CN114887987B - Megasonic cleaning process for silicon carbide wafer - Google Patents
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- 238000004140 cleaning Methods 0.000 title claims abstract description 173
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 57
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 56
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
- B08B3/04—Cleaning involving contact with liquid
- B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
- B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
- B08B3/123—Cleaning travelling work, e.g. webs, articles on a conveyor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B13/00—Accessories or details of general applicability for machines or apparatus for cleaning
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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Abstract
The invention relates to a megasonic cleaning process for silicon carbide wafers, which comprises the steps of firstly placing a silicon carbide wafer to be cleaned in rotary megasonic cleaning equipment, and carrying out intermittent megasonic cleaning by utilizing cleaning liquid; and cleaning, drying, packaging and storing the silicon carbide wafer subjected to megasonic cleaning by using pure water. The invention can clean the silicon carbide wafer under megasonic cleaning with the frequency of 2000KHz for 7.7min, has high cleaning efficiency (the existing megasonic cleaning is at least 20 min), good cleaning effect, high application value and good implementation effect, and can furthest reduce the damage to the surface of the silicon carbide wafer.
Description
Technical Field
The invention relates to a megasonic cleaning process for a silicon carbide wafer, and belongs to the technical field of cleaning of silicon carbide wafers.
Background
Silicon carbide wafers are used in the field of LED solid state lighting and high frequency devices. The material has excellent characteristics of forbidden band, drift speed, breakdown voltage, thermal conductivity, high temperature resistance and the like which are several times higher than those of the traditional silicon, and has irreplaceable advantages in the fields of high temperature, high voltage, high frequency, high power, photoelectricity, radiation resistance, microwaves and other electronic application fields and the extreme environments of aerospace, military industry, nuclear energy and the like.
At present, the silicon carbide wafer is cleaned by the following two cleaning modes:
1) Ultrasonic cleaning
Ultrasonic cleaning is a cleaning method widely applied in the semiconductor industry, and has the advantages that: good cleaning effect, simple operation and capability of cleaning complex devices and containers. The cleaning method is that under the strong ultrasonic action, the liquid medium generates a sparse part and a dense part, the sparse part generates a nearly vacuum cavity bubble, and when the cavity bubble disappears, a strong local pressure is generated nearby, so that chemical bonds in molecules are broken to desorb impurities on the surface of the wafer. The effect of ultrasonic cleaning is related to ultrasonic conditions (e.g., temperature, pressure, ultrasonic frequency, power, etc.), and is often used to remove bulk contaminants and particles from the wafer surface.
2) Megasonic cleaning
Megasonic cleaning not only has the advantage of ultrasonic cleaning, but also overcomes the defects thereof. Megasonic cleaning is a process of cleaning a wafer by the high-energy-frequency vibration effect in combination with chemical reactions of chemical cleaning agents. During cleaning, the solution molecules are accelerated under the pushing of megasonic waves (the maximum instantaneous speed can reach 30 cm/s), and the high-speed fluid waves continuously impact the surface of the wafer, so that the pollutants and fine particles attached to the surface of the wafer are forcedly removed and enter the cleaning liquid. The method can simultaneously play the roles of mechanical wiping and chemical cleaning.
Due to cavitation of ultrasonic cleaning, long-time ultrasonic cleaning may cause a certain damage to the surface of the wafer.
While megasonic cleaning, which is typically in the frequency range of 800-2000 kHz, is selected based on the feature size of the wafer and the particle size removed. Although megasonic waves have no cavitation effect, the surface of the wafer is not greatly damaged; however, once the silicon carbide wafer is subjected to high frequency (e.g., 2000 kHz) and high power (e.g., 3000W for megasonic cleaning) for a long period of time (e.g., 20 min), damage may still occur to the surface of the silicon carbide wafer; because excessive cavitation energy in the vicinity of a substrate having a fine surface or feature (e.g., a silicon carbide wafer) can also cause damage to the substrate, this is correspondingly documented in the patent document entitled "improved sonication methods and apparatus," titled CN 103492092B.
