Wafer ultrasonic cleaning protection plate and method

Abstract

The invention provides a wafer ultrasonic cleaning protection plate and method. The wafer ultrasonic cleaning protection plate comprises a substrate, and a wafer supporting part is arranged on the periphery of the substrate; a plurality of flow guide holes are formed in the surface of the base plate; the surface, facing one side of the wafer, of the substrate is arranged to be a microstructure with continuous fluctuating, and the maximum distance between the adjacent fluctuating microstructures meets a preset threshold value so as to control the acting position of the explosion acting force of bubbles with different diameters generated by ultrasonic cleaning; for the bubbles with the diameter larger than the maximum distance, the generation of the bubbles with the diameter can be hindered through the fluctuating microstructure, so that the impact force generated by the explosion of the bubbles acts on the microstructure instead of directly acting on the surface of the wafer; for the bubbles with the diameter smaller than the maximum spacing, the influence of the surface curvature of the fluctuating microstructure on the bubbles with the diameter is close to the influence of a plane, so that the damage to the wafer caused by the bubbles with larger impact force appearing at different frequencies is improved, and the damage caused by bubble explosion can be prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor processing, and in particular to a wafer ultrasonic cleaning protection plate and method. Background Art

[0002] Ultrasonic cleaning is currently the main method for wafer cleaning. It applies a periodic sound field in the liquid to cause the liquid to exhibit microscopic periodic motion. When the motion is intense enough, vacuum bubbles will be periodically generated in the liquid. The impact force generated by the explosion of the bubbles is used to clean the surface of the wafer, effectively removing particles, organic matter, metal ions and other pollutants on the wafer surface.

[0003] In the existing ultrasonic cleaning process, at the lower frequency stage, the cleaning energy is high and the impact force generated is large, causing the surface of the cleaned wafer to be damaged, which directly affects the quality of the wafer and even directly causes the wafer to be scrapped. Summary of the invention

[0004] The present invention provides a wafer ultrasonic cleaning protection plate to prevent the wafer from being damaged by bubbles with greater impact force appearing at a lower frequency stage during ultrasonic cleaning, especially for different surfaces of the wafer at different cleaning frequencies, so as to improve the cleaning yield of the wafer in different cleaning processes.

[0005] A wafer ultrasonic cleaning protection plate comprises a substrate, a wafer support portion is arranged at the peripheral portion of the substrate; a plurality of guide holes are arranged on the surface of the substrate; the surface of the substrate facing the wafer is arranged as a microstructure with continuous ups and downs, and the maximum spacing between adjacent microstructures with ups and downs meets a preset threshold.

[0006] Of course, the maximum spacing between adjacent undulating microstructures satisfies a preset threshold value to control the position where the explosion force of bubbles of different diameters generated during ultrasonic cleaning acts.

[0007] Furthermore, the continuously undulating microstructures have different heights and structural shapes at different positions of the substrate, and the maximum spacing between adjacent undulating microstructures meets a preset threshold.

[0008] Optionally, in some other embodiments, the microstructure with continuous ups and downs is a microstructure with continuous periodic changes in ups and downs, and the maximum spacing between adjacent ups and downs microstructures meets a preset threshold.

[0009] Furthermore, the preset threshold d 许用 Calculated by the following formula:

[0010]

[0011] In the above formula, P max is the maximum pressure value generated by ultrasonic destruction, and d is the bubble diameter at which ultrasonic destruction generates the maximum pressure; d 许用 The maximum diameter of the wafer that can accept bubble explosion, i.e., the preset threshold; P 许用 is the maximum pressure value that the wafer can withstand; T is the empirical value, T∈[0,100], K is the correction factor, K∈[1,2], H is the distance from the center of the cavitation bubble to the wall, R0 is the initial radius of the cavitation bubble, is the cavitation distribution coefficient, p 大气压 is the atmospheric pressure, p 饱和蒸气压 is the saturated vapor pressure, I is the power during ultrasonic cleaning, c is the speed of sound in water, ρ 水 is the density of water; ω0 is the ultrasonic frequency, ρ 水 is the density of water, γ is the specific heat, p0 is the hydrostatic pressure, and σ is the surface tension;

[0012] The maximum spacing between adjacent high-low undulating microstructures meets a preset threshold, specifically, the maximum spacing between adjacent high-low undulating microstructures h≤d 许用 .

