An etching tray and an etching fixture

Abstract

This invention discloses an etching tray and an etching fixture. The etching tray includes a support plate and multiple bosses located on one side of the support plate. A wafer is loaded onto the side of the bosses facing away from the support plate. The support plate and the bosses are fixed together by connectors, and at least some of the bosses have a first gap with the support plate. The multiple bosses include a first boss and a second boss. In the extension direction of the plane of the support plate, the distance between the first boss and the center of the support plate is different from the distance between the second boss and the center of the support plate. In the thickness direction of the support plate, the surface of the first boss facing the support plate has a first gap with the support plate, and the surface of the second boss facing the support plate has a second gap with the support plate. The first gap and the second gap are different. Through the above solution, the service life of the etching tray can be improved, the stability of the etching process can be guaranteed, and the manufacturing cost can be reduced. In addition, the etching efficiency of wafers in different areas can be adjusted, improving etching consistency.

Description

Technical Field

[0001] This invention relates to the field of semiconductor processing technology, and more particularly to an etching tray and an etching fixture. Background Technology

[0002] The fabrication of patterned sapphire substrates (PSS) consists of two patterning processes. The photolithography process forms heterogeneous resin pillars on the surface of the sapphire wafer. The etching process uses these pillars as a mask to remove excess sapphire and create a homogeneous pattern. To balance efficiency and process control, an etching jig consisting of a tray, cover plate, and sealing ring is typically used. Multiple sapphire wafers covered with heterogeneous resin pillars are loaded into the jig and placed into the etching chamber for the etching process.

[0003] During the use of etching fixtures, friction occurs between the wafer and the tray, causing wear and tear on the tray. The etching material may exacerbate this wear, affecting the tray's lifespan and thus impacting process stability. Furthermore, since the tray is a high-value consumable, its wear also increases manufacturing costs. Additionally, there is the issue of varying etching levels at different locations on the wafer. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the present invention provides an etching tray and an etching fixture to improve the service life of the etching tray, ensure the stability of the etching process, reduce manufacturing costs, and improve etching uniformity.

[0005] In a first aspect, embodiments of the present invention provide an etching tray for carrying a wafer; the etching tray includes a support plate and a plurality of bosses located on one side of the support plate, the wafer is loaded onto the side of the bosses away from the support plate; the support plate and the bosses are fixed together by a connector, and at least some of the bosses and the support plate have a first gap between them;

[0006] The plurality of protrusions include a first protrusion and a second protrusion. In the extension direction of the plane on which the support plate is located, the distance between the first protrusion and the center of the support plate is different from that between the second protrusion and the center of the support plate. In the thickness direction of the support plate, the surface of the first protrusion facing the support plate has a first gap with the support plate, and the surface of the second protrusion facing the support plate has a second gap with the support plate. The first gap and the second gap are different.

[0007] Secondly, embodiments of the present invention provide an etching fixture, including a cover plate, a sealing ring, and an etching tray provided in any embodiment of the present invention.

[0008] In this embodiment of the invention, by designing the etching tray with a separate structure consisting of a support plate and bosses, the bosses can be repaired or replaced individually after wear occurs, without needing to replace the support plate. This extends the service life of the etching tray and reduces manufacturing costs. By differentiating the spacing between the bosses and the support plate at different locations, the etching efficiency of wafers in different areas can be adjusted, thereby improving the problem of uneven etching caused by uneven etching plasma density and enhancing the consistency of the etching degree of wafers within the same etching tray. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of an etching fixture in a related art provided by an embodiment of the present invention;

[0010] Figure 2 This is a schematic diagram of the structure of an etching tray provided in an embodiment of the present invention;

[0011] Figure 3 This is a schematic diagram of another etching tray provided in an embodiment of the present invention;

[0012] Figure 4 This is a schematic diagram of another etching tray provided in an embodiment of the present invention;

[0013] Figure 5 This is a schematic diagram of another etching tray provided in an embodiment of the present invention;

[0014] Figure 6 This is a schematic diagram of another etching tray provided in an embodiment of the present invention;

[0015] Figure 7 This is a schematic diagram of another etching tray provided in an embodiment of the present invention;

[0016] Figure 8 This is a schematic diagram of another etching tray provided in an embodiment of the present invention;

[0017] Figure 9 for Figure 3 A magnified structural diagram at point A. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0019] It should be noted that the terms "having," "comprising," and "including" used in this application have open-ended meanings. That is, when a module is described as "having," "comprising," or "including" a first element, a second element, and / or a third element, it means that the module includes other elements in addition to the first, second, and / or third elements. Furthermore, the ordinal numbers "first," "second," and "third" used in this application are not intended to specify a specific order, but only to distinguish between the various parts.

