A plasma processing chamber and semiconductor manufacturing equipment
By setting an electrostatic electrode and a power supply unit in the plasma processing chamber to change the electron quantity and area of the positive electrode, the problem that the DC self-bias voltage cannot be changed in the prior art is solved, and the etching effect is improved.
Patent Information
- Application Number
- CN202011462024.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-12-10
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2040-12-10
AI Technical Summary
The existing plasma processing chamber cannot change the DC self-bias voltage according to the specific etching requirements, resulting in the inability to improve the etching effect of the etching object.
By providing an electrostatic electrode and a power supply unit in the plasma processing chamber, different voltages are applied to the electrostatic electrode according to the control signal, the amount of electrons accumulated on the positive electrode is changed, thereby changing the area of the positive electrode and the DC self-biasing voltage.
The appropriate DC self-bias voltage is set according to the etching requirements, which improves the etching effect of the etching object.
Smart Images
Figure CN114628212B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of plasma etching, and in particular to a plasma processing chamber and semiconductor manufacturing equipment. Background Art
[0002] In the semiconductor manufacturing process, the plasma processing chamber is used to generate plasma to etch the wafer or other objects to be etched in the plasma processing chamber. The plasma processing chamber needs to use plasma to etch the objects to be etched under the environment of DC self-bias voltage. The area ratio between the positive and negative electrodes of the plasma processing chamber determines the size of the DC self-bias voltage. Due to the area difference between the positive and negative electrodes, the negative electrode with a smaller area accumulates high-density electrons, and the plasma ions are concentrated at the negative electrode to etch the objects to be etched placed on the negative electrode.
[0003] However, after the existing plasma processing chamber is manufactured, the size of the positive electrode and the negative electrode cannot be changed, so the area ratio between the positive electrode and the negative electrode cannot be changed, which leads to the inability to change the DC self-bias voltage of the plasma processing chamber. Therefore, when using plasma to etch the object to be etched, the size of the DC self-bias voltage cannot be changed according to the specific etching requirements, and thus the etching effect of the object to be etched cannot be improved. Summary of the invention
[0004] Based on this, the purpose of the present invention is to provide a plasma processing chamber and semiconductor manufacturing equipment to solve the current technical problem that when using plasma to etch the object to be etched, the size of the DC self-bias voltage cannot be changed according to the specific etching requirements, and thus the etching effect of the object to be etched cannot be improved.
[0005] In a first aspect, the present invention provides a plasma processing chamber for use in a plasma etching process. The plasma processing chamber comprises: a chamber wall, a positive electrode disposed on the inner surface of the chamber wall, an electrostatic electrode disposed on the inner surface of the positive electrode and insulated from the positive electrode, a negative electrode located in the plasma processing chamber, and a power supply unit electrically connected to the electrostatic electrode. An object to be etched is placed on the negative electrode; the power supply unit is used to apply different voltages to the electrostatic electrode according to a control signal to change the amount of electrons accumulated on the positive electrode.
[0006] Compared with the prior art, the plasma processing chamber provided by the present invention includes a chamber wall, a positive electrode arranged on the inner surface of the chamber wall, an electrostatic electrode arranged on the inner surface of the positive electrode, a negative electrode located in the plasma processing chamber, an object to be etched is placed on the negative electrode, and a power supply unit electrically connected to the electrostatic electrode. The power supply unit is used to apply different voltages to the electrostatic electrode according to the control signal to change the amount of electrons accumulated on the positive electrode. Based on this, the present invention can apply a positive voltage or a negative voltage to the positive electrode according to the control signal to change the amount of electrons accumulated on the positive electrode. When the amount of electrons accumulated on the positive electrode changes, the thickness of the sheath layer of the positive electrode wall will also change accordingly, thereby achieving the effect of changing the area of the positive electrode. When the area of the positive electrode changes, the area difference between the positive electrode and the negative electrode also changes, and then the above-mentioned DC self-bias voltage changes accordingly. Therefore, the present invention can set the above-mentioned control signal according to the etching requirements to obtain a suitable DC self-bias voltage, and etch the object to be etched under a suitable DC self-bias voltage, which can improve the etching effect of the object to be etched.
