Plasma processing device

Abstract

The present invention belongs to the field of plasma processing technology and discloses a plasma processing device, comprising a chamber, a first electrode, and a second electrode, the first electrode and the second electrode being arranged opposite each other within the chamber; the first electrode being sequentially divided from the inside out into a first split electrode, a ring-shaped second split electrode, and a third split electrode, the third split electrode being divided into a plurality of edge split electrodes; the first split electrode, the second split electrode, and the plurality of edge split electrodes being insulated from each other and connected to a ground terminal or a radio frequency power supply via an impedance adjustment portion; the first split electrode, the second split electrode, and the plurality of edge split electrodes each having a hole or / and groove of a predetermined depth on a surface proximal to the second electrode. The present invention provides holes or / and grooves in the split electrodes to mitigate the rising trend of the voltage after the electrodes are split, thereby reducing the bombardment of the split electrodes by charged ions and preventing damage to the surface of the split electrodes caused by excessive ion bombardment.

Description

Technical Field

[0001] The present invention belongs to the technical field of plasma processing, and in particular relates to a plasma processing device. Background Art

[0002] Plasma, also known as plasma, is an ionized gaseous substance composed of positive and negative ions produced by the ionization of atoms and atomic clusters that have been deprived of some of their electrons. It is widely used in the production process of semiconductor devices.

[0003] In a plasma processing system, an RF power supply transmits RF energy to a reaction chamber through a matching device. Within the reaction chamber, the RF energy excites a gas at a certain pressure into a plasma. The excited plasma contains a large number of active species, such as electrons, ions, excited atoms, molecules, and free radicals. These active species interact with a wafer placed in the chamber and exposed to the plasma environment, causing various physical and chemical reactions on the wafer surface, thereby changing the surface properties of the material and completing wafer etching or other processing. However, as the chamber size increases, the uniformity of the plasma deteriorates. In particular, when the RF frequency is high and the substrate size is square, the impact of the corners is more serious. To address this problem, the existing technology uses a method of dividing the electrode into multiple corner electrodes located on the corner side and multiple edge electrodes located on the edge side to improve the plasma uniformity. However, this method of dividing the electrode increases the voltage of the divided electrode, thereby increasing the bombardment of the electrode by charged ions. Excessive ion bombardment can easily cause damage to the electrode surface.

[0004] Therefore, the existing technology needs to be improved and developed. Summary of the Invention

[0005] The purpose of the present invention is to provide a plasma processing device that can slow down the rising trend of the voltage of each split electrode after electrode segmentation, thereby weakening the bombardment of charged ions on each split electrode and avoiding damage to the surface of each split electrode caused by excessive ion bombardment.

[0006] The present invention provides a plasma processing device, comprising a chamber, a first electrode, and a second electrode, wherein the first electrode and the second electrode are arranged opposite to each other in the chamber; the first electrode is divided into a first split electrode, a ring-shaped second split electrode, and a third split electrode in sequence from the inside to the outside, and the third split electrode is divided into a plurality of edge split electrodes; the first split electrode, the second split electrode, and the plurality of edge split electrodes are insulated from each other and connected to a ground terminal or a radio frequency power supply via an impedance adjustment portion; and the first split electrode, the second split electrode, and the plurality of edge split electrodes are all provided with holes or / and grooves of a predetermined depth on a surface close to the second electrode.

[0007] The plasma processing device provided by the present invention increases the surface area of ​​the first split electrode, the second split electrode and the multiple edge split electrodes close to the second electrode by arranging holes and / or grooves of predetermined depth on the first split electrode, the second split electrode and the multiple edge split electrodes formed by dividing the first electrode, so that the voltage increase trend of the first split electrode, the second split electrode and the multiple edge split electrodes is slowed down, thereby weakening the bombardment of the first split electrode, the second split electrode and the multiple edge split electrodes by charged ions, thereby avoiding damage to the first split electrode, the second split electrode and the multiple edge split electrodes close to the second electrode caused by excessive ion bombardment.

[0008] Furthermore, the depth of the holes and / or grooves is 10% to 90% of the thickness of the first electrode.

[0009] The present invention reduces the bombardment of the first electrode by charged ions while ensuring the mechanical strength of the first electrode, thereby avoiding surface damage to the first electrode by designing the depth of the holes and / or grooves to be 10% to 90% of the thickness of the first electrode.

[0010] Furthermore, the positions of the holes and / or the depths of the grooves on the first splitting electrode, the second splitting electrode and the plurality of edge splitting electrodes are different.