Therefore, there is a strong need for a megasonic cleaning process that reduces damage to the surface of silicon carbide wafers.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention provides a megasonic cleaning process for silicon carbide wafers, which comprises the following specific technical scheme:
a silicon carbide wafer megasonic cleaning process comprising the steps of:
step one, placing a silicon carbide wafer to be cleaned in rotary megasonic cleaning equipment, and performing intermittent megasonic cleaning by using cleaning liquid;
and step two, cleaning, drying, packaging and storing the silicon carbide wafer cleaned in the step one by using pure water.
Above-mentioned technical scheme's further optimization, rotation type megasonic cleaning equipment includes the megasonic cleaning tank, the internally mounted of megasonic cleaning tank has rotatory square groove, rotatory square groove is rotated by the actuating mechanism drive, actuating mechanism is including being located the outside driving motor of megasonic cleaning tank, being located the outside gearbox, the pivot of megasonic cleaning tank, driving motor's rotor and the input fixed connection of gearbox, the output of gearbox and the lower extreme fixed connection of pivot, the upper end and the bottom fixed connection of rotatory square groove of pivot, install the totally enclosed bearing between the bottom of pivot and megasonic cleaning tank.
According to the technical scheme, at least three groups of rotary supporting ball assemblies are arranged between the bottom of the rotary square groove and the bottom of the megasonic cleaning groove, each rotary supporting ball assembly comprises a supporting ball and a ball seat which completely wraps the lower part of the supporting ball, and the inner wall and the outer wall of each ball seat are of spherical crown structures; the ball seat is characterized in that the supporting ball is rotationally connected with the ball seat, the bottom of the ball seat is fixedly connected with the bottom of the megasonic cleaning tank, the top of the supporting ball is contacted with the bottom of the rotary square tank, and a plurality of through holes are formed in the side wall of the ball seat.
According to the technical scheme, the rotary supporting ball assemblies are provided with three groups, and the three groups of rotary supporting ball assemblies are arranged in a central symmetry mode.
Further optimizing the technical scheme, wherein the cleaning liquid comprises a surfactant, a metal chelating agent and a pH regulating liquid; the pH regulating liquid is one of acidic solution, alkaline solution and water.
Further optimizing the technical scheme, in the intermittent megasonic cleaning process, the frequency of megasonic cleaning is f, and f is more than or equal to 1800kHz and less than or equal to 2000kHz; the total time required for intermittent megasonic cleaning is t z The intermittent megasonic cleaning process is divided into a plurality of period cleaning time periods and a stay time period between two adjacent period cleaning time periods, the silicon carbide wafers in the cleaning liquid are subjected to rotary cleaning in the stay time period, T is the period cleaning time period, and T x For the residence time period, t z ＝mT+(m-1)t x M is an integer greater than 1;
in the period of cleaningIn the period of time, t= (T g1 +t t1 )+(t g2 +t t2 )+…+(t gn +t tn )，t gn For the nth megasonic cleaning time in the cycle, t tn For stopping megasonic cleaning time n times in the period, t gn ＝t g1 +(n-1)(L g +n/10)，t tn ＝t t1 +(n-1)(L t +n/10), n is a positive integer;
when n is less than or equal to 9, L g ＝0.4，L t ＝0.1；
When n is more than or equal to 10 and less than or equal to 15, L g ＝0.4，L t ＝0.2。
Further optimizing the technical proposal, the rotating speed of the rotating square groove is 0-80 rpm and the holding time is at least t at the rotating speed of 80rpm during the rotating cleaning x /2。
In the technical scheme, when the pH regulating solution is an acidic solution or water during rotary cleaning, dry ice is also sprayed into the cleaning solution, and the mass ratio of the sprayed dry ice to the cleaning solution is (8.6-12.5): 1000.
The beneficial technical effects of the invention are as follows:
the invention can clean the silicon carbide wafer under megasonic cleaning with the frequency of 2000KHz for 7.7min, has high cleaning efficiency (the existing megasonic cleaning is at least 20 min), good cleaning effect, high application value and good implementation effect, and can furthest reduce the damage to the surface of the silicon carbide wafer.