[0020] Figure 1 This is a schematic diagram of the structure of an etching fixture in a related art provided by an embodiment of the present invention, with reference to... Figure 1 In related technologies, the tray 10' comprises an integrally formed flat portion 11' and a protrusion 12', with the wafer 20' to be etched placed on the protrusion 12'. In this configuration, when the surface of the protrusion 12' is worn during wafer loading, or when the protrusion 12' is etched by etching plasma, the surface of the protrusion 12' may deform. This deformation can affect the distribution of etching energy, thus affecting the etching effect. Therefore, when the protrusion 12' is severely worn, the entire tray 10' needs to be replaced, resulting in a limited lifespan for the tray 10', increased manufacturing costs, and impact on process stability. Furthermore, the inventors have discovered that in related technologies, the etching plasma density may differ in different areas of the tray 10' during etching, leading to varying etching degrees in different areas of the wafer 20' and affecting the etching uniformity of different wafers 20' within the same tray 10'.

[0021] Based on the deficiencies of the aforementioned related technologies, the present invention proposes an etching tray for carrying wafers; the etching tray includes a support plate and a plurality of bosses located on one side of the support plate, and the wafer is loaded onto the side of the bosses away from the support plate; the support plate and the bosses are fixed together by connectors, and at least some of the bosses and the support plate have a first gap between them.

[0022] The plurality of protrusions include a first protrusion and a second protrusion. In the extension direction of the plane on which the support plate is located, the distance between the first protrusion and the center of the support plate is different from that between the second protrusion and the center of the support plate. In the thickness direction of the support plate, the surface of the first protrusion facing the support plate has a first gap with the support plate, and the surface of the second protrusion facing the support plate has a second gap with the support plate. The first gap and the second gap are different.

[0023] By designing the etching tray with a separate structure consisting of a support plate and bosses, the bosses can be repaired or replaced individually after wear occurs, without needing to replace the support plate. This extends the lifespan of the etching tray and reduces manufacturing costs. Differentiating the spacing between the bosses and the support plate at different locations allows for adjustment of the wafer etching efficiency in different areas. This improves the etching uniformity caused by uneven etching plasma density and enhances the consistency of wafer etching within the same etching tray.

[0024] The above is the core idea of ​​this invention. The technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] The etching tray provided in this embodiment of the invention is suitable for etching fixtures and can be used to carry wafers. The etching tray cooperates with components such as the cover plate in the etching fixture to fix the wafer. Figure 2 This is a schematic diagram of the structure of an etching tray provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of another etching tray provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of another etching tray provided in an embodiment of the present invention. Figure 3 and Figure 4 The diagram also shows the structure of other components in the etching fixture. (Reference) Figures 2-4 The etching tray 10 provided in this embodiment of the invention includes a support plate 11 and a plurality of protrusions 12 located on one side of the support plate 11. The wafer 20 is loaded onto the side of the protrusions 12 facing away from the support plate 11. The support plate 11 and the protrusions 12 are fixed together by a connector 13. At least some of the protrusions 12 and the support plate 11 have a first gap S1 between them. The plurality of protrusions 12 include a first protrusion 121 and a second protrusion 122. In the extension direction of the plane where the support plate 11 is located, the distance between the first protrusion 121 and the center of the support plate 11 is different from the distance between the second protrusion 122 and the center of the support plate 11. In the thickness direction Z of the support plate, the surface of the first protrusion 121 facing the support plate 11 has a first gap d1 with the support plate 11, and the surface of the second protrusion 122 facing the support plate 11 has a second gap d2 with the support plate 11. The first gap d1 and the second gap d2 are different.

[0026] like Figures 2-4As shown, unlike related technologies, in this invention, the etching tray 10 has a split structure. The support plate 11 can be a flat cylindrical shape, and multiple bosses 12 are fixed to one side of the support plate 11. The bosses 12 can be cylindrical in shape, and during the etching process, the wafer 20 is placed on the bosses 12. The support plate 11 and the bosses 12 can be made of the same material, for example, aluminum, which is used in existing trays, but are not limited to this. Aluminum has good thermal conductivity, which is beneficial to enhancing the thermal conductivity of the etching tray 10.

[0027] The boss 12 and the support plate 11 are fixed together by a connector 13. The specific arrangement of the connector 13 is not limited. For example, in some embodiments, the connector 13 may be a metal bolt, but it is not limited thereto.

[0028] By designing the etching tray 10 as a separate structure with the support plate 11 and the boss 12 independently set, the boss 12 can be repaired or replaced individually after wear occurs, without replacing the support plate 11. This extends the service life of the etching tray 10 and reduces manufacturing costs. For example, the wear cycle of the boss 12 material can be predetermined, and surface repair or replacement can be performed periodically.

[0029] Additionally, please continue to refer to Figures 2-4 In this embodiment of the invention, a first gap S1 may exist on the side of the boss 12 facing the support plate 11, that is, at least a portion of the surface of the boss 12 facing the support plate 11 does not contact the support plate 11. Figure 3 As shown, the surface of the boss 12 facing the support plate 11 is the lower surface of the boss 12, and the surface facing away from the support plate 11 is the upper surface of the boss 12. In other words, at least a portion of the lower surface of the support plate 11 does not contact the support plate 11, and a certain gap (i.e., the first gap S1) exists between them.

