Wet etching groove with special shape and its application in wet etching equipment

Abstract

The present invention provides a specially shaped wet etching tank and its application in wet etching equipment. The tank-type wet etching equipment includes an etching tank, a wafer holder for holding a wafer, and a liquid inlet pipe for injecting etching liquid into the etching tank. The etching tank is shaped by symmetrically trimming and deforming the front and rear sides of the top and bottom of a rectangular parallelepiped etching tank. The length of the deformed specially shaped etching tank gradually decreases from the middle to the top and bottom in the vertical direction. The present invention can increase the flow rate of the etching liquid on the wafer surface and improve the flow field distribution, thereby improving the uniformity of wet etching and increasing product yield.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor devices, and in particular relates to a wet etching groove with a special shape and an application thereof in wet etching equipment. Background Art

[0002] The etching process selectively corrodes or strips the surface of a semiconductor substrate or its covering film according to the mask pattern or design requirements. Etching is not only a fundamental manufacturing process for semiconductor devices and integrated circuits, but is also used in the processing of thin-film circuits, printed circuits, and other fine patterns.

[0003] Currently, the two main etching methods are wet etching and dry plasma etching. In wet etching, the etchant is a liquid chemical mixture that reacts with the wafer substrate to produce soluble substances, which then dissolve in the solution. For example, a solution containing hydrofluoric acid is used to etch silicon dioxide films, phosphoric acid is used to etch aluminum films, and phosphoric acid is used to etch silicon nitride films. Tank wet etching equipment, as the main equipment in the wet etching process, typically places the wafer in the etching tank of the tank etching equipment. After the wafer is immersed in the etching solution in the etching tank for a period of time, the unwanted material layer on the wafer is etched away.

[0004] In the semiconductor wet etching process, trench wet etching has always occupied a large proportion, and the trench etching process has become increasingly mature and stable. However, with the increase in wafer size and the continuous reduction in feature process size, wet etching uniformity has gradually become a key parameter affecting product yield, which poses a great challenge to traditional trench wet etching.

[0005] In existing tank wet etching equipment, the wafer is placed on a wafer holder in the etching tank. Since the etching liquid flows from bottom to top, the bottom of the wafer is blocked by the wafer holder, resulting in uneven etching on the wafer surface. On the other hand, the surrounding environment of the wafer at the edge of the etching tank and the center of the etching tank is different, which will also lead to uneven etching between wafers, thereby affecting the product yield.

[0006] Therefore, for slot-type wet etching equipment, finding a method to enhance transfer, improve etching uniformity and product yield is of great significance to wafer production. Summary of the Invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a new wet etching groove with a special shape and a groove-type wet etching device, aiming to solve the problems of uneven etching and low product yield in the groove-type wet etching device.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A wet etching groove with a special shape is provided in the etching groove, wherein a wafer holder for placing a wafer is provided. The shape of the etching groove with a special shape is obtained by symmetrically trimming and deforming the front and rear sides of the original rectangular etching groove. The horizontal length of the rectangular etching groove in the front-to-back direction is 1.15D to 1.25D, the width of the etching groove along the length direction of the wafer holder is 1.65D to 1.75D, and the height is 1.65D to 1.75D, where D is the diameter of the wafer. After deformation, the width and height values of the etching groove with a special shape remain unchanged, and the length value gradually decreases from the middle value of 1.15D to 1.25D in the vertical direction to the top and bottom ends. The top and bottom length values of the etching groove with a special shape are 0.4D to 0.95D.

[0010] The present invention is further configured as follows: the shape of the etching groove with a special shape is a shape obtained by symmetrically trimming and deforming the front and rear sides of the top and bottom of the rectangular etching groove; the front and rear lengths of the rectangular etching groove are 1.7D in the width and 1.7D in the length direction of the wafer holder, and D is the diameter of the wafer; the width and height values of the etching groove with a special shape after deformation remain unchanged, and the length value gradually decreases from the middle value of 1.2D in the vertical direction to the top and bottom ends respectively, and the top length and bottom length of the etching groove with a special shape are 0.4D to 0.95D.