Drawings
Fig. 1 is a schematic structural view of a rotary megasonic cleaning apparatus according to the present invention;
FIG. 2 is a schematic view of a rotary support ball assembly according to the present invention;
fig. 3 is a graph of frequency f of megasonic cleaning as a function of time t required for cleaning.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Example 1
And step one, placing the silicon carbide wafer to be cleaned in rotary megasonic cleaning equipment, and performing intermittent megasonic cleaning by using cleaning liquid.
The rotary megasonic cleaning device comprises a megasonic cleaning tank 10, wherein the megasonic cleaning tank 10 is conventional megasonic cleaning device, and the structure of the rotary megasonic cleaning device is improved; the inside of megasonic cleaning tank 10 is installed rotatory square groove 20, rotatory square groove 20 is rotated by actuating mechanism drive, actuating mechanism is including being located the outside driving motor 34 of megasonic cleaning tank 10, being located the outside gearbox 33 of megasonic cleaning tank 10, pivot 31, driving motor 34's rotor and the input fixed connection of gearbox 33, the output of gearbox 33 and the lower extreme fixed connection of pivot 31, the upper end of pivot 31 and the bottom fixed connection of rotatory square groove 20, install totally enclosed bearing 32 between pivot 31 and the bottom of megasonic cleaning tank 10.
Firstly, the rotor of the driving motor 34 drives the rotating shaft 31 and the rotating square groove 20 to rotate through the gearbox 33, and the rotating square groove 20 is designed into a square groove structure, so that a wafer basket with a wafer placed therein is placed in the square groove, and the wafer basket and the rotating square groove 20 are prevented from rotating relatively during rotation. The arrangement of the totally enclosed bearing 32 ensures the tightness.
And step two, cleaning, drying, packaging and storing the silicon carbide wafer cleaned in the step one by using pure water.
The intermittent megasonic cleaning process is that in one period, megasonic cleaning is firstly carried out for a period of time, then cleaning is stopped, then megasonic cleaning is carried out, then cleaning is stopped, and the cycle is repeated; the period is set to be a plurality of according to the specifications of silicon carbide wafers and cleaning solutions with different formulas; still set up the dwell time between two adjacent periods, in dwell time, megasonic cleaning stops, on the contrary in this time quantum, can be through rotating rotatory square groove 20 to carry out rotatory washing to the carborundum wafer on its upper portion, on the one hand, utilize "scrubbing" effect that rotatory centrifugal force brought to cooperate megasonic cleaning again, further improve cleaning performance.
Example 2
A minimum of three groups of rotary supporting ball assemblies 50 are arranged between the tank bottom of the rotary square tank 20 and the tank bottom of the megasonic cleaning tank 10, the rotary supporting ball assemblies 50 comprise supporting balls 51 and ball seats 52 which completely wrap the lower parts of the supporting balls 51, and the inner walls and the outer walls of the ball seats 52 are of spherical crown structures; the supporting ball 51 is rotatably connected with the ball seat 52, the bottom of the ball seat 52 is fixedly connected with the bottom of the megasonic cleaning tank 10, the top of the supporting ball 51 is contacted with the bottom of the rotary square tank 20, and a plurality of through holes 521 are formed in the side wall of the ball seat 52.
In some embodiments, the rotary support ball assemblies 50 are preferably three sets, and the three sets of rotary support ball assemblies 50 are arranged in a central symmetry. Three-point positioning can provide a support structure with excellent stability. If the spin support ball assembly 50 is provided in excess, it may further occupy the megasonic cleaning space, which may affect the efficiency of the megasonic cleaning.
The supporting ball 51 and the ball seat 52 can rotate relatively, so that the stability of the system can be remarkably improved by adopting the supporting ball 51 and the ball seat 52 to support the bottom of the rotary square groove 20; meanwhile, the rotation of the rotary square groove 20 is not affected, rolling friction is adopted between the rotary square groove 20 and the supporting ball 51, and the resistance is small.
