Wafer retaining ring and bearing disc

Abstract

The invention discloses a wafer retaining ring and a bearing disc, and belongs to the technical field of semiconductor coating, and the wafer retaining ring comprises an annular main body; the first slope is formed at the top of the annular main body along a height direction, and the inner side of the first slope is higher than the outer side of the first slope; the bearing table is formed on the inner side of the annular body in the radial direction and used for bearing a wafer, the top face of the bearing table is lower than the height of the inner side of the first slope, and the inner side of the first slope is provided with a first inner side edge so as to be connected with the bearing table. By arranging the first slope, media accumulated on the wafer retaining ring are reduced, the maintenance period and the service life of the wafer retaining ring are prolonged, external particles are further prevented from reaching a growing wafer, defects caused by the fact that the particles enter the wafer are reduced, and the coating quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor coating, and in particular to a wafer retaining ring and a carrier plate. Background Art

[0002] The coating process is a very important part of the semiconductor, optical and nanomaterial industries, with a wide range of applications. It includes but is not limited to: substrate epitaxy, chip patterning, electrode production, optical material preparation, and two-dimensional material growth. Large-scale, mass-produced coating processes basically use wafer coating.

[0003] During the wafer coating process, the wafer needs to be positioned and restricted by a limiting structure. Most of them use a structure in which the wafer tray and the Ring (retaining ring) are separated or an integrated structure of the wafer tray and the Ring to achieve the above purpose. At present, the general structure of the Ring is a ring structure with a horizontal side and a vertical side, such as Figure 1 and Figure 2 As shown, this structure has the following problems:

[0004] 1. During the wafer coating process, in order to reduce the negative impact on the coating, the Ring needs to be maintained or scrapped and replaced with a new one when it grows to a certain thickness. The deposition thickness on the top horizontal edge 101 of the existing retaining ring 100 is roughly consistent with the coating thickness of the wafer. The maintenance cycle and service life are generally short, resulting in increased maintenance and consumption costs for accessories; frequent Ring maintenance will also waste production time for coating. All of these are not conducive to the industrialization and scale of wafer coating.

[0005] 2. A large number of loose and protruding deposits are easily attached to the horizontal edge 101 and the right angle 102 structure at the top of the existing retaining ring 100. When the growth temperature and flow field change, these loose and protruding deposits have a certain probability of moving to the wafer to form fatal defects, greatly affecting the quality of wafer coating. Furthermore, the protruding deposits at the right angle 102 structure will also affect the placement of the wafer, causing the wafer to get stuck or even crack.

[0006] It should be noted that the information disclosed in the background technology section of the invention is only intended to deepen the understanding of the general background technology of the invention, and should not be regarded as an admission or suggestion in any form that the information constitutes prior art already known to those skilled in the art. Summary of the invention

[0007] The purpose of the present invention is to provide a wafer retaining ring and a carrier plate to solve the problem that the maintenance cycle and service life of the existing retaining ring are generally short, reduce the defects caused by particles entering the wafer, and improve the quality of wafer coating.

[0008] In order to solve the above technical problems, the present invention provides a wafer holding ring, comprising:

[0009] Ring-shaped body;

[0010] A first slope is formed at the top of the annular body along a height direction, and an inner height of the first slope is higher than an outer height; and

[0011] A supporting platform is formed on the inner side of the annular body along the radial direction for supporting the wafer. The top surface of the supporting platform is lower than the inner height of the first slope, and a first inner edge is arranged on the inner side of the first slope to connect with the supporting platform.

[0012] Preferably, it further comprises a second slope, wherein one side of the second slope is connected to the first slope, and the other side is connected to the first inner edge, and the height of one side of the second slope is higher than the height of the other side.

[0013] Preferably, the other side of the second slope is connected to the first inner edge fillet.

[0014] Preferably, the first slope and the second slope are connected with rounded corners on one side.

[0015] Preferably, the bottom of the annular body is also protrudingly provided with latch teeth.

