Method and device for cleaning edge of SOI (Silicon On Insulator) substrate

Abstract

The invention relates to a method and a device for cleaning the edge of an SOI (Silicon On Insulator) substrate. The method for cleaning the edge of the SOI substrate comprises the following steps of: providing the SOI substrate to be cleaned, wherein the SOI substrate comprises a front surface and a back surface which are oppositely distributed; spraying chemical cleaning liquid to the edge area of the front surface of the SOI substrate, and spraying gas to the back surface of the SOI substrate at the same time to form a gas protection layer covering the back surface of the SOI substrate; and washing the SOI substrate by using deionized water, and removing the residual chemical cleaning liquid. According to the invention, corrosion of chemical cleaning liquid to the back surface of the SOI substrate is reduced and even avoided, so that the cleaned SOI substrate meets strict quality requirements of an integrated circuit on the surface of the SOI substrate.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a method and a device for cleaning an edge of an SOI substrate. Background Art

[0002] With the continuous development of integrated circuit manufacturing technology, the requirements for substrate surface quality are getting higher and higher. The SOI (Silicon on Insulator) substrate has a unique "silicon / insulator layer / silicon" three-layer structure, which needs to be chamfered during the manufacturing process. However, after the chamfering process, impurities such as silicon chips will remain at the edge of the top silicon of the SOI substrate. The traditional cleaning method is to immerse the entire SOI substrate in a cleaning solution. However, this immersion cleaning method will corrode the underlying silicon on the back of the SOI substrate, resulting in a decrease in the quality of the underlying silicon on the back of the SOI substrate, affecting the smooth implementation of subsequent semiconductor device manufacturing processes. Moreover, the immersion cleaning method has limited cleaning ability and cannot fully remove impurities remaining at the edge of the top silicon, and cannot meet the strict requirements of integrated circuit manufacturing for substrate surface quality.

[0003] Therefore, how to prevent the underlying silicon on the back of the SOI substrate from being corroded while improving the cleaning effect of the edge of the SOI substrate to ensure the smooth implementation of subsequent semiconductor manufacturing processes is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] The present invention provides a method and device for cleaning an edge of an SOI substrate, which are used to improve the cleaning effect of the edge of the SOI substrate while preventing the underlying silicon on the back of the SOI substrate from being corroded, so as to ensure the smooth implementation of subsequent semiconductor manufacturing processes.

[0005] According to some embodiments, the present invention provides a method for cleaning an edge of an SOI substrate, comprising the following steps:

[0006] Providing an SOI substrate to be cleaned, wherein the SOI substrate includes a front side and a back side that are relatively distributed;

[0007] Spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate, and simultaneously spraying a gas onto the back surface of the SOI substrate to form a gas protection layer covering the back surface of the SOI substrate;

[0008] The SOI substrate is rinsed with deionized water to remove the residual chemical cleaning solution.

[0009] In some embodiments, before spraying the chemical cleaning liquid to the edge area of the front surface of the SOI substrate and simultaneously spraying the gas to the back surface of the SOI substrate, the following steps are further included:

[0010] Placing the SOI substrate on a carrier;

[0011] The supporting platform is driven to rotate.

[0012] In some embodiments, the specific steps of spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate and simultaneously spraying a gas onto the back surface of the SOI substrate include:

[0013] The chemical cleaning liquid is sprayed obliquely from above the carrier platform to the edge area of the front surface of the SOI substrate.

[0014] In some embodiments, the angle between the spray direction of the chemical cleaning liquid and the front surface of the SOI substrate is 15 degrees to 75 degrees.

[0015] In some embodiments, the specific steps of spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate and simultaneously spraying a gas onto the back surface of the SOI substrate include:

[0016] The gas is vertically injected from directly below the SOI substrate to the back surface of the SOI substrate to form a gas protection layer covering the entire back surface of the SOI substrate.

