Edge etching equipment

Abstract

The invention discloses edge etching equipment. The edge etching equipment comprises a reaction cavity; the base is arranged at the inner bottom of the reaction cavity and is used for bearing a wafer; the upper shielding part is arranged at the top of the interior of the reaction cavity; the lower limiting ring is arranged around the base; the upper limiting ring is arranged around the upper shielding part; the upper limiting ring and the lower limiting ring are matched to form a plasma reaction space in the edge area of the wafer; and a first gap facing the plasma reaction space is formed in the upper limiting ring. The volume of the plasma reaction space can be effectively increased due to the arrangement of the first notch, so that more process gas can be accommodated in the plasma reaction space, more plasmas are generated after the process gas is ionized, and the etching rate of the edge area of the wafer is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor preparation, and in particular to an edge etching device. Background Art

[0002] During the process of plasma etching the wafer into a designed pattern, some excess film layers will accumulate in the outer edge area of ​​the wafer, such as polysilicon layer, nitride layer, metal layer, etc.; when these excess film layers accumulate to a certain extent, they are prone to cracking, causing the wafer surface to be contaminated and affecting the yield of wafer preparation. Therefore, it is necessary to use an edge etching process to remove the excess film layers at the edge of the wafer.

[0003] In existing edge etching equipment, a movable upper electrode design is usually used. When transferring the wafer in and out of the reaction chamber, the upper electrode is lifted; when processing the wafer, the upper electrode is lowered and a small distance is maintained between the upper electrode and the wafer. When the upper electrode is lowered near the wafer, it is also necessary to maintain a very high concentricity between the upper electrode, the wafer, and the base, so that the portion of the wafer edge exposed to the plasma is symmetrical in the circumferential direction, so that the wafer edge can be etched uniformly.

[0004] However, in order to ensure that the concentricity of the upper electrode, wafer and susceptor meets the process requirements, it takes a long time to adjust the concentricity of the upper electrode, wafer and susceptor, which affects the processing efficiency of the wafer. Therefore, it is necessary to improve the wafer etching rate in other aspects to increase the output of wafers within a fixed time. Summary of the invention

[0005] The object of the present invention is to provide an edge etching device that can effectively increase the volume of a plasma reaction space, so that the plasma reaction space can accommodate more process gas and generate more plasma, thereby improving the etching rate of the wafer edge area.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] An edge etching device, comprising:

[0008] Reaction chamber;

[0009] A base, disposed at the inner bottom of the reaction chamber, for supporting the wafer;

[0010] An upper shielding portion, disposed at the inner top of the reaction chamber;

[0011] a lower confinement ring disposed about the base; and

[0012] An upper limiting ring is arranged around the upper shielding portion; the upper limiting ring cooperates with the lower limiting ring to form a plasma reaction space in the edge area of ​​the wafer; and a first notch facing the plasma reaction space is provided on the upper limiting ring.

[0013] Optionally, the upper limit ring includes a lower surface facing the wafer, and the first notch is located above the lower surface of the upper limit ring.

[0014] Optionally, the cross-section of the first notch is arc-shaped, U-shaped, V-shaped, L-shaped, or any combination thereof.

[0015] Optionally, the outer diameter of the lower surface of the upper limiting ring is smaller than the diameter of the wafer and the difference between the outer diameter and the lower surface is 2-5 mm.

[0016] Optionally, the lower confinement ring is provided with a second notch facing the plasma reaction space.

[0017] Optionally, the lower confinement ring includes an upper surface supporting the wafer, and the second notch is located below the upper surface of the lower confinement ring.

[0018] Optionally, the cross-section of the second notch is arc-shaped, U-shaped, V-shaped, L-shaped, or any combination thereof.

[0019] Optionally, the outer diameter of the upper surface of the lower limiting ring is smaller than the diameter of the wafer and the difference between the outer diameter and the upper surface of the lower limiting ring is 2-5 mm.

[0020] Optionally, the edge etching device further includes: a lower grounding ring, located below the second notch and arranged around the lower restriction ring.

[0021] Optionally, the edge etching device further includes: an upper grounding ring, located above the first notch and arranged around the upper limiting ring.

[0022] Optionally, a gas channel and a gas inlet hole communicating with the gas channel and the plasma reaction space are provided in the upper grounding ring so as to introduce process gas into the plasma reaction space.