[0007] In a second aspect, the present invention further provides a semiconductor manufacturing equipment, comprising the above-mentioned plasma processing chamber.
[0008] Compared with the prior art, the beneficial effects of the semiconductor manufacturing equipment provided by the present invention are the same as the beneficial effects of the plasma processing chamber of the above-mentioned technical solution, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:
[0010] FIG. 1( a ) shows a schematic diagram of a plasma processing chamber in the prior art;
[0011] FIG. 1( b ) is a schematic diagram showing different numbers of electrons accumulated on the positive plate and the negative plate in the plasma processing chamber of FIG. 1( a );
[0012] FIG. 1( c ) shows a schematic diagram of a plasma processing chamber in the prior art;
[0013] FIG. 1( d ) is a schematic diagram showing that the number of electrons accumulated on the positive plate and the negative plate in the plasma processing chamber in FIG. 1( c ) is the same;
[0014] Figure 2 A schematic structural diagram of a plasma processing chamber provided by an embodiment of the present invention is shown;
[0015] FIG3( a ) shows a schematic diagram of applying a negative voltage to an electrostatic electrode to change the positive electrode wall sheath of a plasma processing chamber provided by an embodiment of the present invention;
[0016] FIG3( b ) shows a schematic diagram of applying a positive voltage to an electrostatic electrode to change the positive electrode wall sheath of a plasma processing chamber provided by an embodiment of the present invention;
[0017] Figure 4 A schematic diagram of a circuit between a plasma processing chamber and a power supply unit provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION
[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.
[0019] Various schematic diagrams of embodiments of the present invention are shown in the accompanying drawings, which are not drawn to scale. For the purpose of clarity, some details are magnified and some details may be omitted. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.
[0020] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.
[0021] In addition, in the present invention, directional terms such as "upper" and "lower" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to the orientation of the components in the drawings.
[0022] In the present invention, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.
[0023] In the semiconductor manufacturing process, the plasma processing chamber is used to generate plasma to etch the wafer or other objects to be etched in the plasma processing chamber. The plasma processing chamber needs to be in a DC self-bias voltage environment to use plasma to etch the objects to be etched. The area ratio between the positive and negative electrodes of the plasma processing chamber determines the size of the DC self-bias voltage. Due to the area difference between the positive and negative electrodes, the negative electrode with a smaller area accumulates high-density electrons. At this time, most of the plasma ions are concentrated at the negative electrode to etch the objects to be etched placed on the negative electrode.
[0024] However, after the existing plasma processing chamber is manufactured, the size of the positive electrode and the negative electrode cannot be changed, and therefore the area ratio between the positive electrode and the negative electrode cannot be changed. Therefore, when using plasma to etch the object to be etched, the size of the DC self-bias voltage cannot be changed according to the specific etching requirements, and thus the etching effect of the object to be etched cannot be improved.
[0025] Specifically, FIG. 1(a) shows a schematic diagram of a plasma processing chamber in the prior art, wherein the areas of the positive electrode plate and the negative electrode plate are different, and there is a DC self-bias voltage. FIG. 1(b) shows a schematic diagram of the plasma processing chamber in FIG. 1(a) in which the number of electrons accumulated on the positive electrode plate and the negative electrode plate are different. FIG. 1(c) shows a schematic diagram of a plasma processing chamber in the prior art, wherein the areas of the positive electrode plate and the negative electrode plate are the same, and there is no DC self-bias voltage. FIG. 1(d) shows a schematic diagram of the plasma processing chamber in FIG. 1(c) in which the number of electrons accumulated on the positive electrode plate and the negative electrode plate are the same.
[0026] Reference Figure 1(a)-Figure 1(d) It can be seen that when there is an area difference between the positive plate and the negative plate of the plasma processing chamber, the number of electrons accumulated on the positive plate and the negative plate is different. At this time, when other factors remain unchanged, there is a DC self-bias voltage in the plasma processing chamber. Specifically, the number of electrons accumulated on the positive plate with a larger area is less than the number of electrons accumulated on the negative plate with a smaller area.