[0017] In some embodiments, the specific steps of spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate and simultaneously spraying a gas onto the back surface of the SOI substrate include:

[0018] The gas is sprayed obliquely from the side surface of the carrier to the back surface of the SOI substrate to form a gas protection layer covering the entire back surface of the SOI substrate.

[0019] In some embodiments, the gas is nitrogen or an inert gas, and the chemical cleaning liquid is an alkaline cleaning agent.

[0020] According to other embodiments, the present invention further provides a cleaning device comprising:

[0021] A carrier, used for carrying an SOI substrate to be cleaned, wherein the SOI substrate includes a front surface and a back surface that are relatively distributed;

[0022] A first nozzle, located above the carrier platform, is used to spray a chemical cleaning liquid onto an edge area of the front surface of the SOI substrate;

[0023] a second nozzle, for spraying gas onto the back side of the SOI substrate to form a gas protection layer covering the back side of the SOI substrate;

[0024] The flushing structure is used to flush the SOI substrate with deionized water to remove the residual chemical cleaning solution.

[0025] In some embodiments, the spray angle of the first nozzle is 15 degrees to 75 degrees.

[0026] In some embodiments, the second nozzle is located in the carrier, and the second nozzle is capable of vertically spraying the gas onto the back side of the SOI substrate; or;

[0027] The second nozzle is located on a side of the supporting platform, and the second nozzle obliquely sprays the gas onto the back side of the SOI substrate.

[0028] The present invention provides a method and apparatus for cleaning the edge of an SOI substrate. This method sprays a chemical cleaning liquid onto the edge region of the front surface of the SOI substrate to clean impurities such as silicon chips from the edge region of the front surface of the SOI substrate, and simultaneously sprays gas onto the back surface of the SOI substrate to form a gas protective layer covering the back surface of the SOI substrate. This reduces or even prevents corrosion of the back surface of the SOI substrate by the chemical cleaning liquid, thereby ensuring the quality of the back surface of the SOI substrate and the smooth progress of subsequent semiconductor manufacturing processes. Furthermore, the present invention uses a method of spraying a chemical cleaning liquid to flush away impurities from the edge region of the front surface of the SOI substrate, resulting in a cleaning effect superior to that of an immersion cleaning method, ensuring that the cleaned SOI substrate meets the stringent quality requirements of integrated circuits for the SOI substrate surface. Furthermore, the method for cleaning the edge of an SOI substrate provided by the present invention is simple to operate and inexpensive, thereby helping to improve the cleaning efficiency and cost of the SOI substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly describes the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0030] Figure 1 is a flow chart of a method for cleaning an edge of an SOI substrate in a specific embodiment of the present invention;

[0031] Figure 2 1 is a schematic structural diagram of cleaning the edge area of an SOI substrate in a specific embodiment of the present invention;

[0032] Figure 3 is another structural schematic diagram of cleaning the edge area of the SOI substrate in a specific embodiment of the present invention;

[0033] Figure 4 This is a schematic structural diagram of a cleaning device in a specific embodiment of the present invention;

[0034] Figure 5 It is another structural schematic diagram of the cleaning device in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0035] The specific embodiments of the SOI substrate edge cleaning method and cleaning device provided by the present invention are described in detail below with reference to the accompanying drawings.

[0036] This embodiment provides a method for cleaning the edge of an SOI substrate. Figure 1 FIG. 1 is a flow chart of a method for cleaning the edge of an SOI substrate in a specific embodiment of the present invention. Figure 1 As shown, the method for cleaning the edge of the SOI substrate includes the following steps:

[0037] Step S11, providing an SOI substrate to be cleaned, wherein the SOI substrate includes a front side and a back side that are relatively distributed;

[0038] Step S12, spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate, and simultaneously spraying a gas onto the back surface of the SOI substrate to form a gas protection layer covering the back surface of the SOI substrate;

[0039] Step S13: rinse the SOI substrate with deionized water to remove the residual chemical cleaning solution.