[0013] In some other implementations, the wafer and the substrate are stacked, and a distance D between the wafer surface and the substrate is greater than or equal to 1.5 times the maximum spacing h.

[0014] Furthermore, it also includes a plurality of guide grooves, and the plurality of guide grooves are formed on the surface of the substrate facing the wafer.

[0015] Furthermore, the support portion is located at the peripheral portion of the substrate and is used to accommodate and support the wafer; the support portion includes an annular step structure, and the wafer is accommodated in the annular step structure.

[0016] At the same time, the present invention also provides a wafer ultrasonic cleaning method, the method comprising the following steps:

[0017] (1) providing an ultrasonic cleaning protection plate, wherein the surface of the base of the protection plate facing the wafer has a continuously undulating microstructure;

[0018] (2) placing the surface of the protection plate having the microstructure toward the wafer, and stacking the protection plate and the wafer; when stacking, the distance between the protection plate and the wafer is greater than or equal to 1.5 times the maximum spacing between adjacent high and low undulating microstructures;

[0019] (3) Turn on the ultrasonic cleaning equipment to complete the ultrasonic cleaning of the wafer.

[0020] Furthermore, in step (1), the maximum spacing between adjacent high and low undulating microstructures satisfies a preset threshold.

[0021] In detail, the preset threshold d 许用 Calculated by the following formula:

[0022]

[0023] In the above formula, P max is the maximum pressure value generated by ultrasonic destruction, and d is the bubble diameter at which ultrasonic destruction generates the maximum pressure; d 许用 The maximum diameter of the wafer that can accept bubble explosion, i.e., the preset threshold; P 许用 is the maximum pressure value that the wafer can withstand; T is the empirical value, T∈[0,100], K is the correction factor, K∈[1,2], H is the distance from the center of the cavitation bubble to the wall, R0 is the initial radius of the cavitation bubble, is the cavitation distribution coefficient, p 大气压 is the atmospheric pressure, p 饱和蒸气压 is the saturated vapor pressure, I is the power during ultrasonic cleaning, c is the speed of sound in water, ρ 水 is the density of water; ω0 is the ultrasonic frequency, ρ 水 is the density of water, γ is the specific heat, p0 is the hydrostatic pressure, and σ is the surface tension;

[0024] The maximum spacing between adjacent high-low undulating microstructures meets a preset threshold, specifically, the maximum spacing between adjacent high-low undulating microstructures h≤d 许用 .

[0025] The present invention defines that the surface of the substrate facing the wafer side is set to have a microstructure with continuous ups and downs, and the maximum spacing between adjacent high and low undulating microstructures meets a preset threshold; by limiting the microstructure, the maximum spacing between adjacent high and low undulating microstructures is controlled within a certain range, and the generation of bubbles of a certain diameter is controlled by limiting the distance of different undulating microstructures, so that bubbles with a diameter greater than the maximum spacing are not generated, and only bubbles with a diameter less than or equal to the maximum spacing are generated.

[0026] For bubbles with a diameter larger than the maximum spacing, due to surface tension and microstructure design, the undulating microstructure can hinder the generation of bubbles with a diameter larger than the maximum spacing. The microstructure will adsorb and affect the generation of this type of bubbles, so that the impact force generated by the explosion of this type of bubbles mainly acts on the microstructure of the substrate, rather than directly on the surface of the wafer, thereby preventing damage caused by the explosion of bubbles of this diameter.

[0027] For bubbles with diameters smaller than the maximum spacing, the effect of the surface curvature of the undulating microstructure on bubbles of this diameter is close to that of a plane, so the cycle from bubble generation to destruction is less affected by the microstructure, which can reduce the impact of bubbles of certain diameters on the wafer surface. This can improve the damage to the wafer caused by bubbles with large impact forces at different frequency stages during ultrasonic cleaning, and improve product integrity during wafer cleaning.