[0030] For example, the side of the boss 12 facing the support portion includes a support structure 120. The support structure 120 is disposed around the edge of the boss 12, and is part of the boss 12 and can be integrally formed with the boss 12. The support structure 120 protrudes from the lower surface of the boss 12, contacts the support plate 11, and forms a sealing first gap S1 around the support structure 120. Specifically, the first gap S1 is formed between the support structure 120, the lower surface of the boss 12, and the support plate 11.

[0031] In the direction extending along the plane of the support plate 11, the dimensions of the support structure 120 (which can be considered as the width of the support structure 120) can be set relatively narrow to ensure the support effect. Since the width of the support structure 120 is relatively narrow, the surface area of ​​the side of the support structure 120 that contacts the support plate 11 is relatively small. The surface of the boss 12 facing the support plate 11 mentioned in this invention mainly refers to the surface of the boss 12 where the support structure 120 is not provided.

[0032] When the boss 12 includes the support structure 120, the connector 13 can be fixed to the support structure 120 and the support plate 11 respectively. For example, bolt holes are provided at opposite positions on the support structure 120 and the support plate 11. One end of the metal bolt is fixed in the bolt hole of the support structure 120, and the other end is fixed in the bolt hole of the support plate 11. Six or more metal bolts can be used to seal and fix one boss 12 to the support plate 11. Here, "sealing" means that the first gap S1 is a sealed space.

[0033] Of course, in other embodiments, the lower surface of the boss 12 can be a plane (i.e., no support structure 120 is provided), and the connector 13 fixes the lower surface of the boss 12 to the support plate 11. In this configuration, the first gap S1 between the boss 12 and the support plate 11 is an open gap.

[0034] Further information can be found by referring to [the relevant resources]. Figures 2-4 In this embodiment of the invention, a plurality of protrusions 12 on a support plate 11 may include a first protrusion 121 and a second protrusion 122, which are located at different positions on the support plate 11. The support plate 11 is generally cylindrical, and the center of the support plate 11 can be any point on the axis of the support plate 11. The extension direction of the plane on which the support plate 11 is located can be defined as the horizontal direction X. In the horizontal direction X, the first protrusion 121 and the second protrusion 122 are at different distances from the center of the support plate 11; in other words, the first protrusion 121 and the second protrusion 122 are at different distances from the edge of the support plate 11. The horizontal direction X shown in the figure can be the radial direction of the support plate 11.

[0035] The size of the first gap S1 between the lower surface of the first boss 121 and the support plate 11 can be set, and the size of the first gap S1 between the lower surface of the second boss 122 and the support plate 11 is different. The size of the first gap S1 between the lower surface of the first boss 121 and the support plate 11 is the first spacing d1, and the size of the first gap S1 between the lower surface of the second boss 122 and the support plate 11 is the second spacing d2. The first spacing d1 and the second spacing d2 are not equal. The first spacing d1 and the second spacing d2 are in... Figure 4 The enlarged view of the local structure circled by an ellipse is marked.

[0036] It should be noted that the first protrusion 121 and the second protrusion 122 do not refer to a specific one or more protrusions 12, but rather to two types of protrusions 12 with different distances from the center of the support plate 11. For example, when the first protrusion 121 consists of n rings of protrusions 12 near the edge of the support plate 11, the second protrusion 122 can be m rings of protrusions 12 within the n rings of the first protrusions 121; when the first protrusion 121 consists of m rings of protrusions 12 near the center of the support plate 11, the second protrusion 122 can be n rings of protrusions 12 outside the m rings of the first protrusions 121; n and m are both positive integers, and the sum of m and n is the total number of rings of protrusions 12 on the support plate 11.

[0037] During the etching process of wafer 20, cooling gas is generally introduced into the etching tray 10. The first gap S1 is filled with cooling gas, which carries away the heat from wafer 20 and cools it. It is understood that the higher the heat exchange efficiency between the etching tray 10 and wafer 20, the better the cooling effect of the cooling gas on wafer 20. The temperature of wafer 20 directly affects its etching efficiency. Generally, the higher the temperature of wafer 20 during etching, the higher the etching efficiency, and vice versa. Therefore, the etching efficiency of wafer 20 can be controlled by adjusting the heat exchange efficiency between the etching tray 10 and wafer 20.

[0038] As mentioned above, the boss 12 and the support plate 11 are generally made of metal. Metal has better thermal conductivity than gas, meaning the thermal conductivity of the boss 12 and the support plate 11 is better than that of the cooling gas within the first gap S1. By adjusting the distance between the boss 12 and the support plate 11, the heat exchange efficiency between the wafer 20 and the etching tray 10 is adjusted, thereby controlling the cooling efficiency of the wafer 20 and regulating its etching efficiency. When the distance between the boss 12 and the support plate 11 is smaller, i.e., the closer they are, the higher the heat exchange efficiency between them, and the better the cooling effect of the wafer 20. Conversely, the cooling effect of the wafer 20 is worse. Furthermore, when the size of the first gap S1 decreases, the cross-sectional area of ​​the cooling gas flow path decreases, and the flow rate increases, which also improves the cooling effect.

