Silicon carbide sheet and cleaning method

Abstract

The invention provides a silicon carbide wafer and a cleaning method. The cleaning method of the silicon carbide wafer comprises the following steps that the silicon carbide wafer is washed for the first time to decompose at least part of pollutants on the surface of the silicon carbide wafer; scrubbing the silicon carbide sheet by using a cleaning piece to separate the pollutants from the silicon carbide sheet; and carrying out second washing treatment on the silicon carbide wafer to decompose and remove at least part of residual pollutants on the surface of the silicon carbide wafer. According to the cleaning method of the silicon carbide wafer, through the process step of combining flushing treatment and scrubbing treatment, organic residues, metal and other pollutants on the surface of the silicon carbide wafer are effectively decomposed and adsorbed, meanwhile, particles on the surface of the silicon carbide wafer are more effectively removed, and the overall efficiency of the silicon carbide wafer cleaning process is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of semiconductor manufacturing, and specifically relates to a silicon carbide wafer and a cleaning method. Background Art

[0002] As semiconductor integrated circuit technology gradually develops, if the surface of silicon wafers is contaminated by particles and metals, it is easy to cause problems such as short circuits and open circuits, resulting in damage to the circuit functions in the chip. Therefore, in addition to avoiding external pollution sources during the entire silicon wafer production process, the silicon wafers also need to be cleaned.

[0003] For silicon carbide wafers before the epitaxial process, the cleaning process has high requirements on the number of particles and metal content on the surface. The current cleaning process has long steps and low efficiency. Summary of the invention

[0004] The present invention provides a silicon carbide wafer and a cleaning method, which aims to solve the problem that the existing silicon wafer cleaning method is low in efficiency for silicon carbide wafers.

[0005] A first embodiment of the present application provides a method for cleaning a silicon carbide wafer, comprising the following steps:

[0006] Performing a first rinsing treatment on the silicon carbide wafer to decompose at least part of the pollutants on the surface of the silicon carbide wafer;

[0007] Using a cleaning member to scrub the silicon carbide sheet to remove the contaminants from the silicon carbide sheet;

[0008] The silicon carbide wafer is rinsed for the second time to decompose and remove at least part of the pollutants remaining on the surface of the silicon carbide wafer.

[0009] In some embodiments, the silicon carbide sheet has a center and an edge, and the step of brushing the silicon carbide sheet further comprises:

[0010] The cleaning member is controlled to move between the first position and the second position, wherein the first position is located at the center and the second position is located at the edge.

[0011] In some embodiments, the distance between the first position and the second position is R mm, and the step of controlling the cleaning member to move between the first position and the second position further comprises:

[0012] Controlling the cleaning member to move from the first position toward the second position by a distance of 0.66R to 0.94R to perform a first scrubbing process;

[0013] Controlling the cleaning member to move from the second position toward the first position by a distance of 0.13 to 0.4R to perform a second scrubbing process;

[0014] The cleaning member is controlled to move from the first position to the second position to perform a third scrubbing process.

[0015] In some embodiments, the first scrubbing process has a first scrubbing number n1, the second scrubbing process has a second scrubbing number n2, and the third scrubbing process has a third scrubbing number n3, and at least one of the following conditions is satisfied:

[0016] i) n1 = (1.1-1.2) n2;

[0017] ii)n3=(1.1~1.2)n2.

[0018] In some embodiments, the first brushing number n1 satisfies: 9≤n1≤14.

[0019] In some embodiments, the second brushing number n2 satisfies: 8≤n2≤12.

[0020] In some embodiments, the third brushing number n3 satisfies: 9≤n3≤14.

[0021] In some embodiments, during the first scrubbing step, the cleaning element rotates at a speed of 5 to 20 rpm.

[0022] In some embodiments, during the second scrubbing step, the cleaning element rotates at a speed of 5 to 15 rpm.

[0023] In some embodiments, during the third scrubbing step, the cleaning element rotates at a speed of 5 to 20 rpm.

[0024] In some embodiments, the first scrubbing process has a first scrubbing time T1, the second scrubbing process has a second scrubbing time T2, and the third scrubbing process has a third scrubbing time T3, satisfying:

[0025] T1=T2=T3.

[0026] In some embodiments, the first scrubbing time T1 satisfies: 50s≤T1≤70s.

[0027] In some embodiments, the second scrubbing time T2 satisfies: 50s≤T2≤70s.

[0028] In some embodiments, the third scrubbing time T3 satisfies: 50s≤T3≤70s.

[0029] In some embodiments, before the second scrubbing step, the method further comprises:

[0030] Controlling the cleaning member to move from the first position to the second position to perform a fourth scrubbing process;

[0031] Wherein, the rotation speed of the cleaning element is 5-20 rpm.