[0011] The present invention is further configured such that the shape of the specially shaped etching groove after trimming and deformation is an octahedron, whose vertical cross-section parallel to the wafer direction is a hexagon; the width of the deformed etching groove is 1.7D, and the height is 1.7D. In the vertical direction, the length value gradually decreases from 1.2D in the middle to the top and bottom ends respectively, and the horizontal length values of the top and bottom ends are 1.2D-2a, and the characteristic parameter a=0.16D~0.25D.

[0012] The present invention is further configured such that the center of the hexagon is consistent with the center of the vertical cross section of the corresponding etching groove, and the hexagon is symmetrical in both vertical and horizontal directions.

[0013] The present invention is further configured such that the specially shaped etching groove is obtained by symmetrically trimming and deforming the front and rear sides of the top and bottom of the rectangular etching groove, specifically: an arc rectangular parallelepiped, whose vertical cross-section parallel to the wafer direction is a rounded rectangle; the width of the deformed etching groove is 1.7D, the height is 1.7D, and the horizontal lengths of the top and bottom are The characteristic parameter b is the radius of the circle where the fillet is located, and b=0.88D~0.95D.

[0014] The present invention is further configured such that the center of the circle where the rounded corner is located is consistent with the center of the vertical cross section of the corresponding etched groove, and the rounded rectangle is a rounded rectangle that is symmetrical in both vertical and horizontal directions.

[0015] The present invention is further configured such that the shape of the etched groove with a special shape after symmetrical trimming and deformation is: a deformed cuboid with elliptical arc surfaces on the front and rear sides, and a vertical cross-section parallel to the wafer direction is a deformed rectangle with elliptical arcs on both sides; the width of the etched groove after deformation is 1.7D, and the height is 1.7D, and the length value gradually decreases in the vertical direction from 1.2D in the middle to the top and bottom ends respectively, and the short radius of the ellipse where the elliptical arc is located is R1 = 0.6D, and the long radius R2 = 0.96D~1.07D.

[0016] The present invention is further configured such that the center of the ellipse where the elliptical arc is located is consistent with the center of the vertical cross section of the corresponding etched groove, and the deformed rectangle is a deformed rectangle that is symmetrical in both the top and bottom and the left and right directions.

[0017] The present invention is further configured such that the diameter of the wafer is D=200-400 mm.

[0018] The present invention is further configured such that the vertical distance between the center of the etching groove and the center of the wafer is ≤0.1D, preferably ≤0.05D. More preferably, the center of the etching groove and the center of the wafer are vertically aligned. This configuration allows the wafer to be placed in the middle of the etching groove.

[0019] The present invention also provides a groove-type wet etching device, which uses the wet etching groove with the special shape described above.

[0020] The present invention is further configured such that the trench wet etching equipment comprises:

[0021] An etching tank for containing etching liquid;

[0022] A wafer holder is installed in the etching groove, and the wafer holder has periodic protrusions, and grooves are formed between adjacent protrusions for supporting the wafer;

[0023] The liquid inlet pipe is located below the wafer support, and the liquid inlet of the liquid inlet pipe faces upward, and is used for injecting etching liquid into the etching tank.

[0024] The present invention is further configured such that the tank-type wet etching equipment is further provided with an overflow circulation channel, and the overflow circulation channel is connected to the tank wall of the etching tank and the liquid inlet pipe.

[0025] Compared with the prior art, the present invention has the following beneficial effects: the technical solution of the present invention can significantly and effectively increase the flow rate of the etching liquid and improve the flow field distribution by designing the shape of the trough-type wet etching equipment, thereby improving the etching uniformity of the wafer and improving the product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural diagram of a special-shaped trough wet etching device in which the vertical cross-section of the etching groove is hexagonal and the etching groove is octahedral.

[0027] Figure 2 for Figure 1 A vertical cross-sectional view parallel to the wafer direction.

[0028] Figure 3 This is a schematic diagram of the structure of a general structure trough wet etching equipment in which the vertical cross-section of the etching groove is rectangular and the etching groove is a cuboid.

