CN114472341B - Cleaning method of lithium niobate single-side polished wafer - Google Patents
Cleaning method of lithium niobate single-side polished wafer Download PDFInfo
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- CN114472341B CN114472341B CN202210407079.4A CN202210407079A CN114472341B CN 114472341 B CN114472341 B CN 114472341B CN 202210407079 A CN202210407079 A CN 202210407079A CN 114472341 B CN114472341 B CN 114472341B
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- 238000004140 cleaning Methods 0.000 title claims abstract description 60
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims abstract description 35
- 230000001680 brushing effect Effects 0.000 claims abstract description 65
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 60
- 239000008367 deionised water Substances 0.000 claims abstract description 29
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 29
- 238000005406 washing Methods 0.000 claims abstract description 21
- 239000003960 organic solvent Substances 0.000 claims abstract description 20
- MIMUSZHMZBJBPO-UHFFFAOYSA-N 6-methoxy-8-nitroquinoline Chemical compound N1=CC=CC2=CC(OC)=CC([N+]([O-])=O)=C21 MIMUSZHMZBJBPO-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000002791 soaking Methods 0.000 claims abstract description 11
- 238000004506 ultrasonic cleaning Methods 0.000 claims abstract description 9
- 239000002245 particle Substances 0.000 claims description 34
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 30
- 238000001035 drying Methods 0.000 claims description 30
- 239000000243 solution Substances 0.000 claims description 28
- 238000005507 spraying Methods 0.000 claims description 26
- 239000012459 cleaning agent Substances 0.000 claims description 20
- 238000003825 pressing Methods 0.000 claims description 18
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 15
- 239000012530 fluid Substances 0.000 claims description 9
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 8
- 238000011109 contamination Methods 0.000 claims description 7
- 239000003085 diluting agent Substances 0.000 claims description 7
- 238000002347 injection Methods 0.000 claims description 6
- 239000007924 injection Substances 0.000 claims description 6
- 238000005498 polishing Methods 0.000 claims description 6
- HXKKHQJGJAFBHI-UHFFFAOYSA-N 1-aminopropan-2-ol Chemical compound CC(O)CN HXKKHQJGJAFBHI-UHFFFAOYSA-N 0.000 claims description 5
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 5
- 239000002738 chelating agent Substances 0.000 claims description 5
- 229940102253 isopropanolamine Drugs 0.000 claims description 5
- 239000002736 nonionic surfactant Substances 0.000 claims description 5
- 238000007599 discharging Methods 0.000 claims description 4
- 238000002156 mixing Methods 0.000 claims description 4
- 239000000377 silicon dioxide Substances 0.000 claims description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims description 4
- 230000005540 biological transmission Effects 0.000 claims description 3
- 238000005096 rolling process Methods 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 2
- ZLMJMSJWJFRBEC-OUBTZVSYSA-N potassium-40 Chemical compound [40K] ZLMJMSJWJFRBEC-OUBTZVSYSA-N 0.000 claims description 2
- 230000003749 cleanliness Effects 0.000 abstract description 13
- 238000013467 fragmentation Methods 0.000 abstract description 4
- 238000006062 fragmentation reaction Methods 0.000 abstract description 4
- 235000012431 wafers Nutrition 0.000 description 130
- 239000008187 granular material Substances 0.000 description 8
- 239000012634 fragment Substances 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 7
- 238000005201 scrubbing Methods 0.000 description 6
- 238000013519 translation Methods 0.000 description 6
- 239000002253 acid Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 238000009987 spinning Methods 0.000 description 4
- ZLMJMSJWJFRBEC-RNFDNDRNSA-N Potassium-43 Chemical compound [43K] ZLMJMSJWJFRBEC-RNFDNDRNSA-N 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- 208000028659 discharge Diseases 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910001385 heavy metal Inorganic materials 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000013618 particulate matter Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000007777 multifunctional material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Images
Classifications
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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
- B08B3/08—Cleaning involving contact with liquid the liquid having chemical or dissolving effect
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B1/00—Cleaning by methods involving the use of tools
- B08B1/10—Cleaning by methods involving the use of tools characterised by the type of cleaning tool
- B08B1/12—Brushes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B1/00—Cleaning by methods involving the use of tools
- B08B1/30—Cleaning by methods involving the use of tools by movement of cleaning members over a surface
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B1/00—Cleaning by methods involving the use of tools
- B08B1/30—Cleaning by methods involving the use of tools by movement of cleaning members over a surface
- B08B1/32—Cleaning by methods involving the use of tools by movement of cleaning members over a surface using rotary cleaning members
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
- H01L21/67011—Apparatus for manufacture or treatment
- H01L21/67017—Apparatus for fluid treatment
- H01L21/67028—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
- H01L21/6704—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing
- H01L21/67046—Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like for wet cleaning or washing using mainly scrubbing means, e.g. brushes
-
- 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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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Cleaning Or Drying Semiconductors (AREA)
Abstract
A method for cleaning a lithium niobate single-side polished wafer. The method comprises the following steps: soaking and cleaning the lithium niobate wafer by ammonium bifluoride; carrying out ultrasonic cleaning on the wafer by using organic solvent cleaning solution; washing the wafer with deionized water; brushing the wafer with a double-sided brush; and brushing the single side of the wafer by a brush to finally obtain the lithium niobate wafer with low fragmentation rate and high cleanliness.
