Electrode assembly and semiconductor pre-cleaning device
By setting a dielectric part on the lower surface of the extension and the connection area of the outer wall of the electrode assembly, and setting an isolation layer on the side wall of the isolation component, the problem of local high electric field intensity in remote plasma process is solved, and the uniformity of electric field intensity and the optimization of plasma distribution are achieved.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- JIANGSU ALPHA-SEMICON EQUIP CO LTD
- Filing Date
- 2025-11-26
- Publication Date
- 2026-06-25
Smart Images
Figure CN2025137842_25062026_PF_FP_ABST
Abstract
Description
An electrode assembly and semiconductor pre-cleaning device Technical Field
[0001] This invention relates to the technical field of semiconductor equipment, and in particular to an electrode assembly and a semiconductor pre-cleaning device. Background Technology
[0002] In recent years, remote plasma technology has been widely used in the semiconductor manufacturing process for cleaning wafer surfaces. This process can selectively remove impurities such as silicon dioxide or silicon nitride from silicon surfaces.
[0003] In remote plasma processing, plasma is generated in a remote plasma source (RPS). Within this plasma generation chamber, process gases are excited to produce plasma and free radicals. Only the free radicals are transported to the process chamber via a spray plate on the lower electrode. This method reduces physical damage to the wafer caused by ion bombardment within the process chamber. The free radicals generated by the plasma chemically react with the oxide layer on the wafer surface to be removed, generating volatile compounds. These compounds are then decomposed and volatilized through heating, making it a pre-cleaning method with minimal damage and high cleaning efficiency. The design of the remote plasma source is crucial for ensuring a stable supply of free radicals to the process chamber during the pre-cleaning process.
[0004] Hollow cathode discharge (HCD) is a special discharge process commonly used in plasma reactors. When a high-voltage electric field is applied to a hollow cathode, electrons are emitted from its surface. These electrons collide with gas molecules, causing ionization and producing free electrons and cations. These electrons and cations form a discharge region inside the hollow cathode, where collisions continue, generating more electrons and cations, thus expanding the discharge region. Within this discharge region, gas molecules react chemically with the free electrons and cations, generating free radicals.
[0005] When a high-voltage electric field is applied to a hollow cathode, a localized high electric field intensity will occur in the cavity region near the ceramic insulator at the bottom of the hollow electrode. Summary of the Invention
[0006] The purpose of this invention is to provide an electrode assembly and a semiconductor pre-cleaning device that reduces local high electric field areas and improves the uniformity of electric field intensity.
[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:
[0008] An electrode assembly includes a first electrode and a second electrode stacked in a vertical direction; the first electrode is located above the second electrode, and a cavity is provided between the first electrode and the second electrode.
[0009] The first electrode is provided with an air inlet and an expansion part. The air inlet is provided with an air inlet and the air inlet is connected to the cavity.
[0010] The extension section has an upper part and a lower part opposite to the upper part. The upper part of the extension section is connected to the air intake section, and the lower part has a lower surface opposite to the second electrode. The extension section also has an inner wall and an outer wall. The inner wall forms the side wall of the cavity, one end of the outer wall is connected to the air intake section, and the other end of the outer wall is connected to the lower surface of the extension section.
[0011] The lower surface of the extension is provided with a dielectric part, which is located in the connection area between the lower surface of the extension and the outer wall.
[0012] Optionally, the motor assembly further includes an isolator located between the first electrode and the second electrode, the isolator electrically isolating the first electrode and the second electrode; the isolator has a first sidewall opposite to the outer wall of the extension portion of the first electrode, and the surface of the first sidewall is provided with an isolation layer.
[0013] Optionally, a separation gap is provided between the first sidewall of the isolator and the outer wall of the extension portion of the first electrode, and the dielectric portion is also disposed on the outer wall of the extension portion of the first electrode.
[0014] Optionally, the dielectric portion fills the separation gap.