[0023] Optionally, the air inlet hole is arranged to be inclined toward the edge of the wafer.

[0024] Optionally, the upper limit ring and the lower limit ring are made of aluminum oxide, silicon oxide or silicon carbide.

[0025] Compared with the prior art, the present invention has at least one of the following advantages:

[0026] The present invention provides an edge etching device, wherein a base for carrying a wafer is provided at the bottom of the reaction chamber, an upper shielding portion is provided at the top of the reaction chamber, a lower limiting ring is provided around the base, and an upper limiting ring is provided around the upper shielding portion; the upper limiting ring and the lower limiting ring cooperate to form a plasma reaction space at the edge region of the wafer, and a first notch facing the plasma reaction space is provided on the upper limiting ring. The provision of the first notch can effectively increase the volume of the plasma reaction space, so that more process gas can be accommodated in the plasma reaction space, and more plasma is generated after the process gas is ionized, so as to greatly increase the etching rate of the edge region of the wafer.

[0027] In the present invention, the upper limiting ring includes a lower surface facing the wafer, and the first notch is located above the lower surface of the upper limiting ring. In this way, the volume of the plasma reaction space can be increased through the first notch, and the original etching path or etching area of ​​the wafer can be ensured not to be changed through the lower surface of the upper limiting ring.

[0028] In the present invention, a second notch is provided on the lower limiting ring toward the plasma reaction space, which can also increase the volume of the plasma reaction space to further improve the etching rate of the edge area of ​​the wafer; and the lower limiting ring includes an upper surface supporting the wafer, and the second notch is located below the upper surface of the lower limiting ring. Similarly, the volume of the plasma reaction space can be increased by the second notch, and the original etching path or etching area of ​​the wafer can be ensured not to be changed by the upper surface of the lower limiting ring.

[0029] In the present invention, the cross-sections of the first notch and the second notch are arc-shaped, U-shaped, V-shaped, L-shaped, or any combination thereof, so that the cross-sectional areas of the first notch and the second notch are as large as possible, thereby making the volumes of the first notch and the second notch as large as possible, thereby increasing the volume of the plasma reaction space as much as possible.

[0030] In the present invention, an upper grounding ring is arranged around the upper limiting ring, and a gas channel and an air inlet hole connected with the gas channel and the plasma reaction space are arranged in the upper grounding ring to introduce process gas into the plasma reaction space; and the air inlet hole is arranged obliquely toward the edge of the wafer, so that the introduced process gas is gathered in the edge area of ​​the wafer as much as possible, so that the plasma concentration in the edge area of ​​the wafer is higher, and the etching rate of the edge area of ​​the wafer is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of an edge etching device provided by an embodiment of the present invention;

[0032] Figure 2 yes Figure 1 A is an enlarged schematic diagram;

[0033] Figure 3 It is a wafer etching rate diagram when the upper limit ring is not provided with the first notch and the lower limit ring is not provided with the second notch in the prior art;

[0034] Figure 4 This is a wafer etching rate diagram when the upper limit ring is provided with a first notch and the lower limit ring is not provided with a second notch in one embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following is a further detailed description of an edge etching device proposed by the present invention in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purposes, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0036] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0037] Combined with Figures 1 to 4As shown, this embodiment provides an edge etching device, including: a reaction chamber 110; a base 130, which is arranged at the inner bottom of the reaction chamber 110 and is used to support a wafer 100; an upper shielding portion 120, which is arranged at the inner top of the reaction chamber 110; and the upper shielding portion 120 is arranged opposite to the base 130; a lower limiting ring 150, which is arranged around the base 130; and an upper limiting ring 140, which is arranged around the upper limiting ring 120; the upper limiting ring 140 and the lower limiting ring 150 cooperate to form a plasma reaction space 180 in the edge area of ​​the wafer 100.

[0038] Please also refer to Figure 1 and Figure 2 The edge etching device further includes: an upper grounding ring 160 , which is arranged around the upper restriction ring 140 ; ​​and a lower grounding ring 170 , which is arranged around the lower restriction ring 150 .