[0028] The positions where the explosion forces of bubbles of different diameters act are controlled in the above manner, thereby achieving damage-preventing cleaning of the wafer surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A schematic diagram of a wafer ultrasonic cleaning protection plate provided by the present invention;

[0031] Figure 2 A schematic diagram of a substrate structure of a wafer ultrasonic cleaning protection plate provided by the present invention Figure 1 ;

[0032] Figure 3 A schematic diagram of a substrate structure of a wafer ultrasonic cleaning protection plate provided by the present invention Figure 2 ;

[0033] Figure 4 A schematic diagram of the microstructure of a wafer ultrasonic cleaning protection plate substrate provided by the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme 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. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] In order to solve the problem in the prior art that the surface of the cleaned wafer is damaged due to the impact force generated by the high cleaning energy, the present invention provides a wafer ultrasonic cleaning protection plate to improve the cleaning yield of the wafer in different cleaning processes.

[0037] like Figures 1-2 As shown, a wafer ultrasonic cleaning protection plate 100 includes a substrate 10, the shape of the substrate 10 is adapted to the shape of the wafer, and a wafer support portion 20 is arranged at the peripheral portion of the substrate 10; a plurality of through guide holes 30 are arranged on the surface of the substrate 10, and the surface of the substrate 10 facing the wafer side is arranged to have a microstructure with continuous ups and downs, and the maximum spacing between adjacent ups and downs microstructures meets a preset threshold.

[0038] Of course, the maximum spacing between adjacent undulating microstructures satisfies a preset threshold value to control the position where the explosion force of bubbles of different diameters generated during ultrasonic cleaning acts.

[0039] Specifically, the "peripheral portion" described in the present invention refers to the peripheral portion of the wafer edge, which is away from the structure area where the wafer may exist. Figure 1 The wafer ultrasonic cleaning protection plate 100 includes a substrate 10. The outer shape and structure of the substrate 10 are adapted to the shape of the wafer. For example, both are circular, that is, the structures and shapes of the two are the same.

[0040] In practice, the maximum spacing between adjacent high and low undulating microstructures satisfies a preset threshold, that is, the spacing between any adjacent undulating microstructures is less than or equal to the preset threshold, which satisfies the limitation of the present invention on the microstructure.

[0041] A wafer support portion 20 is provided at the periphery of the substrate 10. Figure 1 As shown, the support portion 20 is located at the peripheral portion of the substrate 10 and is used to accommodate and support the wafer. Specifically, the support portion 20 includes an annular step structure, and the wafer is accommodated in the annular step structure.

[0042] A plurality of through-going guide holes 30 are provided on the surface of the substrate 10 . The guide holes 30 penetrate the substrate 10 . The number and the arrangement positions of the guide holes 30 are not limited in the present invention and are arranged during ultrasonic cleaning.

[0043] Further, if Figure 2-3 As shown, the surface of the substrate 10 facing the wafer 40 is configured to have a microstructure with continuous ups and downs, and the maximum spacing h between adjacent microstructures with ups and downs meets a preset threshold.

[0044] exist Figure 3 In the embodiment, the microstructure with continuous high and low fluctuations has different heights and structural shapes at different positions, and has a random microstructure with concave and convex changes. In this embodiment, the spacing between adjacent microstructures is different, and the maximum value among several spacings is used as the maximum spacing, and the maximum spacing h between any adjacent random microstructures with concave and convex changes is limited to meet the preset threshold. It can be known that the spacing of random microstructures with concave and convex changes at different positions is different. This embodiment uses the maximum spacing h of random microstructures with any adjacent concave and convex changes at different positions as a quantitative parameter. When the maximum spacing h of any adjacent random microstructures with concave and convex changes is limited within the range of the preset threshold, it means that the spacing between any adjacent undulating microstructures is less than or equal to the preset threshold. At this time, the protective plate with a microstructure formed can prevent the generation of bubbles with larger diameters to prevent their impact and explosion damage to the surface of the wafer.