[0039] Therefore, this invention proposes that the size of the first gap S1 between the first protrusion 121 and the second protrusion 122 and the support plate 11 can be set differently, thereby achieving differentiated settings of the heat exchange efficiency between the first protrusion 121 and the second protrusion 122 and the support plate 11. This results in different cooling efficiencies for the wafers 20 mounted on the first protrusion 121 and the second protrusion 122, thereby controlling the etching efficiency of the wafers 20 at different positions. This compensates for the problem of uneven etching caused by uneven etching plasma density and improves the consistency of the etching degree of the wafers 20 within the same etching tray 10.

[0040] In this embodiment of the invention, the positions of the first protrusion 121 and the second protrusion 122, as well as the specific corresponding schemes of the first spacing d1 and the second spacing d2, are not limited. Those skilled in the art can design according to the actual etching conditions. For example, during the etching process, if the plasma density at the center of the support plate 11 is higher than the plasma density at the edge of the support plate 11, the spacing between the protrusions 12 near the center of the support plate 11 and the support plate 11 can be set to be smaller than the spacing between the protrusions 12 near the edge of the support plate 11 and the support plate 11. This results in higher heat exchange efficiency between the protrusions 12 near the center of the support plate 11 and the wafer 20, and a higher cooling effect for the central wafer 202 than for the edge wafer 201, thereby appropriately reducing the etching efficiency of the central wafer 202 and increasing the etching efficiency of the edge wafer 201. This balances the problem of accelerated etching of the central wafer 202 caused by higher plasma density. Conversely, if the plasma density at the center of the support plate 11 is lower than the plasma density at the edge of the support plate 11, the spacing between the part of the protrusion 12 near the center of the support plate 11 and the support plate 11 can be set to be greater than the spacing between the part of the protrusion 12 near the edge of the support plate 11 and the support plate 11, thereby appropriately improving the etching efficiency of the central wafer 202 and reducing the etching efficiency of the edge wafer 201.

[0041] Optionally, the size of the first spacing d1 and the second spacing d2 can be adjusted by setting different thicknesses for the first boss 121 and the second boss 122. For example... Figure 3 As shown, assuming that the first distance d1 between the first boss 121 and the support plate 11 needs to be set to be greater than the second distance d2 between the second boss 122 and the support plate 11, then the thickness of the first boss 121 can be set to be greater than the thickness of the second boss 122.

[0042] The etching tray provided in this invention includes a support plate and multiple bosses located on one side of the support plate. A wafer is loaded onto the side of the bosses facing away from the support plate. The support plate and the bosses are fixed together by connectors, and at least some of the bosses have a first gap with the support plate. By designing the etching tray as a separate structure with the support plate and bosses independently configured, the bosses can be repaired or replaced individually after wear occurs, without replacing the support plate, thereby improving the service life of the etching tray and reducing manufacturing costs. The multiple bosses include a first boss and a second boss. In the extension direction of the plane where the support plate is located, the distance between the first boss and the center of the support plate is different from the distance between the second boss and the center of the support plate. In the thickness direction of the support plate, the surface of the first boss facing the support plate has a first gap with the support plate, and the surface of the second boss facing the support plate has a second gap with the support plate. The first gap and the second gap are different. By differentiating the gaps between the bosses at different positions and the support plate, the etching efficiency of the wafers in different areas can be adjusted, thereby improving the problem of uneven etching caused by uneven etching plasma density and improving the consistency of the etching degree of the wafers within the same etching tray.

[0043] Optional, you can continue to refer to Figures 2-4 In the extension direction of the plane where the support plate 11 is located, the distance between the first boss 121 and the center of the support plate 11 is greater than the distance between the second boss 122 and the center of the support plate 11; the first spacing d1 is greater than the second spacing d2.

[0044] like Figures 2-4 As shown, in this embodiment, the first boss 121 is close to the edge of the support plate 11, and the second boss 122 is close to the center of the support plate 11. That is, the first boss 121 can refer to the n-ring bosses 12 on the outer ring, and the second boss 122 can refer to the m-ring bosses 12 on the inner ring. Figure 4 The first boss 121 and the second boss 122 shown can correspond to each other. Figure 2 The two protrusions marked are the first protrusion 121 and the second protrusion 122. Figure 4 The side of the first boss 121 away from the second boss 122 is close to the edge of the support plate 11, and the side of the second boss 122 away from the first boss 121 is close to the center of the support plate 11.

[0045] It should be noted that, Figure 2 The attached drawing only exemplarily shows a first boss 121 near the edge and a second boss 122 inside the first boss 121 (located at the center of the support plate 11). This drawing does not represent the actual arrangement of the bosses 12. In actual production applications, the support plate 11 is provided with multiple rings of bosses 12, and any two rings of bosses 12 at different distances from the center of the support plate 11 can be the first boss 121 and the second boss 122.

