Plasma etching device and machine table thereof

Abstract

The application relates to a plasma etching device and a machine table thereof. The device comprises a chamber, a wafer support part at the bottom of the chamber, the wafer support part comprising a first area and a second area surrounding the first area; the first area is used for placing a wafer; a plasma generating part is used for generating plasma in the chamber; an adjusting assembly is used for adjusting the revolution radius of the plasma, is fixed to the second area through a connecting structure, and comprises a blocking ring used for generating a first local magnetic field and a coil surrounding the blocking ring and used for generating a second local magnetic field; the blocking ring is connected to the coil through a positioning structure; and a motor is used for supplying power to the adjusting assembly. By arranging the tightening coil and the telescopic blocking ring, the current size and the positional relationship of the tightening coil and the telescopic blocking ring are changed, and then the adjustment of the inner and outer ring plasma density (motion track) is realized, and the etching uniformity is improved.

Description

Technical Field

[0001] This application relates to the field of plasma etching equipment technology, and in particular to a plasma etching apparatus and its equipment. Background Technology

[0002] Electron Cyclotron Resonance (ECR) etching equipment is an advanced process equipment that uses microwave-excited plasma for etching. It is widely used in the field of dry etching due to its advantages such as high plasma density and etching rate, as well as low emission intensity, simple structure, high stability and long life.

[0003] However, existing plasma etching devices are limited by their overall structure, resulting in uneven plasma density and distribution, and low edge etching rate (ER). This leads to radial or local differences in plasma density in the etching area (especially in large wafers), affecting the overall etching uniformity of the wafer. Utility Model Content

[0004] Therefore, it is necessary to provide a plasma etching apparatus and its setup to address the problems mentioned in the background art, which can at least improve the uniformity of wafer plasma etching.

[0005] To address the aforementioned technical problems and other issues, according to some embodiments, one aspect of this application provides a plasma etching apparatus, comprising: a chamber, including a wafer support portion located at the bottom of the chamber, the wafer support portion including a first region and a second region circumferentially surrounding the first region; the first region being used to place a wafer;

[0006] Plasma generation unit, used to generate plasma within the cavity;

[0007] An adjustment assembly for adjusting the cyclotron radius of the plasma is fixed to the second region via a connecting structure, including a blocking ring for generating a first local magnetic field and a coil circumferentially surrounding the blocking ring to generate a second local magnetic field; the blocking ring is connected to the coil via a positioning structure.

[0008] The motor is used to power the regulating components.

[0009] In the plasma etching apparatus described in the above embodiments, an adjustment component is added to the original plasma etching apparatus. The first local magnetic field generated by the blocking ring inside the adjustment component, together with the second local magnetic field generated by the coil, acts on the plasma region above the wafer edge. By changing the first and second local magnetic fields, the gyration radius of charged particles in the plasma in this region is adjusted to change their trajectory, thereby making the plasma density and ion distribution in the wafer center and edge regions more uniform and improving the uniformity of wafer etching.

[0010] In some embodiments, the positioning structure is a flexible component;

[0011] The regulating component adjusts the plasma's gyroscopic radius by extending and retracting the blocking ring circumferentially.

[0012] In the plasma etching apparatus of the above embodiments, the blocking ring expands and contracts circumferentially to achieve circumferential expansion / contraction (radial deformation), and the positioning structure absorbs the expansion and contraction displacement of the blocking ring through compression / stretching to avoid generating tensile force on the coil.

[0013] In some embodiments, the retaining ring and the coil are connected to the motor via wires;

[0014] The motor drives the blocking ring to extend and retract circumferentially by pulling the wire.

[0015] In the plasma etching apparatus of the above embodiments,

[0016] In some embodiments, the connection structure can extend or retract along a direction perpendicular to the surface of the wafer;

[0017] The regulating component adjusts the gyration radius of the plasma by raising and lowering the coil in the vertical direction.

[0018] In the plasma etching apparatus of the above embodiments, the coil serves as both an electrical connector and a mechanical transmission component, transmitting tension while supplying power to the blocking ring and the coil. The extension and retraction length of the conductor is controlled by a motor, driving the blocking ring to extend and retract circumferentially, thereby adjusting the range of the magnetic field acting on the plasma.

[0019] In some embodiments, the regulating component adjusts the plasma gyration radius by changing the current flowing through the blocking ring and the coil.

[0020] The direction of the first local magnetic field is opposite to the direction of the second local magnetic field.