[0045] In other embodiments, the microstructure is a high-low undulation microstructure with continuous periodic changes, a concave-convex microstructure with periodic changes, and the maximum spacing h between adjacent high-low undulation microstructures meets a preset threshold, such as Figure 2 As shown; in this embodiment, the maximum spacing h of the periodically changing concave-convex microstructures at different positions is the same, that is, the spacing between periodically adjacent structures is the maximum spacing, and the spacing between any periodic structures is the same. The periodic change indicated in this embodiment refers to the situation where the shape and / or height of the microstructure presents continuous periodic changes. Figure 4 A certain type of microstructure with continuous periodic changes in height and depth is shown in FIG. The maximum spacing between connected microstructures is h. Figure 4 The microstructure in the example is only an example, and also includes microstructures with different shapes but the same spacing between adjacent microstructures; or microstructures with different heights but the same spacing between adjacent microstructures; etc. The present invention does not list all microstructures, and as long as they are within the scope of the present invention, they belong to the content for protection of the present invention.

[0046] In the above two embodiments, the continuously undulating microstructure has different heights and structural shape changes at different positions; and / or; a concave-convex microstructure with periodic changes; both belong to the content requested for protection by the present invention and belong to the continuously undulating microstructure defined by the present invention.

[0047] The continuous undulating microstructure in the present invention can be formed by various surface treatment processes such as deposition, sputtering, and etching.

[0048] Further, in more detail, in order to solve the problem that the surface of the cleaned wafer is damaged due to the impact force generated by the high cleaning energy, the present invention stipulates that the surface of the substrate 10 facing the wafer side is set to have a microstructure with continuous ups and downs, and the maximum spacing between adjacent high and low undulating microstructures meets a preset threshold; by limiting the microstructure, the maximum spacing between adjacent high and low undulating microstructures is controlled within a certain range, and the generation of bubbles of a certain diameter is controlled by limiting the distance of different undulating microstructures, so that bubbles with a diameter greater than the maximum spacing are not generated, and only bubbles with a diameter less than or equal to the maximum spacing are generated.

[0049] For bubbles with a diameter greater than the maximum spacing, due to surface tension and microstructure design, the generation of bubbles with a diameter greater than the maximum spacing can be hindered by the undulating microstructure. The microstructure will adsorb and affect the generation of this type of bubbles, so that the impact force generated by the explosion of this type of bubbles mainly acts on the microstructure of the substrate; for bubbles with a diameter less than the maximum spacing, since the surface curvature of the undulating microstructure has an effect on bubbles of this diameter that is close to the effect of the plane, the cycle from bubble generation to destruction is less affected by the microstructure, thereby controlling the impact of bubbles on the wafer surface. In this way, the damage to the wafer caused by bubbles with large impact forces at different frequency stages during ultrasonic cleaning can be improved, and the product integrity during wafer cleaning can be improved. That is, the position of the explosion force of bubbles of different diameters generated during ultrasonic cleaning can be controlled by designing adjacent undulating microstructures.

[0050] Furthermore, in order to further determine whether the maximum spacing h between adjacent high-low undulating microstructures meets a preset threshold, the present invention specifically:

[0051] During ultrasonic cleaning, the impact force generated by the explosion of the bubbles cleans the wafer surface. The maximum pressure generated by ultrasonic destruction is proportional to the cube of the bubble diameter, that is:

[0052] P max =ad 3 (1)

[0053] In formula (1), P max is the maximum pressure value generated by ultrasonic destruction, a is the bubble diameter coefficient, and d is the bubble diameter at which ultrasonic destruction generates the maximum pressure; Pmax The unit is MPa.

[0054] therefore:

[0055] In formula (2), d 许用 P is the maximum diameter of the wafer that can accept bubble explosion; 许用 This is the maximum pressure the wafer can withstand, which is determined by the geometric structure and properties of the material and can be found.

