Etching tray and etching clamp

Abstract

The invention discloses an etching tray and an etching clamp. The etching tray comprises a supporting plate and a plurality of bosses located on one side of the supporting plate, and the wafers are loaded to the sides, away from the supporting plate, of the bosses; the supporting plate and the boss are fixed through a connecting piece, and a first gap exists between at least part of the boss and the supporting plate. The plurality of bosses comprise a first boss and a second boss, and in the extension direction of the plane where the supporting plate is located, the distance between the first boss and the center of the supporting plate is different from the distance between the second boss and the center of the supporting plate; in the thickness direction of the supporting plate, a first interval is formed between the surface of the side, facing the supporting plate, of the first boss and the supporting plate, a second interval is formed between the surface of the side, facing the supporting plate, of the second boss and the supporting plate, and the first interval is different from the second interval. According to the scheme, the service life of the etching tray can be prolonged, the stability of the etching process is ensured, and the manufacturing cost is reduced; in addition, the etching efficiency of wafers in different areas can be adjusted, and the etching consistency is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of semiconductor processing technology, and in particular to an etching tray and an etching fixture. Background Art

[0002] The manufacturing of patterned sapphire substrate (PSS) consists of two pattern transfers. The yellow light process forms heterogeneous glue columns on the surface of the sapphire flat sheet, and the etching process uses the heterogeneous glue columns as a mask to remove the excess sapphire and form a homogeneous pattern. In the etching process, in order to balance efficiency and process, an etching fixture composed of a tray, a cover plate and a sealing ring is generally used. Multiple sapphire wafers covered with heterogeneous glue columns are loaded in the middle and sent to the etching process chamber for operation.

[0003] During the use of the etching fixture, friction occurs between the wafer and the tray, resulting in the loss of the tray. The etching material may increase the loss of the tray, affecting the service life of the tray and thus the stability of the process. In addition, since the tray is a high-value consumable, the loss of the tray will also increase the manufacturing cost. At the same time, there is also the problem of different etching degrees of wafers at different positions. Summary of the invention

[0004] Based on the above-mentioned defects of the prior art, the present invention provides an etching tray and an etching fixture to increase the service life of the etching tray, ensure the stability of the etching process, reduce the manufacturing cost, and improve the etching uniformity.

[0005] In a first aspect, an embodiment of the present invention provides an etching tray for carrying a wafer; the etching tray comprises a support plate and a plurality of bosses located on one side of the support plate, and the wafer is loaded on a side of the boss away from the support plate; the support plate and the bosses are fixed by a connecting member, and a first gap exists between at least some of the bosses and the support plate;

[0006] 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, a first spacing is provided between a side surface of the first boss facing the support plate and the support plate, and a second spacing is provided between a side surface of the second boss facing the support plate and the support plate, and the first spacing and the second spacing are different.

[0007] In a second aspect, an embodiment of the present invention provides an etching fixture, including a cover plate, a sealing ring, and an etching tray provided by any embodiment of the present invention.

[0008] In the embodiment of the present invention, the etching tray is designed to have a split structure in which the support plate and the boss are independently arranged. When the boss is worn, the boss can be repaired or replaced alone without replacing the support plate, thereby increasing the service life of the etching tray and reducing the manufacturing cost. By differentiating the distance between the boss and the support plate at different positions, the etching efficiency of the wafer in different areas can be adjusted, thereby improving the problem of uneven etching caused by uneven etching plasma density and improving the consistency of etching degree of the wafers in the same etching tray. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0010] Figure 2 A schematic diagram of the structure of an etching tray provided by an embodiment of the present invention;

[0011] Figure 3 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention;

[0012] Figure 4 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention;

[0013] Figure 5 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention;

[0014] Figure 6 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention;

[0015] Figure 7 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention;

[0016] Figure 8 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention;

[0017] Fig. 9 for Figure 3 Schematic diagram of the enlarged structure at A. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0019] It should be noted that the words “having”, “including”, “comprising”, etc. described in this application are all open-ended meanings, that is, when describing that a module “has”, “including”, or “comprising” a first element, a second element, and / or a third element, it means that the module includes other elements in addition to the first element, the second element, and / or the third element. In addition, ordinal numbers such as “first”, “second”, and “third” in this application are not intended to limit a specific order, but are only used to distinguish various parts.

