence is set as follows: starting with one of the electromagnetic coils 40 as the starting coil, energizing one by one in a specified direction, the specified direction being clockwise or counterclockwise. Figure 3 As shown in the figure (8 coils A~H are evenly arranged along the circumference), the specified direction is clockwise, and the electromagnetic coil A is set as the starting coil. The preset sequence is to energize one by one in the direction of A→B→C→D→E→F→G→H. One execution according to the preset sequence is a cycle. After the last coil H is energized, start with coil A and repeat the energization according to the preset sequence.

[0027] In another optional embodiment, the plurality of electromagnetic coils 40 are evenly divided into at least two groups, and the electromagnetic coils 40 in each group are spaced at a specified angle. On this basis, the preset sequence is: one group of electromagnetic coils 40 is used as the starting group, and the groups are energized one by one in a specified direction (the electromagnetic coils in the same group are energized synchronously), and the specified direction is clockwise or counterclockwise.

[0028] For example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 3 As shown, the specified direction is clockwise, and the coils spaced 180° apart are a group, that is, A and E are a group, B and F are a group, C and G are a group, and D and H are a group. The A and E groups are set as the starting group, and the preset sequence is: A, E→B, F→C, G→D, H, that is, first A and E are energized at the same time, then B and F are energized at the same time, and then C and G are energized at the same time, and finally D and H are energized at the same time. One cycle is executed once according to this preset sequence. Compared with the previous energization sequence of energizing one by one from A to H, energizing two coils at the same time will be more efficient.

[0029] For another example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 3As shown, the specified direction is clockwise, and the coils spaced 90° apart are a group, that is, A, C, E, G are a group, B, D, F, H are a group, and the A, C, E, G group is set as the starting group, then the preset sequence is: A, C, E, G→B, D, F, H, that is, first A, C, E, G are energized at the same time, and then B, D, F, H are energized at the same time, and one cycle is executed according to this preset sequence. This energization sequence allows the four coils to be energized at the same time, so the efficiency is higher.

[0030] It should be understood that the above 180° or 90° is only used as an example, and this embodiment does not impose any specific restrictions on the angle of the interval during grouping. In actual use, the interval angle can be set according to the specific number of coils and actual needs.

[0031] This embodiment controls the power-on sequence of each electromagnetic coil 40 to generate a magnetic field in sequence along the circumference of the edge area, thereby simulating the circumferential movement of the magnetic field, so that the magnetic field can deflect the charged ions generated by capacitive coupling near the edge area of ​​the upper electrode inside the reaction chamber to assist in the dissociation of the plasma, thereby being able to excite a higher density plasma at the edge of the wafer, thereby improving the wafer edge etching efficiency, and having a simple structure and low cost, which is conducive to large-scale application in the semiconductor industry.

[0032] In one practicable manner, if Figure 2 As shown, in this embodiment, a mounting plate 50 is further provided above the edge region of the upper electrode, and the electromagnetic coil 40 is mounted on the corresponding mounting plate 50 .

[0033] Preferably, the etching device of this embodiment further includes a lifting mechanism (not shown), which, for example, drives the mounting plate 50 to move up and down under the drive of a cylinder or a motor, thereby causing each electromagnetic coil 40 to rise and fall synchronously, so that the magnetic field strength entering the reaction chamber can be adjusted. Specifically, when moving downward, the induction of the magnetic field can be enhanced, and when moving upward, the induction of the magnetic field can be reduced. By adjusting the lifting height of the electromagnetic coil 40, the etching rate of the edge of the wafer 30 can be adjusted.

[0034] See again Figure 2 As shown, in this embodiment, a gas buffer chamber 60 is formed above the gas spraying area S1 of the upper electrode 10, and the gas buffer chamber 60 is connected to an external gas supply device (not shown) to provide etching gas through the external gas supply device. The etching gas includes but is not limited to Cl2, BCl3, A r At the same time, the gas spraying area S1 is evenly provided with a plurality of gas inlet holes 11 connected with the gas buffer chamber 60, so that the etching gas in the gas buffer chamber 60 can enter the reaction chamber through these gas inlet holes 11 and generate plasma under the action of the magnetic field and the electric field.

[0035] Example 2 This embodiment provides a capacitively coupled plasma etching method, which uses a plasma etching device to etch the wafer 30. Figures 2~4 As shown, the etching device includes a reaction chamber, a pair of upper electrodes 10 and lower electrodes 20 are arranged in parallel at the top and bottom of the reaction chamber, and the upper electrode 10 includes a gas spraying area S1 for spraying gas downward and an edge area S2 surrounding the gas spraying area.

[0036] The etching method of this embodiment specifically includes the following steps: S1, a plurality of electromagnetic coils 40 distributed along the circumferential direction are arranged above the edge region of the upper electrode, wherein the electromagnetic coils 40 are used to generate a magnetic field after being energized. It should be understood that the generated magnetic field can pass through the edge region of the upper electrode 10 into the interior of the reaction chamber, and the intensity near the edge region will be the strongest.