[0027] When the positive plate and the negative plate of the plasma processing chamber have the same area, the number of electrons accumulated on the positive plate and the negative plate is the same. At this time, when other factors remain unchanged, there is no DC self-bias voltage in the plasma processing chamber.
[0028] The self-bias voltage is used to accelerate the etching of the ions in the plasma in the object to be etched, so as to anisotropically etch the surface of the object to be etched. The greater the self-bias voltage, the greater the amount of etching of the object to be etched by the plasma per unit time. The magnitude of the self-bias voltage is proportional to the nth power of the area ratio of the positive electrode to the negative electrode, when other factors remain unchanged. That is, the greater the area ratio of the positive electrode to the negative electrode, the greater the DC self-bias voltage. However, after the plasma processing chamber is manufactured, it is difficult to change the area difference between the positive electrode and the negative electrode.
[0029] Based on this, Figure 2 FIG. 1 shows an embodiment of the present invention that provides a plasma processing chamber 10. The plasma processing chamber 10 is used in a plasma etching process. Figure 2 The plasma processing chamber 10 includes: a chamber wall, a positive electrode 11 disposed on the inner surface of the chamber wall, an electrostatic electrode 13 disposed on the inner surface of the positive electrode 11 and insulated from the positive electrode 11, a negative electrode 12 located in the plasma processing chamber 10, and a power supply unit ( Figure 2 (not shown) Wherein, an object to be etched is placed on the negative electrode 12. In the manufacturing process of the semiconductor device, the object to be etched may be a wafer.
[0030] In practice, the material of the chamber wall is the same as that of the positive electrode, and an insulating layer is formed between the chamber wall and the positive electrode to prevent current leakage. The positive electrode 11 and the chamber wall can be made of metal material, such as aluminum.
[0031] In a possible implementation, the electrostatic electrode 13 may be formed on the entire inner surface of the positive electrode 11 to change the amount of electrons accumulated on the positive electrode 11 as a whole. Specifically, the electrostatic electrode changes the amount of electrons accumulated on the positive electrode through Coulomb force. In order to induce the generation of Coulomb force, the electrostatic electrode needs to be isolated from the positive electrode, and the electrostatic electrode needs to be isolated from the plasma.
[0032] For example, an insulating coating may be formed between the electrostatic electrode and the positive electrode to isolate the electrostatic electrode from the positive electrode. A coating may also be formed on the surface of the electrostatic electrode facing away from the positive electrode to isolate the electrostatic electrode from the plasma.
[0033] Specifically, refer to Figure 2 , a first ceramic material layer 14 may be formed between the positive electrode and the electrostatic electrode, and a second ceramic material layer may be formed on the surface of the electrostatic electrode facing the negative electrode. The materials of the first ceramic material layer and the second ceramic material layer include: aluminum oxide, yttrium oxide, yttrium oxyfluoride or yttrium fluoride.
[0034] Exemplarily, in order to prevent leakage current from being generated between the electrostatic electrode and the positive electrode and between the positive electrode and the chamber wall, the thickness of the first ceramic material layer and the second ceramic material layer should be greater than or equal to 200 μm. It is understood that in order to avoid the influence of the excessive thickness of the first ceramic material layer and the second ceramic material layer on the DC self-bias voltage generated in the plasma processing chamber, the thickness of the first ceramic material layer and the second ceramic material layer should be less than or equal to 500 μm.
[0035] In order to facilitate the maintenance of the electrostatic electrode, the electrostatic electrode can be detachably arranged on the inner surface of the positive electrode. Similarly, in order to facilitate the maintenance of the positive electrode, the positive electrode can be detachably arranged on the inner surface of the chamber wall.
[0036] The power supply unit is used to apply different voltages to the electrostatic electrode 13 according to the control signal to change the amount of electrons accumulated on the positive electrode 11. When the amount of electrons accumulated on the positive electrode 11 changes, the thickness of the wall sheath of the positive electrode 11 will also change accordingly, thereby achieving the effect of changing the area of the positive electrode 11, and then changing the DC self-bias voltage in the plasma processing chamber. In practice, the control signal can be set according to the etching requirements to obtain a suitable DC self-bias voltage, and etching the object to be etched under a suitable DC self-bias voltage can improve the etching effect of the object to be etched.