[0039] Specifically, in this embodiment, the reaction chamber 110 includes a chamber body 1102 and a cover plate 1101 disposed on the top of the chamber body 1102. The upper shielding portion 120 can be fixed on a mounting substrate 121, and the upper shielding portion 120, the mounting substrate 121, the upper limiting ring 140 and the upper grounding ring 160 constitute an upper electrode assembly. More specifically, the mounting substrate 121 can be connected to the top cover 1101 through a pulling device 122, so that the upper electrode assembly is fixed on the top cover 1101; and when the top cover 1101 is moved to realize the switch chamber of the edge etching device, the upper electrode assembly moves with the top cover 1101 through the pulling device 122. In addition, a lifting mechanism 123 is provided in the chamber 1102 for receiving the upper electrode assembly and driving the upper electrode assembly to rise and fall; wherein, when the wafer 100 is transferred in and out of the chamber 1102, the upper electrode assembly can be driven to rise upward by the lifting mechanism 123 to leave space for performing the operation of transferring the wafer 100; when the wafer 100 is subjected to an etching process, the upper electrode assembly can be driven to fall downward by the lifting mechanism 123 to adjust the distance between the upper shielding plate 120 and the wafer 100. Optionally, the material of the mounting substrate 121 is aluminum, and the material of the upper shielding portion 120 is ceramic; optionally, the base 130, the lower limiting ring 150 and the lower grounding ring 170 constitute the lower electrode assembly, and the materials of the upper limiting ring 140 and the lower limiting ring 150 are aluminum oxide, silicon oxide or silicon carbide, but the present invention is not limited thereto.

[0040] Specifically, in this embodiment, the upper grounding ring 160 is arranged opposite to the lower grounding ring 170, and the upper grounding ring 160 and / or the lower grounding ring 170 are connected to a radio frequency source to form an electric field in the plasma reaction space 180 through the upper grounding ring 160 and the lower grounding ring 170. More specifically, a gas channel 161 and an air inlet 162 communicating with the gas channel 161 and the plasma reaction space 180 are provided in the upper grounding ring 160 to introduce process gas into the plasma reaction space 180; and the process gas is ionized into plasma under the action of the upper grounding ring 160 and the lower grounding ring 170 to etch the edge region of the wafer 100. Optionally, the air inlet 162 is arranged obliquely toward the edge of the wafer 100 so that the introduced process gas is gathered in the edge region of the wafer 100 as much as possible, so that the plasma concentration in the edge region of the wafer 100 is higher, thereby improving the etching rate of the edge region of the wafer 100. Optionally, the first gas source 101 for storing the process gas is located outside the reaction chamber 110, and the gas channel 161 also passes through the upper shielding portion 120 and the mounting substrate 121 and is connected to the first gas source 101, but the present invention is not limited thereto.

[0041] Specifically, in this embodiment, when the wafer 100 is subjected to an etching process, there is a gap between the upper shielding portion 120 and the wafer 100, and the second gas source 102 storing the purge gas can be connected to the gap through the purge gas passage 103 that penetrates the mounting substrate 121 and the upper shielding portion 120, so that the supplied purge gas can pass through the gap along the radial direction of the surface of the wafer 100 to reach the plasma reaction space 180, thereby preventing the plasma in the plasma reaction space 180 from reaching the central area of ​​the wafer 100 and avoiding etching the central area of ​​the wafer 100. Optionally, the purge gas is an inert gas, and the second gas source 102 is also located outside the reaction chamber 110, but the present invention is not limited thereto.

[0042] Please continue to refer to Figure 1 and Figure 2 The upper limiting ring 140 is provided with a first notch 141 facing the plasma reaction space 180 .