[0021] In the plasma etching apparatus of the above embodiments, after a controllable current is supplied to the regulating component, the strength of the combined magnetic field formed by the superposition of the two can be adjusted by changing the current value flowing through the blocking ring and the coil, thereby realizing the control of the gyroscopic radius of charged particles in the plasma.

[0022] In some embodiments, the connection structure includes:

[0023] Porous sidewalls, located on the side closest to the wafer;

[0024] An exhaust fan, located within the connecting structure and connected to a motor, is used to generate negative pressure within the connecting structure to drive pollutants away from the first area.

[0025] In the plasma etching apparatus of the above embodiments, a porous sidewall and an exhaust fan are provided in the connection structure to prevent contaminants from falling onto the surface of the wafer through negative pressure suction.

[0026] In some embodiments, the cross-sectional shape of the adjusting component is selected from rectangles, circles, ellipses, polygons, rings, and combinations thereof.

[0027] In some embodiments, the adjustment component includes at least three positioning structures, and the spacing between the positioning structures is the same.

[0028] In the plasma etching apparatus of the above embodiments, it is possible to ensure that the blocking ring is subjected to balanced forces during circumferential expansion and contraction, thereby achieving uniform expansion and contraction along the circumferential direction and providing a structural basis for the stable adjustment of the magnetic field.

[0029] Another aspect of this application provides a plasma processing apparatus, including a plasma etching apparatus as described in any of the above embodiments.

[0030] In some embodiments, the plasma etching machine further includes a control device connected to the plasma etching apparatus for controlling the plasma etching apparatus to perform corresponding actions.

[0031] In the plasma processing equipment described in the above embodiments, the operation of the plasma etching device is precisely controlled to ensure that each component (such as the blocking ring and coil in the adjustment component) operates in coordination according to preset parameters during the etching process, thereby ensuring the stability of the plasma processing and the consistency of the etching effect.

[0032] The plasma etching apparatus and its setup described in the above embodiments have the following unexpected technical effects:

[0033] Compared to related technologies, the plasma etching apparatus provided in this application adds an adjustment component. Utilizing the inverse relationship between the plasma cyclotron radius and the magnetic field strength, the magnetic field strength distribution at the top of the wafer support is altered by controlling the current values ​​of the blocking ring and coil, the height of the connection structure, or the radius of the blocking ring (circumferential expansion / contraction) within the adjustment component. This achieves a change in plasma density within the corresponding area, resulting in a uniform plasma distribution on the wafer and significantly improving etching uniformity. The coil and blocking ring themselves can also act as a showerhead, further limiting the plasma distribution area through physical obstruction.

[0034] By using a dual-purpose motor, which can drive both the retractable blocking ring and the exhaust fan, the need for multiple additional drive structures is effectively eliminated, simplifying the layout and reducing costs. Simultaneously, the exhaust fan creates negative pressure within the connection structure, using the pressure difference to drive away contaminants generated during the operation of the regulating components, reducing the risk of wafer contamination or interference with plasma distribution, thereby ensuring the etching effect. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a cross-sectional schematic diagram of a plasma etching apparatus in related technologies;

[0037] Figure 2 for Figure 1 Schematic diagram of plasma fluid distribution within the middle chamber;

[0038] Figure 3 This is a schematic diagram of a plasma etching apparatus provided in one embodiment of this application;

[0039] Figure 4 This is one of the schematic diagrams of the adjustment component provided in one embodiment of this application;

[0040] Figure 5 This is a second schematic diagram of the adjustment component provided in one embodiment of this application;

[0041] Figure 6 This is a schematic diagram of a connection structure provided in one embodiment of this application.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Chamber; 2. Wafer support; 21. First region; 22. Second region; 3. Plasma generation unit; 4. Adjustment assembly; 41. Connection structure; 411. Side wall; 42. Blocking ring; 43. Coil; 44. Positioning structure; 5. Motor; 6. Wire; 7. Exhaust fan. Detailed Implementation

[0044] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0046] When using the terms “including,” “having,” and “comprising” as described herein, another component may be added unless explicitly qualifying terms such as “only,” “consisting of,” etc. are used. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0047] It should be understood that although the terms “first,” “second,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this application, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0048] In this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium, or they can refer to the internal connection of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0049] Figure 1 This is a cross-sectional schematic diagram of a plasma etching apparatus in related technologies, such as... Figure 1 As shown, in a plasma etching apparatus, plasma bombards the surface of a wafer along a diverging magnetic field under the influence of RF radio frequency at the lower electrode. The plasma typically flows downwards in a cone shape from the top to the bottom of the reaction chamber, with the specific path as follows: Figure 2 As shown. Due to the slight deviation in the magnetic field distribution, the plasma confinement ability of the edge region of the etched area (especially large-size wafers) is very weak, and the plasma cannot be uniformly downward. Even if the pores are set near the center of the electrode substrate, the etching rate of the wafer edge region will still be lower than that of the central region.