[0032] In some embodiments, the first scrubbing process has a first scrubbing number n1 and a first scrubbing time T1, and the fourth scrubbing process has a fourth scrubbing number n4 and a fourth scrubbing time T4, and at least one of the following conditions is satisfied:

[0033] iii) n1:n4=2-3:1;

[0034] iv)T1:T4=2~3:1.

[0035] In some embodiments, before the third scrubbing step, the method further comprises:

[0036] Controlling the cleaning member to move from the second position to the first position to perform a fifth scrubbing process;

[0037] Wherein, the rotation speed of the cleaning element is 5-20 rpm.

[0038] In some embodiments, the first scrubbing process has a first scrubbing number n1 and a first scrubbing time T1, and the fifth scrubbing process has a fifth scrubbing number n5 and a fifth scrubbing time T5, and at least one of the following conditions is satisfied:

[0039] v) n1:n5=2-3:1;

[0040] vi)T1:T5=2~3:1.

[0041] In some embodiments, the step of performing a first rinsing treatment on the silicon carbide wafer further comprises:

[0042] Performing a first oxidation treatment on the silicon carbide wafer using an oxidant to convert at least part of pollutants on the surface of the silicon carbide wafer into a first oxide layer;

[0043] The silicon carbide wafer is subjected to a first acid treatment using an acid solution to remove at least a portion of the first oxide layer.

[0044] In some embodiments, the step of performing a second rinsing treatment on the silicon carbide wafer further comprises:

[0045] Performing a second oxidation treatment on the silicon carbide wafer using an oxidant to convert at least part of the pollutants on the surface of the silicon carbide wafer into a second oxide layer;

[0046] Performing a second acid treatment on the silicon carbide wafer using an acid solution to remove at least a portion of the second oxide layer;

[0047] The silicon carbide sheet is corroded by using an alkaline solution to remove the remaining second oxide layer.

[0048] In some embodiments, the oxidant is O3, the acid solution is HF solution, and the alkali solution is a mixed solution of NH4OH and H2O2.

[0049] In some embodiments, the molar concentration of O3 is 10-30 ppm.

[0050] In some embodiments, the molar ratio of HF to solvent in the HF solution is 1:40-60.

[0051] In some embodiments, the molar ratio of NH4OH, H2O2 and solvent in the mixed solution of NH4OH and H2O2 is 1:3:40-60.

[0052] In some embodiments, the silicon carbide wafer has a first rotation speed v1 in the first rinsing step, the silicon carbide wafer has a second rotation speed v2 in the first brushing step to the third brushing step, and the silicon carbide wafer has a third rotation speed v3 in the second rinsing step, satisfying:

[0053] v1=v3=0.1v2.

[0054] In some embodiments, the first rotation speed v1 satisfies: 100 rpm≤v1≤200 rpm.

[0055] In some embodiments, the second rotation speed v2 satisfies: 1000rpm≤v2≤2000rpm.

[0056] In some embodiments, the third rotation speed v3 satisfies: 100rpm≤v3≤200rpm.

[0057] In some embodiments, the first rinsing process has a first rinsing time t1, the second rinsing process has a second rinsing time t2, and in the step of brushing the silicon carbide wafer with a cleaning member, the total brushing time is T, which satisfies:

[0058] T:(t1+t2)=1:1~1.3.

[0059] In some embodiments, after the step of performing a second rinsing treatment on the silicon carbide wafer, the method further includes:

[0060] The silicon carbide sheet is spin-dried.

[0061] In some embodiments, in the step of spinning the silicon carbide wafer, the rotation speed of the silicon carbide wafer is 1000-2000 rpm.

[0062] In some embodiments, the spin-drying time is 50 to 70 seconds.

[0063] In a second embodiment of the present application, a silicon carbide wafer is provided, which is cleaned by using the cleaning method of the silicon carbide wafer in any of the above embodiments, and the number of particles on the silicon carbide wafer is less than or equal to 50.