[0020] Figure 1 A schematic diagram of the structure of an etching fixture in a related art provided by an embodiment of the present invention, referring to Figure 1 In the related art, the tray 10' includes an integrally arranged flat plate portion 11' and a raised portion 12', and the wafer 20' to be etched is placed on the raised portion 12'. Under this arrangement, when the surface of the raised portion 12' is worn during wafer loading and the etching plasma etches the raised portion 12', the surface of the raised portion 12' will be deformed, and the deformation of the surface of the raised portion 12' may affect the distribution of etching energy, thereby affecting the etching effect. Therefore, when the raised portion 12' is severely worn, the entire tray 10' needs to be replaced, resulting in a limited service life of the tray 10', increased manufacturing costs, and affected process stability. In addition, the inventors also found that in the related art, during the etching process, the etching plasma density in different areas of the tray 10' may be different, thereby resulting in different etching degrees of the wafers 20' to be etched in different areas, affecting the etching uniformity of different wafers 20' to be etched in the same tray 10'.

[0021] Based on the defects of the above-mentioned related technologies, the present invention proposes an etching tray for carrying a wafer; the etching tray comprises a support plate and a plurality of bosses located on one side of the support plate, and the wafer is loaded on the side of the boss away from the support plate; the support plate and the boss are fixed by a connecting member, and a first gap exists between at least part of the bosses and the support plate;

[0022] 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, a first spacing is provided between a side surface of the first boss facing the support plate and the support plate, and a second spacing is provided between a side surface of the second boss facing the support plate and the support plate, and the first spacing and the second spacing are different.

[0023] By designing the etching tray as a split structure with independent support plates and bosses, when the bosses are worn, the bosses can be repaired or replaced separately without replacing the support plates, thereby increasing the service life of the etching tray and reducing manufacturing costs. By differentiating the distance between the bosses and the support plates at different positions, 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 etching levels of the wafers in the same etching tray.

[0024] The above is the core idea of ​​the present invention. The technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The etching tray provided in the embodiment of the present invention is suitable for an etching fixture and can be used to carry a wafer. The etching tray cooperates with components such as a cover plate in the etching fixture to fix the wafer. Figure 2 A schematic diagram of the structure of an etching tray provided in an embodiment of the present invention, Figure 3 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention, Figure 4 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention, Figure 3 and Figure 4 Other components of the etching fixture are also shown. Figure 2-Figure 4 The etching tray 10 provided in the embodiment of the present invention includes a support plate 11 and a plurality of bosses 12 located on one side of the support plate 11, and the wafer 20 is loaded to the side of the boss 12 away from the support plate 11; the support plate 11 and the boss 12 are fixed by a connecting member 13, and a first gap S1 exists between at least some of the bosses 12 and the support plate 11; the plurality of bosses 12 include a first boss 121 and a second boss 122, and 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 different from the distance between the second boss 122 and the center of the support plate 11; in the thickness direction Z of the support plate, a first spacing d1 is provided between the side surface of the first boss 121 facing the support plate 11 and the support plate 11, and a second spacing d2 is provided between the side surface of the second boss 122 facing the support plate 11 and the support plate 11, and the first spacing d1 and the second spacing d2 are different.

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

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

[0028] By designing the etching tray 10 as a separate structure in which the support plate 11 and the boss 12 are independently arranged, after the boss 12 is worn, the boss 12 can be repaired or replaced alone without replacing the support plate 11, thereby increasing the service life of the etching tray 10 and reducing the manufacturing cost. For example, the wear cycle of the material of the boss 12 can be predetermined, and the surface can be repaired or replaced regularly.

[0029] In addition, continue to refer to Figure 2-Figure 4 In the embodiment of the present 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 In the illustrated position, the side surface of the boss 12 facing the support plate 11 is the lower surface of the boss 12, and the side surface away from the support plate 11 is the upper surface of the boss 12. In other words, at least part of the lower surface of the support plate 11 is not in contact with the support plate 11, and there is a certain gap (i.e., the first gap S1) between the two.