[0016] Preferably, the ratio of the length of the first slope to the length of the second slope is 2:1 to 10:1.

[0017] Preferably, the length of the second slope is 0.1 mm to 0.8 mm.

[0018] Preferably, a first angle is formed between the first slope and the height direction, and the first angle is 10° to 85°.

[0019] Preferably, a second angle is formed between the second slope and the height direction, and the second angle is 10° to 85°.

[0020] Based on the same technical concept, the present disclosure also provides a wafer carrier, comprising the wafer retaining ring as described above.

[0021] The wafer retaining ring provided by the present invention has the following beneficial effects:

[0022] 1. The first slope tilted outward replaces the original horizontal edge. The top of the annular body is provided with a first slope to replace the original right-angle structure. The first slope has a first angle θ with the height direction. 第一斜坡 =S 水平边 / sinθ, the top area of ​​the first slope is larger than the area of ​​the horizontal side, and the top area of ​​the wafer holding ring is greatly increased. During the wafer coating process, most of the growth sources diffuse from the vertical direction, and the total amount of growth sources from the vertical direction is roughly the same on the hypotenuse and horizontal sides. Here, the product of the first slope coating thickness and the first slope area is equivalent to the product of the horizontal side coating thickness and the hypotenuse area. Expressed as: h 第一斜坡 S 第一斜坡 =h 平边 S 水平边 , and because S 第一斜坡 sinθ=S 水平边 , growth thickness h 第一斜坡 =h 水平边 sinθ; that is, under the same growth conditions, when the existing retaining ring reaches the maintenance or scrap thickness h, the thickness of the first slope growth is h 第一斜坡 sinθ, can continue to grow hh 第一斜坡 sinθ. Therefore, the bevel design increases the maintenance cycle and service life of the Ring.

[0023] 2. The above structure also reduces the introduction of wafer particles and improves the quality of the grown wafer. The details are as follows:

[0024] First, the surface deposition velocity of the first slope and flat edge of the present disclosure can be expressed as: v 第一斜坡 =h 第一斜坡 / t,v 平边 =h 平边 / t, according to the above relationship between the two thicknesses: v 第一斜坡 =v 水平边 sinθ, so the growth rate of deposits on the surface of the newly designed retaining ring is slower, the surface covering the ring is more stable and dense, and the probability of particles entering the wafer is smaller.

[0025] Secondly, compared with the right-angle structure of the horizontal edge, the slope and rounded chamfer of the retaining ring disclosed in the present invention make it difficult for overly loose and protruding sediments to adhere to the ring, and more easily be carried away by the gas, thereby reducing the introduction of particles into the coated wafer.

[0026] Finally, the first slope structure of the new wafer retaining ring is tilted outward, so that when particles brought from other places pass through the ring and enter the wafer, they are blocked by the slope, making them tend to move outside the wafer and difficult to enter the wafer.

[0027] The above records enable the new retaining ring to reduce the number of particles entering the wafer, reduce the number of fatal defects on the wafer, and improve the quality of wafer coating.

[0028] 3. The slope and chamfer structure on the inner side of the ring are less likely to form inward protruding deposits compared to the existing right-angle structure on the horizontal edge, making the area near the wafer and the ring smoother and reducing the probability of wafer jams and cracks during wafer placement.

[0029] The wafer carrier provided by the present invention and the wafer retaining ring provided by the present invention belong to the same inventive concept. Therefore, the wafer carrier provided by the present invention at least has all the advantages of the wafer retaining ring provided by the present invention, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0031] Figure 1 1 is a schematic diagram of a top view structure of an existing retaining ring;

[0032] Figure 2 It is a schematic diagram of a partial cross-sectional structure of an existing retaining ring;

[0033] Figure 3 is a schematic diagram of a top view of a wafer holding ring according to an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of a partial cross-sectional structure of a wafer holding ring according to an embodiment of the present invention;

[0035] Figure 5 is a schematic cross-sectional structure diagram of a wafer retaining ring according to another embodiment of the present invention;

[0036] Figure 6 It is a schematic diagram of the cross-sectional structure of a wafer retaining ring according to an embodiment of the present invention.