Description
Technical Field
The invention belongs to the field of semiconductor material cleaning, and particularly relates to a method for cleaning a single-side polished wafer of a semiconductor material lithium niobate.
Background
Lithium niobate is a multifunctional material integrating piezoelectric, ferroelectric, pyroelectric, nonlinear, photoelectric, photoelastic, photorefractive and other functions. Lithium niobate gets more and more attention due to its excellent physical properties, and is widely used in the fields of aviation, aerospace, civil photoelectric products and the like. The polished lithium niobate substrate is widely applied to sensors, acousto-optic devices, optical gyroscopes and the like. Unlike silicon wafers and sapphire wafers, it is characterized by extremely low fracture toughness, making lithium niobate wafers extremely fragile during cleaning, resulting in high production cost for enterprises.
With the development and progress of IC design technology and manufacturing technology, the requirement for surface cleanliness of lithium niobate wafers is continuously improved, however, lithium niobate wafers have strong electrostatic adsorption capacity, so that particles on the surfaces of the wafers are difficult to process, particle pollution on the surfaces of the lithium niobate wafers can directly influence subsequent processes such as gluing, film plating and the like, and the wafers can be poor. Therefore, not only needs to be clean protected in the packaging and transportation links, but also needs to achieve good quality with high cleanliness from the product source, so that the lithium niobate wafer can keep high requirements on surface cleanliness. The wafer cleaning link is used as a main process for removing particle pollution on the surface of the wafer, and plays a vital role in maintaining the high cleanliness of the surface of the lithium niobate wafer. However, the lithium niobate wafer is very easy to be broken during the cleaning process, which causes great difficulty in the subsequent processing of the wafer, so that it is urgently needed to develop a cleaning method with high cleanliness and low fragment rate.
The invention patent with the publication number of CN101661869B discloses a cleaning method of a polished gallium arsenide wafer, which adopts a concentrated sulfuric acid high-temperature cleaning mode to achieve the purpose of removing the surface dirt of the wafer. However, when the lithium niobate wafer is cleaned, strong acid corrosion and cracking are easily caused to the wafer by the high-temperature cleaning of concentrated sulfuric acid, and the acid liquid is easily volatilized in the processing process, so that potential safety hazards exist to the environment and human bodies. In addition, the traditional sulfuric acid soaking and cleaning method matched with the cleaning agent has poor cleaning effect on particle contamination on the surface of the wafer.
The patent publication No. CN102479669B discloses a wafer brush cleaning device and a wafer brush cleaning method, which achieve the purpose of removing wafer particles by adopting a two-side brush scrubbing mode. However, in practice, the cleaning ability is not strong only by brushing and translating the two-sided brush, but also large particles on the surface of the wafer can be brushed away, and the requirement of high cleanliness cannot be met.
Therefore, a cleaning method for obtaining a lithium niobate wafer with a low chipping rate and high cleanliness is lacking in the prior art.
Disclosure of Invention
The invention provides a method for cleaning a lithium niobate single-side polished wafer, which aims to overcome the defects in the prior art.