[0064] The present application provides a method for cleaning a silicon carbide wafer, comprising the following steps: performing a first rinsing treatment on the silicon carbide wafer to decompose at least part of the contaminants on the surface of the silicon carbide wafer; using a cleaning member to scrub the silicon carbide wafer to remove the contaminants from the silicon carbide wafer; performing a second rinsing treatment on the silicon carbide wafer to decompose and remove at least part of the contaminants remaining on the surface of the silicon carbide wafer. The method for cleaning a silicon carbide wafer provided in the present application combines the rinsing treatment with the scrubbing treatment, effectively decomposing and adsorbing organic residues, metals and other contaminants on the surface of the silicon carbide wafer, while more effectively removing particles on the surface of the silicon carbide wafer, thereby improving the overall efficiency of the silicon carbide wafer cleaning process. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0066] Figure 1 A graph showing the surface inspection results of a silicon carbide wafer after cleaning according to a method for cleaning a silicon carbide wafer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0068] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0069] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0070] A first embodiment of the present application provides a method for cleaning a silicon carbide wafer, comprising the following steps:

[0071] Performing a first rinsing treatment on the silicon carbide wafer to decompose at least part of the contaminants on the surface of the silicon carbide wafer;

[0072] Use a cleaning piece to scrub the silicon carbide sheet to remove contaminants from the silicon carbide sheet;

[0073] The silicon carbide wafer is subjected to a second rinsing treatment to decompose and remove at least part of the pollutants remaining on the surface of the silicon carbide wafer.

[0074] In some embodiments, the silicon carbide wafer has a center and an edge, and the step of brushing the silicon carbide wafer further comprises:

[0075] The cleaning member is controlled to move between a first position and a second position, wherein the first position is located at the center and the second position is located at the edge.

[0076] Traditional silicon wafers or silicon oxide wafers need to be double-sided cleaned before subsequent processing to remove dust, metal ions and organic impurities on the surface of the silicon wafer. In some silicon carbide semiconductor processes, only one side of the silicon carbide substrate needs to be processed, such as epitaxial growth, thin film deposition or photolithography. In these cases, only one side of the silicon carbide substrate needs to be cleaned. The traditional double-sided cleaning process for silicon wafers takes a long time and is inefficient for cleaning the surface of silicon carbide. The cleaning method for silicon carbide wafers provided in this application combines the process steps of rinsing and brushing. While effectively decomposing and adsorbing organic residues, metals and other pollutants on the surface of the silicon carbide wafer, it more effectively removes particles on the surface of the silicon carbide wafer, thereby improving the overall efficiency of the silicon carbide wafer cleaning process.

[0077] In some embodiments, the distance between the first position and the second position is R mm, and the step of controlling the cleaning member to move between the first position and the second position further comprises:

[0078] Controlling the cleaning member to move from the first position toward the second position by a distance of 0.66R to 0.94R to perform a first scrubbing process;

[0079] Controlling the cleaning member to move from the second position toward the first position by a distance of 0.13 to 0.4R to perform a second scrubbing process;

[0080] The cleaning element is controlled to move from the first position to the second position to perform a third scrubbing process.

[0081] The above method is applicable to circular silicon carbide wafers of different sizes, such as 6-inch silicon carbide wafers (R=75), 8-inch silicon carbide wafers (R=100), 12-inch silicon carbide wafers (R=150), etc. It can be understood that the silicon carbide wafers can also be square, rectangular or trapezoidal in shape.

[0082] In some embodiments, the cleaning member can be a round or arbitrarily shaped brush head, which contacts and rubs against the surface of the silicon carbide sheet while rotating to clean the product. When the moving path of the cleaning member meets the above scheme, during the scrubbing process, the liquid medicine will drip onto the surface of the product along with the brush head, which can clean the product while reacting chemically with the liquid medicine, repeatedly from the center to the edge, and the effect will be more significant.

[0083] In some embodiments, the first scrubbing process has a first scrubbing number n1, the second scrubbing process has a second scrubbing number n2, and the third scrubbing process has a third scrubbing number n3, and at least one of the following conditions is satisfied:

[0084] i) n1 = (1.1-1.2) n2;

[0085] ii)n3=(1.1~1.2)n2.

[0086] It is understandable that in the first and third brushing steps, the cleaning element moves from the center to the edge of the silicon carbide wafer, and can cooperate with the cleaning water flow to effectively remove organic residues, metal and other pollutants and particles on the surface of the silicon carbide wafer; in the second brushing step, the cleaning element moves from the center of the silicon carbide wafer and focuses on cleaning the edge area of ​​the silicon carbide wafer, so that the cleaning range can cover the entire silicon carbide wafer, avoiding organic residues, metal and other pollutants and particles from being deposited on the edge surface of the silicon carbide wafer. When the first brushing number, the second brushing number and the third brushing number meet the above relationship, it can ensure that the center and edge of the silicon carbide wafer are effectively cleaned to avoid the deposition of local pollutants.

[0087] In some embodiments, the first brushing number n1 satisfies: 9≤n1≤14.

[0088] It can be understood that the value of the first brushing number n1 can be any value among 9, 10, 11, 12, 13, 14 or a range between any two values.