[0011] Furthermore, the impedance adjustment unit is connected between at least one of the first split electrode, the second split electrode, and the third split electrode and the ground terminal or the radio frequency power supply.

[0012] Furthermore, the impedance adjustment portion connected between the third segmented electrode and the ground terminal or the radio frequency power supply is shared by the plurality of edge segmented electrodes.

[0013] Furthermore, there are multiple impedance adjustment parts connected between the third segmented electrode and the ground terminal or the radio frequency power supply, and the multiple impedance adjustment parts are respectively connected to the multiple edge segmented electrodes.

[0014] Furthermore, the impedance adjustment unit is an electronic component selected from the group consisting of a fixed capacitor, a variable capacitor, a fixed inductor, and a variable inductor, or a combination of multiple electronic components.

[0015] Furthermore, when the impedance adjustment unit is a combination of multiple electronic components among fixed capacitors, variable capacitors, fixed inductors and variable inductors, the multiple electronic components are connected in series or in parallel.

[0016] Furthermore, there are two RF power supplies, one of the two RF power supplies is connected to the first electrode, and the other of the two RF power supplies is connected to the second electrode.

[0017] Furthermore, the number of the radio frequency power supplies is two, and both of the radio frequency power supplies are connected to the first electrode, or both of the radio frequency power supplies are connected to the second electrode.

[0018] From the above, it can be seen that the plasma processing device of the present invention increases the surface area of ​​the first split electrode, the second split electrode and the multiple edge split electrodes close to the second electrode by arranging holes and / or grooves of predetermined depth on the first split electrode, the second split electrode and the multiple edge split electrodes on the side close to the second electrode, so that the voltage increase trend of the first split electrode, the second split electrode and the multiple edge split electrodes is slowed down, thereby weakening the bombardment of the first split electrode, the second split electrode and the multiple edge split electrodes by charged ions, so as to avoid excessive ion bombardment causing damage to the first split electrode, the second split electrode and the multiple edge split electrodes on the side close to the second electrode.

[0019] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood through implementation of the present invention. The purpose and other advantages of the present invention can be realized and obtained through the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a plasma processing device provided by the present invention.

[0021] Figure 2 This is a schematic structural diagram of another plasma processing device provided by the present invention.

[0022] Figure 3 This is a schematic structural diagram of another plasma processing device provided by the present invention.

[0023] Figure 4 This is a structural schematic diagram of a first electrode divided and provided with holes provided in the first embodiment of the present invention.

[0024] Figure 5 This is a structural schematic diagram of a first electrode divided and provided with grooves provided in the second embodiment of the present invention.

[0025] Figure 6 This is a structural schematic diagram of a first electrode divided and provided with holes provided in the third embodiment of the present invention.

[0026] Figure 7This is a structural schematic diagram of a first electrode divided and provided with grooves provided in a fourth embodiment of the present invention.

[0027] Explanation of reference numerals: 10, cavity; 11, first electrode; 111, first splitting electrode; 112, second splitting electrode; 113, third splitting electrode; 113A, edge splitting electrode; 113a, corner edge splitting electrode; 113b, side edge splitting electrode; 114, hole; 115, groove; 12, second electrode; 13, impedance adjustment unit; 14, RF power supply. DETAILED DESCRIPTION

[0028] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0029] In the description of the present invention, it should be understood that the terms "thickness", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0030] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the term "connection" should be understood in a broad sense. For example, it can mean fixed connection, detachable connection, or integral connection; it can mean mechanical connection, electrical connection, or mutual communication; it can mean direct connection or indirect connection through an intermediate medium; it can mean internal communication between two elements or interaction between two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0032] like Figure 1 As shown, a plasma processing device of the present invention includes a chamber 10, a first electrode 11 and a second electrode 12. The first electrode 11 and the second electrode 12 are arranged opposite to each other in the chamber 10; the first electrode 11 is divided into a first split electrode 111, a ring-shaped second split electrode 112 and a third split electrode 113 from the inside to the outside, and the third split electrode 113 is divided into a plurality of edge split electrodes 113A. The first split electrode 111, the second split electrode 112 and the plurality of edge split electrodes 113A are insulated from each other and connected to a radio frequency power supply 14 via an impedance adjustment unit 13. The first split electrode 111, the second split electrode 112 and the plurality of edge split electrodes 113A are each provided with a hole 114 or / and a groove 115 of a predetermined depth on a surface close to the second electrode 12.

[0033] It should be noted that the aforementioned hole 114 and groove 115 are relative concepts. Hole 114 refers to a blind hole that does not penetrate the first electrode 11. Compared with hole 114, groove 115 has a greater length when the hole depth is the same. In other words, both hole 114 and groove 115 can be blind holes, but in the radial direction of the blind hole, the length of groove 115 is greater than that of hole 114.