[0056]

[0057] In formula (3), T is an empirical value, T∈[0,100], K is a correction factor, K∈[1,2], T and K can be determined according to the material properties, H is the distance from the cavitation center to the wall, R0 is the initial radius of the cavitation bubble, is the cavitation distribution coefficient, p 大气压 is the atmospheric pressure, p 饱和蒸气压 is the saturated vapor pressure, I is the power during ultrasonic cleaning, c is the speed of sound in water, ρ 水 is the density of water. The cavitation distribution coefficient can be taken as 1.

[0058]

[0059] In formula (4), ω0 is the ultrasonic frequency, d is the bubble diameter, and ρ 水 is the density of water, γ is the specific heat, p0 is the hydrostatic pressure, and σ is the surface tension.

[0060] By using formulas (2) to (4), P is calculated by formulas (3) and (4) respectively. max and d, and then calculate d using formula 2 许用 ,in,

[0061] In the present invention, d 许用 The preset threshold value defined in the present invention is used to judge the maximum diameter at different powers during ultrasonic cleaning and determine the maximum spacing between adjacent high and low undulating microstructures to adapt to different ultrasonic cleaning environments.

[0062] Based on the above, d 许用 This is the preset threshold value defined in this application. Therefore, the maximum spacing h≤d under different powers is defined. 许用; In this application, the maximum spacing between adjacent high and low undulating microstructures is defined as less than or equal to the maximum diameter of the bubble corresponding to the maximum pressure value that the wafer can withstand, so as to prevent the generation of bubbles with larger diameters, so that the diameter of the bubbles passing through the protective plate meets the preset requirements to prevent the impact force generated by the bubble explosion. Based on this, the surface of the substrate 10 facing the wafer is defined as a microstructure with continuous high and low undulations, and the maximum spacing between adjacent high and low undulating microstructures in the microstructure is defined to satisfy h≤d 许用 , thereby determining the spacing between different undulating structures in the microstructure.

[0063] Of course, in order to further improve the cleaning effect of the wafer surface and prevent the wafer surface from being damaged, during ultrasonic cleaning, the protection plate and the wafer are stacked to limit the distance D between the wafer surface and the substrate to be greater than or equal to 1.5 times the maximum spacing, that is, D ≥ 1.5h, so as to control the position and distance of the impact force generated by the bubble explosion on the wafer surface and control the degree of cleaning.

[0064] Furthermore, the wafer ultrasonic cleaning protection plate 100 also includes a plurality of guide grooves 50, which are formed on the surface of the substrate 10 facing the wafer to guide the cleaning liquid on the wafer surface to flow out of the cleaning area to prevent the cleaned pollutants from staying in the cleaning area and causing secondary pollution.

[0065] In the present invention, based on a plurality of guide holes 30, the ultrasonic liquid flow is driven by ultrasonic energy or external power, flows from under the protective plate through the guide holes 30 into the cleaning area of ​​the wafer 40, directly contacts the surface of the wafer, and removes the contaminants cleaned from the surface of the wafer from the surface of the workpiece, thereby achieving efficient cleaning without damaging the surface of the wafer.

[0066] The positions where the explosion forces of bubbles of different diameters act are controlled in the above manner, thereby achieving damage-preventing cleaning of the wafer surface.

[0067] Furthermore, the present invention provides experimental data at different ultrasonic frequencies, including 20 to 1100 kHz:

[0068] <![CDATA[Frequency ω0 (kHz)]]> Bubble diameter d(μm) 20 150 140 21 213 14 355 8.5 515 5.8 647 4.6 875 3.4 1000 3.0 1056 2.8 1100 2.7

[0069] At different ultrasonic frequencies, the size of the bubble diameter d is controlled to calculate the d at different ultrasonic frequencies. 许用 , and thereby obtain the maximum spacing between different undulating structures in the microstructure.

[0070] In this way, the spacing or distance between the continuous high and low undulating microstructures is determined, thereby achieving control of ultrasonic cleaning bubbles to overcome the problems in the prior art.