[0089] In some embodiments, the second brushing number n2 satisfies: 8≤n2≤12.

[0090] It can be understood that the value of the second brushing number n2 can be any value among 8, 9, 10, 11, 12 or a range between any two values.

[0091] In some embodiments, the third brushing number n3 satisfies: 9≤n3≤14.

[0092] It can be understood that the value of the third brushing number n3 can be any value among 9, 10, 11, 12, 13, 14 or a range between any two values.

[0093] When the first brushing number, the second brushing number and the third brushing number meet the above value range, it can further ensure that the center and edge of the silicon carbide wafer are effectively cleaned to avoid the deposition of local pollutants.

[0094] In some embodiments, during the first scrubbing step, the cleaning element rotates at a speed of 5 to 20 rpm.

[0095] It can be understood that, in the first scrubbing step, the rotation speed of the cleaning element (unit: rpm) can be any value among 5, 10, 15, 20 or a range between any two values.

[0096] In some embodiments, during the second scrubbing step, the rotation speed of the cleaning element is 5-15 rpm.

[0097] It can be understood that, in the second scrubbing step, the rotation speed of the cleaning element (unit: rpm) can be any value among 5, 7, 9, 11, 13, 15 or a range between any two values.

[0098] In some embodiments, during the third scrubbing step, the rotation speed of the cleaning element is 5-20 rpm.

[0099] It can be understood that, in the step of the third scrubbing treatment, the rotation speed of the cleaning element (unit: rpm) can be any value among 5, 10, 15, 20 or a range between any two values.

[0100] In some embodiments, the first scrubbing process has a first scrubbing time T1, the second scrubbing process has a second scrubbing time T2, and the third scrubbing process has a third scrubbing time T3, satisfying:

[0101] T1=T2=T3.

[0102] During the scrubbing process, the scrubbing time and the speed of the cleaning element can determine the cleanliness of the cleaning and the effect of the chemical reaction of the product solution. When the three scrubbing treatments are performed at the same time, the scrubbing intensity of each area on the surface of the silicon carbide wafer can be kept consistent, thereby ensuring the uniformity of the surface quality of the silicon carbide wafer after cleaning.

[0103] In some embodiments, the first scrubbing time T1 satisfies: 50s≤T1≤70s.

[0104] It can be understood that the value of the first scrubbing time T1 (unit: s) can be any value among 50, 55, 60, 65, 70 or a range between any two values.

[0105] In some embodiments, the second brushing time T2 satisfies: 50s≤T2≤70s.

[0106] It can be understood that the value of the second scrubbing time T2 (unit: s) can be any value among 50, 55, 60, 65, 70 or a range between any two values.

[0107] In some embodiments, the third brushing time T3 satisfies: 50s≤T3≤70s.

[0108] It can be understood that the value of the third scrubbing time T3 (unit: s) can be any value among 50, 55, 60, 65, 70 or a range between any two values.

[0109] When the duration of the three scrubbing treatments meets the above value range, the overall cleanliness of the silicon carbide wafer can be further improved.

[0110] In some embodiments, before the second scrubbing step, the method further comprises:

[0111] Controlling the cleaning element to move from the first position to the second position to perform a fourth scrubbing process;

[0112] The rotation speed of the cleaning element is 15 rpm.

[0113] It is understandable that after the first brushing treatment, more pollutants and particles will remain and deposit in the edge area of ​​the silicon carbide wafer. Before the second brushing treatment, controlling the cleaning element to brush the entire surface of the silicon carbide wafer from the first position to the second position can reduce the particles in the unbrushed part in the first brushing treatment, thereby improving the cleaning efficiency of the second brushing treatment.

[0114] In some embodiments, the first scrubbing process has a first scrubbing number n1 and a first scrubbing time T1, and the fourth scrubbing process has a fourth scrubbing number n4 and a fourth scrubbing time T4, and at least one of the following conditions is satisfied:

[0115] iii) n1:n4=2-3:1;

[0116] iv)T1:T4=2~3:1.

[0117] When the time and number of the fourth scrubbing treatment meet the above values, a relatively ideal cleaning effect can be achieved.

[0118] In some embodiments, before the third scrubbing step, the method further comprises:

[0119] Controlling the cleaning member to move from the second position to the first position to perform a fifth scrubbing process;

[0120] The rotation speed of the cleaning element is 15 rpm.

[0121] Based on the same principle as the above embodiment, before performing the third brushing treatment, controlling the cleaning member to brush the entire surface of the silicon carbide wafer from the second position toward the first position can reduce particles in the unbrushed part in the second brushing treatment, thereby improving the cleaning efficiency of the third brushing treatment.