[0029] Figure 4 for Figure 3 A vertical cross-sectional view parallel to the wafer direction.

[0030] Figure 5 The results are a comparison of the wafer surface etching solution temperature of the special-shaped tank wet etching equipment described in Examples 1 and 2 and that of a general tank wet etching equipment.

[0031] Figure 6 The results are a comparison of the etching solution flow rate on the wafer surface of the special-shaped tank wet etching equipment described in Examples 1 and 2 and that of a general tank wet etching equipment.

[0032] Figure 7 The results are a comparison of the wafer surface etching solution temperature of the special-shaped tank wet etching equipment described in Comparative Examples 1 and 2 and that of a general tank wet etching equipment.

[0033] Figure 8 The diagram is a structural diagram of a special-shaped trough wet etching device in which the vertical cross-section of the etching groove is a rounded rectangle and the etching groove is a rounded cuboid.

[0034] Figure 9 for Figure 8 A vertical cross-sectional view parallel to the wafer direction.

[0035] Figure 10 The results are a comparison of the wafer surface etching solution temperature of the special-shaped tank wet etching equipment described in Examples 3 to 5 and that of a general tank wet etching equipment.

[0036] Figure 11 This is a comparison result of the wafer surface etching solution temperature of the special-shaped tank wet etching equipment described in Comparative Example 3 and that of a general tank wet etching equipment.

[0037] Figure 12 This is a structural diagram of a special-shaped slot-type wet etching device in which the etching slot is a deformed rectangle with elliptical arcs on both sides of the cross section, and the etching slot is a deformed cuboid with elliptical arcs on the front and back sides.

[0038] Figure 13 for Figure 12 A vertical cross-sectional view parallel to the wafer direction.

[0039] Figure 14 The results are a comparison of the wafer surface etching solution temperature of the special-shaped tank wet etching equipment described in Examples 6 to 8 and that of a general tank wet etching equipment.

[0040] Figure 15 This is a comparison result of the wafer surface etching solution temperature of the special-shaped tank wet etching equipment described in Comparative Example 4 and that of a general tank wet etching equipment.

[0041] Among them, the above Figures 5-7 、 Figures 10-11 as well as Figures 14-15 , Wafer No.25 and Wafer No.50 represent wafers at different positions in the same batch, respectively. Wafer No.25 represents the wafer located at the center of the etching groove, and Wafer No.50 represents the wafer located at the edge of the etching groove. DETAILED DESCRIPTION

[0042] The present invention is described in detail below using specific embodiments in conjunction with the accompanying drawings. It should be understood that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are considered to fall within the scope of the present invention.

[0043] An embodiment of the present invention provides a trench wet etching device, comprising:

[0044] An etching tank for containing etching liquid;

[0045] A wafer holder is installed in the etching groove, and the wafer holder has periodic protrusions, and grooves are formed between adjacent protrusions for supporting the wafer;

[0046] A liquid inlet pipe is located below the wafer support, with a liquid inlet facing upward, and is used to inject etching liquid into the etching tank;

[0047] The etched grooves are specially shaped, resulting from symmetrically trimming and deforming the front and back sides of a rectangular parallelepiped etched groove. The horizontal length of the rectangular parallelepiped etched groove in the front-to-back direction is 1.2D, and the width and height of the etched groove along the length of the wafer holder are 1.7D, with D being the diameter of the wafer. The deformed etched grooves are 1.7D wide and 1.7D high, with the length gradually decreasing vertically from 1.2D in the middle toward the top and bottom, with the horizontal lengths at the top and bottom ranging from 0.4D to 0.95D. By adjusting the shape of the etched grooves in this manner, heat accumulation on the wafer surface is improved, thereby enhancing wafer etching uniformity.

[0048] In one embodiment of the present invention, the shape of the etched groove with a special shape after symmetrical trimming and deformation is: an octahedron, and its vertical cross-section parallel to the wafer direction is a hexagon; the width of the etched groove after deformation is 1.7D, the height is 1.7D, and the length value gradually decreases in the vertical direction from 1.2D in the middle to the top and bottom respectively, the horizontal length of the top and bottom is 1.2D-2a, and the characteristic parameter a=0.16D~0.25D.