The technical scheme adopted by the invention for solving the problems is as follows: a method for cleaning a lithium niobate single-side polished wafer comprises the following steps:
a) soaking the lithium niobate wafer in ammonium bifluoride diluent at 30-40 ℃ for 10-30 minutes, removing the silicon dioxide polishing solution residue on the surface of the polished wafer, and then rinsing the wafer in pure water at 30-40 ℃ for 3-5 minutes;
b) placing the lithium niobate wafer treated in the step a) in pure water at 55-65 ℃ for pre-soaking for 1-3 minutes, then placing the wafer in organic solvent cleaning solution at 70-80 ℃ for ultrasonic cleaning for 10-20 minutes, and removing organic contamination, heavy metal ion contamination and the like on the surface of the wafer;
c) placing the lithium niobate wafer treated in the step b) in a deionized water flushing tank, performing spraying, water injection, overflow and quick discharge treatment, repeating for 4-6 times, and removing the residue of a cleaning agent on the surface of the wafer;
d) brushing the lithium niobate wafer treated in the step c) by using a double-sided brush in an alkaline cleaning solution, then brushing and spraying and washing by using the double-sided brush in deionized water, and then carrying out drying treatment;
e) adsorbing the back of the lithium niobate wafer treated in the step d) on a vacuum platform, brushing the polished surface of the lithium niobate wafer by a single-sided brush, spraying two fluids during brushing, and then washing and spin-drying the lithium niobate wafer by deionized water to ensure that the particles not less than 0.3 mu m on the surface of the lithium niobate wafer are not more than 30.
In the step a), the ammonium bifluoride diluent is adopted to heat and soak to remove the silicon dioxide polishing solution residue on the polished wafer surface, so that the polished surface is not damaged, and meanwhile, intractable pollution caused by the crystallization of the polishing solution is prevented.
Preferably, in the step a), the mass fraction of ammonium bifluoride is 98%, and the ammonium bifluoride diluent is prepared from pure water and ammonium bifluoride according to a mass ratio of 10-15: 1 are mixed.
In the step b), organic contamination, heavy metal ion contamination and the like on the surface of the wafer are removed by adopting a heating ultrasonic cleaning mode of an organic solvent cleaning solution, a cleaning mode of concentrated sulfuric acid corrosion is replaced, the problem of wafer fragmentation caused by strong acid corrosion is avoided, and the ultrasonic frequency is 40 kHz.
Preferably, the organic solvent cleaning solution in the step b) is prepared from pure water and an organic solvent according to a volume ratio of 5-10: 1, wherein the organic solvent cleaning agent comprises 15-20% by mass of isopropanolamine, 30-40% by mass of N-methyl pyrrolidone, 3-10% by mass of potassium hydroxide and 40-60% by mass of pure water.
In the step c), the cleaning treatment is repeated by adopting four steps of spraying, water injection, overflowing and quick discharging, and particle impurities and cleaning solution residues on the surface of the wafer are removed.
Preferably, the spraying time in step c) is 50-70s, the water injection amount is used for submerging the wafer, the overflow time is 20-30s, the fast discharge time is 10s, and the repetition times are 4-6 times.
In the step d), the double-sided brush is adopted for brushing treatment, so that large particles on the front polished surface of the wafer are removed, the single-sided brushing particle dirt accumulation burden is reduced, the large particles on the back of the wafer are removed, and the influence of the large particles on the back of the wafer on the granularity of the polished surface in the post-process processing and operation is prevented. The double-sided brushing is a double-sided transmission rolling brush mode, and the brush rotates and drives the wafer to move horizontally.
Preferably, in the step d), the double-sided brushing is performed in a double-sided transmission rolling brush mode, the brush rotates and drives the wafer to translate, the brush for double-sided brushing is a PVA roller brush, the rotating speed of the brush is 6-10rpm, the pressing distance between the upper brush and the lower brush is 1300 microns, the brushing time is 3-5 minutes, the diameter of the brush is 2-3cm, the spraying and washing are performed for 10-20 seconds, the wafer spin-drying rotating speed is 1200-1500rpm, and the spin-drying time is 15-20 seconds.
Preferably, the alkaline cleaning solution in the step d) is prepared by mixing deionized water and an alkaline cleaning agent according to a volume ratio of 30-50: 1, and the alkaline cleaning agent comprises 0.2-0.6% of sodium hydroxide, 1-3% of potassium hydroxide, 0.5-2% of chelating agent, 2-5% of nonionic surfactant and 90-96% of deionized water by mass ratio.