[0037] In the attached figure:

[0038] 100. existing retaining ring; 101. horizontal edge; 102. right angle.

[0039] 200, wafer holding ring; 201, ring body; 202, first slope; 203, second slope; 204, first inner edge; 205, support platform; 206, second inner edge; 207, latching teeth; 208, outer edge; 209, third inner edge. DETAILED DESCRIPTION

[0040] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0041] As used in the present invention, the singular forms "a", "an" and "the" include plural objects, the term "or" is generally used in a sense including "and / or", the term "several" is generally used in a sense including "at least one", and the term "at least two" is generally used in a sense including "two or more". In addition, the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features. The term "proximal end" is usually the end close to the operator, and the term "distal end" is usually the end close to the patient. "One end" and "the other end" as well as "proximal end" and "distal end" usually refer to two corresponding parts, which include not only the endpoints. The terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of the two elements or the interaction relationship between the two elements. In addition, as used in the present invention, an element is arranged on another element, which usually only means that there is a connection, coupling, matching or transmission relationship between the two elements, and the connection, coupling, matching or transmission between the two elements can be direct or indirect through an intermediate element, and it cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, one element can be in any position such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] The inventors have found that in CVD and PVD coatings, such as epitaxial layer coatings of SiC, GaN, PVD coatings of Pt, Ni and Au, and CVD deposition of oxides, although the structure of the existing retaining ring can play a good role in positioning and limiting the wafer to be coated, a certain thickness of medium is easily deposited on the top of the retaining ring during the coating process as the wafer is coated, which puts forward certain requirements for production and maintenance. In addition, the medium deposited on the top of the existing retaining ring is easily moved to the wafer surface, affecting the growth quality of the wafer coating.

[0043] Based on this, the core idea of ​​the present invention is to reduce the medium accumulated on the wafer retaining ring by setting a first slope, thereby extending the maintenance cycle and service life of the wafer retaining ring, and further blocking external particles from reaching the growing wafer to reduce defects.

[0044] For details, please refer to Figure 3-Figure 6 , which is a schematic diagram of an embodiment of the present invention. Figure 3 As shown, a wafer holding ring is used for wafer coating, comprising:

[0045] An annular body 201;

[0046] A first slope 202 is formed at the top of the annular body 201 along a height direction, and the inner height of the first slope 202 is higher than the outer height; and

[0047] A supporting platform 205 is formed on the inner side of the annular body 201 along the radial direction for supporting the wafer. The top surface of the supporting platform 205 is lower than the inner height of the first slope 202 , and a first inner edge 204 is provided on the inner side of the first slope 202 to connect with the supporting platform 205 .

[0048] like Figure 4 and Figure 6 As shown, a first slope 202 is provided on the top of the annular body 201 to replace the original right-angle structure, and a first angle θ is formed between the first slope 202 and the height direction. 第一斜坡 =S 水平边 / sinθ, the top area of ​​the first slope 202 is larger than the area of ​​the horizontal side, and the top area of ​​the wafer holding ring 200 is greatly increased. During the thin film growth process, the total amount of growth sources from the vertical direction is roughly the same as the horizontal side. Therefore, under the same growth conditions, the relationship between the growth speed of the first slope 202 and the horizontal side is v 第一斜坡 =v 水平边 sinθ, growth thickness h 第一斜坡 =h 水平边 sinθ, that is, under the same growth conditions, when the existing retaining ring reaches the maintenance or scrap thickness h, the thickness of the first slope 202 is h 第一斜坡 sinθ, can continue to grow hh 第一斜坡 sinθ, which greatly prolongs the maintenance cycle and service life of the retaining ring.