[0015] Optionally, the first sidewall of the isolator contacts the outer wall of the extension portion of the first electrode; the dielectric portion is disposed at the junction area between the lower surface of the extension portion of the first electrode and the first sidewall of the isolator, the connection surface between the dielectric portion and the first sidewall is the first connection surface, and the connection surface between the dielectric portion and the lower surface of the first electrode is the second connection surface.
[0016] Optionally, the dielectric portion forms a first contact width D on the first connecting surface, and the dielectric portion forms a second contact width d on the second connecting surface, wherein D ≥ d.
[0017] Optionally, the second electrode has a third surface opposite to the first electrode, the lower surface of the first electrode extension and the third surface of the second electrode form an electrode distance L, and the first contact width D is less than the electrode distance L.
[0018] Optionally, the cross-section of the dielectric portion is fan-shaped or triangular.
[0019] Optionally, the connection between the outer wall of the first electrode extension and the lower surface is provided with an arc-shaped chamfer, and the dielectric part is disposed at the arc-shaped chamfer.
[0020] Optionally, the dielectric part is a dielectric material with a dielectric constant of 4 to 6.
[0021] Optionally, the thickness of the dielectric portion is greater than or equal to 0.2 mm.
[0022] Optionally, the dielectric material of the isolation layer has a dielectric constant of 2 to 8, and the thickness of the isolation layer is greater than 0.1 mm.
[0023] Optionally, the air inlet and the extension of the first electrode are integrally formed. The extension is an annular part, and the diameter of the inner wall of the extension gradually increases from the air inlet to the direction away from the air inlet, while the diameter of the outer wall of the extension remains unchanged.
[0024] A semiconductor pre-cleaning apparatus includes: an electrode assembly; and a process chamber disposed below the electrode assembly.
[0025] Compared with the prior art, the present invention has the following advantages:
[0026] (1) By providing a dielectric part on the lower surface of the first electrode extension and the outer wall of the extension, the dielectric constant of the dielectric part is located between the plasma and the isolator in the cavity. By introducing the dielectric part, the electric field distribution is homogenized and the local electric field intensity is reduced. By providing the dielectric part in the connection area between the lower surface of the extension and the outer wall, the influence on the electric field environment of other areas of the cavity is reduced.
[0027] (2) By setting an isolation layer on the first sidewall of the isolation component, the characteristics of the plasma interface between the isolation component and the cavity are improved, the surface structure of the isolation component is optimized, the flatness of the isolation component surface is improved, and the uniformity of the electric field distribution is improved. Attached Figure Description
[0028] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:
[0029] Figure 1 is a schematic diagram of the semiconductor pre-cleaning equipment;
[0030] Figure 2 is a schematic diagram of the structure of the first electrode;
[0031] Figure 3A is a schematic diagram of the structure at point A in an embodiment of the present invention;
[0032] Figure 3B is a simulation result diagram of point A in an embodiment of the present invention;
[0033] Figure 4A is a schematic diagram of the structure at point A in another embodiment of the present invention;
[0034] Figure 4B shows the simulation results at point A in another embodiment of the present invention;
[0035] Figure 5A is a schematic diagram of the structure at point A in another embodiment of the present invention;
[0036] Figure 5B shows the simulation results at point A in another embodiment of the present invention;
[0037] Figure 6 is a schematic diagram of the structure at point A in another embodiment of the present invention. Detailed Implementation
[0038] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the solution proposed by the present invention. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clearly illustrate the embodiments of the present invention. Please refer to the drawings to make the objectives, features, and advantages of the present invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention.
[0039] Semiconductor equipment typically includes a wafer front-end module (EFEM), a load-locked cavity, a wafer transfer cavity (TM), and a process cavity (PM), connected in sequence. The EFEM transports the wafer to the load-locked cavity and applies negative pressure. Then, under the action of a robot in the wafer transfer cavity, the wafer located in the load-locked cavity is moved to the wafer transfer cavity, and then transferred to the process cavity for the corresponding process. Depending on the semiconductor process, it can be divided into pre-cleaning, epitaxy, etching, ion implantation, etc., and different processes correspond to different process cavities.