[0050] Based on this, please refer to Figure 3 This application provides a plasma etching apparatus, including: a chamber 1, including a wafer support portion 2 located at the bottom of the chamber 1, the wafer support portion 2 including a first region 21 and a second region 22 circumferentially surrounding the first region 21; the first region 21 is used to place a wafer;

[0051] Plasma generation unit 3, used to generate plasma within chamber 1;

[0052] The adjustment component 4, used to adjust the gyration radius of the plasma, is fixed to the second region 22 via the connection structure 41. It includes a blocking ring 42 for generating a first local magnetic field and a coil 43 that circumferentially surrounds the blocking ring 42 and generates a second local magnetic field. The blocking ring 42 is connected to the coil 43 via the positioning structure 44.

[0053] A motor (not shown) is used to power the regulating component 4.

[0054] Based on the equations of motion and the Lorentz force formula:

[0055]

[0056]

[0057]

[0058] Where m is mass, B is magnetic flux density, v is velocity, and q is charge. Based on this, the electron cyclotron radius satisfies the formula:

[0059]

[0060] As can be seen from the above formula, the cyclotron radius of the plasma can be adjusted by regulating the magnetic field strength. Based on this theory, in this embodiment, the cyclotron radius of the plasma can be affected by the magnetic effect of current in the following ways: first, by adjusting the current in coil 43 and blocking ring 42 to change the strength of the first and second local magnetic fields; second, by adjusting the positioning structure and connecting structure to change the spatial distribution of the magnetic field.

[0061] For example, chamber 1 is substantially symmetrical in orientation, with a quartz window at the top serving as an injection channel for etching gas; multiple sets of magnetic coils on the sidewalls are used to form a magnetic field within chamber 1; and a baffle (shower head) is disposed on the central axis to define the distribution area of ​​the plasma.

[0062] In the plasma etching apparatus of the above embodiments, the wafer support 2 is disposed on the central axis of the chamber 1, and the first region located at the center is used for electrostatic adsorption of the wafer as the etching region; the second region circumferentially surrounds the first region and is used to install the adjustment component 4.

[0063] The plasma generation unit 3 is located at the top opening of the chamber 1. A certain proportion of mixed etching gases, coupled with glow discharge, are used to transmit ECR plasma to the sample to be etched within the chamber 1 under the combined action of microwaves and a magnetic field. Within the chamber 1, the magnetic field distribution is controlled by the adjusting component 4, altering the plasma density in the first region. Guided by the RF radio frequency of the lower electrode of the wafer support unit 2, this plasma bombards the surface of the wafer, breaking the chemical bonds of the semiconductors in the patterned areas of the wafer. This breaks the chemical bonds and generates volatile substances with the etching gas, which detach from the substrate in gaseous form and are then extracted from the vacuum line.

[0064] On the other hand, coil 43 and blocking ring 42 also act as a showerhead, further limiting the distribution area of ​​plasma through physical blocking.

[0065] For example, please refer to 4- Figure 6 ,in, Figure 4 This is one of the specific structural schematic diagrams of the adjustment component 4 in this embodiment. For example... Figure 4 As shown, in an optional embodiment, the regulating component 4 adjusts the gyration radius of the plasma by changing the current value flowing through the blocking ring 42 and the coil 43. For example, after energizing the wire 6, the current flowing through the blocking ring 42 forms a first local magnetic field perpendicular to the plane of the paper and outwards, while the current flowing through the coil 43 forms a second local magnetic field perpendicular to the plane of the paper and inwards. By changing the current value flowing through the blocking ring and the coil, the strength of the combined magnetic field formed by their superposition can be adjusted, thereby controlling the gyration radius of charged particles in the plasma. Figure 4 In the diagram, X indicates that the direction of the magnetic field / current is perpendicular to the paper and inwards; · indicates that the direction of the magnetic field / current is perpendicular to the paper and outwards. It should be understood that... Figure 4 This is an example of the magnetic field distribution of the adjustment component provided in this application. The directions of the first local magnetic field and the second local magnetic field can be the same or opposite, and can be adjusted according to actual needs.