[0040] Figure 2 1 is a schematic structural diagram of cleaning the edge area of an SOI substrate in a specific embodiment of the present invention, wherein: Figure 2 The solid arrow in the figure indicates the direction of the chemical cleaning liquid spraying, and the dotted arrow indicates the direction of the gas spraying. In some embodiments, before spraying the chemical cleaning liquid to the edge area of the front surface 201 of the SOI substrate 20 and simultaneously spraying the gas to the back surface 202 of the SOI substrate 20, the following steps are also included:

[0041] Placing the SOI substrate 20 on a carrier;

[0042] The supporting platform is driven to rotate.

[0043] Specifically, the SOI substrate includes bottom silicon, a buried oxide layer covering the bottom silicon, and top silicon covering the surface of the buried oxide layer facing away from the bottom silicon, with the surface of the top silicon facing away from the buried oxide layer serving as the front side 201 of the SOI substrate 20, and the surface of the bottom silicon facing away from the buried oxide layer serving as the back side of the SOI substrate 20. The front side 201 of the SOI substrate 20 includes a functional area and an edge area distributed around the periphery of the functional area. The SOI substrate 20 is placed on the supporting platform with the back side 202 of the SOI substrate 20 facing the supporting platform. The supporting platform is driven to rotate, and the rotation of the supporting platform drives the SOI substrate on the supporting platform to rotate synchronously, so as to fully clean the entire edge area of the front side 201 of the SOI substrate.

[0044] When the rotation speed of the SOI substrate 20 is too slow, the chemical cleaning liquid sprayed onto the edge region of the front surface 201 of the SOI substrate 20 tends to accumulate in the edge region. When the thickness of the chemical cleaning liquid accumulated in the edge region reaches a threshold thickness, it flows along the side of the SOI substrate 20 to the back surface 202 of the SOI substrate 20. To reduce or even prevent the chemical cleaning liquid on the front surface 201 of the SOI substrate 20 from flowing to the back surface 202 of the SOI substrate 20, thereby further preventing the chemical cleaning liquid from corroding the back surface 202 of the SOI substrate 20, in one example, the rotation speed of the SOI substrate 20 is greater than 1000 RPM, i.e., the SOI substrate 20 rotates at a high speed during the cleaning process.

[0045] In some embodiments, as Figure 2 As shown, the specific steps of spraying the chemical cleaning liquid to the edge area of the front surface 201 of the SOI substrate 20 and simultaneously spraying the gas to the back surface 202 of the SOI substrate 20 include:

[0046] The chemical cleaning liquid is sprayed obliquely from above the carrier to the edge area of the front surface 201 of the SOI substrate 20 .

[0047] Specifically, since the edge area of the SOI substrate 20 has been chamfered, the chemical cleaning liquid is obliquely sprayed from above the carrier to the edge area of the front side 201 of the SOI substrate 20 through the first nozzle 21 while the SOI substrate 20 is rotating at a high speed. On the one hand, the cleaning area of a single spray of the chemical cleaning liquid can be increased, thereby improving the cleaning efficiency of the edge area of the SOI substrate 20; on the other hand, the obliquely sprayed chemical cleaning liquid can not only remove impurities such as silicon chips remaining on the front side 201 of the SOI substrate 20 through chemical reaction, but also use the high-pressure impact force generated by the oblique spraying to flush impurities such as silicon chips away from the front side 201 of the SOI substrate 20, thereby further improving the cleaning effect of the edge area of the SOI substrate 20.

[0048] In order to simultaneously improve the cleaning effect and cleaning efficiency of the edge area of the SOI substrate 20, in some embodiments, the angle β between the spray direction of the chemical cleaning liquid and the front surface 201 of the SOI substrate 20 is 15 degrees to 75 degrees, that is, the spray angle of the first nozzle 21 is 15 degrees to 75 degrees.