[0034] In a specific application, there are two RF power sources 14, both of which are connected to the first electrode 11. It should be noted that, of the two RF power sources 14, one has a higher frequency and the other has a lower frequency. When both RF power sources 14 are connected to the first electrode 11, the lower frequency has a stronger pulling and guiding effect on the charged ions. Therefore, the bombardment and damage of the charged ions on the surface of the first electrode 11 will be more serious. The holes 114 and / or grooves 115 formed on the first splitting electrode 111, the second splitting electrode 112, and the third splitting electrode 113, which are formed by splitting the first electrode 11, increase the surface area of ​​the first splitting electrode 111, the second splitting electrode 112, and the third splitting electrode 113, thereby slowing down the voltage increase trend of the first splitting electrode 111, the second splitting electrode 112, and the plurality of edge splitting electrodes 113A after splitting, thereby weakening the bombardment of the first splitting electrode 111, the second splitting electrode 112, and the plurality of edge splitting electrodes 113A by charged ions, thereby preventing damage to the surfaces of the first splitting electrode 111, the second splitting electrode 112, and the plurality of edge splitting electrodes 113A caused by excessive ion bombardment.

[0035] In some preferred embodiments, the depth of the holes 114 and / or the grooves 115 is 10% to 90% of the thickness of the first electrode 11. In specific applications, the deeper the holes 114 and / or the grooves 115, the greater the increased surface area. However, in order to ensure the mechanical strength of the first electrode 11, the depth of the holes 114 and / or the grooves 115 is designed to be 10% to 90% of the thickness of the first electrode 11. This reduces the bombardment of the first electrode 11 by charged ions while ensuring the mechanical strength of the first electrode 11, thereby avoiding surface damage to the first electrode 11.

[0036] It should be noted that the specific depth of the hole 114 and / or the groove 115 depends on the required voltage ratio (ion bombardment effect on the surface of the first electrode 11). Generally, the depth of the hole 114 and / or the groove 115 is greater than 50% and less than 90% of the thickness of the first electrode 11, which can reduce the plasma bombardment effect.

[0037] In some preferred embodiments, the holes 114 and / or grooves 115 on the first splitting electrode 111, the second splitting electrode 113, and the plurality of edge splitting electrodes 113A have different depths. By designing the holes 114 and / or grooves 115 on the first splitting electrode 111, the second splitting electrode 113, and the plurality of edge splitting electrodes 113A to have different depths, the mechanical strength of the first electrode 11 can be further ensured. Preferably, the depth of the holes 114 and / or grooves 115 on the inner first splitting electrode 111 is greater than the depth of the holes 114 and / or grooves 115 on the outer second splitting electrode 112 and the edge splitting electrode 113A. In specific applications, holes 114 and / or grooves 115 of different depths may be designed on the first splitting electrode 111, the second splitting electrode 112, and the plurality of edge splitting electrodes 113A based on the different surface areas after splitting. That is, the depth of the holes 114 and / or grooves 115 on the inner first splitting electrode 111 may be less than or equal to the depth of the holes 114 and / or grooves 115 on the outer second splitting electrode 112 and the edge splitting electrode 113A.

[0038] In some preferred embodiments, the impedance adjustment unit 13 is connected between at least one of the first split electrode 111, the second split electrode 112, and the third split electrode 113 and the ground or the RF power source 14. In specific applications, the impedance adjustment unit 13 can adjust the impedance of the circuit between the first split electrode 111 and the ground or the RF power source 14, the impedance of the circuit between the second split electrode 112 and the ground or the RF power source 14, or the impedance of the circuit between the third split electrode 113 and the ground or the RF power source 14, thereby improving the uniformity of the plasma density within the chamber 10.

[0039] In some preferred embodiments, the impedance adjustment section 13 connected between the third dividing electrode 113 and the ground terminal is shared by multiple edge dividing electrodes 113A. In specific applications, by sharing a single impedance adjustment section 13, multiple edge dividing electrodes 113A can be adjusted simultaneously to ensure uniform plasma density within the regions corresponding to the multiple edge dividing electrodes 113A within the chamber 10. It should be noted that the number of impedance adjustment sections 13 connected between the third dividing electrode 113 and the ground terminal can also be multiple, with the multiple impedance adjustment sections 13 being connected to the multiple edge dividing electrodes 113A, respectively. This technical solution allows for the impedance between the multiple edge dividing electrodes 113A and the ground terminal to be adjusted separately, thereby adjusting the plasma density within the regions corresponding to the multiple edge dividing electrodes 113A according to actual needs. Specifically, the impedance adjustment section 13 is an electronic component selected from the group consisting of a fixed capacitor, a variable capacitor, a fixed inductor, and a variable inductor, or a combination of multiple electronic components. It is worth noting that when the impedance adjustment section 13 is a combination of multiple electronic components selected from the group consisting of a fixed capacitor, a variable capacitor, a fixed inductor, and a variable inductor, the multiple electronic components are connected in series or in parallel.