[0046] The inventors discovered that, generally, within the etching chamber, the plasma density in the central region of the etching tray 10 is greater than that in the edge region. Considering only the influence of the etching gas, the etching efficiency of the central wafer 202 is higher than that of the edge wafer 201, resulting in a lower pattern height for the central wafer 202 on the tray in the prior art. Based on this, in this embodiment, the size of the first gap S1 between the first protrusion 121 and the support plate 11 can be set to be larger than the size of the second gap S2 between the second protrusion 122 and the support plate 11. This makes the second protrusion 122, which is closer to the center of the support plate 11, more closely aligned with the support plate 11. The wafer 20 above the second protrusion 122 experiences better cooling, relatively reducing the temperature of the central wafer 202. This appropriately lowers the etching efficiency of the central wafer 202, compensating for the high etching efficiency caused by uneven distribution of the etching gas. This makes the etching efficiencies of the central wafer 202 and the edge wafer 201 more consistent, improving the problem of the low pattern height of the central wafer 202.

[0047] Optional, Figure 5 This is a schematic diagram of another etching tray provided in an embodiment of the present invention. Figure 5 The cross-sectional structure of the etching tray is shown below for reference. Figure 5 In a possible embodiment, the boss 12 may include a main body 123 and a hardening layer 124 stacked along the thickness direction Z of the support plate, with the hardening layer 124 located on the side of the main body 123 away from the support plate 11.

[0048] refer to Figure 5 In this embodiment, during the manufacturing of the boss 12, the surface of the boss 12 facing the wafer 20 can be hardened to form a hardened layer 124. The presence of the hardened layer 124 can improve the wear resistance of the upper surface of the boss 12, increase the service life of the boss 12, and reduce process fluctuations caused by wear of the boss 12.

[0049] The specific hardening process is not limited; any hardening process is acceptable, such as anodizing, silicon carbide coating, or sandblasting, but is not limited to these.

[0050] Further optional, Figure 6 This is a schematic diagram of another etching tray provided in an embodiment of the present invention, which can be referred to. Figure 6 In some embodiments, the first boss 121 includes a first hardened layer 1241, and the second boss 122 includes a second hardened layer 1242; the first hardened layer 1241 and the second hardened layer 1242 have different thicknesses.

[0051] It is understandable that the thermal conductivity of the hardened layer 124 differs from that of the main body 123 after the hardening process. Under the same helium pressure, different thicknesses of the hardened layer 124 may also affect the thermal conductivity of the boss 12, thereby affecting the cooling efficiency of the wafer 20. Based on this, this embodiment further proposes a scheme to differentiate the thickness of the hardened layer 124 of the bosses 12 at different positions on the support plate 11. For example... Figure 6 As shown, the hardening layer 124 on the main body 123 of the first protrusion 121 is the first hardening layer 1241, and the hardening layer 124 on the main body 123 of the second protrusion 122 is the second hardening layer 1242. The first hardening layer 1241 and the second hardening layer 1242 have different thicknesses. This results in different thermal conductivity efficiencies for the first protrusion 121 and the second protrusion 122, which also allows for the control of the etching efficiency of the wafer 20 above the first protrusion 121 and the second protrusion 122.

[0052] Further information can be found by referring to [the relevant resources]. Figure 6 , Figure 6 The relative positional relationship between the first boss 121 and the second boss 122 shown is as follows: Figure 4 As shown, the side of the first boss 121 furthest from the second boss 122 is closer to the edge of the support plate 11, and the side of the second boss 122 furthest from the first boss 121 is closer to the center of the support plate 11. In the extending direction of the plane containing the support plate 11, the distance between the first boss 121 and the center of the support plate 11 is greater than the distance between the second boss 122 and the center of the support plate 11; the thermal conductivity of the hardened layer 124 material is less than the thermal conductivity of the main body 123 material, and the thickness of the first hardened layer 1241 is greater than the thickness of the second hardened layer 1242.

[0053] For current hardening processes such as anodizing, silicon carbide coating, or sandblasting, the thermal conductivity of the hardened layer 124 is lower than that of the metal body 123. A thicker hardened layer 124 may result in a lower overall thermal conductivity of the boss 12. Considering that the plasma density in the middle region of the etching tray 10 is greater than that in the edge region, the etching efficiency of the central wafer 202 is higher than that of the edge wafer 201. In this embodiment, the thickness of the first hardened layer 1241 can be set to be greater than the thickness of the second hardened layer 1242, making the thermal conductivity of the first boss 121 lower than that of the second boss 122. This further improves the cooling effect of the wafer 20 (i.e., the central wafer 202) on the second boss 122, compensates for the uneven etching caused by uneven etching plasma density, and further improves the problem of the low pattern height of the central wafer 202.

[0054] Optionally, the surface of the support plate 11 facing the boss 12 is not hardened but structurally designed to facilitate a sealing relationship with the boss 12.