[0071] At the same time, the present invention provides a method for ultrasonic cleaning of a wafer, the method comprising the following steps:

[0072] (1) providing an ultrasonic cleaning protection plate, wherein the surface of the base of the protection plate facing the wafer has a continuously undulating microstructure;

[0073] (2) placing the surface of the protection plate with the microstructure facing the wafer, and stacking the protection plate and the wafer; when stacking, the distance between the protection plate and the wafer is greater than or equal to 1.5 times the maximum spacing between adjacent high and low undulating microstructures;

[0074] (3) Turn on the ultrasonic cleaning equipment to complete the ultrasonic cleaning of the wafer.

[0075] In step (1), the maximum spacing between adjacent high and low undulating microstructures meets a preset threshold.

[0076] Furthermore, the preset threshold d 许用 Calculated by the following formula:

[0077]

[0078] In the above formula, P max is the maximum pressure value generated by ultrasonic destruction, and d is the bubble diameter at which ultrasonic destruction generates the maximum pressure; d 许用 The maximum diameter of the wafer that can accept bubble explosion, i.e., the preset threshold; P 许用 is the maximum pressure value that the wafer can withstand; T is the empirical value, T∈[0,100], K is the correction factor, K∈[1,2], H is the distance from the center of the cavitation bubble to the wall, R0 is the initial radius of the cavitation bubble, is the cavitation distribution coefficient, p 大气压 is the atmospheric pressure, p 饱和蒸气压 is the saturated vapor pressure, I is the power during ultrasonic cleaning, c is the speed of sound in water, ρ 水 is the density of water; ω0 is the ultrasonic frequency, ρ 水 is the density of water, γ is the specific heat, p0 is the hydrostatic pressure, and σ is the surface tension;

[0079] The maximum spacing between adjacent high-low undulating microstructures meets a preset threshold, specifically, the maximum spacing between adjacent high-low undulating microstructures h≤d 许用 .

[0080] The present invention defines that the surface of the substrate facing the wafer side is set to have a microstructure with continuous ups and downs, and the maximum spacing between adjacent high and low undulating microstructures meets a preset threshold; by limiting the microstructure, the maximum spacing between adjacent high and low undulating microstructures is controlled within a certain range, and the generation of bubbles of a certain diameter is controlled by limiting the distance of different undulating microstructures, so that bubbles with a diameter greater than the maximum spacing are not generated, and only bubbles with a diameter less than or equal to the maximum spacing are generated.

[0081] For bubbles with a diameter larger than the maximum spacing, due to surface tension and microstructure design, the undulating microstructure can hinder the generation of bubbles with a diameter larger than the maximum spacing. The microstructure will adsorb and affect the generation of this type of bubbles, so that the impact force generated by the explosion of this type of bubbles mainly acts on the microstructure of the substrate, rather than directly on the surface of the wafer, thereby preventing damage caused by the explosion of bubbles of this diameter.

[0082] For bubbles with diameters smaller than the maximum spacing, the effect of the surface curvature of the undulating microstructure on bubbles of this diameter is close to that of a plane, so the cycle from bubble generation to destruction is less affected by the microstructure, which can reduce the impact of bubbles of certain diameters on the wafer surface. This can improve the damage to the wafer caused by bubbles with large impact forces at different frequency stages during ultrasonic cleaning, and improve product integrity during wafer cleaning.

[0083] The positions where the explosion forces of bubbles of different diameters act are controlled in the above manner, thereby achieving damage-preventing cleaning of the wafer surface.

[0084] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer ultrasonic cleaning protection plate, comprising a substrate, a wafer support portion is arranged at the peripheral portion of the substrate; a plurality of through guide holes are arranged on the surface of the substrate; the surface of the substrate facing the wafer is arranged to have a microstructure with continuous ups and downs, and the maximum spacing between adjacent microstructures with ups and downs meets a preset threshold.

2. A wafer ultrasonic cleaning protection plate according to claim 1, characterized in that: The continuously undulating microstructures have different heights and structural shapes at different positions of the substrate, and the maximum spacing between adjacent undulating microstructures meets a preset threshold.

