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

Abstract

The invention provides a wet etching groove with a special shape and application thereof in wet etching equipment. The groove type wet etching equipment comprises an etching groove, a wafer support used for bearing wafers and a liquid inlet pipeline used for injecting etching liquid into the etching groove. The shape of the etching groove is obtained by symmetrically trimming and deforming the front side and the rear side of the top and the bottom of the cuboid etching groove, and the length of the deformed etching groove with the special shape is gradually reduced from the middle to the top end and the bottom end in the vertical direction. According to the invention, the flow velocity of the etching liquid on the surface of the wafer can be improved, and the flow field distribution is improved, so that the uniformity of wet etching is improved, and the product yield is improved.

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 the application of the wet etching groove in wet etching equipment. Background Art

[0002] The etching process is a process of selectively corroding or stripping the surface of a semiconductor substrate or the film covering it according to the mask pattern or design requirements. The etching process is not only the basic 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] At present, there are two main etching methods: wet etching and dry plasma etching. In wet etching, the etchant is a liquid chemical mixture that reacts chemically 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 film, phosphoric acid is used to etch aluminum film, and phosphoric acid is used to etch silicon nitride film. As the main equipment for wet etching process, the trench wet etching equipment usually places the wafer in the etching tank of the trench etching equipment. After the wafer is immersed in the etching solution in the etching tank for a period of time, the unnecessary material layer on the wafer can be etched away.

[0004] In the semiconductor wet etching process, trench wet etching has always occupied a large proportion, and the process of trench etching has become more 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 the existing trench wet etching equipment, the wafer is placed on a wafer holder in the etching trench. 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 different surrounding environments of the wafers at the edge of the etching trench and the center of the etching trench will also lead to uneven etching between wafers, thereby affecting the yield of the product.

[0006] Therefore, for trench 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, wherein a wafer holder for placing a wafer is arranged in the etching groove, and 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 and rear directions is 1.15D-1.25D, the width of the etching groove along the length direction of the wafer holder is 1.65D-1.75D, and the height is 1.65D-1.75D, where 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 1.15D-1.25D in the vertical direction to the top and bottom ends, and the top length value and the bottom length value of the etching groove with a special shape are 0.4D-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 length of the rectangular etching groove in the front and rear directions is, the width of the etching groove along the length direction of the wafer holder is 1.7D, and the height is 1.7D, 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 respectively, and the top length and bottom length of the etching groove with a special shape are 0.4D~0.95D.

[0011] The present invention is further configured such that the shape of the etched groove with a special shape after 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, 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 value of the top and bottom ends is 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 a hexagon that is symmetrical in both the top and bottom and in the left and right directions.

[0013] The present invention is further configured that the etching groove with a special shape 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 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.

[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 the upper and lower parts and in both the left and right parts.

[0015] The present invention is further configured such that the shape of the etching groove with a special shape after symmetrical trimming and deformation is: a deformed rectangular parallelepiped with elliptical arc surfaces on the front and rear sides, and a vertical section thereof parallel to the wafer direction is a deformed rectangle with elliptical arcs on both sides; the width of the deformed etching groove is 1.7D, the height is 1.7D, and the length value gradually decreases from 1.2D in the middle to the top and bottom ends in the vertical direction, and the elliptical short radius R where the elliptical arc is located is 1 =0.6D, long radius R 2 =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 etching groove, and the deformed rectangle is a deformed rectangle that is symmetrical in both the upper and lower parts and in the left and right parts.

[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 distance between the center of the etching groove and the center of the wafer in the vertical direction is ≤0.1D, preferably ≤0.05D, and more preferably, the center of the etching groove and the center of the wafer are the same in the vertical direction. 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 above-mentioned wet etching groove with a special shape.

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

[0021] An etching tank, used for containing etching liquid;

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

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

[0024] The present invention is further configured such that the tank-type wet etching equipment is also 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 solution and improve the flow field distribution by designing the shape of the slot-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 The schematic diagram of the structure of a special-shaped slot-type wet etching device is that the vertical cross-section of the etching slot is hexagonal and the etching slot is octahedral.

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

[0028] Figure 3 It is a schematic diagram of the structure of a general structure slot-type wet etching equipment in which the vertical cross-section of the etching slot is a rectangle and the etching slot 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 slot-type wet etching equipment described in Examples 1 and 2 and that of a general slot-type wet etching equipment.