[0055] Optional, Figure 7 This is a schematic diagram of another etching tray provided in an embodiment of the present invention. Figure 8 This is a schematic diagram of another etching tray provided in an embodiment of the present invention, which can be referred to in conjunction with reference to... Figure 7 and Figure 8 The boss 12 includes a first surface 125 and a second surface 126 disposed opposite to each other along the thickness direction Z of the support plate. The second surface 126 is located between the first surface 125 and the support plate 11. The first surface 125 is the upper surface of the boss 12 described above, and the second surface 126 is the lower surface of the boss 12. The first surface 125 includes a first position P1 and a second position P2, and the thickness of the boss 12 at the first position P1 is different from the thickness at the second position P2; and / or, the second surface 126 includes a third position P3 and a fourth position P4, and the thickness of the boss 12 at the third position P3 is different from the thickness at the fourth position P4.

[0056] After the wafer 20 is loaded onto the etching tray 10, it is fixed with a cover plate 30, typically by using the clamping claws (not shown in the figure) of the cover plate 30 to press the edge of the wafer 20. The inventors discovered that in this configuration, the presence of the clamping claws may affect the potential distribution in different areas of the wafer 20, leading to differences in etching energy at different locations on the same wafer 20. This, in turn, results in different pattern heights in different areas of the same wafer 20, affecting the uniformity of pattern height on the wafer 20. Based on this, this embodiment proposes that the first surface 125 and / or the second surface 126 of the boss 12 can be shaped to adjust the potential distribution and improve the uniformity of pattern height on the same wafer 20.

[0057] exist Figure 7 In the illustrated embodiment, the first surface 125 of the protrusion 12 can be shaped. After the wafer 20 is mounted on one side of the first surface 125 of the protrusion 12, when the thickness of the protrusion 12 at the first position P1 and the second position P2 is different, the distance between the protrusion 12 and the wafer 20 at these two positions is different. The protrusion 12 is generally made of metal, and the wafer 20 is made of semiconductor silicon. A capacitor may be formed between the protrusion 12 and the wafer 20. The protrusion 12 and the wafer 20 respectively serve as the two plates of the capacitor, and the presence of the capacitor may change the distribution of the electric field near the wafer 20. According to the capacitance calculation formula, the capacitance value of the capacitor is inversely proportional to the distance between the two plates. When the distance between the protrusion 12 and the wafer 20 at the first position P1 and the second position P2 is different, the capacitance formed by the protrusion 12 and the wafer 20 at the first position P1 is different in size from the capacitance formed at the second position P2. Thus, the potential at different positions of the wafer 20 can be adjusted by utilizing the capacitance formed by the protrusion 12 and the wafer 20, ensuring a uniform distribution of etching energy. For example, Figure 7Taking the thickness of the boss 12 at the first position P1 as greater than the thickness at the second position P2 as an example, the distance between the first position P1 and the wafer 20 is less than the distance between the second position P2 and the wafer 20. The capacitance formed by the boss 12 and the wafer 20 at the first position P1 is greater than the capacitance formed at the second position P2, thereby reducing the potential of the area of ​​the wafer 20 close to the first position P1.

[0058] exist Figure 8 In the illustrated embodiment, the shape of the second surface 126 of the protrusion 12 can be designed so that when the thickness of the protrusion 12 at the third position P3 and the fourth position P4 is different, the distance between the protrusion 12 and the support plate 11 at these two positions is different. Both the protrusion 12 and the support plate 11 are made of metal, and a capacitor may be formed between them. The protrusion 12 and the support plate 11 respectively act as the two plates of the capacitor, and the presence of this capacitor can also change the distribution of the electric field near the wafer 20. When the distance between the protrusion 12 and the support plate 11 at the third position P3 and the fourth position P4 is different, the capacitance formed by the protrusion 12 and the support plate 11 at the third position P3 is different in size from the capacitance formed at the fourth position P4. Thus, the capacitance formed by the protrusion 12 and the support plate 11 is used to adjust the potential at different positions of the wafer 20, ensuring a uniform distribution of etching energy. For example, Figure 8 Taking the thickness of the boss 12 at the third position P3 as greater than that at the fourth position P4 as an example, the distance between the third position P3 and the support plate 11 is less than the distance between the fourth position P4 and the support plate 11. The capacitance formed by the boss 12 and the support plate 11 at the third position P3 is greater than the capacitance formed at the fourth position P4, thereby reducing the potential of the area of ​​the wafer 20 close to the third position P3.

[0059] In embodiments not shown in this invention, the above can be performed simultaneously. Figure 7 and Figure 8 The first surface 125 and the second surface 126 of the boss 12 are shown to be shaped, and the embodiments of the present invention will not be described in detail.

[0060] In this embodiment of the invention, the specific positions of the first position P1 and the second position P2 on the first surface 125, and the specific positions of the third position P3 and the fourth position P4 on the second surface 126 are not limited. Those skilled in the art can design based on the actual potential distribution near the wafer 20.

[0061] For example, in some embodiments, reference continues to be made to... Figure 7 and Figure 8When the first surface 125 includes the first position P1 and the second position P2, the first surface 125 is an arc-shaped protrusion, and the second surface 126 is a plane; when the second surface 126 includes the third position P3 and the fourth position P4, the second surface 126 is an arc-shaped protrusion, and the first surface 125 is a plane.