[0049] In one example, the first nozzle 21 sprays the chemical cleaning liquid at an inclined pressure of 0.5 MPa to 1 MPa to match the size and chamfer structure of the SOI substrate 20, ensuring that the entire edge area of the front surface of the SOI substrate 20 can be fully covered by the chemical cleaning liquid.

[0050] During the process of cleaning the edge area of the SOI substrate 20, the spray angle and spray pressure of the chemical cleaning liquid can be dynamically adjusted in real time, thereby adjusting the spray range of the chemical cleaning liquid to improve the flexibility and cleaning effect of the edge area of the SOI substrate 20.

[0051] In some embodiments, the specific steps of spraying a chemical cleaning liquid onto an edge region of the front surface 201 of the SOI substrate 20 and simultaneously spraying a gas onto the back surface 202 of the SOI substrate 20 include:

[0052] The gas is vertically injected from directly below the SOI substrate 20 to the back surface 202 of the SOI substrate 20 to form a gas protection layer covering the entire back surface 202 of the SOI substrate 20 .

[0053] For example, if Figure 2As shown, while the SOI substrate 20 rotates, the chemical cleaning liquid is sprayed obliquely from above the carrier platform onto the edge region of the front surface 201 of the SOI substrate 20 through the first nozzle 21, and the gas is sprayed vertically from directly below the SOI substrate 20 onto the back surface 202 of the SOI substrate 20 through the second nozzle 22, forming a gas protective layer covering the entire back surface 202 of the SOI substrate 20. This effectively cleans the edge region of the front surface 201 of the SOI substrate 20 while preventing the chemical cleaning liquid from flowing to the back surface 202 of the SOI substrate 20 through the gas protective layer, thereby preventing the chemical cleaning liquid from corroding the back surface 202 of the SOI substrate 20. The gas is sprayed vertically from directly below the SOI substrate 20 onto the back surface 202 of the SOI substrate 20, i.e., the center of the gas spray is aligned with the center of the SOI substrate 20, ensuring that the entire back surface 202 of the SOI substrate 20 is evenly covered by the gas protective layer.

[0054] In one example, the second nozzle 22 vertically sprays the gas from directly below the carrier at a flow rate of 10 L / min to 20 L / min and a pressure of 0.2 MPa to 0.5 MPa, to match the size of the SOI substrate 20 and the rotation speed of the SOI substrate 20. The high-speed rotation of the SOI substrate 20 allows the gas protective layer to more fully cover the entire backside 202 of the SOI substrate 20. For example, as the rotation speed of the SOI substrate 20 increases, the gas flow rate or pressure also increases.

[0055] During the cleaning process of the edge region of the SOI substrate 20, the injection flow rate and injection pressure of the gas can be dynamically adjusted in real time to maintain a match with the injection angle and injection pressure of the chemical cleaning liquid in real time, thereby preventing the chemical cleaning liquid from flowing to the back side 202 of the SOI substrate 20. For example, when the injection flow rate or injection pressure of the chemical cleaning liquid increases, the injection flow rate or injection pressure of the gas also increases accordingly.

[0056] Figure 3 1 is another structural diagram of cleaning the edge area of the SOI substrate in a specific embodiment of the present invention, wherein: Figure 3 The solid arrow in FIG represents the spray direction of the chemical cleaning liquid, and the dotted arrow represents the spray direction of the gas. Figure 3 As shown, the specific steps of spraying the chemical cleaning liquid to the edge area of the front surface of the SOI substrate and simultaneously spraying the gas to the back surface of the SOI substrate include:

[0057] The gas is sprayed obliquely from the side of the carrier to the back surface 202 of the SOI substrate 20 to form a gas protection layer covering the entire back surface 202 of the SOI substrate 20 .