[0040] Figure 1 is a schematic diagram of the semiconductor pre-cleaning device 100 provided by the present invention. As shown in Figure 1, the semiconductor pre-cleaning device 100 includes an electrode assembly, a dispensing assembly, a process chamber, and a support assembly. The electrode assembly is disposed at the upper end of the process chamber. The motor assembly includes a first electrode 10, a second electrode 11, and an isolator 12 stacked vertically. The first electrode 10 is located above the second electrode 11, and a cavity 104 for confining plasma is provided between the first electrode 10 and the second electrode 11. There is a certain electrode distance L between the first electrode 10 and the second electrode 11. The first electrode 10 is connected to a power source, which is a radio frequency power source. The second electrode is grounded, thereby forming a capacitor between the first electrode 10 and the second electrode 11.
[0041] The first electrode 10 includes an air inlet 101 and an extension 102, with the extension 102 positioned below the air inlet 101. The air inlet has one or more air inlets 103 communicating with a cavity 104. Reaction gas enters the cavity 104 through the air inlets 103, and the reaction gas entering the cavity 104 is excited to generate plasma. The air inlet includes a first surface 106 opposite to the second electrode and a second surface 107 opposite to the first surface. The air inlets 103 penetrate the first surface 106 and the second surface 107 of the air inlet. Furthermore, the air inlets 103 are symmetrically distributed along the center line of symmetry of the cavity 104. Further, the air inlet 101 also has a side surface connecting the first and second surfaces. The air inlet pipe is parallel to the second surface, with the inlet end of the air inlet pipe located on the side surface of the air inlet, and the outlet end of the air inlet pipe, i.e., the air inlets 103, symmetrically distributed along the center line of symmetry of the cavity. Optionally, the air intake is disc-shaped.
[0042] In some embodiments, as shown in Figures 1 and 2, the extension is an annular member, comprising an upper portion and a lower portion opposite to the upper portion. The upper portion of the extension is connected to the first surface 106 of the air intake, and the lower portion has a lower surface 205 opposite to the lower electrode, as well as an inner wall 206 and an outer wall 204. The inner wall forms the sidewall of the cavity 104, and the diameter of the inner wall of the extension gradually increases from the air intake 103 away from the air intake, resembling an inverted cone or funnel shape. Further, the diameter of the inner wall of the extension remains constant from the air intake 103 away from the air intake, i.e., the inner wall of the extension is cylindrical. One end of the outer wall 204 is connected to the first surface 106 of the air intake, and the other end of the outer wall is connected to the lower surface 205 of the extension, with the diameter of the outer wall of the extension remaining constant. The outer diameter of the extension remains unchanged, meaning that when there is a certain distance between the extension and the isolator, the distance between the outer wall of the extension and the isolator remains unchanged, thus avoiding arcing caused by excessive local electric field due to the reduced distance.
[0043] In some embodiments, as shown in FIG1, an isolator 12 is disposed between the first electrode 10 and the second electrode 11. The isolator 12 provides electrical isolation between the first electrode and the second electrode. The isolator 12 is a ring-shaped member, and is disposed around or substantially around the extension portion 102 of the first electrode. The height of the isolator is greater than the height of the extension portion (i.e., the distance from the first surface to the lower surface of the extension portion). The isolator 12 can be made of alumina ceramic or any other insulating material. The dielectric constant of the alumina ceramic is between 9 and 10.
[0044] In some embodiments, the second electrode 11 has a third surface 112 opposite to the first electrode 10. The lower surface 205 of the first electrode extension and the third surface 112 of the second electrode form an electrode distance L. Adjusting the electrode distance L can improve the uniformity of plasma distribution between the first electrode 10 and the second electrode 11. Further, the second electrode includes a plurality of gas passages 111 formed below the cavity to allow plasma within the cavity to flow through the gas passages 111 and enter the process chamber 14. A distribution assembly (not shown) is also provided below the gas passages of the second electrode. Further, the distribution assembly is a circular gas distribution disk with openings. These openings can slow down the airflow speed and guide the airflow to a uniform distribution, preventing free radicals flowing from the gas passages from directly impacting the surface of the wafer 15.