In the step e), the polished surface of the lithium niobate wafer is brushed by a single-sided brush, two-fluid spraying is carried out during brushing, and then deionized water washing and spin-drying treatment are carried out, wherein the brushing process can directly influence the fragment rate of the wafer during brushing and the cleanliness of the wafer after brushing.
Preferably, the brush brushed on one side in the step e) is a PVA gyroscope type brush, the pressing distance of the brush is 900-.
Compared with the prior art, the invention has the following beneficial technical effects:
on the first hand, the cleaning method solves the problem that the polishing solution remained on the surface of the lithium niobate wafer is crystallized after the lithium niobate wafer is polished by the silicon dioxide polishing solution;
in the second aspect, the cleaning method replaces a mode of cleaning a wafer by using a mixed cleaning solution of concentrated sulfuric acid and hydrogen peroxide, so that the problem of strong acid corrosion and cracking caused by the concentrated sulfuric acid cleaning solution is avoided, and the problem of potential safety hazards to the environment and human bodies due to easy volatilization of acid liquor in the processing process is also prevented;
in a third aspect, the cleaning method solves the problem that the traditional acetone, absolute ethyl alcohol ultrasonic cleaning and RCA cleaning modes have poor cleaning effect on particle contamination on the surface of the wafer.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is a schematic diagram showing the relationship between pure water preheating soaking and the fragment rate in examples 1, 2 and 3 of the present invention;
FIG. 3 is a schematic diagram showing the relationship between the ratio of alkaline clear solutions and the particle size in examples 4, 5 and 6 of the present invention;
FIG. 4 is a schematic diagram showing the relationship between the brush pressing distance, the fragment rate and the particle size in examples 7, 8 and 9 of the present invention;
FIG. 5 is a schematic diagram showing the relationship between the brush stopping at the edge of the wafer and the particle size in the embodiments 8, 10, 11, and 12 of the present invention.
Detailed Description
The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the invention. The process flow of the examples is shown in FIG. 1, where examples 1-3 comprise only the first two flows, examples 4-6 comprise the first four flows, and examples 7-12 are complete cleaning processes.
Example 1:
a) according to the weight ratio of pure water and ammonium bifluoride 12: 1 to obtain ammonium bifluoride diluent. Soaking the lithium niobate wafer in an ammonium bifluoride diluent at 35 ℃ for 15 minutes, and then rinsing the wafer in pure water at 35 ℃ for 3 minutes;
b) preparing an organic solvent cleaning agent according to the following components by mass percent, namely 18 percent of isopropanolamine, 35 percent of N-methyl pyrrolidone, 4 percent of potassium hydroxide and 43 percent of pure water, and according to the pure water and the organic solvent cleaning agent 8: 1, the wafers are not preheated by pure water, the lithium niobate wafers are placed in organic solvent cleaning solution at 75 ℃ for 40kHZ ultrasonic cleaning for 15 minutes, 1273 wafers are thrown in, and the wafers are cracked into 12 wafers, wherein the rate of the chips is 1.02%;
example 2:
a) the same as example 1;
b) preparing an organic solvent cleaning agent according to the following components by mass percent, namely 18 percent of isopropanolamine, 35 percent of N-methyl pyrrolidone, 4 percent of potassium hydroxide and 43 percent of pure water, and according to the pure water and the organic solvent cleaning agent 8: 1, placing the lithium niobate wafer in pure water at 60 ℃ for preheating and soaking for 2 minutes, then placing the wafer in organic solvent cleaning solution at 75 ℃ for 40kHZ ultrasonic cleaning for 15 minutes, putting 1677 wafers, and cracking 4 wafers, wherein the rate of the chips is 0.24%;
example 3:
a) the same as example 1;
b) preparing an organic solvent cleaning agent according to the following components by mass percent, namely 18 percent of isopropanolamine, 35 percent of N-methyl pyrrolidone, 4 percent of potassium hydroxide and 43 percent of pure water, and according to the pure water and the organic solvent cleaning agent 8: 1, placing the lithium niobate wafer in pure water at 75 ℃ for preheating and soaking for 2 minutes, then placing the wafer in organic solvent cleaning solution at 75 ℃ for 40kHZ ultrasonic cleaning for 15 minutes, and throwing 1412 chips and 11 chips with the chip rate of 0.78%;
in comparative examples 1, 2 and 3, as shown in table 1 and fig. 2, the wafer fragments caused by thermal shock can be effectively reduced by pre-heating and soaking the wafer in pure water at 60 ℃ for 2 minutes before the organic solvent cleaning solution is subjected to high-temperature ultrasonic cleaning at 75 ℃.