[0049] It can be understood that the inner side of the first slope 202 is the side close to the axis of the annular body 201, and the outer side is the side away from the axis. The first slope 202 is set to be high inside and low outside. On the one hand, due to the increase in its surface area, the growth rate of the sediment is slower than that of the horizontal side, and the surface of the wafer retaining ring 200 is more stable and dense. On the other hand, the inclined first slope 202 makes it difficult for the sediment that is too loose and protruding to adhere to its surface, and it is easy to slide out of the wafer retaining ring 200 along the first slope 202, so that the wafer retaining ring 200 is not easy to become a particle source during the wafer growth process.

[0050] The outwardly inclined first slope 202 structure causes particles generated by other particle sources to tend to move outward from the ring when passing through the slope, making it difficult for them to enter the ring, thereby preventing the particles from reaching the growing wafer.

[0051] Specifically, it further includes a second slope 203 , one side of the second slope 203 is connected to the first slope 202 , and the other side is connected to the first inner edge 204 , and the height of one side of the second slope 203 is higher than the height of the other side.

[0052] like Figure 5 As shown, a second slope 203 connected to the first slope 202 is provided to facilitate the placement and removal of wafers, and even if the deposits on the top of the wafer holding ring 200 are thick, there will be no problem of wafer jamming. The first slope 202 is longer than the second slope 203, and a protruding structure is formed at the junction of the second slope 203 and the first slope 202, which can effectively block particles from the first slope 202.

[0053] Wherein, the ratio of the length L of the first slope 202 to the length S of the second slope 203 is 2:1 to 10:1. Figure 5 As shown, the length S of the second slope 203 is 0.1 mm to 0.8 mm.

[0054] like Figure 5 As shown, a supporting platform 205 protrudes from the inner side of the annular body 201 for supporting the wafer, and separates the inner side of the annular body 201 into two discontinuous edges, namely a first inner edge 204 and a second inner edge 206. The first inner edge 204 and the second inner edge 206 are both vertical edges. The height h1 of the first inner edge 204 is, for example, 0.1 mm to 1.2 mm, and the height h2 of the second inner edge 206 is, for example, 0.1 mm to 0.8 mm.

[0055] The bottom of the annular body 201 is also protruded with a latching tooth 207. The latching tooth 207 extends from the outer edge 208 of the annular body 201 and can be used to connect with the wafer carrier. The inner side of the latching tooth 207 is the third inner edge 209, and its height h3 is, for example, 0.15 mm to 0.8 mm.

[0056] Specifically, the other side of the second slope 203 is connected to the first inner edge 204 with a rounded corner. The first slope 202 is connected to one side of the second slope 203 with a rounded corner. The first slope 202 is also connected to the outer edge 208 with a rounded corner, so as to avoid bumping against the corners when taking and placing the wafer, thereby preventing the wafer from being damaged. Even if the deposit on the wafer retaining ring 200 is thick, it is not easy to get stuck. For example, Figure 6 As shown, the radius of each fillet R is the same, both ranging from 0.2 mm to 0.8 mm.

[0057] The first slope 202, the second slope 203 and the rounded chamfer structure are designed to reduce the coverage of sediments on the wafer retaining ring, and sediments that are too loose and protruding are not easy to adhere to it and are more likely to be taken away, thereby increasing the maintenance cycle and service life of the wafer retaining ring; the first slope structure inclined outward blocks particles outside the retaining ring from entering the wafer inside the ring when particles generated by other particle sources pass through the slope, hindering the particles from reaching the growing sample, reducing the number of defects caused by particles entering the wafer, and reducing the difficulty of taking and placing the wafer through the second slope 203, reducing the probability of wafer contamination, edge collapse and even wafer cracking caused by taking and placing the wafer.

[0058] like Figure 6 As shown, there is a first angle θ between the first slope 202 and the height direction, and the first angle θ is 10° to 85°. There is a second angle α between the second slope 203 and the height direction, and the second angle α is 10° to 85°. More preferably, the height of the first inner edge 204 and the second angle α are set according to the mechanical structure of the wafer placement to ensure that there is sufficient space between the second slope 203 and the side wall of the wafer for the mechanical structure to operate.