[0037] Preferably, the electromagnetic coil 40 is substantially square, and its length or width direction may extend along the radial direction of the upper electrode 10 (eg Figure 3 As shown), it is also possible not to extend along the radial direction of the upper electrode 10 (i.e., to form a certain angle with the radial direction, such as Figure 4 Of course, the electromagnetic coil 40 can also be configured into any other suitable shape (such as a circle, etc.), and this embodiment does not impose any specific limitation on this.

[0038] S2, placing the wafer 30 in the reaction chamber, and specifically fixing it above the lower electrode 20 through a base such as an electrostatic chuck.

[0039] S3, setting etching parameters, and introducing etching gas into the reaction chamber through the gas spray area to etch the wafer according to the etching parameters. During the etching process, the electromagnetic coils are controlled to be energized in a preset sequence to generate a magnetic field in sequence along the circumference of the edge area according to the preset sequence, thereby simulating the circumferential movement of the magnetic field, so that the magnetic field can deflect the charged ions generated by capacitive coupling near the edge area of ​​the upper electrode inside the reaction chamber to assist in the dissociation of the plasma, thereby exciting a higher density plasma at the edge of the wafer, thereby improving the etching rate of the edge of the wafer, and further improving the uniformity of the etching of the center area and the edge of the wafer.

[0040] In this embodiment, the set etching parameters include a preset sequence for energizing the electromagnetic coil 40 .

[0041] In an optional embodiment, the preset sequence is set as follows: one of the electromagnetic coils 40 is used as the starting coil, and electricity is supplied one by one along a specified direction, and the specified direction is clockwise or counterclockwise.

[0042] For example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 3As shown in the figure (8 coils A~H are evenly arranged along the circumference), the specified direction is clockwise, and the electromagnetic coil A is set as the starting coil. The preset sequence is to energize one by one in the direction of A→B→C→D→E→F→G→H. One execution according to the preset sequence is a cycle. After the last coil H is energized, start with coil A and repeat the energization according to the preset sequence.

[0043] For another example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 5 As shown in the figure (6 coils a~f are evenly arranged along the circumference), the specified direction is clockwise, and the electromagnetic coil a is set as the starting coil. The preset sequence is to energize one by one in the direction of a→b→c→d→e→f. One execution according to the preset sequence is a cycle. After the last coil f is energized, it starts with coil a and repeats the energization according to the preset sequence.

[0044] In another optional embodiment, the plurality of electromagnetic coils 40 are divided into at least two groups, and the electromagnetic coils 40 in each group are spaced apart by a specified angle. On this basis, the preset sequence is: one group of electromagnetic coils 40 is used as the starting group, and the groups are energized one by one in a specified direction (the electromagnetic coils in the same group are energized synchronously), and the specified direction is clockwise or counterclockwise.

[0045] For example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 3 As shown, the specified direction is clockwise, and the coils spaced 180° apart are a group, that is, A and E are a group, B and F are a group, C and G are a group, and D and H are a group. The A and E groups are set as the starting group, and the preset sequence is: A, E→B, F→C, G→D, H, that is, first A and E are energized at the same time, then B and F are energized at the same time, and then C and G are energized at the same time, and finally D and H are energized at the same time. One cycle is executed once according to this preset sequence. Compared with the previous energization sequence of energizing one by one from A to H, energizing two coils at the same time will be more efficient.

[0046] For another example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 3 As shown, the specified direction is clockwise, and the coils spaced 90° apart are a group, that is, A, C, E, G are a group, B, D, F, H are a group, and the A, C, E, G group is set as the starting group, then the preset sequence is: A, C, E, G→B, D, F, H, that is, first A, C, E, G are energized at the same time, and then B, D, F, H are energized at the same time, and one cycle is executed according to this preset sequence. This energization sequence allows the four coils to be energized at the same time, so the efficiency is higher.

[0047] For another example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 5As shown in the figure, the specified direction is clockwise, and the coils spaced 180° apart are a group, that is, a and d are a group, b and e are a group, and c and f are a group, and the a and d groups are set as the starting group, then the preset sequence is: a, d→b, e→c, f, that is, first a and d are energized at the same time, then b and e are energized at the same time, and then c and f are energized at the same time, and one cycle is executed once according to this preset sequence. Compared with the previous energization sequence of energizing one by one from a to f, energizing two coils at the same time will be more efficient.

[0048] For another example, assuming that the layout of the electromagnetic coil 40 is as follows Figure 5 As shown in the figure, the specified direction is clockwise, and the coils spaced 120° apart are a group, that is, a, c, e are a group, b, d, f are a group, and the group a, c, e is set as the starting group, then the preset sequence is: a, c, e→b, d, f, that is, first a, c, e are energized at the same time, then b, d, f are energized at the same time, and one cycle is executed according to this preset sequence. This energization sequence allows the three coils to be energized at the same time, so the efficiency is higher.