[0049] In one embodiment of the present invention, the center of the hexagon is consistent with the center of the vertical cross section of the corresponding etching groove, and the hexagon is symmetrical in both vertical and horizontal directions.

[0050] In one embodiment of the present invention, the shape of the etching groove with a special shape is a shape obtained by symmetrically trimming and deforming the front and back sides of the top and bottom of the original rectangular etching groove, specifically: an arc rectangular parallelepiped, whose vertical cross-section parallel to the wafer direction is a rounded rectangle; the width of the deformed etching groove is 1.7D, the height is 1.7D, and the horizontal length in the front and back directions of the top and bottom is The characteristic parameter b is the radius of the circle where the fillet is located, and b=0.88D~0.95D.

[0051] In one embodiment of the present invention, the center of the circle where the rounded corner is located is consistent with the center of the vertical cross section of the corresponding etched groove, and the rounded rectangle is symmetrical in both vertical and horizontal directions.

[0052] In one embodiment of the present invention, the shape of the etched groove with a special shape after symmetrical trimming and deformation is: a deformed cuboid with elliptical arc surfaces on the front and rear sides, and its vertical section parallel to the wafer direction is a deformed rectangle with elliptical arcs on both sides; the width of the etched groove after deformation is 1.7D, the height is 1.7D, and the length value gradually decreases in the vertical direction from 1.2D in the middle to the top and bottom ends respectively, and the short radius of the ellipse where the elliptical arc is located is R1 = 0.6D, and the long radius R2 = 0.96D~1.07D.

[0053] In one embodiment of the present invention, the center of the ellipse where the elliptical arc is located is consistent with the center of the vertical cross section of the corresponding etched groove, and the deformed rectangle is a deformed rectangle that is symmetrical in both vertical and horizontal directions.

[0054] In one embodiment of the present invention, the vertical distance between the center of the etching groove and the center of the wafer placed in the etching groove is ≤0.05D; more preferably, the center of the etching groove and the center of the wafer are the same in the vertical direction, so that the wafer is placed in the middle of the etching groove.

[0055] In one embodiment of the present invention, the diameter of the wafer is D=200-400 mm.

[0056] In one embodiment of the present invention, the tank-type wet etching equipment is further provided with an overflow circulation channel, and the overflow circulation channel is connected to the tank wall of the etching tank and the liquid inlet pipe.

[0057] The technical solution of the present invention is further described below with reference to specific embodiments.

[0058] Example 1

[0059] refer to Figures 1 and 2 , this embodiment provides a groove-type wet etching device for improving etching uniformity, comprising an etching groove 1, a plurality of wafer holders 2 arranged inside the etching groove 1, and a plurality of liquid inlet pipes 3 arranged below the wafer holders 2; the wafer holders 2 are uniformly distributed with periodic protrusions along their length direction, and grooves are formed between adjacent protrusions for supporting wafers 4; in this embodiment, three wafer holders are installed; a pair of the liquid inlet pipes 3 are symmetrically distributed at the bottom of the etching groove 1, and the liquid inlet pipes 3 are horizontally arranged along the length direction of the wafer holder 2, and the liquid inlet 5 opened on the liquid inlet pipe 3 faces upward, and the etching liquid is injected into the etching groove 1 through the liquid inlet 5.

[0060] The wet etching groove provided in this embodiment is shaped by symmetrically trimming and deforming the front and back sides of the original rectangular etching groove. Symmetrical trimming means symmetrical trimming of the upper and lower sides and the front and back sides. The trimmed shape is specifically: an octahedral shape, with a vertical cross-section parallel to the wafer direction forming a hexagon, which is symmetrical in both the upper and lower directions and the left and right sides. The vertical height of the deformed etching groove remains unchanged at 1.7D; the horizontal width of the etching groove along the length of the wafer holder 2 remains unchanged at 1.7D; the horizontal length of the etching groove in the front-to-back direction gradually decreases from the middle length of 1.2D to the top and bottom ends in the vertical direction. The horizontal length of the etching groove at the top and bottom is 1.2D-2a, where D is the diameter of the wafer and a is the structural parameter of the specially shaped etching groove. In this embodiment, the structural parameter a=0.16D.

