Pre-processing chamber wafer support structure and pre-processing chamber

Abstract

This invention provides a wafer support structure for a pre-processing chamber and a pre-processing chamber. The wafer support structure includes a base, a cooling plate disposed on the base, and an edge ring surrounding the cooling plate. The sidewall of the edge ring is provided with at least three protrusions extending toward the cooling plate, and the sidewall of the cooling plate is provided with at least three grooves that mate with the protrusions. The protrusions are at least partially accommodated within the grooves. This wafer support structure, through the protrusions on the sidewall of the edge ring and the grooves on the sidewall of the cooling plate that mate with the protrusions, restricts the slippage of the edge ring in the horizontal direction. In the wafer pre-processing process, this ensures that the airflow channel for purging the wafer edge remains uniform, thereby improving the etching uniformity of the wafer edge and optimizing and stabilizing the process results in the wafer edge region.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor manufacturing technology, and more specifically, it relates to a pre-processing process chamber wafer support structure and a pre-processing process chamber. Background Technology

[0002] In the semiconductor manufacturing field, selective silicon-germanium epitaxy has become a key process in the manufacturing of advanced logic and analog chips. High-quality epitaxial growth requires an absolutely clean wafer surface. Any residual natural oxides or contaminants such as carbon, oxygen, and fluorine will lead to epitaxial layer defects and lattice mismatches, seriously affecting device performance and yield.

[0003] To address this issue, the industry widely employs plasma-enhanced dry etching pretreatment processes to achieve efficient and non-destructive removal of surface oxides. The etching amount and its uniformity on the wafer surface directly determine the critical dimensions and morphology of subsequent epitaxial processes. The gas distribution within the pretreatment chamber, especially the mixing and distribution of the main etching gas from top to bottom and the purge gas introduced from the bottom of the substrate in the wafer edge region, is a core factor affecting etching uniformity. Currently, the wafer support structure of mainstream pretreatment chambers typically includes a cooling plate, an edge ring, and a substrate. The cooling plate supports the wafer and provides back-side purge gas; the edge ring surrounds the cooling plate, and one of its core functions is to form and control the flow field of the edge purge gas while preventing wafer slippage.

[0004] However, there is a significant drawback in the existing technology: the relative position between the edge ring and the cooling plate is prone to slight slippage due to mechanical vibration or thermal cycling. Figure 1 This is a schematic diagram showing the relative positions between the edge ring of the wafer support structure in the preprocessing chamber and the cooling plate. Figure 2 This diagram illustrates the non-uniformity distribution at the wafer edge caused by edge ring slippage during existing wafer pretreatment processes. Please refer to [link / reference needed]. Figure 1 and Figure 2 This slippage alters the gap between the two, causing instability and non-uniformity in the purge airflow field at the wafer edge, which in turn leads to fluctuations in the amount of etching at the wafer edge, thus worsening the non-uniformity of etching across the entire wafer. Utility Model Content

[0005] The purpose of this invention is to provide a wafer support structure for a preprocessing chamber and a preprocessing chamber, which can improve the non-uniformity of wafer etching in the preprocessing chamber.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: The first aspect of this utility model provides a wafer support structure for a pre-processing chamber, including a base, a cooling plate disposed on the base, and an edge ring surrounding the cooling plate. The sidewall of the edge ring is provided with at least three protrusions extending toward the cooling plate, and the sidewall of the cooling plate is provided with at least three grooves that mate with the protrusions. The protrusions are at least partially accommodated within the grooves, and the protrusions mate with the grooves to restrict the horizontal movement of the edge ring.

[0007] In one embodiment, the protrusion is located on the sidewall near the top surface of the edge ring.

[0008] In one embodiment, the protrusion structure is located on the sidewall near the bottom surface of the edge ring.

[0009] In one embodiment, the protrusion is shaped as a cylinder, a cone, or a cuboid.

[0010] In one embodiment, the protrusion is a cylinder with a spherical head and the diameter of the head is the same as the diameter of the cylinder.

[0011] In one embodiment, the diameter of the protrusion structure is 3-5 mm and the length is 3-5 mm.

[0012] In one embodiment, the number of the protrusions is three, and the three protrusions are evenly distributed along the circumference of the edge ring.

[0013] In one embodiment, the base is provided with a screw or bolt on the side opposite to the edge ring for threaded connection with the bottom of the edge ring, so as to restrict the movement of the edge ring in the vertical direction.

[0014] In one embodiment, the top surface of the edge ring is provided with a plurality of bump structures for preventing wafer slippage.