[0058] For example, if Figure 3 As shown, while the SOI substrate 20 rotates, the first nozzle 21 sprays the chemical cleaning liquid at an angle from above the carrier onto the edge region of the front surface 201 of the SOI substrate 20, and the second nozzle 22 sprays the gas at an angle from the side of the carrier onto the back surface 202 of the SOI substrate 20, forming a gas protective layer covering the entire back surface 202 of the SOI substrate 20. This effectively cleans the edge region of the front surface 201 of the SOI substrate 20 while preventing the chemical cleaning liquid from flowing to the back surface 202 of the SOI substrate 20 through the gas protective layer, thereby preventing the chemical cleaning liquid from corroding the back surface 202 of the SOI substrate 20. Spraying the gas at an angle from the side of the carrier onto the back surface 202 of the SOI substrate 20 facilitates flexible adjustment of the gas spray angle according to actual needs, thereby further helping to prevent the chemical cleaning liquid from flowing to the back surface 202 of the SOI substrate 20.

[0059] In one example, the second nozzle 22 obliquely sprays the gas from the side of the carrier at a flow rate of 10 L / min to 20 L / min and a pressure of 0.2 MPa to 0.5 MPa, to match the size of the SOI substrate 20 and the rotation speed of the SOI substrate 20. The high-speed rotation of the SOI substrate 20 allows the gas protective layer to more fully cover the entire back surface 202 of the SOI substrate 20. For example, as the rotation speed of the SOI substrate 20 increases, the gas injection flow rate or pressure also increases.

[0060] During the cleaning process of the edge region of the SOI substrate 20, the injection angle, injection flow rate, and injection pressure of the gas can be dynamically adjusted in real time to keep them aligned with the injection angle and injection pressure of the chemical cleaning liquid, thereby preventing the chemical cleaning liquid from flowing to the back side 202 of the SOI substrate 20. For example, when the injection flow rate or injection pressure of the chemical cleaning liquid increases, the injection flow rate or injection pressure of the gas also increases accordingly.

[0061] In some embodiments, the gas is nitrogen or an inert gas, and the chemical cleaning liquid is an alkaline cleaning agent. In one example, the gas is nitrogen, and the chemical cleaning liquid is KOH.

[0062] This embodiment also provides a cleaning device, Figure 4: is a structural diagram of a cleaning device in a specific embodiment of the present invention, wherein: Figure 4 The solid arrow in FIG represents the spray direction of the chemical cleaning liquid, and the dotted arrow represents the spray direction of the gas. Figure 4 As shown, the cleaning device includes:

[0063] A carrier, used for carrying an SOI substrate 20 to be cleaned, wherein the SOI substrate 20 includes a front surface 201 and a back surface 202 that are relatively distributed;

[0064] A first nozzle 21 is located above the carrier platform and is used to spray a chemical cleaning liquid onto an edge region of the front surface 201 of the SOI substrate 20 ;

[0065] a second nozzle 22 for spraying gas onto the back side 202 of the SOI substrate 20 to form a gas protection layer covering the back side 202 of the SOI substrate 20;

[0066] The flushing structure is used to flush the SOI substrate 20 with deionized water to remove the residual chemical cleaning solution.

[0067] In some embodiments, the spraying angle of the first nozzle 21 is 15 degrees to 75 degrees.

[0068] Figure 5 is another structural diagram of a cleaning device in a specific embodiment of the present invention, wherein: Figure 5 The solid arrow in FIG represents the spray direction of the chemical cleaning liquid, and the dotted arrow represents the spray direction of the gas. In some embodiments, the second nozzle 22 is located in the carrier 40, and the second nozzle 22 can vertically spray the gas to the back side 202 of the SOI substrate 20, as shown in FIG. Figure 2 and Figure 4 as shown; or

[0069] The second nozzle 22 is located on the side of the carrier 40, and the second nozzle 22 sprays the gas obliquely to the back side 202 of the SOI substrate 20. Figure 3 and Figure 5 shown.