[0030] Exemplarily, the side of the boss 12 facing the support portion includes a support structure 120, which is arranged around the edge of the boss 12. The support structure 120 is a part of the boss 12 and can be integrally arranged with the boss 12. The support structure 120 is a structure protruding from the lower surface of the boss 12, and the support structure 120 is in contact with the support plate 11. The support structure 120 surrounds and forms a sealed first gap S1. In other words, 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 extension direction of the plane where the support plate 11 is located, the size of the support structure 120 (which can be regarded as the width of the support structure 120) can be set to be relatively narrow, as long as the support effect is guaranteed. Since the width of the support structure 120 is relatively narrow, the surface area of ​​the side where the support structure 120 contacts the support plate 11 is relatively small, and the side surface of the boss 12 facing the support plate 11 mentioned in the present invention mainly refers to the surface of the boss 12 where the support structure 120 is not set.

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

[0033] Of course, in other embodiments, the lower surface of the boss 12 may be a plane (ie, the support structure 120 is not provided), and the connecting member 13 fixes the lower surface of the boss 12 to the support plate 11. In this setting, the first gap S1 between the boss 12 and the support plate 11 is an open gap.

[0034] For further information, please refer to Figure 2-Figure 4 In the embodiment of the present invention, the plurality of bosses 12 on a support plate 11 may include a first boss 121 and a second boss 122, and the first boss 121 and the second boss 122 are located at different positions of the support plate 11. The support plate 11 is cylindrical as a whole, and the center of the support plate 11 may be any point on the axis of the support plate 11. The extension direction of the plane where the support plate 11 is located may be defined as a horizontal direction X. In the horizontal direction X, the first boss 121 and the second boss 122 are at different distances from the center of the support plate 11. In other words, the first boss 121 and the second boss 122 are at different distances from the edge of the support plate 11. The horizontal direction X shown in the figure may 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 to be different from the size of the first gap S1 between the lower surface of the second boss 122 and the support plate 11. 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 different in size. The first spacing d1 and the second spacing d2 are Figure 4 The local enlarged structure diagram enclosed by an ellipse is marked.

[0036] It should be noted that the first boss 121 and the second boss 122 do not refer to one or more specific bosses 12, but refer to two types of bosses 12 at different distances from the center of the support plate 11. Exemplarily, when the first boss 121 is an n-circle boss 12 close to the edge of the support plate 11, the second boss 122 may be an m-circle boss 12 inside the n-circle first boss 121; when the first boss 121 is an m-circle boss 12 close to the center of the support plate 11, the second boss 122 may be an n-circle boss 12 outside the m-circle first boss 121; n and m are both positive integers, and the sum of m and n is the total number of circles of bosses 12 on the support plate 11.

[0037] During the etching process of the wafer 20, it is generally necessary to introduce cooling gas into the etching tray 10, fill the first gap S1 with cooling gas, and use the cooling gas to take away the heat of the wafer 20 to cool the wafer 20. It can be understood that when the heat exchange efficiency between the etching tray 10 and the wafer 20 is higher, the cooling effect of the cooling gas on the wafer 20 is better. The temperature of the wafer 20 directly affects the etching efficiency of the wafer 20. Generally, the higher the temperature of the wafer 20 during the etching process, the higher the etching efficiency, and vice versa. Therefore, the etching efficiency of the wafer 20 can be regulated by adjusting the heat exchange efficiency between the etching tray 10 and the wafer 20.

[0038] As mentioned above, the boss 12 and the support plate 11 are generally made of metal, and the thermal conductivity of metal is better than that of gas, that is, the thermal conductivity efficiency of the boss 12 and the support plate 11 is better than the thermal conductivity efficiency of the cooling gas in the first gap S1. By adjusting the distance between the boss 12 and the support plate 11, the heat exchange efficiency between the chip 20 and the etching tray 10 is adjusted, and then the cooling efficiency of the chip 20 is regulated, and the etching efficiency of the chip 20 is adjusted. When the distance between the boss 12 and the support plate 11 is small, that is, the closer the distance between the two, the higher the heat exchange efficiency between the two, the better the cooling effect of the chip 20, and vice versa. The worse the cooling effect of the chip 20. In addition, when the size of the first gap S1 is reduced, the cross-sectional area of ​​the flow path of the cooling gas is smaller, and the flow rate increases, which can also improve the cooling effect.

[0039] Therefore, the present invention proposes that the size of the first gap S1 between the first boss 121 and the second boss 122 and the support plate 11 can be set differently, so as to achieve the differentiated setting of the cold and heat exchange efficiency between the first boss 121 and the second boss 122 and the support plate 11, so that the cooling efficiency of the wafer 20 loaded on the first boss 121 and the second boss 122 is different, and then the etching efficiency of the wafer 20 at different positions is regulated. Compensate for the uneven etching problem caused by the uneven density of the etching plasma, and improve the consistency of the etching degree of the wafer 20 in the same etching tray 10.