[0015] The second aspect of this utility model provides a pre-processing chamber, including the pre-processing chamber wafer carrier structure as described above.

[0016] The wafer support structure for the preprocessing chamber provided by this utility model includes a base, a cooling plate disposed on the base, and an edge ring surrounding the cooling plate. The sidewall of the edge ring is provided with at least three protrusions extending toward the cooling plate, and the sidewall of the cooling plate is provided with at least three grooves that mate with the protrusions. The protrusions are at least partially accommodated within the grooves. The protrusions and grooves cooperate to restrict the horizontal movement of the edge ring. This wafer support structure, through the protrusions on the sidewall of the edge ring and the grooves on the sidewall of the cooling plate that mate with the protrusions, restricts the horizontal slippage of the edge ring. In the wafer preprocessing process, this ensures that the airflow channel for wafer edge cleaning remains uniform, thereby improving the etching uniformity of the wafer edge and optimizing and stabilizing the process results in the wafer edge region. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram showing the relative positions of the edge ring and the cooling plate of the wafer support structure in the preprocessing chamber. Figure 2 This is a diagram showing the distribution of wafer edge non-uniformity caused by edge ring slippage during wafer preprocessing in existing technologies. Figure 3 A schematic diagram of the pretreatment process chamber wafer support structure provided in this embodiment of the utility model; Figure 4 A cross-sectional view of the pretreatment process chamber wafer support structure provided in this embodiment of the utility model; Figure 5 This is a schematic diagram of the base and cooling plate of the pretreatment process chamber wafer support structure provided in this embodiment of the utility model; Figure 6 A schematic diagram of the front structure of the edge ring of the wafer support structure of the pretreatment process chamber provided in this embodiment of the utility model; Figure 7 A schematic diagram of the reverse side structure of the edge ring of the wafer support structure of the pretreatment process chamber provided in this embodiment of the utility model; Figure 8 This is a diagram showing the non-uniformity distribution of wafer edge etching before and after using the pretreatment process chamber wafer support structure provided in this embodiment of the invention; Figure 9This is an enlarged schematic diagram of the protrusion structure on the edge ring of the pretreatment process chamber wafer support structure provided in this embodiment of the utility model.

[0019] The following are the labeling elements in the figure: 1-Base; 2-Cooling plate; 3-Edge ring; 21-Groove structure; 31-Protruding structure. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0021] In the description of this utility model, it should be understood that the terms "comprising" and "having" as used herein, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0022] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. It should be understood that the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships may exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. In the description of this utility model, unless otherwise stated, "multiple" means two or more.

[0024] Current technologies generally employ plasma-enhanced dry etching pretreatment processes to achieve efficient and non-destructive removal of surface oxides. The etching amount and uniformity of the pretreatment process on the wafer surface directly determine the critical dimensions and morphology of subsequent epitaxial processes. For example, in selective silicon-germanium epitaxy, residual oxides and elements such as C, O, and F on the wafer surface can affect normal growth. Currently, the industry mainly uses plasma-enhanced etching methods to pretreat wafers to remove impurities such as SiO2 generated by surface oxidation, ensuring normal SiGe growth. The gas distribution within the pretreatment chamber, especially the mixing and distribution of the main etching gas from top to bottom and the purge gas introduced from the bottom of the substrate in the wafer edge region, is a core factor affecting etching uniformity. Currently, the wafer support structure of mainstream pretreatment chambers typically includes a cooling plate, an edge ring, and a substrate. The cooling plate supports the wafer and provides back-side purge gas, while the edge ring surrounds the cooling plate. One of its core functions is to form and control the flow field of the edge purge gas, while preventing wafer slippage.

[0025] However, existing technologies have a significant drawback: the relative position between the edge ring and the cooling plate is prone to slight slippage due to mechanical vibration or thermal cycling. This slippage alters the gap between them, leading to instability and non-uniformity in the purge gas flow field at the wafer edge, which in turn causes fluctuations in the etching amount at the wafer edge, worsening the overall etching non-uniformity of the wafer. This problem has become a bottleneck restricting further improvements in the performance of advanced epitaxial processes. Therefore, there is an urgent need for a technical solution that can stably and precisely fix the relative position of the edge ring and the cooling plate to eliminate process fluctuations caused by component slippage and improve the overall uniformity and stability of pretreatment and subsequent epitaxial processes.

[0026] The pretreatment process chamber wafer support structure and pretreatment process chamber provided by this utility model will be described in detail below with reference to specific embodiments.