[0070] For example, if Figure 2 and Figure 4As shown, the carrier includes a base 40 and a limiting structure 41 located above the base 40. The SOI substrate 20 is placed on the limiting structure 41 with the back surface 202 of the SOI substrate 20 facing the base 40. The base 40 has a second nozzle 22 extending through the base 40 and aligned with the center of the SOI substrate 20. The first nozzle 21 is disposed above the carrier. While the carrier 40 rotates the SOI substrate 20, the chemical cleaning liquid is sprayed obliquely from above the carrier onto the edge of the front surface 201 of the SOI substrate 20 through the first nozzle 21, and the gas is sprayed vertically from directly below the SOI substrate 20 onto the back surface 202 of the SOI substrate 20 through the second nozzle 22, forming a gas protective layer covering the entire back surface 202 of the SOI substrate 20. This effectively cleans the edge of the front surface 201 of the SOI substrate 20 while preventing the chemical cleaning liquid from flowing to the back surface 202 of the SOI substrate 20, thereby preventing the chemical cleaning liquid from corroding the back surface 202 of the SOI substrate 20. The gas is sprayed vertically from directly below the SOI substrate 20 onto the back surface 202 of the SOI substrate 20, i.e., the center of the gas spray is aligned with the center of the SOI substrate 20, ensuring that the entire back surface 202 of the SOI substrate 20 is evenly covered by the gas protective layer.

[0071] For example, Figure 3 and Figure 5As shown, the SOI substrate 20 is placed on the supporting surface of the supporting platform 50 with the back side of the SOI substrate 20 facing the supporting platform 50. The first nozzle 21 is disposed above the supporting platform 50, and the second nozzle 22 is positioned below the supporting surface of the supporting platform and is located on the side of the supporting platform 50. As the SOI substrate 20 rotates, the first nozzle 21 sprays the chemical cleaning liquid at an angle from above the supporting platform 50 onto the edge area of the front side 201 of the SOI substrate 20, and the second nozzle 22 sprays the gas at an angle from the side of the supporting platform 50 onto the back side 202 of the SOI substrate 20, forming a gas protection layer covering the entire back side 202 of the SOI substrate 20. This effectively cleans the edge area of the front side 201 of the SOI substrate 20, while the gas protection layer blocks the chemical cleaning liquid from flowing to the back side 202 of the SOI substrate 20, thereby preventing the chemical cleaning liquid from corroding the back side 202 of the SOI substrate 20. The gas is sprayed obliquely from the side of the support platform 50 toward the back surface 202 of the SOI substrate 20, allowing for flexible adjustment of the gas spray angle according to actual needs, thereby further helping to prevent the chemical cleaning liquid from flowing onto the back surface 202 of the SOI substrate 20. In one example, there are multiple second nozzles 22, and the multiple second nozzles 22 are symmetrically distributed around the periphery of the support platform 50.

[0072] The SOI substrate edge cleaning method and cleaning device provided in this embodiment sprays a chemical cleaning liquid onto the edge region of the front side of the SOI substrate to clean impurities such as silicon chips from the edge region of the front side of the SOI substrate, and simultaneously sprays gas onto the back side of the SOI substrate to form a gas protective layer covering the back side of the SOI substrate, thereby reducing or even preventing corrosion of the back side of the SOI substrate by the chemical cleaning liquid, thereby ensuring the quality of the back side of the SOI substrate and the smooth progress of subsequent semiconductor manufacturing processes. Furthermore, this embodiment uses a spraying chemical cleaning liquid flushing method to remove impurities from the edge region of the front side of the SOI substrate, resulting in a cleaning effect superior to that of an immersion cleaning method, so that the cleaned SOI substrate meets the stringent quality requirements of the integrated circuit for the SOI substrate surface. Furthermore, the SOI substrate edge cleaning method provided in this embodiment is simple to operate and low-cost, thereby helping to improve the cleaning efficiency and cleaning cost of the SOI substrate.

[0073] The following are three embodiments of a method for cleaning the edge of an SOI substrate.