[0066] Please continue reading. Figure 4 In an optional embodiment, the positioning structure 44 is an elastic component;

[0067] The blocking ring 42 and the coil 43 are connected to the motor via the wire 6.

[0068] For example, the blocking ring 42 can be a one-piece structure or a split structure, with each part connected end to end to form a closed structure.

[0069] For example, the conductor 6 is made of a non-magnetic metal material (such as beryllium copper alloy or titanium wire), which has both current transmission and mechanical traction functions. One end of the conductor 6 is connected to the motor, and after the coil 43 is wound along the connecting structure 41 with a specific number of turns, it passes through the pre-set wire-passing channel on the positioning structure 44 and enters the blocking ring 42.

[0070] For example, the elastic component is specifically a spring, one end of which is connected to the outer ring of the blocking ring 42, and the other end is connected to the coil 43 to provide an elastic force.

[0071] For example, the cross-sectional shape of the adjusting component 4 is selected from rectangle, circle, ellipse, polygon, ring, and combinations thereof. In this embodiment, the adjusting component 4 is a concentric circle structure. The adjusting component 4 includes at least three elastic components, and the spacing between each elastic component is the same.

[0072] In this embodiment, four elastic components are included between the coil 43 and the blocking ring 42 to ensure mechanical stability and uniform circumferential expansion and contraction. The coil 43 is fixed to the connecting structure 41 and its shape remains unchanged. When the motor operates and pulls the wire, the blocking ring 42 expands circumferentially, and the range of the first local magnetic field extends towards the edge region of the wafer. When the motor operates and releases the wire 6, the blocking ring 42 contracts circumferentially, and the range of the first local magnetic field moves closer to the center region of the wafer.

[0073] Please see Figure 5 , Figure 5 The second schematic diagram of the specific structure of the adjustment component 4 in this embodiment shows that, in an optional embodiment, the connection structure 41 can extend and retract along a direction perpendicular to the surface of the wafer.

[0074] For example, the connecting structure 41 is a height-adjustable lifting rod. For instance, by adjusting the height of the lifting rod, the coil 43 and the blocking ring 42 can be raised or lowered vertically, thereby changing the axial magnetic field gradient and adjusting the gyration radius of the plasma.

[0075] In the plasma etching apparatuses described in the different embodiments above, the height adjustment of the connecting structure is not an independent action, but rather it can be coordinated with parameters such as the circumferential expansion and contraction of the blocking ring and the coil current, resulting in greater flexibility and effectively improving the versatility of the apparatus in different process scenarios, better meeting diverse etching needs. Researchers can select the components to be adjusted based on specific process conditions, such as the wafer material, size, and etching pattern precision requirements. For example, when high edge etching uniformity is required for large wafers, the height of the lifting rod can be adjusted simultaneously to change the axial magnetic field gradient, and the circumferential expansion and contraction of the blocking ring can be controlled to adjust the range of the magnetic field acting on the plasma. In processes with specific requirements for etching rate, the coil current can be adjusted primarily, supplemented by appropriate fine-tuning of the lifting rod height.

[0076] Further, please refer to Figure 6 , Figure 6 The internal structure of the lifting rod provided in this application, the connecting structure 41 includes:

[0077] Porous sidewall 411 is located on the side closest to the wafer;

[0078] The exhaust fan 7, located within the connecting structure 41 and connected to the motor 5, is used to generate negative pressure within the connecting structure 41 to drive pollutants away from the first area.

[0079] In this embodiment, the motor is a dual-purpose motor, which can control the retractable blocking coil and also drive the exhaust fan. The centrifugal force generated by the rotation of the fan blades will exhaust the air inside the connecting structure from the porous sidewall, making the air pressure inside the structure lower than the external ambient air pressure. Driven by the air pressure difference, contaminants (such as debris generated by etching, reaction byproducts, etc.) are forcibly carried away from the first area due to their own mass and the carrying effect of the airflow, thereby reducing the risk of contaminants adhering to the surface of the wafer or affecting the plasma distribution.

[0080] In some embodiments, this disclosure also provides a plasma etching machine, including: a plasma etching apparatus as described in any of the foregoing embodiments.