In some embodiments, when the cross sections of the inner wall and the outer wall of the ball seat 52 are both in a major arc structure, the support ball 51 and the ball seat 52 can rotate without falling off. The through hole 521 is provided to discharge the liquid accumulation between the support ball 51 and the ball seat 52 to the maximum.
In some embodiments, when the cross sections of the inner wall and the outer wall of the ball seat 52 are both semicircular structures, the supporting ball 51 can be a magnetic ball, and the ball seat 52 can be a magnet shell which is attracted with the magnetic ball. The rotating square groove 20 is preferably made of a non-ferromagnetic material.
Example 3
Based on example 1, in the intermittent megasonic cleaning process, the frequency of megasonic cleaning isf,1800kHz is more than or equal to f and less than or equal to 2000kHz; the total time required for intermittent megasonic cleaning is t z The intermittent megasonic cleaning process is divided into a plurality of period cleaning time periods and a stay time period between two adjacent period cleaning time periods, the silicon carbide wafers in the cleaning liquid are subjected to rotary cleaning in the stay time period, T is the period cleaning time period, and T x For the residence time period, t z ＝mT+(m-1)t x M is an integer greater than 1;
in the periodic cleaning period, t= (T g1 +t t1 )+(t g2 +t t2 )+…+(t gn +t tn )，t gn For the nth megasonic cleaning time in the cycle, t tn For stopping megasonic cleaning time n times in the period, t gn And t tn Is adjacently arranged and forms an intermittent structure, t gn ＝t g1 +(n-1)(L g +n/10)，t tn ＝t t1 +(n-1)(L t +n/10), n is a positive integer;
when n is less than or equal to 9, L g ＝0.4，L t ＝0.1；
When n is more than or equal to 10 and less than or equal to 15, L g ＝0.4，L t ＝0.2。
In the spin cleaning, the rotation speed of the spin basket 20 is 0 to 80rpm, and since the start and stop of the spin basket 20 require time, the minimum t is maintained at the rotation speed of 80rpm to secure the cleaning effect x /2。
When the pH adjusting liquid is an acidic solution or water during the spin cleaning, dry ice is also sprayed into the cleaning liquid, and the mass ratio of the sprayed dry ice to the cleaning liquid is (8.6-12.5): 1000.
Example 4
In example 3, the cleaning liquid includes a surfactant, a metal chelator, a pH adjusting liquid; the pH regulating liquid is one of acidic solution, alkaline solution and water.
When the pH regulating solution is an acidic solution or water during rotary cleaning, dry ice is also sprayed into the cleaning solution, and the mass ratio of the sprayed dry ice to the cleaning solution is 11.3:1000.
In the embodiment, the fatty alcohol-polyoxyethylene ether with the mass fraction of 2.5% is used as a surfactant, the ethylenediamine tetraacetic acid with the mass fraction of 0.8% is used as a metal chelating agent, and the hydrochloric acid with the mass fraction of 6.7-7.2 mol/L is used as a pH regulating solution; the temperature of the washing was 65 ℃.
In this embodiment, the megasonic cleaning frequency is f=2000 kHz. In the present embodiment, t is as shown in FIG. 3 z ＝2T+t x M=2; in the periodic cleaning period, t= (T g1 +t t1 )+(t g2 +t t2 )+…+(t g9 +t t9 )，t g9 For the 9 th megasonic cleaning time in the cycle, t t9 To stop the megasonic cleaning time at the 9 th of the cycle,
t gn ＝t g1 +(n-1)(0.4+n/10)，t tn ＝t t1 + (n-1) (0.1+n/10), n being a positive integer;
when n=9, L g ＝0.4，L t ＝0.1；t g1 ＝1s，t t1 ＝0.5s；t x ＝50s，T＝205.5s，t z ＝461s。
When n is too large, L needs to be raised t Thereby increasing the "cool" time; n cannot be infinitely large, otherwise a single megasonic cleaning time t in one cycle gn Oversized, eventually resulting in damage to the silicon carbide wafer; therefore, n.ltoreq.15.