TABLE 1 wafer cleaning debris Rate for examples 1, 2, 3
| Detecting items | Example 1 | Example 2 | Example 3 |
| Fraction rate | 0.94% | 0.24% | 0.78% |
Example 4:
a) the same as example 2;
b) the same as example 2;
c) placing the lithium niobate wafer in a deionized water washing tank, spraying for 60s, flooding the wafer with water, overflowing for 30s, and quickly discharging for 10s, and repeating for 5 times;
d) preparing an alkaline cleaning agent according to the following components by mass percent, namely 0.4 percent of sodium hydroxide, 2 percent of potassium hydroxide, 1.2 percent of chelating agent, 4 percent of nonionic surfactant and 92.4 percent of deionized water, and according to the mass percent of the deionized water and the alkaline cleaning agent 25: 1, firstly brushing a lithium niobate wafer by using an alkaline cleaning solution double-sided brush, then brushing and spraying and washing by using a deionized water double-sided brush, wherein the rotating speed of the brush is 6rpm, the pressing distance between an upper brush and a lower brush is 1200 mu m, the brushing time is 3 minutes, the diameter of the brush is 2.2cm, the spraying and washing time is 14s, then carrying out spin-drying treatment, the spin-drying rotating speed of the wafer is 1300rpm, the spin-drying time is 18s, putting 764 pieces, sampling 62 pieces, and the number of particles with the diameter being more than or equal to 0.3 mu m is less than or equal to 314;
example 5:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) preparing an alkaline cleaning agent according to the mass fractions of the following components, namely 0.4% of sodium hydroxide, 2% of potassium hydroxide, 1.2% of chelating agent, 4% of nonionic surfactant and 92.4% of deionized water, and according to the mass fractions of the deionized water and the alkaline cleaning agent 40: 1, firstly brushing a lithium niobate wafer by using an alkaline cleaning solution double-sided brush, then brushing and spraying and washing by using a deionized water double-sided brush, wherein the rotating speed of the brush is 6rpm, the pressing distance between an upper brush and a lower brush is 1200 mu m, the brushing time is 3 minutes, the diameter of the brush is 2.2cm, the spraying and washing time is 14s, then carrying out spin-drying treatment, the spin-drying rotating speed of the wafer is 1300rpm, the spin-drying time is 18s, putting 827 wafers, sampling 67 wafers, and the number of particles larger than or equal to 0.3 mu m is less than or equal to 169 particles;
example 6:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) preparing an alkaline cleaning agent according to the mass fractions of 0.4% of sodium hydroxide, 2% of potassium hydroxide, 1.2% of chelating agent, 4% of nonionic surfactant and 92.4% of deionized water according to the mass fractions of deionized water and the alkaline cleaning agent 60: 1, firstly brushing a lithium niobate wafer by using an alkaline cleaning solution double-sided brush, then brushing and spraying and washing by using a deionized water double-sided brush, wherein the rotating speed of the brush during brushing is 6rpm, the pressing distance between an upper brush and a lower brush is 1200 mu m, the brushing time is 3 minutes, the diameter of the brush is 2.2cm, the spraying and washing time is 14s, then carrying out spin-drying treatment, the spin-drying rotating speed of the wafer is 1300rpm, the spin-drying time is 18s, putting 883 wafers, sampling 71 wafers, and the number of particles larger than or equal to 0.3 mu m is less than or equal to 204;
comparative examples 4, 5, 6, as shown in table 2 and figure 3, were prepared in a batch with deionized water and alkaline cleaner 40: 1, the cleanliness of the wafer brushed by the double-sided brush is high.