[0062] The inventors discovered that the presence of the grippers causes a lower potential at the edge of the wafer 20 and a higher potential in the middle region. As a result, energy is transferred to the edge of the wafer 20, leading to higher etching energy and a faster etching rate at the edge. Based on this, this embodiment proposes that, as... Figure 7 As shown, only the shape of the first surface 125 of the boss 12 can be designed. The first position P1 can refer to the middle area of ​​the first surface 125, and the second position P2 can refer to the edge area of ​​the first surface 125. The first surface 125 can be designed as an arc shape that arches away from the support plate 11, so that the thickness of the boss 12 at the first position P1 is greater than the thickness of the boss 12 at the second position P2. The capacitance formed between the boss 12 and the wafer 20 at the first position P1 is greater than the capacitance formed at the second position P2, thereby reducing the potential in the middle area of ​​the wafer 20, transferring energy to the middle of the wafer 20, relatively increasing the etching rate in the middle of the wafer 20, and making the etching energy evenly distributed in the middle and edge areas of the wafer 20, thus improving etching uniformity. In this configuration, the second surface 126 of the boss 12 can be a plane.

[0063] Correspondingly, such as Figure 8 As shown, only the shape of the second surface 126 of the boss 12 can be designed. The third position P3 can refer to the middle region of the second surface 126, and the fourth position P4 can refer to the edge region of the second surface 126. The second surface 126 can be designed as an arc shape that arches away from the wafer 20, so that the thickness of the boss 12 at the third position P3 is greater than the thickness of the boss 12 at the fourth position P4. The capacitance formed by the boss 12 and the support plate 11 at the third position P3 is greater than the capacitance formed at the fourth position P4, thereby reducing the potential in the middle region of the wafer 20, transferring energy to the middle of the wafer 20, relatively increasing the etching rate in the middle of the wafer 20, and making the etching energy evenly distributed in the middle and edge regions of the wafer 20, thus improving etching uniformity. In this configuration, the first surface 125 of the boss 12 can be a plane.

[0064] Alternatively, when the second surface 126 includes a third position P3 and a fourth position P4, the boss 12 is electrically isolated from the support plate 11. Electrical isolation between the boss 12 and the support plate 11 ensures the formation of a capacitor between them.

[0065] For example, the connector 13 can be made of insulating material, and / or the contact surface between the boss 12 and the support plate 11 can be insulated to ensure electrical isolation between the boss 12 and the support plate 11.

[0066] The shape design schemes of the first surface 125 and / or the second surface 126 can be applied to the first boss 121 and the second boss 122.

[0067] Optional, Figure 9 for Figure 3 For a magnified structural diagram at point A, please refer to... Figure 3 and Figure 9 In a possible embodiment, the etching tray 10 and the cover plate 30 cooperate to fix the wafer 20. The cover plate 30 and the boss 12 are located on the same side of the support plate 11. The cover plate 30 includes an opening 31 corresponding to the boss 12. The edge of the opening 31 includes a clamping claw (not shown in the figure) for clamping the edge of the wafer 20. After the wafer 20 is loaded onto the etching tray 10, there is a second gap S2 between the sidewall of the opening 31 and the wafer 20. The side of the boss 12 away from the support plate 11 includes a sealing groove 127 for placing a sealing ring 40. After the wafer 20 is loaded onto the etching tray 10, the sealing groove 127 covers the second gap S2 in the thickness direction Z of the support plate.

[0068] The structure of the cover plate 30 can be any existing solution, and the embodiments of the present invention do not limit it. The cover plate 30 may include a plurality of openings 31. The distribution of the openings 31 on the cover plate 30 is the same as the distribution of the bosses 12 on the support plate 11, and the shape of the openings 31 is the same as the shape of the bosses 12, and the size may be slightly larger than the size of the bosses 12. The openings 31 correspond to the bosses 12.

[0069] Among them, such as Figure 3 and Figure 9 As shown, the diameter of the wafer 20 can be smaller than the diameter of the boss 12, such that the opening 31 covers the wafer 20 along the thickness direction Z of the support plate. After the wafer 20 is fixed, a second gap S2 exists between the edge of the opening 31 and the wafer 20 in the horizontal direction X. Multiple pressure claws are provided on the edge of the opening 31, and these claws can be evenly distributed along the edge of the opening 31. The pressure claws extend from the edge of the opening 31 towards the center of the opening 31. When fixing the wafer 20, the pressure claws extend above the edge of the wafer 20 to press the wafer 20 firmly.

[0070] like Figure 3 and Figure 9 As shown, a sealing groove 127 is provided on the side surface of the boss 12 facing the wafer 20 (i.e., the first surface). The sealing groove 127 extends from the first surface to the second surface to a certain depth. The sealing groove 127 is located near the edge of the boss 12 and is used to place the sealing ring 40. The sealing ring 40 seals the gap between the wafer 20 and the boss 12, ensuring the sealing effect of the cooling gas.