[0043] Specifically, in this embodiment, the provision of the first notch 141 can increase the volume of the plasma reaction space 180, so that the plasma reaction space 180 can accommodate more of the process gas, and then generate more plasma after ionization, further improving the etching rate of the edge area of ​​the wafer 100. More specifically, the upper limit ring 140 includes a lower surface 1401 facing the wafer 100, and the first notch 141 is located above the lower surface 1401 of the upper limit ring 140, so that the volume of the plasma reaction space 180 can be increased by the first notch 141, and the original etching path or etching area of ​​the wafer 100 can be ensured not to be changed by the lower surface 1401, that is, the etching rate of the edge area of ​​the wafer 100 can be improved, and the original etching requirements of the wafer 100 can be met. Specifically, the lower surface 1401 of the upper limit ring 140 can shield the edge area of ​​the wafer and limit the plasma processing of the edge area of ​​the wafer; because the edge area sizes of wafers for different applications need to be etched are different, the present invention can set a plurality of upper limit rings 140 for replacement selection, and by setting the outer diameter size of the lower surface 1401 of the upper limit ring 140 to be different, the edge area of ​​the wafer with different requirements can be etched. Optionally, the outer diameter of the lower surface 1401 of the upper limit ring 140 is smaller than the diameter of the wafer 100 and the difference between the two is 2 to 5 mm, so that the edge area of ​​the upper surface of the wafer 100 is exposed to the plasma reaction space 180 for etching process treatment, but the present invention is not limited to this.

[0044] Specifically, in the present embodiment, the cross section of the first notch 141 is one of an arc shape, a U shape, a V shape, an L shape, or any combination thereof, so that the cross-sectional area of ​​the first notch 141 is as large as possible, thereby making the volume of the first notch 141 as large as possible, thereby increasing the volume of the plasma reaction space 180 as much as possible. More specifically, if there is a first angle in the cross section of the first notch 141, the opening direction of the first angle avoids facing the upper limiting ring 140 or the upper grounding ring 160, so as to prevent the process gas or the plasma from accumulating at the first angle and being unable to flow to the edge area of ​​the wafer 100. Optionally, the upper grounding ring 160 is located above the first notch 141, so that the upper grounding ring 160 can ionize the process gas in the plasma reaction space 180 with an increased volume into the plasma, but the present invention is not limited thereto.

[0045] In some applications, plasma etching is also required below the edge region of the wafer. According to the above description, in order to increase the volume of the plasma region, such as Figure 1 and Figure 2As shown, the lower confinement ring 150 may also be provided with a second notch 151 facing the plasma reaction space 180 .

[0046] Specifically, similar to the first notch 141, the second notch 151 can also increase the volume of the plasma reaction space 180 to further improve the etching rate of the edge region of the wafer 100. The lower limit ring 150 includes an upper surface 1501 supporting the wafer 100, and the second notch 151 is located below the upper surface 1501 of the lower limit ring 150, so that the volume of the plasma reaction space 180 can be increased by the second notch 151, and the upper surface 1501 can be used to ensure that the original etching path or etching area of ​​the wafer 100 is not changed (similar to the lower surface 1401 of the upper limit ring 140), and the etching rate of the edge region of the wafer 100 can be improved, and the original etching requirements of the wafer 100 can be met. Optionally, the outer diameter of the upper surface 1501 of the lower limiting ring 150 is smaller than the diameter of the wafer 100 and the difference between the two is 2 to 5 mm, so that the edge area of ​​the lower surface of the wafer 100 is exposed to the plasma reaction space 180 for etching process, but the present invention is not limited to this.

[0047] Specifically, the cross section of the second notch 151 can also be one of arc, U, V, L, or any combination thereof, so that the cross-sectional area of ​​the second notch 151 is as large as possible, thereby making the volume of the second notch 151 as large as possible, thereby increasing the volume of the plasma reaction space 180 as much as possible. If there is a second angle in the cross section of the second notch 151, the opening direction of the second angle avoids facing the lower restriction ring 150 or the lower grounding ring 170, so as to prevent the process gas or the plasma from accumulating at the second angle and being unable to flow to the edge area of ​​the wafer 100. Optionally, the lower grounding ring 170 is located below the second notch 151, so that the lower grounding ring 170 can ionize the process gas in the plasma reaction space 180 with an increased volume into the plasma, but the present invention is not limited thereto.

[0048] In addition, in order to verify the improvement of the etching rate of the edge area of ​​the wafer by the edge etching device provided in this embodiment, the etching process is performed on the wafers with different radii without setting the first notch 141 and with setting the first notch 141, and the comparison results are as follows: Figure 3 (No first gap is set) and Figure 4 (Set the first gap) as shown; from Figure 3 and Figure 4 It can be seen from FIG. 1 that when etching the edge region of the wafer having the same radius, Figure 4 The etching rate of the wafer is significantly higher than Figure 3 The etching rate of the wafer in the embodiment is effectively proved to be improved in the etching rate of the wafer edge area.