[0037] Referring to Figures 3(a) and 3(b), the positive electrode wall sheath of the plasma processing chamber is changed by applying a positive voltage or a negative voltage to the electrostatic electrode through the power supply unit. Referring to Figure 3(a), when a negative voltage is applied to the electrostatic electrode through the power supply unit, the amount of electrons accumulated on the positive electrode decreases, and the thickness of the positive electrode wall sheath decreases. At this time, the DC self-bias voltage increases. Referring to Figure 3(b), when a positive voltage is applied to the electrostatic electrode through the power supply unit, the amount of electrons accumulated on the positive electrode increases, and the thickness of the positive electrode wall sheath increases. At this time, the DC self-bias voltage decreases.
[0038] In practice, it is possible to choose whether to apply a positive voltage or a negative voltage to the electrostatic electrode according to the above principle. For example, when the required DC self-bias voltage is greater than the DC self-bias voltage obtained based on the current plasma processing chamber structure, a negative voltage can be applied to the electrostatic electrode through the power supply unit. When the required DC self-bias voltage is less than the DC self-bias voltage obtained based on the current plasma processing chamber structure, a positive voltage can be applied to the electrostatic electrode through the power supply unit. The magnitudes of the positive and negative voltages can be adjusted according to actual conditions.
[0039] Reference Figure 4The power supply unit includes a signal controller, a voltage controller and a DC power supply 16. The signal controller is used to generate a control signal and send the control signal to the voltage controller. The voltage controller controls the output voltage of the DC power supply 16 according to the control signal. The DC power supply 16 is used to provide an output voltage to the electrostatic electrode.
[0040] The signal controller can generate a control signal according to the user's instruction, and the signal controller sends the control signal to the voltage controller, and the voltage controller generates a corresponding voltage control signal according to the control signal, and the voltage control signal is used to control the output voltage of the DC power supply 16. The output voltage is applied to the electrostatic electrode so that the plasma processing chamber has a DC self-bias voltage environment corresponding to the user's instruction.
[0041] Reference Figure 4 In order to ensure that the output voltage applied to the electrostatic electrode meets the user's instructions, the power supply unit also includes a current sensor 17 connected in series between the DC power supply and the electrostatic electrode. The current sensor 17 is connected to the voltage controller for communication, and is used to send the detected current value between the DC power supply 16 and the electrostatic electrode 13 to the voltage controller. The voltage controller is used to determine whether the current value meets the required current value. If it does not meet the required current value, the output voltage is adjusted according to the relationship between the current value and the required current value so that the current value meets the required current value.
[0042] In order to ensure the direct current connection between the electrostatic electrode and the DC power supply, the electrostatic electrode is connected to the DC power supply via a DC connector. At this time, a through hole can be provided on the chamber wall and the positive electrode, and the through hole is used to pass the DC connector.
[0043] Furthermore, when it is necessary to use plasma to remove etching byproducts generated on the chamber wall, this can be achieved by increasing the thickness of the chamber wall sheath layer on the chamber wall.
[0044] Therefore, compared with the prior art, the plasma processing chamber provided in the embodiment of the present invention includes a chamber wall, a positive electrode arranged on the inner surface of the chamber wall, an electrostatic electrode arranged on the inner surface of the positive electrode, a negative electrode located in the plasma processing chamber, an object to be etched is placed on the negative electrode, and a power supply unit electrically connected to the electrostatic electrode. The power supply unit is used to apply different voltages to the electrostatic electrode according to the control signal to change the amount of electrons accumulated on the positive electrode. Based on this, the embodiment of the present invention can apply a positive voltage or a negative voltage to the positive electrode according to the control signal to change the amount of electrons accumulated on the positive electrode. When the amount of electrons accumulated on the positive electrode changes, the thickness of the sheath layer of the positive electrode wall will also change accordingly, thereby achieving the effect of changing the area of the positive electrode. When the area of the positive electrode changes, the area difference between the positive electrode and the negative electrode also changes, and then the above-mentioned DC self-bias voltage changes accordingly. Therefore, the present invention can set the above-mentioned control signal according to the etching requirements to obtain a suitable DC self-bias voltage, and etch the object to be etched under a suitable DC self-bias voltage, which can improve the etching effect of the object to be etched.