[0040] Among them, the embodiment of the present invention does not limit the position of the first boss 121 and the second boss 122, and the specific corresponding scheme of the first spacing d1 and the second spacing d2. Those skilled in the art can design it according to the actual etching situation. Exemplarily, 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 partial boss 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 partial boss 12 near the edge of the support plate 11 and the support plate 11. The heat exchange efficiency between the partial boss 12 near the center of the support plate 11 and the wafer 20 is high, and the cooling effect of the center wafer 202 is higher than the cooling effect of the edge wafer 201, thereby appropriately reducing the etching efficiency of the center wafer 202 and improving the etching efficiency of the edge wafer 201. This balances the problem of accelerated etching of the center wafer 202 caused by the high plasma density. On the contrary, 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 distance between the partial boss 12 near the center of the support plate 11 and the support plate 11 can be set to be larger than the distance between the partial boss 12 near the edge of the support plate 11 and the support plate 11, thereby appropriately improving the etching efficiency of the center chip 202 and reducing the etching efficiency of the edge chip 201.

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

[0042] The etching tray provided by the embodiment of the present invention comprises a support plate and a plurality of bosses located on one side of the support plate, and the wafer is loaded to the side of the boss away from the support plate; the support plate and the boss are fixed by a connecting member, and there is a first gap between at least part of the boss and the support plate. By designing the etching tray as a split structure in which the support plate and the boss are independently arranged, after the boss is worn, the boss can be repaired or replaced separately without replacing the support plate, thereby improving the service life of the etching tray and reducing the manufacturing cost. Among them, the plurality of bosses include a first boss and a second boss, and 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, there is a first spacing between the surface of the first boss facing the support plate and the support plate, and there is a second spacing between the surface of the second boss facing the support plate and the support plate, and the first spacing and the second spacing are different. By differentiating the spacing between the bosses and the support plate at different positions, the etching efficiency of the wafers in different regions can be adjusted, thereby improving the problem of uneven etching caused by uneven etching plasma density, and improving the consistency of etching degree of the wafers in the same etching tray.

[0043] Optional, you can continue to refer to Figure 2-Figure 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 Figure 2-Figure 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-circle boss 12 of the outer circle, and the second boss 122 can refer to the m-circle boss 12 of the inner circle. Figure 4 The first boss 121 and the second boss 122 shown may correspond to Figure 2 Two first bosses 121 and second bosses 122 are marked in FIG. Figure 4 As shown in the figure, 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 figure only shows a circle of first bosses 121 near the edge of the support plate 11 and a second boss 122 (located at the center of the support plate 11) inside the first boss 121. The figure does not represent the actual arrangement of the bosses 12. In actual production applications, multiple circles of bosses 12 are arranged on the support plate 11, and any two circles of bosses 12 with different distances from the center of the support plate 11 can be the first boss 121 and the second boss 122.

[0046] The inventor has found that, in general, in the etching chamber, the plasma density in the middle area of ​​the etching tray 10 is greater than the plasma density in the edge area. Considering only the influence of the etching gas, the etching efficiency of the center wafer 202 is higher than that of the edge wafer 201, resulting in a lower height of the center wafer 202 pattern on the tray in the prior art. Based on this, in this embodiment, the size of the first gap S1 between the first boss 121 and the support plate 11 can be set to be greater than the size of the second gap S2 between the second boss 122 and the support plate 11, so that the second boss 122 close to the center of the support plate 11 is closer to the support plate 11, and the cooling effect of the wafer 20 on the second boss 122 is better, which relatively reduces the temperature of the center wafer 202, thereby appropriately reducing the etching efficiency of the center wafer 202, compensating for the high etching efficiency of the center wafer 202 caused by the uneven distribution of the etching gas, making the etching efficiencies of the center wafer 202 and the edge wafer 201 tend to be consistent, and improving the problem of the low height of the center wafer 202 pattern.

[0047] Optional, Figure 5 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention, Figure 5 The cross-sectional structure of the etching tray is shown. 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, and the hardening layer 124 is located on a side of the main body 123 away from the support plate 11.

[0048] refer to Figure 5 In this embodiment, when manufacturing 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 the wear of the boss 12.

[0049] The specific process of hardening treatment is not limited, and any hardening treatment process may be used, such as anodizing, silicon carbide coating or sandblasting, but not limited thereto.