[0027] Figure 3 This is a schematic diagram of the pretreatment process chamber wafer carrier structure provided in an embodiment of the present invention. Figure 4 A cross-sectional view of the pretreatment process chamber wafer support structure provided in this embodiment of the present invention. Figure 5 This is a schematic diagram of the base and cooling plate of the pretreatment process chamber wafer support structure provided in this embodiment of the utility model. Figure 6 This is a front view of the edge ring of the wafer support structure in the pretreatment process chamber provided in an embodiment of the present invention. Figure 7 Please refer to the schematic diagram of the reverse side of the edge ring of the pretreatment process chamber wafer support structure provided in this embodiment of the utility model. Figures 3-7The first aspect of this embodiment provides a pre-processing chamber wafer support structure, including a base 1, a cooling plate 2 disposed on the base 1, and an edge ring 3 disposed around the cooling plate 2. The sidewall of the edge ring 3 is provided with at least three protrusions 31 extending toward the edge ring. The sidewall of the cooling plate 2 is provided with at least three grooves 21 that cooperate with the protrusions 31. The protrusions 31 are at least partially accommodated in the grooves 21. The protrusions 31 cooperate with the grooves 21 to restrict the movement of the edge ring 3 in the horizontal direction.

[0028] In this embodiment, the base 1 supports the cooling plate 2 during the process. The cooling plate 2 is fixedly mounted on the base 1 and typically has cooling channels inside to control the wafer temperature. The upper surface of the cooling plate 2 has multiple holes for providing back pressure and purge gas to the back of the wafer. Exemplarily, the base 1 has air channel grooves, and the cooling plate 2 has through-holes that communicate with the air channel grooves. The wafer placed on the cooling plate 2 can transfer heat through the air outlets and air channel grooves, for example, by venting air through the air channel grooves and air outlets to maintain a certain temperature on the wafer. This embodiment does not impose any particular limitations on the material and size of the base 1 and the cooling plate 2.

[0029] In this embodiment, the edge ring 3 surrounds the cooling plate 2, and there is a precise annular gap between the edge ring 3 and the cooling plate 2. The purge gas introduced from the bottom of the base 1 flows upward through this gap, forming a gas curtain around the edge of the wafer, preventing volatile byproducts generated by the etching reaction (such as SiF4 and NH3 in the sublimation stage) from flowing back and redepositing on the lower temperature edge of the wafer, causing contamination.

[0030] In this embodiment, the sidewall of the edge ring 3 is provided with at least three protruding structures 31, and the sidewall of the cooling plate 2 is provided with at least three groove structures 21 that cooperate with the protruding structures 31. The cooperation between the protruding structures 31 and the groove structures 21 restricts the movement of the edge ring 3 in the horizontal direction. For example, in this embodiment, three protruding structures 31 are machined near the top surface of the sidewall of the edge ring 3, which are evenly distributed circumferentially. In this embodiment, the protruding structure 31 is a cylindrical protrusion, and correspondingly, a groove structure 21 is machined on the sidewall of the cooling plate 2, opposite to each protruding structure 31. The cooperation between the protrusions and grooves in this embodiment forms a mechanical limit. When the base 1 vibrates or moves during the process, the protruding structure 31 is confined within the groove structure 21, effectively preventing the edge ring 3 from rotating horizontally or sliding radially relative to the cooling plate 2. That is, this structure ensures that the annular gap (i.e., the edge blowing channel) between the inner wall of the edge ring 3 and the outer wall of the cooling plate 2 remains constant in the circumferential direction.

[0031] In this embodiment, the cooperation between the protruding structure 31 and the groove structure 21 restricts the movement of the edge ring 3 in the horizontal direction, fundamentally solving the problem of uneven distribution of edge purging gas caused by the slippage of the edge ring 3. Figure 8 For a diagram showing the non-uniformity distribution of wafer edge etching before and after using the pretreatment process chamber wafer support structure provided in this embodiment, please refer to [link / reference needed]. Figure 8 In actual process verification, after adopting this improved structure, the etching non-uniformity was significantly reduced from 2.8% to 0.8%. This not only greatly improves the uniformity of a single process, but also facilitates process matching between multiple process chambers, thereby improving the yield and stability of semiconductor production.