[0081] In an optional embodiment, the plasma etching apparatus further includes a control device (not shown), connected to the plasma etching apparatus, for controlling the plasma etching apparatus to perform corresponding actions. For example, based on a preset process formula (such as etching rate, uniformity target), during the wafer etching process, control commands are output to the etching apparatus. By controlling the current value of the adjustment component 4 (blocking ring 42 and coil 43), the height position of the connection structure 41, or the radius value (circumferential expansion and contraction) of the blocking ring 42, the magnetic field strength in the chamber 1 is adjusted to correct the non-uniformity of the plasma density distribution, thereby achieving uniform etching of the wafer.

[0082] In an optional embodiment, the plasma etching machine may also be equipped with sensors (not shown), such as an optical film thickness measuring instrument, to measure the surface etching distribution of the wafer in real time. When the etching rate at the wafer edge is insufficient, the control device automatically performs adjustment actions.

[0083] The plasma etching apparatus and its setup described in the above embodiments include the following unexpected technical effects:

[0084] Compared to plasma etching devices in related technologies, adding an adjustment component to change the magnetic field strength at the top of the wafer support, utilizing the inverse relationship between the gyro radius and the magnetic field, and controlling the current value of the blocking ring and coil within the adjustment component, as well as the connection structure height position or the blocking ring radius value (circumferential expansion), can generate a spatial gradient change in the magnetic field strength, achieving directional control of the plasma movement range, thereby effectively improving etching efficiency, while ensuring the etching uniformity, stability, and controllability of the ECR etching device.

[0085] In addition, there is no need to set up multiple drive structures. The above device uses a dual-purpose motor, which can control the retractable blocking ring and drive the exhaust fan. This simplifies the overall layout and reduces costs. At the same time, it creates an internal negative pressure in the connection structure. Under the action of air pressure difference, contaminants such as etching debris and reaction byproducts are carried away from the first area by the airflow, reducing the risk of contaminating the wafer or interfering with the plasma distribution and ensuring the etching effect.

[0086] Please note that the above embodiments are for illustrative purposes only and do not imply any limitation on the present invention.

[0087] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0088] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A plasma etching apparatus, characterized in that, include: The chamber includes a wafer support located at the bottom of the chamber, the wafer support including a first region and a second region circumferentially surrounding the first region; The first area is used to place the wafer; A plasma generation unit for generating plasma within the cavity; An adjustment component for adjusting the gyration radius of the plasma, fixed to the second region via a connecting structure, includes a blocking ring for generating a first local magnetic field, and a coil circumferentially surrounding the blocking ring to generate a second local magnetic field. The blocking ring is connected to the coil via a positioning structure; An electric motor is used to power the regulating assembly.

2. The plasma etching apparatus according to claim 1, characterized in that, The positioning structure is an elastic component; The regulating component adjusts the gyration radius of the plasma by extending and retracting the blocking ring circumferentially.

3. The plasma etching apparatus according to claim 2, characterized in that, The blocking ring and the coil are connected to the motor via wires; The motor drives the blocking ring to extend and retract circumferentially by pulling the wire.

4. The plasma etching apparatus according to claim 1, characterized in that, The connection structure can extend and retract in a direction perpendicular to the surface of the wafer; The adjustment component adjusts the gyration radius of the plasma by raising and lowering the coil in a vertical direction.

5. The plasma etching apparatus according to claim 1, characterized in that, The regulating component adjusts the gyration radius of the plasma by changing the current value flowing through the blocking ring and the coil; The direction of the first local magnetic field is opposite to the direction of the second local magnetic field.

6. The plasma etching apparatus according to any one of claims 1-5, characterized in that, The connection structure includes: Porous sidewalls are located on the side closest to the wafer; An exhaust fan, located within the connecting structure and connected to the motor, is used to generate negative pressure within the connecting structure to drive pollutants away from the first area.

7. The plasma etching apparatus according to any one of claims 1-5, characterized in that, The cross-sectional shape of the adjustment component is selected from rectangle, circle, ellipse, polygon, ring and combination thereof.

8. The plasma etching apparatus according to any one of claims 1-4, characterized in that, The adjustment component includes at least three positioning structures, and the spacing between each positioning structure is the same.

9. A plasma etching machine, characterized in that, Includes the plasma etching apparatus as described in any one of claims 1-8.

10. The plasma etching apparatus according to claim 9, characterized in that, Also includes: A control device, connected to the plasma etching apparatus, is used to control the plasma etching apparatus to perform corresponding actions.

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