[0040] like Figure 2 As shown, in some preferred embodiments, one of the two RF power sources 14 is connected to the first electrode 11, and the other of the two RF power sources 14 is connected to the second electrode 12. By connecting the lower-frequency RF power source 14 to the second electrode 12, compared to when both RF power sources 14 are connected to the first electrode 11, the charged ions are more strongly pulled and guided toward the second electrode 12, thereby further weakening the bombardment of the charged ions on the first split electrode 111, the second split electrode 112, and the third split electrode 113 into which the first electrode 11 is split, thereby preventing damage to the surfaces of the first split electrode 111, the second split electrode 112, and the plurality of edge split electrodes 113A caused by excessive ion bombardment.

[0041] like Figure 3 As shown, in some preferred embodiments, both RF power sources 14 are connected to the second electrode 12. Compared to a case where one of the two RF power sources 14 is connected to the first electrode 11 and the other of the two RF power sources 14 is connected to the second electrode 12, the bombardment effect of charged ions on the first segmented electrode 111, the second segmented electrode 112, and the third segmented electrode 113, into which the first electrode 11 is divided, is weaker. Therefore, a thinner first electrode 11 can be used to save material. In addition, both RF power sources 14 are connected to the second electrode 12, which makes the bombardment effect of charged ions on the second electrode 12 stronger, thereby being applicable to scenarios where a certain bombardment effect is required on a substrate supported by the second electrode 12.

[0042] Example 1

[0043] like Figure 4 As shown, in this embodiment, the first split electrode 111 is circular, the second split electrode 112 is annular, and the third split electrode 113 is annular with a rectangular outer edge and a circular inner edge. The third split electrode 113 is further divided into four corner edge split electrodes 113a, each having the same shape as the corners of the third split electrode 113. Holes 114 of a predetermined depth are provided on the surfaces of the first, second, and third split electrodes 111, 112, and 113 adjacent to the second electrode 12. The holes 114 are arranged in an array. Specifically, when the thickness of the first electrode 11 is 70 mm, the depth of the holes 114 is designed to be 58 mm. This more than doubles the surface area of ​​the first electrode 11 adjacent to the second electrode 12, thereby reducing the voltage to less than approximately one-sixteenth. Specifically, when the thickness of the first electrode 11 is 35 mm, the depth of the holes 114 is designed to be 28 mm. This increases the surface area of ​​the first electrode 11 adjacent to the second electrode 12 by more than 50%, thereby reducing the voltage to less than approximately one-fifth. The segmentation method of the first electrode 11 in this embodiment can be applied to improve the uniformity of the four corners of a rectangle that is close to a square.

[0044] Example 2

[0045] like Figure 5 As shown, the difference between this embodiment and the first embodiment is that in this embodiment, grooves 115 of a predetermined depth are provided on the surfaces of the first split electrode 111, the second split electrode 112, and the third split electrode 113 that are adjacent to the second electrode 12. Specifically, the grooves 115 on the first split electrode 111 and the second split electrode 112 are both annular, while the groove 115 on the third split electrode 113 is arc-shaped. By designing the grooves 115 on the first split electrode 111 and the second split electrode 112 as annular, and the groove 115 on the third split electrode 113 as arc-shaped, compared to the first embodiment, the surface area of ​​the surface of the first electrode 11 that is adjacent to the second electrode 12 is increased while further reducing the weight of the first electrode 11. Furthermore, machining the annular and arc-shaped grooves 115 is more convenient and quicker than machining the holes 114, thereby simplifying the machining process.

[0046] Example 3

[0047] like Figure 6As shown, this embodiment differs from the first embodiment in that: in this embodiment, the first splitting electrode 111 is rectangular, the second splitting electrode 112 and the third splitting electrode 113 are both in the shape of a U-shaped square ring, and the third splitting electrode 113 is further divided into four corner edge splitting electrodes 113a having the same shape as the corners of the third splitting electrode 113 and four side edge splitting electrodes 113b located between two adjacent corner edge splitting electrodes 113a. By changing the division method of the first electrode 11, this embodiment can further improve the uniformity of the four corners of the rectangle that is close to a square.