[0122] In some embodiments, the first scrubbing process has a first scrubbing number n1 and a first scrubbing time T1, and the fifth scrubbing process has a fifth scrubbing number n5 and a fifth scrubbing time T5, and at least one of the following conditions is satisfied:

[0123] v) n1:n5=2-3:1;

[0124] vi)T1:T5=2~3:1.

[0125] When the time and number of the fifth scrubbing treatment meet the above values, a relatively ideal cleaning effect can be achieved.

[0126] In some embodiments, the step of performing a first rinsing treatment on the silicon carbide wafer further comprises:

[0127] Performing a first oxidation treatment on the silicon carbide wafer using an oxidant to convert at least part of the pollutants on the surface of the silicon carbide wafer into a first oxide layer;

[0128] The silicon carbide wafer is subjected to a first acid treatment using an acid solution to remove at least a portion of the first oxide layer.

[0129] In some embodiments, the step of performing a second rinsing treatment on the silicon carbide wafer further comprises:

[0130] Performing a second oxidation treatment on the silicon carbide wafer using an oxidant to convert at least part of the pollutants on the surface of the silicon carbide wafer into a second oxide layer;

[0131] Performing a second acid treatment on the silicon carbide wafer using an acid solution to remove at least a portion of the second oxide layer;

[0132] The silicon carbide wafer is corroded with an alkaline solution to remove the remaining second oxide layer.

[0133] In some embodiments, the oxidant is O3, the acid solution is HF solution, and the alkali solution is a mixed solution of NH4OH and H2O2.

[0134] O3 can effectively decompose various pollutants, including organic residues, metals and particles. By exposing silicon carbide wafers to a cleaning solution containing ozone, pollutants on the surface of the silicon carbide wafer can be removed, making the surface clean and free of impurities, while effectively eliminating microbial contamination. Ozone can be used for oxidation reactions in semiconductor production, such as the preparation of silicon oxide. As an oxidant, ozone can oxidize organic matter on the surface of silicon to form a pure silicon oxide layer. Ozone water can be used for surface treatment of semiconductors to improve surface properties, such as changes in surface energy and regulation of surface chemical reactions, making the surface easier to bond and wet, and improving the performance of semiconductor devices.

[0135] HF is used to remove the oxide layer, and at the same time, particles and metals adsorbed on the oxide layer can be removed.

[0136] In the SC1 solution (NH4OH+H2O2), the oxidation reaction of hydrogen peroxide forms an oxide film, which is corroded by NH4OH. Oxidation occurs immediately after corrosion. Oxidation and corrosion are repeated, and the particles attached to the surface of the silicon wafer fall into the cleaning solution along with the corrosion layer.

[0137] In some embodiments, the molar concentration of O3 is 10-30 ppm.

[0138] It can be understood that the molar concentration of O3 (unit: ppm) can be any value among 10, 15, 20, 25, 30 or a range between any two values.

[0139] In some embodiments, the molar ratio of HF to solvent in the HF solution is 1:40-60.

[0140] It is understood that the molar ratio of HF to solvent in the HF solution may be any value among 1:40, 1:45, 1:50, 1:55, 1:60 or a range between any two values.

[0141] In some embodiments, the molar ratio of NH4OH, H2O2 and solvent in the mixed solution of NH4OH and H2O2 is 1:3:40-60.

[0142] When the molar concentration of O3 and the concentrations of acid and alkali are within the above ranges, it can ensure that the organic oxides and metal particles on the surface of the silicon carbide wafer are fully removed, while avoiding corrosion of the silicon carbide wafer itself by excessive oxidants and acid and alkali.

[0143] In some embodiments, the step of brushing the silicon carbide wafer also includes: spraying alkaline solution on the silicon carbide wafer while brushing the silicon carbide wafer, thereby further removing the oxide layer formed on the surface of the silicon carbide wafer after the first rinsing treatment.

[0144] Based on the above embodiments, after spraying the silicon carbide wafer with an oxidant, acid or alkali solution, deionized water or pure water may also be sprayed on the silicon carbide wafer to remove the oxidant, acid or alkali solution remaining on the surface of the silicon carbide wafer to achieve a further cleaning effect.

[0145] In some embodiments, the silicon carbide wafer has a first rotation speed v1 in the first rinsing step, has a second rotation speed v2 in the first to third brushing steps, and has a third rotation speed v3 in the second rinsing step, satisfying:

[0146] v1=v3=0.1v2.