[0059] Based on the same technical concept, the present disclosure also provides a wafer carrier, including the wafer retaining ring as described above. The wafer carrier is fixedly provided with a wafer retaining ring, and the two can be an integrated structure, or obviously can be a separate structure, which is not specifically limited here.

[0060] In the wafer holding ring and the carrier provided by the present disclosure, a new holding ring structure is provided, and the existing horizontal edge and right-angle structure are replaced by the connected first slope and second slope. The original horizontal edge is replaced by the first slope inclined outward, and a shorter second slope is designed on the inner side of the ring, and finally, rounded corners are respectively set at the edges of the holding ring surface where the attached growth may be deposited.

[0061] The above structure greatly prolongs the maintenance cycle and service life of the retaining ring. A first slope 202 is provided on the top of the annular body 201 to replace the original right-angle structure, and a first angle θ is formed between the first slope 202 and the height direction. 第一斜坡 =S 水平边 / sinθ, the top area of ​​the first slope 202 is larger than the area of ​​the horizontal side, and the top area of ​​the wafer holding ring 200 is greatly increased. During the thin film growth process, the total amount of growth sources from the vertical direction is roughly the same as the horizontal side. Therefore, under the same growth conditions, the relationship between the growth speed of the first slope 202 and the horizontal side is v 第一斜坡 =v 水平边 sinθ, growth thickness h 第一斜坡 =h 水平边 sinθ, that is, under the same growth conditions, when the existing retaining ring reaches the maintenance or scrap thickness h, the thickness of the first slope 202 is h 第一斜坡 sinθ, can continue to grow hh 第一斜坡 sinθ.

[0062] The above structure reduces the introduction of wafer particles and improves the quality of growing wafers. On the one hand, the growth rate of the sediment on the surface of the retaining ring is slower than that of the horizontal edge, making the deposits on the surface of the retaining ring more stable and dense; on the other hand, the new retaining ring, compared with the right-angle structure of the horizontal edge, the overly loose and protruding sediments are not easy to adhere to it and are more likely to be carried away. Both aspects make the new retaining ring less likely to become a particle source. The outward-inclined first slope structure makes the particles generated by other particle sources tend to move outward from the ring when passing through the slope, making it difficult to enter the ring, hindering the particles from reaching the growing sample.

[0063] In summary, the above structure reduces the particles introduced onto the wafer, thereby reducing fatal defects and improving product quality.

[0064] The above description is only a description of the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A wafer holding ring for wafer coating, characterized in that: include: Ring-shaped body; A first slope is formed on the top of the annular body along a height direction, and the inner height of the first slope is higher than the outer height; as well as A supporting platform is formed on the inner side of the annular body along the radial direction for supporting the wafer. The top surface of the supporting platform is lower than the inner height of the first slope, and a first inner edge is arranged on the inner side of the first slope to connect with the supporting platform.

2. The wafer holding ring according to claim 1, characterized in that: It also includes a second slope, one side of the second slope is connected to the first slope, and the other side is connected to the first inner edge, and the height of one side of the second slope is higher than the height of the other side.

3. The wafer holding ring according to claim 2, characterized in that: The other side of the second slope is connected to the first inner edge fillet.

4. The wafer holding ring according to claim 2, characterized in that: The first slope and the second slope are connected at one side with a rounded corner.

5. The wafer holding ring according to claim 1, characterized in that: The bottom of the annular body is also protrudingly provided with latch teeth.

6. The wafer holding ring according to claim 2, characterized in that: The ratio of the length of the first slope to the length of the second slope is 2:1 to 10:

1.

7. The wafer holding ring according to claim 2, characterized in that: The length of the second slope is 0.1 mm to 0.8 mm.

8. The wafer holding ring according to claim 1, characterized in that: A first angle is formed between the first slope and the height direction, and the first angle is 10° to 85°.

9. The wafer holding ring according to claim 2, characterized in that: A second angle is formed between the second slope and the height direction, and the second angle is 10° to 85°.

10. A wafer carrier, characterized in that: Comprising a wafer holding ring as described in any one of claims 1-9.

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