[0048] Example 4

[0049] like Figure 7 As shown, this embodiment differs from the third embodiment in that, in this embodiment, grooves 115 of a predetermined depth are provided on the surfaces of the first, second, and third splitting electrodes 111, 112, and 113 adjacent to the second electrode 12. Specifically, the grooves 115 on the first and second splitting electrodes 111, 112 are each in the shape of a square U-shaped ring. The groove 115 on the corner edge splitting electrode 113a is L-shaped, while the groove on the side edge splitting electrode 113b is a long strip. The grooves 115 on the corner edge splitting electrode 113a and the grooves on the side edge splitting electrode 113b, connected end to end, form a square U-shaped ring. This embodiment is easier to manufacture than the third embodiment.

[0050] Example 5

[0051] The difference between this embodiment and the second embodiment is that in this embodiment, holes 114 and grooves 115 of a predetermined depth are simultaneously provided on the surfaces of the first splitting electrode 111, the second splitting electrode 112, and the third splitting electrode 113 that are close to the second electrode 12. Specifically, the grooves 115 can be arranged in the same manner as the grooves 115 in the second embodiment, and the holes 114 can be provided between adjacent grooves 155. In this way, the surface area of ​​the surface of the first electrode 11 that is close to the second electrode 12 is further increased compared to the second embodiment.

[0052] In summary, the plasma processing apparatus of the present invention increases the surface area of ​​the first split electrode 111, the second split electrode 112, and the plurality of edge split electrodes 113A on the side close to the second electrode 12 by providing holes 114 and / or grooves 115 of a predetermined depth on the side close to the second electrode 12, thereby slowing down the increasing trend of the voltage of the first split electrode 111, the second split electrode 112, and the plurality of edge split electrodes 113A, thereby weakening the bombardment of the first split electrode 111, the second split electrode 112, and the plurality of edge split electrodes 113A by charged ions, thereby preventing excessive ion bombardment from causing damage to the side close to the second electrode 12 of the first split electrode 111, the second split electrode 112, and the plurality of edge split electrodes 113A.

[0053] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A plasma processing device comprising a chamber, a first electrode, and a second electrode, wherein the first electrode and the second electrode are disposed opposite to each other in the chamber; characterized in that: The first electrode is sequentially divided from the inside to the outside into a first divided electrode, a ring-shaped second divided electrode, and a third divided electrode, the third divided electrode is divided into a plurality of edge divided electrodes, the first divided electrode, the second divided electrode, and the plurality of edge divided electrodes are insulated from each other and connected to a ground terminal or a radio frequency power supply via an impedance adjustment portion, and the first divided electrode, the second divided electrode, and the plurality of edge divided electrodes are each provided with a hole or / and groove of a predetermined depth on a surface close to the second electrode; The positions of the holes and / or the depths of the grooves on the first splitting electrode, the second splitting electrode, and the plurality of edge splitting electrodes are different.

2. The plasma processing apparatus according to claim 1, wherein The depth of the holes and / or grooves is 10% to 90% of the thickness of the first electrode.

3. The plasma processing apparatus according to claim 1, wherein The impedance adjustment unit is connected between at least one of the first split electrode, the second split electrode, and the third split electrode and the ground terminal or the radio frequency power supply.

4. The plasma processing apparatus according to claim 3, wherein: The impedance adjustment portion connected between the third segmented electrode and the ground terminal or the radio frequency power supply is shared by the plurality of edge segmented electrodes.

5. The plasma processing apparatus according to claim 3, wherein: There are multiple impedance adjustment parts connected between the third segmented electrode and the ground terminal or the radio frequency power supply, and the multiple impedance adjustment parts are respectively connected to the multiple edge segmented electrodes.

6. The plasma processing apparatus according to claim 1, wherein The impedance adjustment unit is an electronic component selected from the group consisting of a fixed capacitor, a variable capacitor, a fixed inductor, and a variable inductor, or a combination of multiple electronic components.

7. The plasma processing apparatus according to claim 6, wherein: When the impedance adjustment unit is a combination of multiple electronic components including a fixed capacitor, a variable capacitor, a fixed inductor, and a variable inductor, the multiple electronic components are connected in series or in parallel.

8. The plasma processing apparatus according to claim 1, wherein There are two RF power supplies, one of which is connected to the first electrode, and the other of which is connected to the second electrode.

9. The plasma processing apparatus according to claim 1, wherein: There are two RF power sources, and both of the two RF power sources are connected to the first electrode, or both of the two RF power sources are connected to the second electrode.

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