[0147] In the steps of rinsing and scrubbing, controlling the silicon carbide sheet to rotate can increase the effective contact between the surface of the silicon carbide sheet and the cleaning member and the cleaning liquid. At the same time, since the stability of the edge of the silicon carbide sheet during rotation is slightly lower than that of the center of the silicon carbide sheet, controlling the second rotation speed v2 to be lower than the first rotation speed and the third rotation speed can protect the silicon carbide sheet body from excessive wear.

[0148] In some embodiments, the first rotation speed v1 satisfies: 100 rpm≤v1≤200 rpm.

[0149] It can be understood that the value of the first rotation speed v1 (unit: rpm) can be any value among 1000, 1200, 1400, 1600, 1800, 2000 or a range between any two values.

[0150] In some embodiments, the second rotation speed v2 satisfies: 1000rpm≤v2≤2000rpm.

[0151] It can be understood that the value of the second rotation speed v2 (unit: rpm) can be any value of 100, 120, 140, 160, 180, 200 or a range between any two values.

[0152] In some embodiments, the third rotation speed v3 satisfies: 100rpm≤v3≤200rpm.

[0153] It can be understood that the value of the third rotation speed v3 (unit: rpm) can be any value of 1000, 1200, 1400, 1600, 1800, 2000 or a range between any two values.

[0154] In some embodiments, the first rinsing process has a first rinsing time t1, the second rinsing process has a second rinsing time t2, and in the step of brushing the silicon carbide wafer with a cleaning member, the total brushing time is T, which satisfies:

[0155] T:(t1+t2)=1:1~1.3.

[0156] It can be understood that the total scrubbing time T is the sum of the scrubbing times in all scrubbing steps. When the scrubbing steps include the first scrubbing, the second scrubbing and the third scrubbing, T = T1 + T2 + T3; when the scrubbing steps include the first scrubbing, the second scrubbing, the third scrubbing and the fourth scrubbing, T = T1 + T2 + T3 + T4; when the scrubbing steps include the first scrubbing, the second scrubbing, the third scrubbing and the fifth scrubbing, T = T1 + T2 + T3 + T5; when the scrubbing steps include the first scrubbing, the second scrubbing, the third scrubbing, the fourth scrubbing and the fifth scrubbing, T = T1 + T2 + T3 + T4 + T5. Preferably, 150s≤T≤280s. It can be understood that the value of T (unit: s) can be any value among 150, 170, 190, 210, 230, 250, 280 or a range between any two values. When the rinsing time and the total scrubbing time meet the above value range, it can ensure that both physical cleaning and chemical cleaning of the silicon carbide wafer surface achieve better effects.

[0157] In some embodiments, after the step of performing a second rinsing treatment on the silicon carbide wafer, the method further includes:

[0158] The silicon carbide wafer is dried.

[0159] In some embodiments, in the step of spinning the silicon carbide wafer, the rotation speed of the silicon carbide wafer is 1000-2000 rpm.

[0160] It can be understood that, in the step of drying the silicon carbide wafer, the rotation speed of the silicon carbide wafer (unit: rpm) can be any value among 1000, 1200, 1400, 1600, 1800, 2000 or a range between any two values.

[0161] In some embodiments, the spin-drying time is 50 to 70 seconds.

[0162] It is understandable that the spin-drying time (unit: s) can be any value among 50, 55, 60, 65, 70 or a range between any two values, so as to ensure that the silicon carbide wafer is fully dried.

[0163] In a second embodiment of the present application, a silicon carbide wafer is provided, which is cleaned by the silicon carbide wafer cleaning method in any of the above embodiments, and the number of particles on the silicon carbide wafer is less than or equal to 50.

[0164] The following is a description of the cleaning method and device for the silicon carbide wafer provided by the present application in conjunction with specific embodiments:

[0165] Example 1

[0166] This embodiment provides a method for cleaning a silicon carbide wafer, which is implemented by the following steps:

[0167] Performing a first oxidation treatment on the 6-inch silicon carbide wafer using an oxidant to convert at least a portion of pollutants on the surface of the silicon carbide wafer into a first oxide layer;

[0168] The silicon carbide wafer is subjected to a first acid treatment using an acid solution to remove at least a portion of the first oxide layer.

[0169] Controlling the cleaning member to move from the first position toward the second position by a distance of 60 mm, and performing 14 scrubbing operations;

[0170] Controlling the cleaning element to move from the first position to the second position to perform 5 scrubbing operations;

[0171] Control the cleaning member to move from the second position toward the first position by a distance of 10 mm, and perform 12 scrubbing operations;

[0172] Controlling the cleaning element to move from the second position to the first position to perform 5 scrubbing operations;

[0173] Controlling the cleaning member to move from the first position to the second position to perform 14 scrubbing operations;

[0174] Performing a second oxidation treatment on the silicon carbide wafer using an oxidant to convert at least part of the pollutants on the surface of the silicon carbide wafer into a second oxide layer;

[0175] Performing a second acid treatment on the silicon carbide wafer using an acid solution to remove at least a portion of the second oxide layer;

[0176] The silicon carbide wafer is corroded with an alkaline solution to remove the remaining second oxide layer.