[0045] In some embodiments, the support assembly 18 is located inside the process cavity and is used to support the wafer 5 during the process. During the process, the wafer can be raised to a position adjacent to the gas distribution disk by the support assembly, allowing free radicals to act on the wafer surface.
[0046] In some embodiments, the process cavity 14 is further provided with a bushing (not shown), which is disposed on the inner surface of the sidewall of the process cavity and surrounding the support assembly 18, for uniformly distributing the process gas on the wafer surface and discharging the remaining process gas from the process cavity 14 after the process is completed.
[0047] In some embodiments, as shown in Figures 3A and 5A, a dielectric portion is provided on the lower surface of the extension portion, and the dielectric portion is located in the connection region 207 between the lower surface of the extension portion and the outer wall.
[0048] When the radio frequency power supply is applied to the first electrode 10, it causes a high electric field strength in the cavity region near the end 207 of the first electrode, which is significantly higher than the electric field strength at other locations in the cavity. To improve the uniformity of the electric field strength, a dielectric part is provided at the end 207 of the first electrode. The dielectric part is a dielectric material with a dielectric constant between 4 and 6, and its dielectric constant is between that of the plasma inside the cavity and the ceramic isolator. The dielectric part can be one or a mixture of epoxy resin, polyimide, polycarbonate, titanate, alumina, or silicon carbide. The dielectric part can be applied to the connection area 207 between the lower surface of the extension and the outer wall by spraying, coating, electroplating, etc. The specific method depends on the characteristics of the dielectric material and is not limited thereto. The dielectric part has the ability to shield the electric field. By providing a dielectric part at the end 207 of the first electrode, the electric field distribution can be changed, reducing the risk of direct discharge between the electrodes. By placing the dielectric portion at the end 207 of the first electrode, i.e., the connection area 207 between the lower surface of the extension portion and the outer wall, the local electric field strength of the cavity near the end of the first electrode can be reduced, but it will not affect the electric field environment of other areas, especially the electric field environment above the gas channel of the second electrode.
[0049] In some embodiments, as shown in FIG6, the isolator has a first sidewall opposite to the outer wall of the extension portion of the first electrode, and an isolation layer 121 is provided on the surface of the first sidewall. The isolation layer is a dielectric material with a dielectric constant of 2 to 8, and the thickness of the isolation layer is greater than 0.1 mm. Providing an isolation layer 121 on the surface of the first sidewall of the isolator can improve the interface characteristics between the isolator and the gas inside the cavity, and avoid uneven electric field distribution caused by uneven surface of the isolator itself or material reasons.
[0050] In some embodiments, a separation gap is provided between the first sidewall of the isolator and the outer wall of the extension portion of the first electrode, and the dielectric portion is also provided on the outer wall of the extension portion of the first electrode. Further, the dielectric portion is disposed on the outer wall of the extension portion near its lower surface. When a separation gap is provided between the first sidewall of the isolator and the first electrode, a strong electric field will occur in the separation gap due to the voltage difference between the first electrode and the isolator. By providing a dielectric portion on the outer wall of the extension portion of the first electrode, the electric field distribution can be smoothed, reducing localized high electric field regions.
[0051] In some embodiments, the dielectric portion fills the separation gap. The gas gap between the first electrode and the isolator is filled with the dielectric portion, which, as an electric field homogenizing material, can significantly reduce the local electric field strength.
[0052] In some embodiments, as shown in FIG3A, the first sidewall of the insulating member contacts the outer wall of the extension portion of the first electrode; a dielectric portion 16 is provided at the junction of the lower surface of the first electrode extension portion and the first sidewall of the insulating member, the connection surface between the dielectric portion and the first sidewall is a first connection surface 161, and the connection surface between the dielectric portion and the lower surface is a second connection surface 162. The dielectric portion forms a first contact width D on the first connection surface, and the dielectric portion forms a second contact width d on the second connection surface, wherein D ≥ d. The thickness of the dielectric portion, i.e., the second contact width, is greater than or equal to 0.2 mm.