[0032] The preprocessing chamber wafer support structure provided in this embodiment includes a base, a cooling plate disposed on the base, and an edge ring surrounding the cooling plate. The sidewall of the edge ring is provided with at least three protrusions extending toward the cooling plate, and the sidewall of the cooling plate is provided with at least three grooves that mate with the protrusions. The protrusions are at least partially accommodated within the grooves. The protrusions and grooves mate to restrict the horizontal movement of the edge ring. This wafer support structure, through the protrusions on the sidewall of the edge ring and the grooves on the sidewall of the cooling plate that mate with the protrusions, restricts the horizontal slippage of the edge ring. In the wafer preprocessing process, this ensures that the airflow channel for wafer edge cleaning remains uniform, thereby improving the etching uniformity of the wafer edge and optimizing and stabilizing the process results in the wafer edge region.

[0033] Optionally, the protruding structure 31 is located on the sidewall near the top surface of the edge ring 3 or on the sidewall near the bottom surface of the edge ring 3. For example, the protruding structure 31 is positioned on the sidewall of the edge ring 3 near the bottom surface. After the edge ring 3 is installed, these protruding structures 31 are also embedded in the corresponding groove structure 21 on the sidewall of the cooling plate 2. The advantage of this design is that the protruding structure 31 is closer to the connection point between the edge ring 3 and the base 1, resulting in better stress distribution on the limiting structure and higher overall stability.

[0034] Furthermore, the protruding structure 31 is shaped like a cylinder, a cone, or a cuboid, and the corresponding groove structure 21 is a groove structure 21 corresponding to the cylindrical, conical, or cuboid protruding structure 31. In this embodiment, the protruding structure 31 is shaped like a cylinder, a cone, or a cuboid, making manufacturing simpler. Moreover, compared to some irregular shapes or shapes with sharp corners, cylinders (especially those with a spherical head) and cones can better distribute stress generated during installation, vibration, or accidental collisions, avoiding cracking or wear at the root of the protruding structure 31 due to stress concentration.

[0035] Figure 9 Please refer to the enlarged schematic diagram of the protrusion structure on the edge ring of the pretreatment process chamber wafer carrier structure provided in this embodiment of the utility model. Figure 9 Preferably, the protruding structure 31 is a cylinder with a spherical head, and the diameter of the head is the same as the diameter of the cylinder. In this embodiment, the protruding structure 31 is a cylinder with a spherical head. When the edge ring 3 is fitted into the cooling plate 2, even if there is a slight misalignment between the protruding structure 31 and the groove structure 21, the spherical head can easily slide into the groove structure 21 through its smooth curved surface. This achieves a self-aligning effect, greatly simplifies the assembly process, avoids the need for installers to repeatedly adjust the position, improves maintenance efficiency, and reduces the risk of bumps and scratches on the edges of the protruding structure 31 or the groove structure 21 caused by forced insertion. When there is slight vibration during equipment operation, the point contact or line contact friction of the spherical surface is small, which can reduce the wear of the contact surface with the groove structure 21 compared to the straight contact of a pure cylinder. This ensures that even after multiple disassemblies and long-term use, the fit gap between the protruding structure 31 and the groove structure 21 will not increase significantly due to wear, thereby maintaining long-term and stable positioning accuracy and extending the service life of the edge ring 3.

[0036] Preferably, the diameter and length of the protrusion structure 31 are 3-5 mm. During the installation, disassembly, and vibration of the edge ring 3, the protrusion structure 31 will be subjected to forces from the sidewall of the groove structure 21. A protrusion structure 31 with a diameter and length less than 3 mm would be too thin, and its root (stress concentration point) would be at risk of cracking or bending deformation under repeated stress. The 3-5 mm dimension ensures its structural rigidity and can reliably perform the limiting function. The 3-5 mm length of the protrusion structure 31 ensures sufficient embedding and provides stable constraint. Moreover, if the length is too long (e.g., >5 mm), it may cause interference between the protrusion structure 31 and the bottom of the groove structure 21, increasing the difficulty of installation and even creating a risk of jamming under thermal expansion.

[0037] Preferably, please refer to Figure 6 and Figure 7 The number of protruding structures 31 is three, and they are evenly distributed along the circumference of the edge ring 3. In this embodiment, the number of protruding structures 31 is three, which provides sufficient limiting strength while minimizing obstruction of the edge-blowing airflow and avoiding the introduction of new non-uniformity due to the limiting structure itself. Of course, in other embodiments, the number of protruding structures 31 can also be four or five.