[0177] The number of particles on the surface of the cleaned silicon carbide wafer was detected, and the results were as follows: Figure 1 shown.

[0178] Embodiments 2 to 6

[0179] The cleaning methods of Examples 2 to 6 are consistent with those of Example 1, with only the process parameters being adjusted.

[0180] Comparative Examples 1 to 3

[0181] The cleaning methods of Comparative Examples 1 to 3 are consistent with those of Example 1, except that only the process parameters are adjusted.

[0182] The process parameters in Examples 1 to 6 and Comparative Examples 1 to 3 and the number of particles on the surface of the cleaned silicon carbide wafer are shown in Tables 1 to 3.

[0183] Table 1

[0184]

[0185] Table 2

[0186]

[0187]

[0188] Table 3

[0189] Large particle quantity Medium particle number Small particle quantity Example 1 0 4 9 Example 2 2 8 11 Example 3 1 9 6 Example 4 0 10 15 Example 5 2 5 14 Example 6 1 6 18 Comparative Example 1 1 23 31 Comparative Example 2 1 25 35 Comparative Example 3 0 26 25

[0190] according to Figure 1 As can be seen from Tables 1 to 3, the cleaning method of the silicon carbide wafer provided in the present application can effectively reduce the number of particles on the surface of the silicon carbide wafer, especially the number of small and medium-sized particles, and improve the overall cleaning efficiency of the silicon carbide wafer.

[0191] The above is a detailed introduction to a silicon carbide wafer and a cleaning method provided in the embodiments of the present application. Specific examples are used in the present application to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for cleaning a silicon carbide wafer, characterized in that: The steps include: Performing a first rinsing treatment on the silicon carbide wafer to decompose at least part of the pollutants on the surface of the silicon carbide wafer; Using a cleaning member to scrub the silicon carbide sheet to remove the contaminants from the silicon carbide sheet; The silicon carbide wafer is rinsed for the second time to decompose and remove at least part of the pollutants remaining on the surface of the silicon carbide wafer.

2. A method for cleaning a silicon carbide wafer according to claim 1, characterized in that: The silicon carbide sheet has a center and an edge, and the step of brushing the silicon carbide sheet further comprises: The cleaning member is controlled to move between the first position and the second position, wherein the first position is located at the center and the second position is located at the edge.

3. A method for cleaning a silicon carbide wafer according to claim 2, characterized in that: The distance between the first position and the second position is R mm, and the step of controlling the cleaning member to move between the first position and the second position further comprises: Controlling the cleaning member to move from the first position toward the second position by a distance of 0.66R to 0.94R to perform a first scrubbing process; Controlling the cleaning member to move from the second position toward the first position by a distance of 0.13 to 0.4R to perform a second scrubbing process; The cleaning member is controlled to move from the first position to the second position to perform a third scrubbing process.

4. A method for cleaning a silicon carbide wafer according to claim 3, characterized in that: The first scrubbing process has a first scrubbing number n1, the second scrubbing process has a second scrubbing number n2, and the third scrubbing process has a third scrubbing number n3, and at least one of the following conditions is satisfied: i) n1 = (1.1-1.2) n2; ii)n3=(1.1~1.2)n2.

5. The method for cleaning a silicon carbide wafer according to claim 3, characterized in that: The first brushing number n1 satisfies: 9≤n1≤14; and / or, The second brushing number n2 satisfies: 8≤n2≤12; and / or, The third brushing number n3 satisfies: 9≤n3≤14.

6. The method for cleaning a silicon carbide wafer according to claim 3, characterized in that: In the first scrubbing step, the rotation speed of the cleaning element is 5 to 20 rpm; and / or, In the second scrubbing step, the rotation speed of the cleaning element is 5 to 15 rpm; and / or, In the third scrubbing step, the rotation speed of the cleaning element is 5 to 20 rpm.

7. A method for cleaning a silicon carbide wafer according to claim 3, characterized in that: The first scrubbing process has a first scrubbing time T1, the second scrubbing process has a second scrubbing time T2, and the third scrubbing process has a third scrubbing time T3, satisfying: T1=T2=T3.

8. A method for cleaning a silicon carbide wafer according to claim 7, characterized in that: The first scrubbing time T1 satisfies: 50s≤T1≤70s; and / or, The second scrubbing time T2 satisfies: 50s≤T2≤70s; and / or, The third scrubbing time T3 satisfies: 50s≤T3≤70s.