[0050] Further optional, Figure 6 A schematic diagram of another etching tray provided in an embodiment of the present invention 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 after hardening treatment is different from that of the main body 123. Under the same helium pressure, when the thickness of the hardened layer 124 is different, it 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 solution for differentially setting the thickness of the hardened layer 124 of the boss 12 at different positions of the support plate 11. Figure 6 As shown, the hardened layer 124 on the main body 123 of the first boss 121 is a first hardened layer 1241, and the hardened layer 124 on the main body 123 of the second boss 122 is a second hardened layer 1242. The first hardened layer 1241 and the second hardened layer 1242 have different thicknesses. This makes the thermal conductivity of the first boss 121 and the second boss 122 different, and the etching efficiency of the wafer 20 above the first boss 121 and the second boss 122 can also be regulated.

[0052] For further information, please refer to Figure 6 , Figure 6 The relative position relationship between the first boss 121 and the second boss 122 is shown in FIG. Figure 4 As shown in the figure, 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. 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 thermal conductivity of the material of the hardened layer 124 is less than the thermal conductivity of the material of the main body 123, and the thickness of the first hardened layer 1241 is greater than the thickness of the second hardened layer 1242.

[0053] For the current hardening treatment processes such as anodizing, silicon carbide coating or sandblasting, the thermal conductivity of the hardened layer 124 is lower than the thermal conductivity of the main body 123 made of metal material. The thicker the hardened layer 124 is, the lower the overall thermal conductivity of the boss 12 may be. It is still considered that the plasma density in the middle area of ​​the etching tray 10 is greater than the plasma density in the edge area, resulting in the etching efficiency of the center chip 202 being higher than the etching efficiency of the edge chip 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, so that the thermal conductivity of the first boss 121 is lower than the thermal conductivity of the second boss 122, further improving the cooling effect of the chip 20 (i.e., the center chip 202) on the second boss 122, compensating for the problem of uneven etching caused by uneven etching plasma density, and further improving the problem of low height of the center chip 202 pattern.

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

[0055] Optional, Figure 7 A schematic diagram of the structure of another etching tray provided in an embodiment of the present invention, Figure 8 A schematic diagram of another etching tray provided in an embodiment of the present invention can be used in conjunction with reference to Figure 7 and Figure 8 , the boss 12 includes a first surface 125 and a second surface 126 which are arranged opposite to each other along the thickness direction Z of the support plate, and 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 mentioned 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, the cover plate 30 is used to fix the wafer 20, generally by using the pressure claws (not shown in the figure) of the cover plate 30 to press the edge of the wafer 20. The inventors have found that under this setting, the presence of the pressure claws may affect the potential distribution of different regions of the wafer 20, resulting in differences in etching energy at different positions of the same wafer 20, and then causing different graphic heights in different regions of the same wafer 20, affecting the consistency of the graphic height on the wafer 20. Based on this, the present embodiment proposes that the shape design of the first surface 125 and / or the second surface 126 of the boss 12 can be performed, and the potential distribution can be adjusted by shape design to improve the uniformity of the graphic height on the same wafer 20.

[0057] exist Figure 7 In the illustrated embodiment, the shape of the first surface 125 of the boss 12 can be designed. After the wafer 20 is loaded onto one side of the first surface 125 of the boss 12, when the thickness of the boss 12 at the first position P1 and the second position P2 are different, the distances between the boss 12 and the wafer 20 at these two positions are different. The boss 12 is generally made of metal, and the wafer 20 is semiconductor silicon. A capacitor may be formed between the boss 12 and the wafer 20. The boss 12 and the wafer 20 serve as two plates of the capacitor, respectively. 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 distances between the boss 12 and the wafer 20 at the first position P1 and the second position P2 are different, the capacitance formed by the boss 12 and the wafer 20 at the first position P1 and the second position P2 are different. There is a difference in the capacitance formed by the boss 12 and the wafer 20. The electric potential at different positions of the wafer 20 is adjusted by using the capacitance formed by the boss 12 and the wafer 20 to ensure uniform distribution of etching energy. Exemplarily, Figure 7Taking the example that the thickness of the boss 12 at the first position P1 is greater than the thickness at the second position P2, the distance between the first position P1 and the chip 20 is smaller than the distance between the second position P2 and the chip 20, and the capacitance formed by the boss 12 and the chip 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 chip 20 close to the first position P1.