[0038] Optionally, the base 1, on the side facing away from the edge ring 3, is provided with screws or bolts for threaded connection to the bottom of the edge ring 3, thereby restricting the movement of the edge ring 3 in the vertical direction. During the process, wafer back pressure and edge purge gas may generate upward forces, attempting to lift the edge ring 3. The screw or bolt connection provides sufficient preload to effectively prevent any minor displacement or vibration of the edge ring 3 in the vertical direction. The horizontal protrusion structure 31 and groove structure 21, in combination, restrict the edge ring 3's translation in the X and Y directions and rotation about the Z axis, i.e., three degrees of freedom in the horizontal plane. The screw connection of this claim, however, restricts the edge ring 3's translation in the Z direction and tilting about the X and Y axes, i.e., three degrees of freedom in the vertical direction.

[0039] Optionally, the top surface of the edge ring 3 is provided with multiple bump structures to prevent wafer slippage. Inside the chamber, the wafer is fed in and out by a robotic arm, and may be accompanied by the lifting and lowering movement of the base 1. These operations involve inertial forces and vibrations. The multiple bump structures can effectively prevent the wafer from slipping off the bearing surface of the cooling plate 2 or colliding with other components in the chamber, avoiding wafer breakage. Moreover, it ensures that the wafer is precisely confined to the predetermined center position of the cooling plate 2 each time, achieving uniform temperature distribution, back pressure distribution, and airflow distribution across the entire wafer surface.

[0040] A second aspect of this embodiment provides a preprocessing chamber, which includes the preprocessing chamber wafer carrier structure as described in the above embodiment.

[0041] For example, the wafer support structure includes a base, a cooling plate disposed on the base, and an edge ring disposed around the cooling plate. The sidewall of the edge ring is provided with at least three protrusions extending toward the cooling plate, and the sidewall of the cooling plate is provided with at least three grooves that mate with the protrusions. The protrusions are at least partially accommodated within the grooves, and the protrusions mate with the grooves to restrict the movement of the edge ring in the horizontal direction.

[0042] The wafer support structure of the preprocessing chamber provided in this embodiment includes a base, a cooling plate disposed on the base, and an edge ring surrounding the cooling plate. The sidewall of the edge ring is provided with at least three protrusions extending toward the cooling plate, and the sidewall of the cooling plate is provided with at least three grooves that mate with the protrusions. The protrusions are at least partially accommodated within the grooves. The protrusions and grooves cooperate to restrict the horizontal movement of the edge ring. This wafer support structure, through the protrusions on the sidewall of the edge ring and the grooves on the sidewall of the cooling plate that mate with the protrusions, restricts the horizontal slippage of the edge ring. In the wafer preprocessing process, this ensures that the airflow channel for wafer edge cleaning remains uniform, thereby improving the etching uniformity of the wafer edge and optimizing and stabilizing the process results in the wafer edge region.

[0043] In the above description, the terms "an embodiment," "some embodiments," "example," "specific example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0044] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A wafer support structure for a pre-processing chamber, characterized in that: The device includes a base, a cooling plate disposed on the base, and an edge ring surrounding the cooling plate. The sidewall of the edge ring is provided with at least three protrusions extending toward the cooling plate, and the sidewall of the cooling plate is provided with at least three grooves that mate with the protrusions. The protrusions are at least partially accommodated within the grooves, and the protrusions and grooves mate to restrict the movement of the edge ring in the horizontal direction.

2. The pretreatment process chamber wafer support structure according to claim 1, characterized in that: The protruding structure is located on the sidewall near the top surface of the edge ring.

3. The pretreatment process chamber wafer support structure according to claim 1, characterized in that: The protruding structure is located on the sidewall near the bottom surface of the edge ring.

4. The pretreatment process chamber wafer support structure according to claim 1, characterized in that: The shape of the protrusion structure is one of a cylinder, a cone, or a cuboid.

5. The pretreatment process chamber wafer support structure according to claim 4, characterized in that: The protruding structure is a cylinder with a spherical head, and the diameter of the head is the same as the diameter of the cylinder.

6. The pretreatment process chamber wafer support structure according to claim 5, characterized in that: The diameter of the protrusion is 3-5 mm and the length is 3-5 mm.

7. The pretreatment process chamber wafer support structure according to claim 4, characterized in that: The number of the protruding structures is three, and the three protruding structures are evenly distributed along the circumference of the edge ring.

8. The pretreatment process chamber wafer support structure according to any one of claims 1-7, characterized in that: The base has a screw or bolt on the side opposite to the edge ring for threaded connection with the bottom of the edge ring, so as to restrict the movement of the edge ring in the vertical direction.

9. The pretreatment process chamber wafer support structure according to claim 8, characterized in that: The top surface of the edge ring is provided with multiple bump structures to prevent wafer slippage.

10. A pretreatment process chamber, characterized in that: The pretreatment process chamber wafer carrier structure includes any one of claims 1-9.

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