TABLE 2 debris Rate and particle size of single-sided scrub wafers of examples 4, 5, 6
| Detecting items | Example 4 | Example 5 | Example 6 |
| Particles with a diameter of more than or equal to 0.3 mu m | Less than or equal to 314 granules | Not more than 169 granules | Less than or equal to 204 |
Example 7:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) the same as example 5;
e) brushing a polished surface of a lithium niobate wafer by using a single-sided brush, simultaneously spraying two fluids during brushing, wherein the downward pressing distance of the brush during brushing is 600 microns, the rotating speed of the brush is 1300rpm/min, the translation speed of the brush is 17mm/s, the center of the wafer stops for 1s, the edge of the wafer stops for 1s, the brushing rotating speed of the wafer is 400rpm, the brush is brushed and reciprocated for 5 times, then deionized water is used for washing for 8s, then the wafer is subjected to spin-drying treatment, the spin-drying rotating speed is 3500rpm, the spin-drying time is 26s, 922 pieces are put in, the fragmentation is 0 piece, the fragmentation rate is 0%, 74 pieces are sampled, and the number of particles larger than or equal to 0.3 microns is less than or equal to 97;
example 8:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) the same as example 5;
e) brushing a polished surface of a lithium niobate wafer by using a single-sided brush, simultaneously spraying two fluids during brushing, wherein the downward pressing distance of the brush during brushing is 1000 microns, the rotating speed of the brush is 1300rpm/min, the translation speed of the brush is 17mm/s, the center of the wafer stops for 1s, the edge of the wafer stops for 1s, the brushing rotating speed of the wafer is 400rpm, the brush brushes are brushed and reciprocated for 5 times, then deionized water is used for washing for 8s, then the wafer is subjected to spin-drying treatment, the spin-drying rotating speed is 3500rpm, the spin-drying time is 26s, 1002 pieces are thrown in, the wafer is cracked for 1 piece, the fragment rate is 0.10%, 81 pieces are sampled, and the number of particles larger than or equal to 0.3 microns is smaller than or equal to 47;
example 9:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) the same as example 5;
e) carrying out single-side brush scrubbing treatment on a polished surface of a lithium niobate wafer, simultaneously carrying out two-fluid spraying during scrubbing, wherein the downward pressing distance of a brush during scrubbing is 1400 mu m, the rotating speed of the brush is 1300rpm/min, the translation speed of the brush is 17mm/s, the center of the wafer stops for 1s, the edge of the wafer stops for 1s, the scrubbing rotating speed of the wafer is 400rpm, the brush scrubbing is carried out 5 times, then deionized water is carried out for washing for 8s, then the wafer is subjected to spin-drying treatment, the spin-drying rotating speed is 3500rpm, the spin-drying time is 26s, 1161 pieces are thrown in, 5 pieces are crushed, the fragment rate is 0.58%, 93 pieces are sampled, and the number of particles larger than or equal to 0.3 mu m is smaller than or equal to 39;
in comparative examples 7, 8 and 9, as shown in table 3 and fig. 4, the wafer was cleaned with higher cleanliness when the brush pressing distance was increased during one-side brushing, but the proportion of chips increased during brushing when the brush pressing distance was increased, and the chip cleaning rate was low and cleanliness was high when the brush pressing distance was 1000 μm during brushing.