[0058] exist Figure 8 In the illustrated embodiment, the shape of the second surface 126 of the boss 12 can be designed. When the thickness of the boss 12 at the third position P3 and the fourth position P4 is different, the distances between the boss 12 and the support plate 11 at these two positions are different. The boss 12 and the support plate 11 are both made of metal, and a capacitor may be formed between the two. The boss 12 and the support plate 11 serve as two plates of the capacitor, respectively. The existence of the capacitor can also change the distribution of the electric field near the chip 20. When the distances between the boss 12 and the support plate 11 at the third position P3 and the fourth position P4 are different, there is a difference in the size of the capacitor formed by the boss 12 and the support plate 11 at the third position P3 and the capacitor formed by the boss 12 and the support plate 11 at the fourth position P4. The capacitor formed by the boss 12 and the support plate 11 is thus used to adjust the electric potential at different positions of the chip 20 to ensure uniform distribution of etching energy. Exemplarily, Figure 8 Taking the example that the thickness of the boss 12 at the third position P3 is greater than the thickness at the fourth position P4, the distance between the third position P3 and the support plate 11 is smaller than the distance between the fourth position P4 and the support plate 11, and the capacitance formed between 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 chip 20 close to the third position P3.

[0059] In an embodiment not shown in the present invention, the above Figure 7 and Figure 8 As shown, the shape design of the first surface 125 and the second surface 126 of the boss 12 is performed, which will not be described in detail in the embodiment of the present invention.

[0060] The embodiment of the present invention does not limit 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. Those skilled in the art can design according to the actual potential distribution near the wafer 20.

[0061] Exemplary, in some embodiments, continue to refer 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 convexity 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 convexity and the first surface 125 is a plane.

[0062] The inventors have found that the presence of the pressure claws will cause the edge area of ​​the wafer 20 to have a lower potential and the middle area of ​​the wafer 20 to have a higher potential. At this time, energy will be transferred to the edge of the wafer 20, resulting in a larger etching energy at the edge of the wafer 20 and a faster etching rate. Based on this, the present embodiment proposes that, if 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 to be an arc that arches toward the side 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, and 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, so that the potential in the middle area of ​​the wafer 20 is reduced, and energy is transferred to the middle of the wafer 20, which relatively improves the etching rate in the middle of the wafer 20, so that the etching energy is evenly distributed in the middle area and the edge area of ​​the wafer 20, and the etching uniformity is improved. In this setting, the second surface 126 of the boss 12 can be a plane.

[0063] Correspondingly, such as Figure 8 As shown, only the second surface 126 of the boss 12 can be designed in shape, the third position P3 can refer to the middle area of ​​the second surface 126, and the fourth position P4 can refer to the edge area of ​​the second surface 126. The second surface 126 can be designed to be an arc that arches toward the side 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, and 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, so that the potential in the middle area of ​​the wafer 20 is reduced, and energy is transferred to the middle of the wafer 20, which relatively improves the etching rate in the middle of the wafer 20, so that the etching energy is evenly distributed in the middle area and the edge area of ​​the wafer 20, and the etching uniformity is improved. In this setting, the first surface 125 of the boss 12 can be a plane.

[0064] Further optionally, when the second surface 126 includes the third position P3 and the fourth position P4, the boss 12 is electrically isolated from the support plate 11. The boss 12 is electrically isolated from the support plate 11 to ensure that a capacitor is formed therebetween.

[0065] Exemplarily, the connector 13 may be made of insulating material, and / or an insulating design may be made on the contact surface between the boss 12 and the support plate 11 to ensure electrical isolation between the boss 12 and the support plate 11 .

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

[0067] Optional, Fig. 9 for Figure 3 For the enlarged structural diagram at A, please refer to Figure 3 and Fig. 9 In a possible embodiment, the etching tray 10 cooperates with the cover plate 30 to fix the wafer 20, and 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, and the opening 31 corresponds to the boss 12; the edge of the opening 31 includes a pressure claw (not shown in the figure), and the pressure claw is used to press 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 side wall 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, and the sealing groove 127 is used to place the 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 may adopt any existing solution, and the embodiment of the present invention is not limited thereto. The cover plate 30 may include a plurality of openings 31, and 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 that of the bosses 12, and the size may be slightly larger than that of the bosses 12, and the openings 31 correspond to the bosses 12.