[0061] This example uses phosphoric acid wet etching of silicon nitride as an example, and uses Fluent software to simulate and compare the impact of the above-mentioned special-shaped slot wet etching equipment and the general-structure slot wet etching equipment on the surface temperature distribution of the wafer. The structural diagram of the general-structure slot wet etching equipment and the vertical cross-section of the etching slot are shown in Figure 2. Figure 3 and 4 As shown in the figure, the structure is an undeformed cuboid structure with a rectangular vertical cross section. The length of the etched groove is 1.2D, the width is 1.7D, and the vertical height is 1.7D. The simulation results are shown in the figure. Figure 5 and Figure 6 shown.

[0062] Example 2

[0063] The special groove wet etching equipment described in Example 1 is used. Compared with Example 1, the only difference is the structural parameter a of the etching groove. In this embodiment, the structural parameter a = 0.25D. The simulation results are shown in FIG. Figure 5 and Figure 6 shown.

[0064] Comparative Examples 1-2

[0065] The special shape wet etching equipment described in Example 1 is used. Compared with Example 1, the only difference is the structural parameter a of the etching groove. In Comparative Examples 1 and 2, the structural parameter a is 0.08D and 0.30D respectively. The simulation results are shown in FIG. Figure 7 shown.

[0066] Depend on Figure 5 and 7From the results shown, it can be seen that the special shape of the etching groove will have a significant impact on the wafer etching effect; when the structural parameter is a=0.16D~0.25D, the heat accumulation on the wafer surface is improved, the average temperature of the wafer surface decreases, and the temperature uniformity of the wafer surface is greatly improved; the etching uniformity between wafers is greatly improved. When the structural parameter a is not within the range of 0.16D~0.25D, the heat accumulation on the wafer surface worsens, the wafer surface temperature increases, and the temperature distribution uniformity decreases, which in turn leads to a decrease in wafer etching uniformity. Therefore, the special shape slot-type wet etching equipment with a hexagonal cross-section and an octahedral etching groove with structural parameters of 0.16D~0.25D can greatly improve the wafer etching uniformity. And according to Figure 6 It can be seen from the results shown that, compared with the etching tank of general structure, the etching solution flow rate of the special-shaped wet etching tank described in Examples 1 and 2 is also improved.

[0067] Example 3

[0068] Compared with Example 1, the difference is that the shape of the etching groove of the special-shaped wet etching equipment is different. Figures 8 and 9 The shape of the etching groove in this embodiment is a shape obtained by symmetrically trimming and deforming the top and bottom of the front and rear sides of the rectangular etching groove. The symmetrical trimming is symmetrical trimming on the upper and lower sides and symmetrical trimming on the front and rear sides. The specific shape is: an arc rectangular parallelepiped, whose vertical cross-section parallel to the wafer direction is a rounded rectangle, that is, the four corners of the rectangle are rounded, and the rounded rectangle is symmetrical up and down and left and right, and the center of the circle where the rounded corner is located is consistent with the center of the corresponding vertical cross-section of the etching groove; the edges on the front and rear sides of the top and bottom of the deformed arc rectangular parallelepiped are deformed into arc curved surfaces.

[0069] The vertical height of the etching groove is 1.7D, the width of the etching groove along the length direction of the wafer holder is 1.7D, and the horizontal length of the upper and lower parts of the etching groove along the front-back direction gradually decreases from 1.2D to the top and bottom. The characteristic parameter b is the radius of the circle where the fillet is located; in this embodiment, b = 0.88D. Fluent software was used to simulate and compare the influence of the temperature distribution on the wafer surface inside the rectangular etching groove in the special-shaped groove wet etching equipment described in this embodiment and the general-structure groove wet etching equipment described in Example 1. The simulation results are shown in Figure 2. Figure 10 shown.