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

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

[0033] Figure 8 The schematic diagram of the structure of a special-shaped slot-type wet etching device is that the vertical cross-section of the etching slot is a rounded rectangle and the etching slot is a rounded cuboid.

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

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

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

[0037] Fig.12 The schematic diagram of the structure of a special-shaped slot-type wet etching device is that the etching slot cross section is a deformed rectangle with elliptical arcs on both sides, and the etching slot is a deformed cuboid with elliptical arc surfaces on the front and rear sides.

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

[0039] Fig.14 The results are compared between the wafer surface etching solution temperature of the special-shaped slot-type wet etching equipment described in Examples 6 to 8 and that of a general slot-type wet etching equipment.

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

[0041] Among them, the above Figures 5 to 7 , Figures 10-11 as well as Figures 14-15 In the figure, 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 and completely with specific embodiments and 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. 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 the present invention.

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

[0044] An etching tank, used for containing etching liquid;

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

[0046] A liquid inlet pipeline, located below the wafer support, with a liquid inlet facing upwards, for injecting etching liquid into the etching tank;

[0047] The etching groove is selected to have a special shape. The shape of the etching groove is obtained by symmetrically trimming and deforming the front and back sides of the rectangular etching groove. The horizontal length of the rectangular etching groove in the front and back direction is 1.2D, and the width of the etching groove along the length direction of the wafer holder is 1.7D, and the height is 1.7D, where D is the diameter of the wafer; the width of the etching groove with a special shape after deformation is 1.7D, and the height is 1.7D. The length value gradually decreases from the middle 1.2D to the top and bottom in the vertical direction, and the horizontal length of the top and bottom is 0.4D to 0.95D. By making the above adjustment to the shape of the etching groove, the accumulation of heat on the wafer surface can be improved, thereby improving the uniformity of wafer etching.

[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 in the vertical direction gradually decreases from 1.2D in the middle to the top and bottom ends respectively, and the horizontal length of the top and bottom ends 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 rear 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 of the front and rear 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 a rounded rectangle that 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 rectangular parallelepiped with elliptical arc surfaces on the front and rear sides, and a 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 from 1.2D in the middle to the top and bottom in the vertical direction, and the elliptical short radius R of the ellipse where the elliptical arc is located is 1.7D. 1=0.6D, long radius R 2 =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 etching groove, and the deformed rectangle is a deformed rectangle that is symmetrical in both top and bottom and left and right.

[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 in conjunction with specific embodiments.

[0058] Example 1

[0059] refer to Figure 1-2 The present 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 provided with periodic protrusions along their length direction, and grooves are formed between adjacent protrusions for carrying wafers 4; in the present 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 port 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 port 5.

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

[0061] This embodiment takes phosphoric acid wet etching of silicon nitride as an example, and uses Fluent software to simulate and compare the influence 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 schematic diagram of the general-structure slot wet etching equipment and the vertical cross-sectional diagram of the etching slot are shown in Figure 1. 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 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 that the structural parameter a of the etching groove is different. 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 that the structural parameter a of the etching groove is different. 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 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 a structural parameter 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 grooves of general structures, the etching solution flow rate of the special-shaped wet etching grooves 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. Figure 8-Figure 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 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 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 support is 1.7D, and the horizontal length of the upper and lower parts of the etching groove along the front-to-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 of the wafer surface inside the rectangular etching groove in the special shape 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 FIG. Fig.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 that the structural parameter b of the etching groove is different. In this embodiment, b=0.92D. The simulation results are shown in FIG. Fig.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 that the structural parameter b of the etching groove is different. In this embodiment, b=0.95D. The simulation results are shown in FIG. Fig.10 shown.

[0074] according to Fig.10 The results shown show that for Figures 8-9 For the etching groove of the special shape shown, 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 that the structural parameter b of the etching groove is different. In this comparative example, b=1.00D. The influence of the temperature distribution on the surface of the wafer inside the special-shaped groove wet etching equipment in this embodiment and the general structure groove wet etching equipment is simulated and compared. The simulation results are shown in FIG. Fig.11 The results show that the heat accumulation on the wafer surface worsens under the structural parameters of the etching groove, the wafer surface temperature increases, and the temperature distribution uniformity decreases, which in turn leads to a decrease in wafer etching uniformity.