TABLE 3 debris Rate and particle size of single-sided scrub wafers of examples 7, 8, 9
| Detecting items | Example 7 | Example 8 | Example 9 |
| Fraction rate | 0.00% | 0.10% | 0.58% |
| Particles of not less than 0.3 mu m | Less than or equal to 97 granules | Not more than 47 granules | Less than or equal to 39 granules |
Example 10:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) the same as example 5;
e) brushing a polished surface of a lithium niobate wafer with a single-sided brush, simultaneously spraying two fluids during brushing, wherein the downward pressing distance of the brush during brushing is 1000 microns, the rotating speed of the brush is 1300rpm/min, the translation speed of the brush is 17mm/s, the center of the wafer stops for 1s, the edge does not stop, the brushing rotating speed of the wafer is 400rpm, the brushing of the brush is carried out for 5 times, then deionized water is used for washing for 8s, then the wafer is spun-dried, the spinning rotating speed is 3500rpm, the spinning time is 26s, 768 wafers are thrown in, 62 wafers are sampled, and the number of particles larger than or equal to 0.3 micron is less than or equal to 113;
example 11:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) the same as example 5;
e) brushing a polished surface of a lithium niobate wafer by using a single-sided brush, simultaneously spraying two fluids during brushing, wherein the downward pressing distance of the brush during brushing is 1000 microns, the rotating speed of the brush is 1300rpm/min, the translation speed of the brush is 17mm/s, the center of the wafer stops for 1s, the edge of the wafer stops for 3s, the brushing rotating speed of the wafer is 400rpm, the brushing of the brush is carried out for 5 times, then deionized water is used for washing for 8s, then the wafer is subjected to spin-drying treatment, the spin-drying rotating speed is 3500rpm, the spin-drying time is 26s, 960 pieces are put in, 77 pieces are sampled, and particles larger than or equal to 0.3 micron are smaller than or equal to 27 particles;
example 12:
a) the same as example 2;
b) the same as example 2;
c) the same as example 4;
d) the same as example 5;
e) brushing a polished surface of a lithium niobate wafer with a single-sided brush, simultaneously spraying two fluids during brushing, wherein the downward pressing distance of the brush during brushing is 1000 mu m, the rotating speed of the brush is 1300rpm/min, the translation speed of the brush is 17mm/s, the center of the wafer stops for 1s, the edge of the wafer stops for 5s, the brushing rotating speed of the wafer is 400rpm, the brushing and brushing are carried out for 5 times, then deionized water is used for washing for 8s, then the wafer is spun-dried, the spinning rotating speed is 3500rpm, the spinning time is 26s, 944 wafers are thrown in, 76 wafers are sampled, and the number of particles larger than or equal to 0.3 mu m is less than or equal to 26;
in comparative examples 8, 10, 11 and 12, as shown in table 4 and fig. 5, the cleanliness of the brush was high at a standstill of the wafer edge for 3 seconds or more during the brushing, and particles accumulated on the wafer edge during the brushing from the inside of the wafer to the outside were effectively removed.
TABLE 4 single side scrub wafer particle size for examples 8, 10, 11, 12
| Detecting items | Example 8 | Example 10 | Example 11 | Example 12 |
| Particles with a diameter of more than or equal to 0.3 mu m | Not more than 47 granules | Less than or equal to 113 | Less than or equal to 27 granules | Less than or equal to 26 granules |
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (8)
1. A method for cleaning a lithium niobate single-side polished wafer is characterized by comprising the following specific steps:
a) soaking the single-side polished lithium niobate wafer in an ammonium bifluoride diluent, removing silicon dioxide polishing solution residues on the surface of the polished wafer, and then rinsing the wafer in pure water;
b) placing the wafer treated in the step a) in pure water at 55-65 ℃ for pre-soaking for 1-3 minutes, then placing the wafer in organic solvent cleaning solution at 70-80 ℃ for ultrasonic cleaning for 10-20 minutes, and removing the surface contamination of the wafer;
c) adopting deionized water to repeatedly perform spraying, water injection, overflow and quick discharge on the wafer treated in the step b), and removing particle impurities and cleaning solution residues on the surface of the wafer;
d) brushing the wafer treated in the step c) by using a double-sided brush in an alkaline cleaning solution, then brushing and spraying and washing the wafer in deionized water, and then carrying out drying treatment, wherein the alkaline cleaning solution is prepared by mixing deionized water and an alkaline cleaning agent according to a volume ratio of 30-50: 1, mixing;
e) adsorbing the back surface of the wafer treated in the step d) on a vacuum platform, brushing the polished surface upwards by a single-sided brush, pressing the brush for 900-1200 mu m, rotating and translating the brush on the surface of the wafer, stopping for 3-5s when brushing the edge of the wafer, simultaneously spraying two fluids during brushing, and then washing and spin-drying by deionized water so that particles not smaller than 0.3 mu m on the surface of the wafer are not more than 30.
2. The method for cleaning a lithium niobate single-side polished wafer according to claim 1, wherein in the step a), the lithium niobate single-side polished wafer is immersed in an ammonium bifluoride diluted solution at a temperature of 30 to 40 ℃ for 10 to 30 minutes, and the wafer is rinsed in pure water at a temperature of 30 to 40 ℃ for 3 to 5 minutes.