[0070] Example 4

[0071] The special shape wet etching equipment described in Example 3 is used. Compared with Example 3, the only difference is the structural parameter b of the etching groove. In this embodiment, b=0.92D. The simulation results are shown in FIG. Figure 10 shown.

[0072] Example 5

[0073] The special shape wet etching equipment described in Example 3 is used. Compared with Example 3, the only difference is the structural parameter b of the etching groove. In this embodiment, b=0.95D. The simulation results are shown in FIG. Figure 10 shown.

[0074] according to Figure 10 The results shown show that for Figures 8-9 For the etching groove with a special shape shown in the figure, when the structural parameter b=0.88D~0.95D, the heat accumulation on the wafer surface is improved, the average temperature of the wafer surface is reduced, and the temperature uniformity of the wafer surface is greatly improved; the etching uniformity between wafers is greatly improved.

[0075] Comparative Example 3

[0076] The special-shaped wet etching equipment described in Example 3 is used. Compared with Example 3, the only difference is the structural parameter b of the etching groove. In this comparative example, b = 1.00D. The influence of the temperature distribution on the internal wafer surface of the special-shaped groove wet etching equipment and the general-structure groove wet etching equipment in this embodiment is simulated and compared. The simulation results are shown in FIG. Figure 11 The results show that the heat accumulation on the wafer surface worsens under the structural parameters of the etched groove, the wafer surface temperature increases, the temperature distribution uniformity decreases, and thus the wafer etching uniformity decreases.

[0077] Example 6

[0078] Compared with Example 1, the difference is that the shape of the etching groove of the wet etching equipment is different. Figure 12 and Figure 13The etched groove shape used in this embodiment is obtained by symmetrically trimming and deforming the front and back sides of a rectangular etched groove. Symmetrical trimming refers to symmetrical trimming of the top and bottom sides, as well as the front and back sides. The deformed shape is specifically: a deformed rectangular prism with elliptical arc surfaces on the front and back sides. The vertical cross-section parallel to the wafer direction is a deformed rectangle with elliptical arcs on both vertical sides. The center of the elliptical arc coincides with the center of the corresponding vertical cross-section of the etched groove. The deformed rectangle is symmetrical in both the top and bottom directions. The vertical height of the etched groove is 1.7D, and the width of the etched groove along the length of the wafer holder is 1.7D. The horizontal length of the etched groove in the front-to-back direction gradually decreases from a vertical length of 1.2D in the middle to the top and bottom. The short radius R1 of the ellipse containing the elliptical arc is 0.6D, and the long radius R2 is 0.96D to 1.07D. In this embodiment, R2 = 0.96D. Fluent software was used to simulate and compare the effects of the temperature distribution on the wafer surface inside the special-shaped slot wet etching equipment and the general-structure slot wet etching equipment described in Example 1. The simulation results are shown in Figure 2. Figure 14 shown.

[0079] Example 7

[0080] Use Figures 12-13 The special shape etched groove shown in the figure is different from that in Example 6 only in that the structural parameter R2 of the etched groove is different. In this embodiment, R2=1.03D. The simulation results are shown in FIG. Figure 14 shown.

[0081] Example 8

[0082] Use Figures 12-13 The special shape etched groove shown in the figure is different from that in Example 6 only in that the structural parameter of the etched groove is R2=1.07D. Figure 14 shown.

[0083] according to Figure 14 The results shown show that for Figures 12-13 For the etching groove with a special shape shown in the figure, when the structural parameter R2 is 0.96D~1.07D, the heat accumulation on the wafer surface is improved, the average temperature of the wafer surface is reduced, and the temperature uniformity of the wafer surface is greatly improved; the etching uniformity between wafers is greatly improved.