When n=1 to 9, t gn 、t tn The corresponding values are shown in Table 1:
TABLE 1
| n | t gn | t tn |
| 1 | 1.0 | 0.5 |
| 2 | 1.6 | 0.8 |
| 3 | 3.0 | 1.6 |
| 4 | 5.4 | 3.1 |
| 5 | 9.0 | 5.5 |
| 6 | 14.0 | 9.0 |
| 7 | 20.6 | 13.8 |
| 8 | 29.0 | 20.1 |
| 9 | 39.4 | 28.1 |
Method for producing and detecting silicon carbide wafer
Manufacturing a silicon carbide wafer standard sample, performing ultrasonic cleaning on the silicon carbide wafers in the same batch, performing ultrasonic cleaning at 30-50 kHz, and observing by using a metallographic microscope, wherein the metallographic microscope can be G-100 type equipment of A electronic technology Co., shenzhen City; randomly selecting 20 points as test points, then observing the number of the surface particle pollutants of the wafer in the visual field, and carrying out statistics and arrangement on the obtained data to respectively obtain the average value of the total number of the surface particle pollutants; average of surface particle contamination total/field area of view of metallographic microscope = surface particle contamination density.
When the density of surface particle pollutants with the particle diameter of more than or equal to 200nm is 600-800 particles/cm 2 And when the silicon carbide wafer standard sample is manufactured, the manufacturing of the silicon carbide wafer standard sample is completed.
Cleaning the silicon carbide wafer standard sample according to different cleaning processes, and detecting the density of the removed surface particle pollutants according to the detection method after cleaning; meanwhile, the removal rate is calculated.
Damage Rate detection
Observing the surface of the cleaned silicon carbide wafer standard sample by using a metallographic microscope, and judging that the appearance is disqualified if defects such as scratches, pits and the like appear; calculating the damage rate according to a batch, wherein the standard sample of the silicon carbide wafer in the batch is not less than 500; damage ratio = number of failed appearance silicon carbide wafer samples/total number of silicon carbide wafer samples.
In the embodiment, the silicon carbide wafer is cleaned by adopting the megasonic cleaning process of the silicon carbide wafer, the removal rate of surface particle pollutants is more than or equal to 99.5 percent, and the density of the surface particle pollutants is less than or equal to 0.52 particles/cm 2 The method comprises the steps of carrying out a first treatment on the surface of the Wherein, according to the industry practice, the wafer diameter is 150mm, so long as the surface particle pollutant density is less than or equal to 0.87 particles/cm 2 The product is qualified; the damage rate is less than or equal to 0.4 percent.
Example 5
In this embodiment, the cleaning solution includes a surfactant, a metal chelating agent, and a pH adjusting solution; the pH regulating solution is an acidic solution, wherein fatty alcohol polyoxyethylene ether with mass fraction of 2.5% is used as a surfactant, ethylenediamine tetraacetic acid with mass fraction of 0.8% is used as a metal chelating agent, and hydrochloric acid with mass fraction of 6.7-7.2 mol/L is used as the pH regulating solution; the temperature of the washing was 65 ℃.
The silicon carbide wafer standard sample is subjected to ultrasonic cleaning at 65 ℃ for at least 20min at 200KHz, the damage rate is calculated according to damage rate detection, meanwhile, the removal rate is calculated, and the ultrasonic cleaning time, the damage rate and the removal rate are shown in Table 2:
TABLE 2
| Ultrasonic cleaning time (min) | 20 | 30 | 40 | 50 | 60 | 80 | 100 | 120 |
| Damage Rate (%) | 0.6 | 0.9 | 1.2 | 1.5 | 2.6 | 5.2 | 8.3 | 8.5 |
| Removal rate (%) | 88.7％ | 90.5％ | 91.4％ | 93.5％ | 93.7％ | 93.8％ | 93.7％ | 93.8％ |
Example 6
In this embodiment, the cleaning solution includes a surfactant, a metal chelating agent, and a pH adjusting solution; the pH regulating solution is an acidic solution, wherein fatty alcohol polyoxyethylene ether with mass fraction of 2.5% is used as a surfactant, ethylenediamine tetraacetic acid with mass fraction of 0.8% is used as a metal chelating agent, and hydrochloric acid with mass fraction of 6.7-7.2 mol/L is used as the pH regulating solution; the temperature of the washing was 65 ℃.