9. The method for cleaning a silicon carbide wafer according to claim 3, characterized in that: Before the second scrubbing step, the method further comprises: Controlling the cleaning member to move from the first position to the second position to perform a fourth scrubbing process; Wherein, the rotation speed of the cleaning element is 5-20 rpm.

10. A method for cleaning a silicon carbide wafer according to claim 9, characterized in that: The first scrubbing process has a first scrubbing number n1 and a first scrubbing time T1, and the fourth scrubbing process has a fourth scrubbing number n4 and a fourth scrubbing time T4, and satisfies at least one of the following conditions: iii) n1:n4=2-3:1; iv)T1:T4=2~3:

1.

11. A method for cleaning a silicon carbide wafer according to claim 3, characterized in that: Before the third scrubbing step, the method further comprises: Controlling the cleaning member to move from the second position to the first position to perform a fifth scrubbing process; Wherein, the rotation speed of the cleaning element is 5-20 rpm.

12. A method for cleaning a silicon carbide wafer according to claim 11, characterized in that: The first scrubbing process has a first scrubbing number n1 and a first scrubbing time T1, and the fifth scrubbing process has a fifth scrubbing number n5 and a fifth scrubbing time T5, and at least one of the following conditions is satisfied: v) n1:n5=2-3:1; vi)T1:T5=2~3:

1.

13. The method for cleaning a silicon carbide wafer according to claim 1, characterized in that: The step of performing a first rinsing treatment on the silicon carbide wafer further comprises: Performing a first oxidation treatment on the silicon carbide wafer using an oxidant to convert at least part of pollutants on the surface of the silicon carbide wafer into a first oxide layer; The silicon carbide wafer is subjected to a first acid treatment using an acid solution to remove at least a portion of the first oxide layer.

14. The method for cleaning a silicon carbide wafer according to claim 1, characterized in that: The step of performing a second rinsing treatment on the silicon carbide wafer further comprises: Performing a second oxidation treatment on the silicon carbide wafer using an oxidant to convert at least part of the pollutants on the surface of the silicon carbide wafer into a second oxide layer; Performing a second acid treatment on the silicon carbide wafer using an acid solution to remove at least a portion of the second oxide layer; The silicon carbide sheet is corroded by using an alkaline solution to remove the remaining second oxide layer.

15. A method for cleaning a silicon carbide wafer according to claim 13 or 14, characterized in that: The oxidant is O3, the acid solution is HF solution, and the alkali solution is a mixed solution of NH4OH and H2O2.

16. A method for cleaning a silicon carbide wafer according to claim 15, characterized in that: The molar concentration of O3 is 10 to 30 ppm; and / or, The molar ratio of HF to solvent in the HF solution is 1:40-60; and / or, The molar ratio of NH4OH, H2O2 and solvent in the mixed solution of NH4OH and H2O2 is 1:3:40-60.

17. The method for cleaning a silicon carbide wafer according to claim 3, characterized in that: The silicon carbide wafer has a first rotation speed v1 in the first rinsing step, a second rotation speed v2 in the first brushing step to the third brushing step, and a third rotation speed v3 in the second rinsing step, satisfying: v1=v3=0.1v2.

18. A method for cleaning a silicon carbide wafer according to claim 17, characterized in that: The first speed v1 satisfies: 100 rpm ≤ v1 ≤ 200 rpm; and / or, The second speed v2 satisfies: 1000rpm≤v2≤2000rpm; and / or, The third rotation speed v3 satisfies: 100rpm≤v3≤200rpm.

19. The method for cleaning a silicon carbide wafer according to claim 1, characterized in that: The first rinsing process has a first rinsing time t1, the second rinsing process has a second rinsing time t2, and in the step of brushing the silicon carbide wafer with a cleaning member, the total brushing time is T, which satisfies: T:(t1+t2)=1:1~1.

3.

20. The method for cleaning a silicon carbide wafer according to claim 1, characterized in that: After the step of performing a second rinsing treatment on the silicon carbide wafer, the method further comprises: The silicon carbide sheet is spin-dried.

21. The method for cleaning a silicon carbide wafer according to claim 15, characterized in that: In the step of drying the silicon carbide sheet, the rotation speed of the silicon carbide sheet is 1000-2000 rpm; and / or, The drying time is 50 to 70 seconds.

22. A silicon carbide wafer obtained by cleaning the silicon carbide wafer according to any one of claims 1 to 21, characterized in that: The number of particles on the silicon carbide wafer is less than or equal to 50.

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