[0049] In summary, the edge etching device provided in this embodiment has a base for carrying a wafer at the bottom of the reaction chamber, an upper shielding portion at the top of the reaction chamber, a lower limiting ring around the base, and an upper limiting ring around the upper shielding portion; the upper limiting ring and the lower limiting ring cooperate to form a plasma reaction space in the edge area of ​​the wafer, and the upper limiting ring is provided with a first notch facing the plasma reaction space. The provision of the first notch can effectively increase the volume of the plasma reaction space, so that more process gas can be accommodated in the plasma reaction space, and then more plasma is generated after the process gas is ionized, so as to greatly increase the etching rate of the edge area of ​​the wafer. In this embodiment, the upper limiting ring includes a lower surface facing the wafer, and the first notch is located above the lower surface of the upper limiting ring, so that the volume of the plasma reaction space can be increased by the first notch, and the original etching path or etching area of ​​the wafer can be ensured not to be changed by the lower surface of the upper limiting ring. In addition, in this embodiment, a second notch is provided on the lower limiting ring facing the plasma reaction space, which can also increase the volume of the plasma reaction space to further improve the etching rate of the edge area of ​​the wafer; and the lower limiting ring includes an upper surface supporting the wafer, and the second notch is located below the upper surface of the lower limiting ring, which can also increase the volume of the plasma reaction space through the second notch, and ensure that the original etching path or etching area of ​​the wafer is not changed through the upper surface of the lower limiting ring. The cross-section of the first notch and the second notch is one of an arc shape, a U shape, a V shape, and an L shape or any combination, so that the cross-sectional area of ​​the first notch and the second notch is as large as possible, so that the volume of the first notch and the second notch is as large as possible, thereby increasing the volume of the plasma reaction space as much as possible.

[0050] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. An edge etching device, characterized in that: include: Reaction chamber; A base, disposed at the inner bottom of the reaction chamber, for supporting the wafer; An upper shielding portion, disposed at the inner top of the reaction chamber; a lower confinement ring disposed around the base; as well as An upper limiting ring is arranged around the upper shielding portion; the upper limiting ring cooperates with the lower limiting ring to form a plasma reaction space in the edge area of ​​the wafer; and a first notch facing the plasma reaction space is provided on the upper limiting ring.

2. The edge etching device according to claim 1, characterized in that: The upper limit ring includes a lower surface facing the wafer, and the first notch is located above the lower surface of the upper limit ring.

3. The edge etching device according to claim 1, characterized in that: The cross section of the first notch is one of arc-shaped, U-shaped, V-shaped, and L-shaped, or any combination thereof.

4. The edge etching device according to claim 2, characterized in that: The outer diameter of the lower surface of the upper limiting ring is smaller than the diameter of the wafer, and the difference between the outer diameter and the lower surface is 2-5 mm.

5. The edge etching device according to claim 1, characterized in that: The lower confinement ring is provided with a second notch facing the plasma reaction space.

6. The edge etching device according to claim 5, characterized in that: The lower confinement ring includes an upper surface supporting the wafer, and the second notch is located below the upper surface of the lower confinement ring.

7. The edge etching device according to claim 5, characterized in that: The cross section of the second notch is one of arc-shaped, U-shaped, V-shaped, and L-shaped, or any combination thereof.

8. The edge etching device according to claim 6, characterized in that: The outer diameter of the upper surface of the lower limiting ring is smaller than the diameter of the wafer, and the difference between the two is 2-5 mm.

9. The edge etching device according to claim 6, characterized in that: Also includes: The lower grounding ring is located below the second notch and is arranged around the lower limiting ring.

10. The edge etching device according to claim 1, characterized in that: Also includes: An upper grounding ring is located above the first notch and is arranged around the upper limiting ring.

11. The edge etching device according to claim 10, characterized in that: A gas channel and a gas inlet hole communicating with the gas channel and the plasma reaction space are arranged in the upper grounding ring so as to introduce process gas into the plasma reaction space.

12. The edge etching device according to claim 11, characterized in that: The air inlet hole is arranged obliquely toward the edge of the wafer.

13. The edge etching device according to claim 1, characterized in that: The upper limit ring and the lower limit ring are made of aluminum oxide, silicon oxide or silicon carbide.

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