3. The wafer ultrasonic cleaning protection plate according to claim 1, characterized in that: The continuously undulating microstructure is a microstructure with continuous periodic changes, and the maximum spacing between adjacent microstructures with high and low fluctuations meets a preset threshold.

4. A wafer ultrasonic cleaning protection plate according to any one of claims 1 or 2, characterized in that: The preset threshold d 许用 Calculated by the following formula: In the above formula, P max is the maximum pressure value generated by ultrasonic destruction, and d is the bubble diameter at which ultrasonic destruction generates the maximum pressure; d 许用 The maximum diameter of the wafer that can accept bubble explosion, i.e., the preset threshold; P 许用 is the maximum pressure value that the wafer can withstand; T is the empirical value, T∈[0,100], K is the correction factor, K∈[1,2], H is the distance from the center of the cavitation bubble to the wall, R0 is the initial radius of the cavitation bubble, is the cavitation distribution coefficient, p 大气压 is the atmospheric pressure, p 饱和蒸气压 is the saturated vapor pressure, I is the power during ultrasonic cleaning, c is the speed of sound in water, ρ 水 is the density of water; ω0 is the ultrasonic frequency, ρ 水 is the density of water, γ is the specific heat, p0 is the hydrostatic pressure, and σ is the surface tension; The maximum spacing between adjacent high-low undulating microstructures meets a preset threshold, specifically, the maximum spacing between adjacent high-low undulating microstructures h≤d 许用 .

5. A wafer ultrasonic cleaning protection plate according to claim 1 or 4, characterized in that: The wafer and the substrate are stacked, and a distance D between the surface of the wafer and the substrate is greater than or equal to 1.5 times of a maximum spacing h.

6. The wafer ultrasonic cleaning protection plate according to claim 4, characterized in that: It also includes a plurality of guide grooves, which are formed on the surface of the substrate facing the wafer.

7. The wafer ultrasonic cleaning protection plate according to claim 6, characterized in that: The support portion is located at the peripheral portion of the substrate and is used to accommodate and support the wafer; the support portion includes an annular step structure, and the wafer is accommodated in the annular step structure.

8. A wafer ultrasonic cleaning method, characterized in that: The method comprises the following steps: (1) providing an ultrasonic cleaning protection plate, wherein the surface of the base of the protection plate facing the wafer has a continuously undulating microstructure; (2) placing the surface of the protection plate having the microstructure toward the wafer, and stacking the protection plate and the wafer; when stacking, the distance between the protection plate and the wafer is greater than or equal to 1.5 times the maximum spacing between adjacent high and low undulating microstructures; (3) Turn on the ultrasonic cleaning equipment to complete the ultrasonic cleaning of the wafer.

9. A wafer ultrasonic cleaning method according to claim 8, characterized in that: In step (1), the maximum spacing between adjacent high and low undulating microstructures meets a preset threshold.

10. A wafer ultrasonic cleaning method according to claim 9, characterized in that: The preset threshold d 许用 Calculated by the following formula: In the above formula, P max is the maximum pressure value generated by ultrasonic destruction, and d is the bubble diameter at which ultrasonic destruction generates the maximum pressure; d 许用 The maximum diameter of the wafer that can accept bubble explosion, i.e., the preset threshold; P 许用 is the maximum pressure value that the wafer can withstand; T is the empirical value, T∈[0,100], K is the correction factor, K∈[1,2], H is the distance from the center of the cavitation bubble to the wall, R0 is the initial radius of the cavitation bubble, is the cavitation distribution coefficient, P 大气压 is the atmospheric pressure, p 饱和蒸气压 is the saturated vapor pressure, I is the power during ultrasonic cleaning, c is the speed of sound in water, ρ 水 is the density of water; ω0 is the ultrasonic frequency, ρ 水 is the density of water, γ is the specific heat, p0 is the hydrostatic pressure, and σ is the surface tension; The maximum spacing between adjacent high-low undulating microstructures meets a preset threshold, specifically, the maximum spacing between adjacent high-low undulating microstructures h≤d 许用 .

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