[0045] An embodiment of the present invention further provides a semiconductor manufacturing device, which includes the above-mentioned plasma processing chamber.
[0046] Since the semiconductor manufacturing equipment includes a plasma processing chamber, the semiconductor manufacturing equipment provided by the embodiment of the present invention can apply a positive voltage or a negative voltage to the positive electrode according to the control signal to change the amount of electrons accumulated on the positive electrode. When the amount of electrons accumulated on the positive electrode changes, the thickness of the positive electrode wall sheath will also change accordingly, thereby achieving the effect of changing the area of the positive electrode. When the area of the positive electrode changes, the area difference between the positive electrode and the negative electrode also changes, and then the above-mentioned DC self-bias voltage changes accordingly. Therefore, the embodiment of the present invention can set the above-mentioned control signal according to the etching requirements to obtain a suitable DC self-bias voltage, and etch the object to be etched under a suitable DC self-bias voltage, which can improve the etching effect of the object to be etched.
[0047] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.
[0048] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A plasma processing chamber, characterized in that: Applied in a plasma etching process, the plasma processing chamber comprises: A chamber wall, a positive electrode disposed on the inner surface of the chamber wall, an electrostatic electrode disposed on the inner surface of the positive electrode and insulated from the positive electrode, a negative electrode located in the plasma processing chamber, and a power supply electrically connected to the electrostatic electrode; wherein an object to be etched is placed on the negative electrode; The power supply unit is used to apply different voltages to the electrostatic electrode according to a control signal to change the amount of electrons accumulated on the positive electrode and the thickness of the wall sheath layer, thereby changing the area of the positive electrode.
2. The plasma processing chamber according to claim 1, characterized in that: The plasma processing chamber further includes a first ceramic material layer formed between the positive electrode and the electrostatic electrode, and a second ceramic material layer formed on a surface of the electrostatic electrode facing the negative electrode.
3. The plasma processing chamber according to claim 2, characterized in that: The materials of the first ceramic material layer and the second ceramic material layer include: aluminum oxide, yttrium oxide, yttrium oxyfluoride or yttrium fluoride.
4. The plasma processing chamber according to claim 2, characterized in that: The thickness of the first ceramic material layer is greater than or equal to 200 μm and less than or equal to 500 μm; and / or, The thickness of the second ceramic material layer is greater than or equal to 200 μm and less than or equal to 500 μm.
5. The plasma processing chamber according to claim 1, wherein: The positive electrode is detachably disposed on the inner surface of the chamber wall; The electrostatic electrode is detachably disposed on an inner surface of the positive electrode.
6. The plasma processing chamber according to claim 1, wherein: The material of the chamber wall is the same as that of the positive electrode, and an insulating layer is formed between the chamber wall and the positive electrode.
7. The plasma processing chamber according to any one of claims 1 to 6, characterized in that: The power supply unit includes a signal controller, a voltage controller and a DC power supply; The signal controller is used to generate a control signal and send the control signal to a voltage controller. The voltage controller controls the output voltage of the DC power supply according to the control signal, and the DC power supply provides the output voltage to the electrostatic electrode.
8. The plasma processing chamber according to claim 7, characterized in that: The plasma processing chamber further includes a current sensor, which is connected in series between the DC power supply and the electrostatic electrode, and is used to detect a current value between the DC power supply and the electrostatic electrode, and send the current value to the voltage controller.
9. The plasma processing chamber according to claim 7, characterized in that: The electrostatic electrode is connected to the DC power supply via a DC connector; The chamber wall and the positive electrode are provided with through holes, and the through holes are used for passing the DC connector.
10. A semiconductor manufacturing equipment, characterized in that: A plasma processing chamber comprising any one of claims 1-9.