[0069] Among them, Figure 3 and Fig. 9 As shown, the diameter of the wafer 20 may be smaller than the diameter of the boss 12, so that along the thickness direction Z of the support plate, the opening 31 covers the wafer 20. After the wafer 20 is fixed, there is a second gap S2 between the edge of the opening 31 and the wafer 20 in the horizontal direction X. A plurality of pressing claws are provided at the edge of the opening 31, and the plurality of pressing claws may be evenly distributed at the edge of the opening 31. The pressing claws extend from the edge of the opening 31 to the center of the opening 31. When the wafer 20 is fixed, the pressing claws extend above the edge of the wafer 20 to press the wafer 20.

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

[0071] Continue to refer Figure 3 and Fig. 9, the width of the sealing groove 127 in the horizontal direction X (the direction in which the side wall of the wafer 20 and the side wall of the opening 31 are relative) can be greater than the width of the opening 31 in this direction. And the orthographic projection of the sealing groove 127 on the plane where the support plate 11 is located covers the orthographic projection of the second gap S2 on the plane where the support plate 11 is located. The sealing groove 127 is generally filled in the sealing groove 127 relatively tightly. Under this setting, the lower side of the sealing ring 40 is in contact with the inside of the sealing groove 127, and the upper side of the sealing ring 40 is in contact with the cover plate 30 and the wafer 20. The orthographic projection of the sealing ring 40 on the plane where the support plate 11 is located can also cover the orthographic projection of the second gap S2 on the plane where the support plate 11 is located. When etching the wafer 20, the sealing ring 40 can block the etching plasma entering the opening 31 to prevent the outside of the sealing groove 127 from being etched, thereby further improving the service life of the boss 12.

[0072] For example, Fig. 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 side wall.

[0073] In addition, the sealing ring 40 may be made of a material resistant to plasma etching, such as fluorine-doped rubber, so as to improve the etching resistance of the sealing ring 40 .

[0074] Based on the same concept, an embodiment of the present invention further provides an etching fixture, which includes a cover plate, a sealing ring, and an etching tray provided by any embodiment of the present invention. The specific structure of the etching fixture can refer to the description of the above embodiment. The etching fixture provided by the embodiment of the present invention has the corresponding beneficial effects of the etching tray provided by the embodiment of the present invention, which will not be repeated here.

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

Claims

1. An etching tray, characterized in that: Used to carry a wafer; the etching tray comprises a support plate and a plurality of bosses located on one side of the support plate, the wafer is loaded on the side of the boss away from the support plate; the support plate and the bosses are fixed by a connecting member, and a first gap exists between at least part of the bosses and the support plate; 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, a side surface of the first boss facing the support plate has a first spacing from the support plate, and a side surface of the second boss facing the support plate has a second spacing from the support plate, and the first spacing and the second spacing are different.

2. The etching tray according to claim 1, characterized in that: 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 greater than the distance between the second boss and the center of the support plate; The first interval is greater than the second interval.

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, and the hardening layer is located on a side of the main body away from 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 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 greater than the distance between the second boss and the center of the support plate; The thermal conductivity of the hardened layer material is smaller than the thermal conductivity of the main body material, and the thickness of the first hardened layer is greater than the thickness of the second hardened layer.

6. The etching tray according to claim 1, characterized in that: The boss comprises a first surface and a second surface which are arranged 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, and 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, and a thickness of the boss at the third position is different from a thickness of the boss at the fourth position.

7. The etching tray according to claim 6, characterized in that: When the first surface includes the first position and the second position, the first surface is an arc-shaped convexity, 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 convexity, and the first surface is a plane.

8. The etching tray according to claim 6, characterized in that: When the second surface includes the third position and the fourth position, the boss is electrically isolated from the support plate.

9. The etching tray according to claim 1, characterized in that: The etching tray cooperates with the cover plate to fix the wafer, and the cover plate and the boss are located on the same side of the support plate; the cover plate includes an opening, and the opening corresponds to the boss; the edge of the opening includes a pressing claw, and the pressing claw is used to press the edge of the wafer; after the wafer is loaded onto the etching tray, a second gap exists between the side wall of the opening and the wafer; The side of the boss facing away from the support plate includes a sealing groove, and the sealing groove is used to place 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.

10. An etching fixture, characterized in that: It comprises a cover plate, a sealing ring and an etching tray as described in any one of claims 1 to 9.

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