[0084] Comparative Example 4

[0085] Use Figures 12-13The special-shaped etching groove shown in the comparative example differs from Example 6 only in that the structural parameter of the etching groove is R2 = 1.10D. Fluent software was used to simulate and compare the influence of the temperature distribution on the internal wafer surface of the special-shaped groove wet etching equipment in this comparative example and the general-structure groove wet etching equipment described in Example 1. The simulation results are shown in FIG. Figure 15 As shown. Figure 15 The results show that in the etching groove under the structural parameters of this comparative example, the heat accumulation on the wafer surface worsens, the wafer surface temperature increases, and the temperature distribution uniformity decreases, which in turn leads to a decrease in wafer etching uniformity.

[0086] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A wet etching groove with a special shape, characterized in that: A wafer holder for placing a wafer is provided in the etching tank. The specially shaped etching tank is obtained by symmetrically trimming and deforming the front and rear sides of a rectangular etching tank. The rectangular etching tank has a horizontal length of 1.2D in the front-to-back direction, a width of 1.7D and a height of 1.7D along the length direction of the wafer holder, where D is the diameter of the wafer. The shape of the specially shaped etching groove after trimming and deformation is an octahedron, whose vertical cross-section parallel to the wafer direction is a hexagon; the width and height values of the deformed etching groove remain unchanged, both 1.7D, and in the vertical direction, the length value gradually decreases from 1.2D in the middle to the top and bottom respectively, and the horizontal length values of the top and bottom are 1.2D-2a, and the characteristic parameter a=0.16D~0.25D.

2. A wet etching groove with a special shape, characterized in that: A wafer holder for placing a wafer is provided in the etching tank. The specially shaped etching tank is obtained by symmetrically trimming and deforming the front and rear sides of a rectangular etching tank. The rectangular etching tank has a horizontal length of 1.2D in the front-to-back direction, a width of 1.7D and a height of 1.7D along the length direction of the wafer holder, where D is the diameter of the wafer. The shape obtained by symmetrically trimming and deforming the front and back sides of the top and bottom of the rectangular etched groove is: an arc cuboid, whose vertical cross-section parallel to the wafer direction is a rounded rectangle; the width and height of the etched groove remain unchanged, both 1.7D, and the length of the top and bottom is The characteristic parameter b is the radius of the circle where the fillet is located, and b=0.88D~0.95D.

3. A wet etching groove with a special shape, characterized in that: A wafer holder for placing a wafer is provided in the etching tank. The specially shaped etching tank is obtained by symmetrically trimming and deforming the front and rear sides of a rectangular etching tank. The rectangular etching tank has a horizontal length of 1.2D in the front-to-back direction, a width of 1.7D and a height of 1.7D along the length direction of the wafer holder, where D is the diameter of the wafer. The shape of the etched groove with a special shape after symmetrical trimming and deformation is: a deformed cuboid with elliptical arc surfaces on the front and rear sides, and its vertical section parallel to the wafer direction is a deformed rectangle with elliptical arcs on both sides; the width of the etched groove is 1.7D, the height is 1.7D, and the length value gradually decreases in the vertical direction from 1.2D in the middle to the top and bottom ends respectively. The short radius of the ellipse where the elliptical arc of the deformed rectangle is located is R1 = 0.6D, and the long radius R2 = 0.96D~1.07D.

4. The wet-etched groove with a special shape according to any one of claims 1 to 3, characterized in that: The diameter of the wafer is D=200-400 mm.

5. A trench wet etching device, characterized in that: The etching groove of the groove type wet etching equipment is a wet etching groove with a special shape as described in any one of claims 1 to 4.

6. The trench wet etching equipment according to claim 5, characterized in that: include: An etching tank for containing etching liquid; A wafer holder is installed in the etching groove, and the wafer holder has periodic protrusions, and grooves are formed between adjacent protrusions for supporting the wafer; The liquid inlet pipe is located below the wafer support, and the liquid inlet of the liquid inlet pipe faces upward, and is used for injecting etching liquid into the etching tank.

7. The trench wet etching equipment according to claim 6, characterized in that: The tank-type wet etching equipment is further provided with an overflow circulation channel, and the overflow circulation channel is connected to the tank wall of the etching tank and the liquid inlet pipe.

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