Megasonic cleaning is carried out on a silicon carbide wafer standard sample at 65 ℃, cleaning is carried out for a minimum of 5min at 2000KHz, the damage rate is calculated according to damage rate detection, meanwhile, the removal rate is calculated, and the ultrasonic cleaning time, the damage rate and the removal rate are shown in Table 3:
TABLE 3 Table 3
| Megasonic cleaning time (min) | 5 | 10 | 15 | 20 | 30 | 40 | 50 |
| Damage Rate (%) | ≤0.1 | 0.6 | 1.4 | 2.6 | 3.2 | 4.4 | 6.2 |
| Removal rate (%) | 93.3％ | 95.7％ | 97.2％ | 98.1％ | 98.8％ | 98.7％ | 98.9％ |
Example 7
This example differs from example 4 in that in this example, no matter was added to the cleaning liquid when the pH adjusting liquid was an acidic solution (6.7 to 7.2mol/L hydrochloric acid) or water during the spin cleaning. The maximum surface particle contaminant removal rate was calculated to be 95.2% for the final cleaned silicon carbide wafer standard.
Example 8
The difference between this example and example 4 is that in this example, the pH adjusting liquid is an alkaline solution (1 mol/L sodium hydroxide solution) during spin cleaning, dry ice is sprayed into the cleaning liquid, and the mass ratio of the sprayed dry ice to the cleaning liquid is 11.3:1000. The final cleaned silicon carbide wafer standard was calculated to have a surface particle contaminant removal of 89.7%.
Example 9
The difference between this embodiment and embodiment 4 is that in this embodiment, t gn ＝k＝40s，t g1 ＝t g2 ＝…＝t g9 ＝40，t tn ＝y＝30s，t t1 ＝t t2 ＝…＝t t9 =30; at t z At > 15min, the final cleaned silicon carbide wafer standard was calculated to have a surface particle contaminant removal of 96.3% and a damage rate of 1%.
In the above embodiment, when the amount of dry ice sprayed into the cleaning solution is too large, the damage rate is increased sharply, for example, the damage rate reaches 33.6% when the mass ratio of the sprayed dry ice to the cleaning solution is 22:1000.
When the amount of dry ice sprinkled into the cleaning liquid is too small, the removal rate is limited, for example, when the mass ratio of the sprinkled dry ice to the cleaning liquid is 5:1000, the removal rate is 90.7%.
The invention can clean the silicon carbide wafer in the megasonic cleaning with the frequency of 2000KHz for 7.7min, and has high cleaning efficiency (the existing megasonic cleaning is at least 20 min), good cleaning effect, high application value and good implementation effect, and can furthest reduce the damage to the surface of the silicon carbide wafer.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (7)
1. A megasonic cleaning process for silicon carbide wafers, comprising the steps of:
step one, placing a silicon carbide wafer to be cleaned in rotary megasonic cleaning equipment, and performing intermittent megasonic cleaning by using cleaning liquid;
step two, cleaning, drying, packaging and storing the silicon carbide wafer cleaned in the step one by using pure water;
in the intermittent megasonic cleaning process, the frequency of megasonic cleaning is f, and f is more than or equal to 1800kHz and less than or equal to 2000kHz; the total time required for intermittent megasonic cleaning is t z The intermittent megasonic cleaning process is divided into a plurality of period cleaning time periods and a stay time period between two adjacent period cleaning time periods, the silicon carbide wafers in the cleaning liquid are subjected to rotary cleaning in the stay time period, T is the period cleaning time period, and T x For the residence time period, t z =mT+(m-1)t x M is an integer greater than 1;
in the periodic cleaning period, t= (T g1 +t t1 )+(t g2 +t t2 )+…+(t gn +t tn )，t gn For the nth megasonic cleaning time in the cycle, t tn For stopping megasonic cleaning time n times in the period, t gn =t g1 +(n-1)(L g +n/10)，t tn =t t1 +(n-1)(L t +n/10), n is a positive integer;
when n is less than or equal to 9, L g =0.4，L t =0.1；
When n is more than or equal to 10 and less than or equal to 15, L g =0.4，L t =0.2。
2. A silicon carbide wafer megasonic cleaning process according to claim 1, wherein: the rotary megasonic cleaning equipment comprises a megasonic cleaning tank, wherein a rotary square tank is arranged in the megasonic cleaning tank and driven to rotate by a driving mechanism, the driving mechanism comprises a driving motor positioned outside the megasonic cleaning tank, a gearbox and a rotating shaft positioned outside the megasonic cleaning tank, a rotor of the driving motor is fixedly connected with an input end of the gearbox, an output end of the gearbox is fixedly connected with a lower end of the rotating shaft, an upper end of the rotating shaft is fixedly connected with a bottom of the rotary square tank, and a totally-enclosed bearing is arranged between the rotating shaft and the bottom of the megasonic cleaning tank.