[0053] By providing a dielectric portion at the interface between the lower surface of the first electrode extension and the first sidewall of the isolator, the local electric field strength is reduced not only by the dielectric portion but also by increasing the distance between the first electrode and the isolator, thereby reducing the local electric field strength. As shown in Figures 4A and 4B, after chamfering the end 207 of the first electrode, the local electric field strength is 32201.1 V / m. As shown in Figures 3A and 3B, the first electrode is not chamfered, and a dielectric portion is only provided at the interface 207 between the lower surface of the first electrode extension and the first sidewall of the isolator. The dielectric portion is a dielectric material with a dielectric constant of 4. By providing the dielectric portion at the same location, the electric field strength is only 3113.8 V / m, significantly reducing the local electric field strength and making the electric field more uniform.
[0054] In some embodiments, the second electrode has a third surface opposite to the first electrode, the lower surface of the first electrode extension and the third surface of the second electrode form an electrode distance L, and the first contact width D is less than the electrode distance L.
[0055] In some embodiments, the cross-section of the dielectric portion is fan-shaped or triangular. The connection surface between the dielectric portion and the first sidewall of the insulating member is the first connection surface, and the connection surface between the dielectric portion and the lower surface of the first electrode is the second connection surface. If one side of the first connection surface is connected to one side of the second connection surface, and the other side of the first connection surface is connected to the other side of the second connection surface through a curved surface, then the cross-section of the dielectric portion is fan-shaped; if the other side of the first connection surface is connected to the other side of the second connection surface through a plane, then the cross-section of the dielectric portion is triangular. The other side of the first connection surface and the other side of the second connection surface can also be connected in other ways, and are not limited thereto.
[0056] In some embodiments, the junction between the outer wall and the lower surface of the first electrode extension is provided with an arc-shaped chamfer, and the dielectric portion is disposed at the arc-shaped chamfer. As shown in FIG5A, the dielectric portion can be disposed along the shape of the arc-shaped chamfer, and the thickness of the dielectric portion refers to the shortest distance from the outer edge of the chamfer to the outer edge of the dielectric portion, and the thickness of the dielectric portion is greater than or equal to 0.2 mm. Further, the dielectric portion forms a first contact width D on the first connecting surface, and the dielectric portion forms a second contact width d on the second connecting surface, wherein D ≥ d.
[0057] As shown in Figures 4A and 4B, when a high-voltage electric field is applied to the first electrode, a rounded chamfer is made at the end 207 of the first electrode to prevent charge accumulation at sharp points and arc discharge. However, since the electric field is also very strong in areas with small radii of curvature, simply making a rounded chamfer on the first electrode, i.e., increasing the radius of curvature, cannot effectively improve the problem of localized high electric field intensity. As shown in Figures 5A and 5B, by setting a dielectric part in the rounded chamfer area, the dielectric part is a dielectric material with a dielectric constant of 6. Under the same conditions, the simulation showed that the electric field intensity at the chamfer in the cavity was 32201.1 V / m. After setting the dielectric part at the chamfer, the electric field intensity at the same location was 10274.4 V / m, which was reduced to 1 / 3 of the original electric field intensity, significantly improving the situation of excessively strong localized electric field.
[0058] In some embodiments, the air inlet portion of the first electrode further includes a first surface opposite to the second electrode; the separator includes an upper mounting surface and a lower mounting surface opposite to the upper mounting surface; the first surface of the first electrode is connected to the upper mounting surface of the separator, and the third surface of the second electrode is connected to the lower mounting surface of the separator. A sealing element, which is an annular sealing ring, is also provided between the first electrode and the upper mounting surface of the separator; a sealing element, which is also an annular sealing ring, is also provided between the third surface of the second electrode and the lower mounting surface of the separator.