[0074] Example 1

[0075] Step 1: Place the SOI substrate on a rotating table and rotate the SOI wafer at a high speed of 1200 RPM by a rotating motor;

[0076] Step 2: Spray 30% KOH solution onto the front edge of the SOI substrate through a first nozzle to clean the front edge of the SOI substrate and remove silicon chips remaining due to chamfering; wherein the spray angle of the first nozzle is 45 degrees, the spray pressure is 0.5 MPa, and the spray range covers the entire edge area of the front of the SOI substrate; at the same time, high-purity nitrogen is introduced into the back of the SOI substrate to form a nitrogen protective layer to ensure that the back of the SOI substrate is not corroded by the KOH solution; wherein the flow rate of the high-purity nitrogen is 10 L / min, the pressure is 0.2 MPa, the nitrogen nozzle (i.e., the second nozzle) is located below the center of the back of the silicon wafer, and the spray angle is 90 degrees;

[0077] Step 3: The cleaning process is monitored in real time by a computer control system. When it is found that the silicon layer in the edge area has been completely removed, the spraying of the KOH solution is stopped;

[0078] Step 4: Rinse the SOI substrate with deionized water to remove the residual KOH solution.

[0079] Example 2

[0080] Step 1: Place the SOI substrate on a rotating table and rotate the SOI substrate at a high speed of 1500 RPM by a rotating motor;

[0081] Step 2: Spray 25% KOH solution onto the front edge of the SOI substrate through a first nozzle to clean the front edge of the SOI substrate and remove silicon chips remaining due to chamfering. The spray angle of the first nozzle is 60 degrees, the spray pressure is 0.8 MPa, and the spray range is adjusted according to the size and chamfer shape of the SOI substrate. At the same time, high-purity nitrogen is introduced into the back of the SOI substrate to form a nitrogen protective layer to ensure that the back of the SOI substrate is not corroded by the KOH solution. The flow rate of the high-purity nitrogen is 15 L / min and the pressure is 0.3 MPa. The position and angle of the nitrogen nozzle (i.e., the second nozzle) are adjusted according to the size and rotation speed of the silicon wafer.

[0082] Step 3: The cleaning process and the nitrogen protective layer status are monitored in real time by a computer control system, and the KOH injection parameters and the nitrogen injection parameters are dynamically adjusted according to the monitoring results until the silicon chips in the edge area are completely removed;

[0083] Step 4: Rinse the SOI substrate with deionized water to remove the residual KOH solution.

[0084] Example 3

[0085] Step 1: Place the SOI substrate on a rotating table and rotate the SOI substrate at a high speed of 1800 RPM by a rotating motor;

[0086] Step 2: Spray 20% KOH solution onto the front edge of the SOI substrate through a first nozzle to clean the front edge of the SOI substrate and remove silicon chips remaining due to chamfering; wherein the spray angle of the first nozzle is 30 degrees, the spray pressure is 0.6 MPa, and the spray range covers the entire edge area; at the same time, high-purity nitrogen is introduced into the back of the SOI substrate to form a nitrogen protective layer to ensure that the back of the SOI substrate is not corroded by the KOH solution; wherein the flow rate of the high-purity nitrogen is 20 L / min and the pressure is 0.4 MPa. The nitrogen nozzle (i.e., the second nozzle) is located around the back of the SOI substrate, and the spray angle of the nitrogen nozzle is 45 degrees;

[0087] Step 3: The cleaning process is monitored in real time by a computer control system. When it is found that the silicon chips in the edge area have been completely removed, the spraying of the KOH solution is stopped;

[0088] Step 4: Rinse the SOI substrate with deionized water to remove the residual KOH solution.