3. The method for cleaning the lithium niobate single-side polished wafer according to claim 1, wherein in the step a), the mass fraction of ammonium bifluoride is 98%, and the ammonium bifluoride diluent is pure water and ammonium bifluoride in a mass ratio of 10-15: 1 by mixing.
4. The method for cleaning the lithium niobate single-side polished wafer according to claim 1, wherein in the step b), the ultrasonic frequency is 40kHZ, and the organic solvent cleaning solution is prepared from pure water and an organic solvent in a volume ratio of 5-10: 1, wherein the organic solvent cleaning agent comprises 15-20% by mass of isopropanolamine, 30-40% by mass of N-methyl pyrrolidone, 3-10% by mass of potassium hydroxide and 40-60% by mass of pure water.
5. The method for cleaning a lithium niobate single-sided polished wafer according to claim 1, wherein in the step c), the spraying time is 50 to 70s, the water injection amount is used for flooding the wafer, the flooding time is 20 to 30s, the fast discharging time is 10s, and the spraying, water injection, flooding and fast discharging processes are repeated 4 to 6 times.
6. The method for cleaning the lithium niobate single-side polished wafer as claimed in claim 1, wherein in the step d), the double-side brushing is performed in a double-side transmission rolling brush manner, the brush rotates and drives the wafer to move horizontally, the brush for double-side brushing is a PVA roller brush, the rotating speed of the brush is 6-10rpm, the pressing distance between the upper brush and the lower brush is 1300 μm, the brushing time is 3-5 minutes, the diameter of the brush is 2-3cm, the spraying and washing time is 10-20s, the spin-drying rotating speed of the wafer is 1200 + 1500rpm, and the spin-drying time is 15-20 s.
7. The method for cleaning the lithium niobate single-side polished wafer according to claim 1, wherein in the step d), the alkaline cleaning agent comprises 0.2 to 0.6 mass% of sodium hydroxide, 1 to 3 mass% of potassium hydroxide, 0.5 to 2 mass% of a chelating agent, 2 to 5 mass% of a nonionic surfactant, and 90 to 96 mass% of deionized water.
8. The method as claimed in claim 1, wherein in the step e), the brush for brushing the single side is a PVA-made gyro-type brush, the pressing distance of the brush is 900-.
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| JP2742114B2 (en) * | 1989-11-15 | 1998-04-22 | 株式会社荏原製作所 | Method and apparatus for precision cleaning of wafer carrier |
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| JPH11102849A (en) * | 1997-09-17 | 1999-04-13 | Lsi Logic Corp | Method and device for removing particles on semiconductor wafer |
| US6526995B1 (en) * | 1999-06-29 | 2003-03-04 | Intersil Americas Inc. | Brushless multipass silicon wafer cleaning process for post chemical mechanical polishing using immersion |
| FR2816527B3 (en) * | 2000-11-14 | 2003-04-04 | Lionel Girardie | PROCESS FOR WET-CLEANING SEMICONDUCTOR WAFERS COMPRISING A DAMASCENE STRUCTURE |
| CN101972754B (en) * | 2010-07-21 | 2012-09-05 | 河北工业大学 | Surface cleaning method after carrying out chemical-mechanical polishing (CMP) on lithium niobate wafer in alkalinity |
| CN103537453B (en) * | 2013-08-20 | 2015-06-10 | 曾锡强 | Method for ultrasonic cleaning of polished sapphire substrate wafer |
| CN104377119B (en) * | 2014-10-23 | 2017-05-24 | 中国电子科技集团公司第四十六研究所 | Method for cleaning germanium single crystal polished wafer |
| CN105405746B (en) * | 2015-11-24 | 2020-09-11 | 北京华进创威电子有限公司 | Cleaning method of gallium antimonide single crystal polished wafer |
| CN208879181U (en) * | 2018-07-19 | 2019-05-21 | 北京世维通科技股份有限公司 | A kind of cleaning system of lithium niobate modulator chip |
| CN109821810A (en) * | 2018-12-28 | 2019-05-31 | 江苏澳洋顺昌集成电路股份有限公司 | A kind of sapphire substrate sheet finished product cleaning process |
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| CN110744364B (en) * | 2019-11-06 | 2021-07-13 | 天通控股股份有限公司 | Double-side polishing method for large-size ultrathin lithium niobate substrate |
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