[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. Fig.12 and Fig.13 The shape of the etching groove used in this embodiment is the shape obtained by symmetrically trimming and deforming the front and rear sides of the rectangular etching groove. Symmetrical trimming means symmetrical trimming on the upper and lower sides and symmetrical trimming on the front and rear sides. The deformed shape is specifically: a deformed rectangular parallelepiped with elliptical arc surfaces on the front and rear sides, and a vertical section parallel to the wafer direction is a deformed rectangle with elliptical arcs on both vertical sides. The center of the ellipse where the elliptical arc is located is consistent with the center of the corresponding vertical section of the etching groove. The deformed rectangle is symmetrical up and down and left and right. 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 etching groove in the front and rear directions gradually decreases from the length 1.2D in the middle of the vertical direction to the top and bottom. The short radius R of the ellipse where the elliptical arc is located 1 =0.6D, long radius R 2 =0.96D~1.07D. In this embodiment, R2 =0.96D. Fluent software was used to simulate and compare the influence of the temperature distribution on the wafer surface inside the special-shaped slot-type wet etching equipment and the general-structure slot-type wet etching equipment described in Example 1. The simulation results are shown in Fig.14 shown.

[0079] Example 7

[0080] Use Figures 12-13 The special shape etching groove shown in the figure is different from that of Example 6 only in that the structural parameter R of the etching groove 2 Different, in this embodiment, R 2 =1.03D. The simulation results are as follows Fig.14 shown.

[0081] Example 8

[0082] Use Figures 12-13 The special shape etching groove shown in the figure is different from that of Example 6 only in that the structural parameter R of the etching groove 2 =1.07D. The simulation results are as follows Fig.14 shown.

[0083] according to Fig.14 The results shown show that for Figures 12-13 The special shape of the etched groove shown in the figure, when the structural parameter R 2 When it 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 12-13 The special shape etching groove shown in the figure is different from that of Example 6 only in that the structural parameter R of the etching groove 2 =1.10D. Fluent software was used to simulate and compare the influence of the temperature distribution on the wafer surface inside the special-shaped slot-type wet etching equipment in the comparative example and the general-structure slot-type wet etching equipment described in Example 1. The simulation results are shown in FIG. Fig.15 As shown. Fig.15 It can be seen from the results that in the etching groove under the comparative structural parameters, 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 only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A wet etching groove with a special shape, characterized in that: A wafer holder for placing wafers is provided in the etching groove, and 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 rectangular etching groove; the horizontal length of the rectangular etching groove in the front and rear directions is 1.15D~1.25D, the width of the etching groove along the length direction of the wafer holder is 1.65D~1.75D, and the height is 1.65D~1.75D, 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 1.15D~1.25D in the vertical direction to the top and bottom respectively, and the top length value and the bottom length value of the etching groove with a special shape are 0.4D~0.95D.

2. The wet etching groove with a special shape according to claim 1, characterized in that: 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 length of the rectangular etching groove in the front and rear directions is 1.7D, and the height is 1.7D along the length direction of the wafer holder, where 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.

3. The wet-etched groove with a special shape according to claim 1 or 2, characterized in that: The shape of the specially shaped etching groove after trimming and deformation is: an octahedron, and its vertical cross-section parallel to the wafer direction is a hexagon; the width and height values ​​of the deformed etching groove remain unchanged, both of which are 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.

4. The wet etching groove with a special shape according to claim 1 or 2, characterized in that: The shape obtained by symmetrically trimming and deforming the front and rear sides of the top and bottom of the rectangular etching groove is: an arc rectangular parallelepiped, and its vertical section parallel to the wafer direction is a rounded rectangle; the width and height of the etching groove remain unchanged, both are 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.

5. The wet-etched groove with a special shape according to claim 1 or 2, characterized in that: The shape of the etching 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 section parallel to the wafer direction is a deformed rectangle with elliptical arcs on both sides; the width of the etching groove is 1.7D, the height is 1.7D, and the length value gradually decreases from 1.2D in the middle to the top and bottom in the vertical direction, 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 is R2=0.96D~1.07D.

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

7. 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 6.

8. The trench wet etching equipment according to claim 7, characterized in that: include: An etching tank, used for containing an etching solution; A wafer holder is installed in the etching groove, the wafer holder has periodic protrusions, and grooves are formed between adjacent protrusions for carrying wafers; The liquid inlet pipeline is located below the wafer support, and the liquid inlet of the liquid inlet pipeline faces upward, and is used for injecting etching liquid into the etching groove.

9. The trench wet etching equipment according to claim 8, characterized in that: The tank-type wet etching equipment is also 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 pipeline.

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