[0089] It should be noted that the terms "including," "having," and their variations, as used in this document, are intended to cover non-exclusive inclusions. Terms such as "first," "second," and the like are used to distinguish similar items and are not necessarily used to describe a specific order or precedence, unless the context clearly indicates otherwise. Such usage should be understood to be interchangeable where appropriate. The term "one or more" may be used to describe a feature, structure, or characteristic in the singular, or in the plural, depending at least in part on the context, to describe a feature, structure, or combination of features. The term "based on" should be understood as not necessarily intended to express an exclusive set of factors, but may alternatively, also depending at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described. Furthermore, the embodiments of the present invention and the features therein may be combined with one another, unless there is a conflict. Furthermore, descriptions of well-known components and technologies have been omitted from the above description to avoid unnecessary confusion regarding the concepts of the present invention. In each of the above embodiments, each embodiment focuses on its differences from the other embodiments, and reference may be made to the same or similar parts between the embodiments.

[0090] The above description is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for cleaning the edge of an SOI substrate, characterized in that: The steps include: Providing an SOI substrate to be cleaned, wherein the SOI substrate includes a front side and a back side that are relatively distributed; Spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate, and simultaneously spraying a gas onto the back surface of the SOI substrate to form a gas protection layer covering the back surface of the SOI substrate; The SOI substrate is rinsed with deionized water to remove the residual chemical cleaning solution.

2. The method for cleaning the edge of an SOI substrate according to claim 1, wherein: Before spraying the chemical cleaning liquid to the edge area of the front surface of the SOI substrate and simultaneously spraying the gas to the back surface of the SOI substrate, the following steps are also included: Placing the SOI substrate on a carrier; The supporting platform is driven to rotate.

3. The method for cleaning the edge of an SOI substrate according to claim 2, wherein: The specific steps of spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate and simultaneously spraying a gas onto the back surface of the SOI substrate include: The chemical cleaning liquid is sprayed obliquely from above the carrier platform to the edge area of the front surface of the SOI substrate.

4. The method for cleaning the edge of an SOI substrate according to claim 3, wherein: The angle between the spray direction of the chemical cleaning liquid and the front surface of the SOI substrate is 15 degrees to 75 degrees.

5. The method for cleaning the edge of an SOI substrate according to claim 2, wherein: The specific steps of spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate and simultaneously spraying a gas onto the back surface of the SOI substrate include: The gas is vertically injected from directly below the SOI substrate to the back surface of the SOI substrate to form a gas protection layer covering the entire back surface of the SOI substrate.

6. The method for cleaning the edge of an SOI substrate according to claim 2, wherein: The specific steps of spraying a chemical cleaning liquid onto an edge region of the front surface of the SOI substrate and simultaneously spraying a gas onto the back surface of the SOI substrate include: The gas is sprayed obliquely from the side surface of the carrier to the back surface of the SOI substrate to form a gas protection layer covering the entire back surface of the SOI substrate.

7. The method for cleaning the edge of an SOI substrate according to claim 1, wherein: The gas is nitrogen or an inert gas, and the chemical cleaning liquid is an alkaline cleaning agent.

8. A cleaning device, characterized in that: include: A carrier, used for carrying an SOI substrate to be cleaned, wherein the SOI substrate includes a front surface and a back surface that are relatively distributed; A first nozzle, located above the carrier platform, is used to spray a chemical cleaning liquid onto an edge area of the front surface of the SOI substrate; a second nozzle, for spraying gas onto the back side of the SOI substrate to form a gas protection layer covering the back side of the SOI substrate; The flushing structure is used to flush the SOI substrate with deionized water to remove the residual chemical cleaning solution.

9. The cleaning device according to claim 8, characterized in that: The spraying angle of the first nozzle is 15 degrees to 75 degrees.

10. The cleaning device according to claim 8, characterized in that The second nozzle is located in the carrier, and the second nozzle is capable of vertically spraying the gas onto the back side of the SOI substrate; or; The second nozzle is located on a side of the supporting platform, and the second nozzle obliquely sprays the gas onto the back side of the SOI substrate.

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