[0071] Continue to refer to Figure 3 and Figure 9The width of the sealing groove 127 in the horizontal direction X (the direction opposite to the sidewall of the wafer 20 and the sidewall of the opening 31) can be greater than the width of the opening 31 in that direction. Furthermore, the orthographic projection of the sealing groove 127 onto the plane of the support plate 11 covers the orthographic projection of the second gap S2 onto the plane of the support plate 11. The sealing groove 127 is generally tightly filled. In this configuration, the lower side of the sealing ring 40 contacts the interior of the sealing groove 127, and the upper side of the sealing ring 40 contacts the cover plate 30 and the wafer 20. The orthographic projection of the sealing ring 40 onto the plane of the support plate 11 also covers the orthographic projection of the second gap S2 onto the plane of the support plate 11. During etching of the wafer 20, the sealing ring 40 can block the etching plasma entering the opening 31, preventing the outer side of the sealing groove 127 from being etched, further improving the service life of the boss 12.

[0072] For example, such as Figure 9 As shown, the sealing ring 40 can be designed as an X-shaped sealing ring 40 with pressure on both sides, ensuring that the wafer 20 and the cover plate 30 press the upper side of the sealing ring 40, and the boss 12 presses the lower side of the sealing ring 40 and at least part of the sidewall.

[0073] Alternatively, a plasma-resistant material can be used to prepare the sealing ring 40, such as fluorinated rubber, thereby improving the corrosion resistance of the sealing ring 40.

[0074] Based on the same concept, embodiments of the present invention also provide an etching fixture, which includes a cover plate, a sealing ring, and an etching tray provided in any embodiment of the present invention. The specific structure of the etching fixture can be referred to the description of the embodiments above. The etching fixture provided in the embodiments of the present invention possesses the corresponding beneficial effects of the etching tray provided in the embodiments of the present invention, which will not be elaborated further here.

[0075] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An etching tray, characterized in that, Used to carry wafers; the etching tray includes a support plate and a plurality of protrusions located on one side of the support plate, the wafer is loaded onto the side of the protrusions opposite to the support plate; the support plate and the protrusions are fixed together by connectors, and at least a portion of the protrusions and the support plate have a first gap between them; The plurality of protrusions include a first protrusion and a second protrusion. In the extension direction of the plane where the support plate is located, the distance between the first protrusion and the center of the support plate and the distance between the second protrusion and the center of the support plate are different. In the thickness direction of the support plate, the side surface of the first protrusion facing the support plate has a first gap with the support plate, and the side surface of the second protrusion facing the support plate has a second gap with the support plate. The first gap and the second gap are different. The boss includes a first surface and a second surface that are disposed opposite to each other along the thickness direction of the support plate, and the second surface is located between the first surface and the support plate. The first surface includes a first position and a second position, wherein the thickness of the boss at the first position is different from the thickness at the second position; And / or, The second surface includes a third position and a fourth position, wherein the thickness of the boss at the third position is different from the thickness at the fourth position; The potential at different positions on the wafer is adjusted by utilizing the capacitance formed by the protrusion and the wafer to ensure uniform distribution of etching energy.

2. The etching tray according to claim 1, characterized in that, In the extending direction of the plane where the support plate is located, the distance between the first boss and the center of the support plate is greater than the distance between the second boss and the center of the support plate; The first spacing is greater than the second spacing.

3. The etching tray according to claim 1, characterized in that, The boss includes a main body and a hardening layer stacked along the thickness direction of the support plate, wherein the hardening layer is located on the side of the main body opposite to the support plate.

4. The etching tray according to claim 3, characterized in that, The first boss includes a first hardened layer, and the second boss includes a second hardened layer; the first hardened layer and the second hardened layer have different thicknesses.

5. The etching tray according to claim 4, characterized in that, In the extending direction of the plane where the support plate is located, the distance between the first boss and the center of the support plate is greater than the distance between the second boss and the center of the support plate; The thermal conductivity of the hardened layer material is less than that of the main body material, and the thickness of the first hardened layer is greater than that of the second hardened layer.

6. The etching tray according to claim 1, characterized in that, When the first surface includes the first position and the second position, the first surface is an arc-shaped protrusion, and the second surface is a plane; When the second surface includes the third position and the fourth position, the second surface is an arc-shaped protrusion, and the first surface is a plane.

7. The etching tray according to claim 1, characterized in that, When the second surface includes the third position and the fourth position, the boss is electrically isolated from the support plate.

8. The etching tray according to claim 1, characterized in that, The etching tray and the cover plate cooperate to fix the wafer. The cover plate and the boss are located on the same side of the support plate. The cover plate includes an opening, which corresponds to the boss. The edge of the opening includes a pressure claw, which is used to press the edge of the wafer. After the wafer is loaded onto the etching tray, there is a second gap between the sidewall of the opening and the wafer. The side of the boss away from the support plate includes a sealing groove for placing a sealing ring. After the wafer is loaded onto the etching tray, the sealing groove covers the second gap in the thickness direction of the support plate.

9. An etching fixture, characterized in that, Includes a cover plate, a sealing ring, and an etched tray as described in any one of claims 1-8.

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