[0059] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, the term "connection" in this document indicates a direct connection between A and B, or an indirect connection between A and B, such as an indirect connection between A and B via C, or even via C and D, or more components. The connection between A and B can be integral or separate, detachable or fixed. The term "optional" in this document indicates that the technical feature can be combined with or not combined with any feature in the document.
[0060] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.
Claims
1. An electrode assembly, characterized in that, The electrode assembly includes a first electrode and a second electrode stacked vertically; the first electrode is located above the second electrode, and a cavity is provided between the first electrode and the second electrode; The first electrode is provided with an air inlet and an expansion part. The air inlet is provided with an air inlet and the air inlet is connected to the cavity. The extension section has an upper part and a lower part opposite to the upper part. The upper part of the extension section is connected to the air intake section, and the lower part has a lower surface opposite to the second electrode. The extension section also has an inner wall and an outer wall. The inner wall forms the side wall of the cavity, one end of the outer wall is connected to the air intake section, and the other end of the outer wall is connected to the lower surface of the extension section. The lower surface of the extension is provided with a dielectric part, which is located in the connection area between the lower surface of the extension and the outer wall.
2. The electrode assembly according to claim 1, characterized in that, It also includes an isolator disposed between the first electrode and the second electrode, which electrically isolates the first electrode and the second electrode; the isolator has a first sidewall opposite to the outer wall of the extension portion of the first electrode, and the surface of the first sidewall is provided with an isolation layer.
3. An electrode assembly according to claim 2, characterized in that, A separation gap is provided between the first sidewall of the isolator and the outer wall of the extension portion of the first electrode, and the dielectric portion is also disposed on the outer wall of the extension portion of the first electrode.
4. An electrode assembly according to claim 3, characterized in that, The dielectric portion fills the separation gap.
5. An electrode assembly according to claim 2, characterized in that, The first sidewall of the isolator is in contact with the outer wall of the extension portion of the first electrode; the dielectric portion is disposed at the junction area between the lower surface of the extension portion of the first electrode and the first sidewall of the isolator, the connection surface between the dielectric portion and the first sidewall of the isolator is the first connection surface, and the connection surface between the dielectric portion and the lower surface of the first electrode is the second connection surface.
6. An electrode assembly according to claim 5, characterized in that, The dielectric part forms a first contact width D on the first connecting surface, and the dielectric part forms a second contact width d on the second connecting surface, wherein D ≥ d.
7. An electrode assembly according to claim 6, characterized in that, The second electrode has a third surface opposite to the first electrode, and the lower surface of the first electrode extension and the third surface of the second electrode form an electrode distance L, and the first contact width D is less than the electrode distance L.
8. An electrode assembly according to claim 7, characterized in that, The cross-section of the dielectric part is fan-shaped or triangular.
9. An electrode assembly according to claim 5, characterized in that, The connection between the outer wall and the lower surface of the first electrode extension is set with an arc-shaped chamfer, and the dielectric part is disposed at the arc-shaped chamfer.
10. An electrode assembly according to claim 1, characterized in that, The dielectric part is a dielectric material with a dielectric constant of 4 to 6.
11. An electrode assembly according to claim 10, characterized in that, The thickness of the dielectric part is greater than or equal to 0.2 mm.
12. A motor assembly according to claim 2, characterized in that, The insulating layer is a dielectric material with a dielectric constant of 2 to 8, and the thickness of the insulating layer is greater than 0.1 mm.
13. An electrode assembly according to claim 1, characterized in that, The air inlet and the extension of the first electrode are integrally formed. The extension is an annular part. The diameter of the inner wall of the extension gradually increases from the air inlet to the direction away from the air inlet, while the diameter of the outer wall of the extension remains unchanged.
14. A semiconductor pre-cleaning device, characterized in that, include: The electrode assembly as described in any one of claims 1-13; A process chamber is located below the electrode assembly.