3. A silicon carbide wafer megasonic cleaning process according to claim 2, wherein: a minimum of three groups of rotary supporting ball assemblies are arranged between the tank bottom of the rotary square tank and the tank bottom of the megasonic cleaning tank, each rotary supporting ball assembly comprises a supporting ball and a ball seat which completely wraps the lower part of the supporting ball, and the inner wall and the outer wall of each ball seat are of spherical crown structures; the ball seat is characterized in that the supporting ball is rotationally connected with the ball seat, the bottom of the ball seat is fixedly connected with the bottom of the megasonic cleaning tank, the top of the supporting ball is contacted with the bottom of the rotary square tank, and a plurality of through holes are formed in the side wall of the ball seat.
4. A silicon carbide wafer megasonic cleaning process according to claim 3, wherein: the rotary type supporting ball components are provided with three groups, and the three groups of rotary type supporting ball components are arranged in a central symmetry mode.
5. A silicon carbide wafer megasonic cleaning process according to claim 1, wherein: the cleaning liquid comprises a surfactant, a metal chelating agent and a pH regulating liquid; the pH regulating liquid is one of acidic solution, alkaline solution and water.
6. A silicon carbide wafer megasonic cleaning process according to claim 5, wherein: during the rotary cleaning, the rotating speed of the rotary square groove is 0-80 rpm, and the holding time is at least t under the rotating speed of 80rpm x /2。
7. A silicon carbide wafer megasonic cleaning process according to claim 6, wherein: when the pH adjusting solution is an acidic solution or water during the rotary cleaning, dry ice is also sprayed into the cleaning solution, and the mass ratio of the sprayed dry ice to the cleaning solution is (8.6-12.5): 1000.
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| US5520205A (en) * | 1994-07-01 | 1996-05-28 | Texas Instruments Incorporated | Apparatus for wafer cleaning with rotation |
| US8327861B2 (en) * | 2006-12-19 | 2012-12-11 | Lam Research Corporation | Megasonic precision cleaning of semiconductor process equipment components and parts |
| CN102059230B (en) * | 2010-12-30 | 2012-08-08 | 常州松晶电子有限公司 | Rocking washing device for washing wafer |
| CN204996772U (en) * | 2015-06-29 | 2016-01-27 | 上海华力微电子有限公司 | Million sound wave grooves |
| CN205628774U (en) * | 2016-05-13 | 2016-10-12 | 晋谱（福建）光电科技有限公司 | Optical lens piece belt cleaning device |
| TWI771501B (en) * | 2018-09-28 | 2022-07-21 | 大陸商盛美半導體設備（上海）股份有限公司 | Substrate cleaning device |
| CN210516687U (en) * | 2019-11-04 | 2020-05-12 | 河北广创电子科技有限公司 | Groove body structure of megasonic cleaning machine |
| CN112893302A (en) * | 2020-12-22 | 2021-06-04 | 江西龙芯微科技有限公司 | Cleaning device for electronic semiconductor processing |
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