[0049] This embodiment controls the power-on sequence of each electromagnetic coil 40 to generate a magnetic field in sequence along the circumference of the edge area, thereby simulating the circumferential movement of the magnetic field, so that the magnetic field can deflect the charged ions generated by capacitive coupling near the edge area of ​​the upper electrode inside the reaction chamber to assist in the dissociation of the plasma, thereby being able to excite a higher density plasma at the edge of the wafer, thereby improving the wafer edge etching efficiency, and having a simple structure and low cost, which is conducive to large-scale application in the semiconductor industry.

[0050] During etching, in this embodiment, one of the upper electrode 10 and the lower electrode 20 is grounded, and the other is connected to a radio frequency power source, so that a radio frequency electric field is generated between the upper electrode 10 and the lower electrode 20 to ionize the etching gas introduced into the reaction chamber to form plasma, and then the wafer 30 placed between the upper electrode 10 and the lower electrode 20 and supported by the base is etched. The set etching parameters include but are not limited to the frequency and power of the radio frequency power source, the chamber pressure of the reaction chamber, the etching gas type and its flow rate, etc.

[0051] In an operative manner, the etching method of the present embodiment further comprises: a lifting mechanism for driving the electromagnetic coil 40 to rise and fall is arranged above the upper electrode 10, and the lifting mechanism drives the mounting plate of the electromagnetic coil 40 to move up and down under the drive of a cylinder or a motor, for example, so that the electromagnetic coil 40 is lifted and lowered accordingly, thereby adjusting the strength of the magnetic field entering the reaction chamber. Specifically, when moving downward, the induction of the magnetic field can be enhanced, and when moving upward, the induction of the magnetic field can be reduced, thereby adjusting the etching rate of the edge of the wafer 30. On this basis, the aforementioned etching parameters also include a target lifting height of the electromagnetic coil 40. By adjusting the target lifting height, the strength of the magnetic field dissociation plasma can be adjusted, thereby adjusting the etching rate of the edge of the wafer 30.

[0052] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A capacitively coupled plasma etching device, comprising a reaction chamber, wherein a pair of upper electrodes and a lower electrode are arranged in parallel at the top and bottom of the reaction chamber, wherein the upper electrode comprises a gas spraying area for spraying gas downward and an edge area surrounding the gas spraying area, wherein: A plurality of electromagnetic coils evenly distributed along the circumferential direction are arranged above the edge area, and each of the electromagnetic coils is energized cyclically in a preset sequence to sequentially generate a magnetic field along the circumference of the edge area in the preset sequence.

2. The plasma etching equipment according to claim 1, characterized in that: The preset sequence is: taking one of the electromagnetic coils as the starting coil, energizing them one by one in a specified direction, wherein the specified direction is a clockwise direction or a counterclockwise direction.

3. The plasma etching equipment according to claim 1, characterized in that: The plurality of electromagnetic coils are divided into at least two groups, and the electromagnetic coils in each group are spaced apart by a specified angle; The preset sequence is: taking one group of the electromagnetic coils as the starting group, energizing each group one by one along a specified direction, wherein the specified direction is a clockwise direction or a counterclockwise direction.

4. The plasma etching device according to claim 3, characterized in that: The number of the electromagnetic coils is n, wherein n / 2 is an integer greater than 2, or n / 4 is an integer greater than 2.

5. The plasma etching equipment according to claim 1, characterized in that: A mounting plate is provided above the edge area, and the electromagnetic coil is mounted on the mounting plate.

6. The plasma etching equipment according to claim 5, characterized in that: The etching device also includes a lifting mechanism, which drives the mounting plate to move up and down, thereby driving the electromagnetic coils to move up and down synchronously.

7. A capacitively coupled plasma etching method, for etching a wafer using a capacitively coupled plasma etching device, the etching device comprising a reaction chamber, a pair of upper electrodes and a lower electrode being arranged in parallel at the top and bottom of the reaction chamber, the upper electrode comprising a gas spraying area for spraying gas downward and an edge area surrounding the gas spraying area, characterized in that: The etching method comprises: A plurality of electromagnetic coils are arranged above the edge area and are evenly distributed along the circumferential direction; placing a wafer between the upper electrode and the lower electrode; The etching parameters are set, and the etching gas is introduced into the reaction chamber through the gas spray area to etch the wafer according to the etching parameters. During the etching process, each of the electromagnetic coils is controlled to be energized in a preset sequence to generate a magnetic field in sequence along the circumference of the edge area according to the preset sequence.

8. The plasma etching method according to claim 7, characterized in that: The preset sequence is: taking one of the electromagnetic coils as the starting coil, energizing them one by one in a specified direction, wherein the specified direction is a clockwise direction or a counterclockwise direction.

9. The plasma etching method according to claim 7, characterized in that: The electromagnetic coils are divided into a plurality of groups, and the electromagnetic coils in each group are spaced apart by a specified angle; The preset sequence is: taking one group of the electromagnetic coils as the starting group, energizing each group one by one along a specified direction, wherein the specified direction is a clockwise direction or a counterclockwise direction.

10. The plasma etching method according to claim 7, characterized in that: The etching method further includes: arranging a lifting mechanism above the upper electrode for driving the electromagnetic coils to move synchronously, and the etching parameters include a target lifting height of the electromagnetic coils.

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