CN116598191A - Planarization method for large-size sapphire wafer - Google Patents

Planarization method for large-size sapphire wafer Download PDF

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Publication number
CN116598191A
CN116598191A CN202310645416.8A CN202310645416A CN116598191A CN 116598191 A CN116598191 A CN 116598191A CN 202310645416 A CN202310645416 A CN 202310645416A CN 116598191 A CN116598191 A CN 116598191A
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sapphire wafer
processing
wafer
double
sided
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龙校良
苏瑶
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Biel Crystal Manufactory Huizhou Ltd
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Biel Crystal Manufactory Huizhou Ltd
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Priority to CN202310645416.8A priority Critical patent/CN116598191A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
    • B24B37/07—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool
    • B24B37/08—Lapping machines or devices; Accessories designed for working plane surfaces characterised by the movement of the work or lapping tool for double side lapping
    • 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
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002—Preparing wafers
    • H01L21/02005—Preparing bulk and homogeneous wafers
    • H01L21/02008—Multistep processes
    • H01L21/0201—Specific process step
    • 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
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02002—Preparing wafers
    • H01L21/02005—Preparing bulk and homogeneous wafers
    • H01L21/02008—Multistep processes
    • H01L21/0201—Specific process step
    • H01L21/02013—Grinding, lapping

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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)
  • Mechanical Engineering (AREA)
  • Mechanical Treatment Of Semiconductor (AREA)

Abstract

The application discloses a planarization method of a large-size sapphire wafer, which comprises the following steps of: a primary rough grinding step: performing first double-sided rough grinding on the sapphire wafer by using a grinding pad and a green silicon carbide solution to control TTV within 10 um; and (3) a secondary rough grinding step: performing second double-sided rough grinding on the sapphire wafer by using a double-sided fine grinding pad and matching with diamond polishing liquid to control TTV to be 5-7um; and (3) a high-temperature annealing step: taking out the sapphire wafer to perform high-temperature annealing; fine grinding: carrying out double-sided fine grinding on a sapphire wafer by using a polyurethane polishing pad and an alumina polishing solution to control TTV within 5um; therefore, the application can reduce the processing auxiliary material cost, optimize the warping problem of the cutting part, reduce the internal stress generated by uneven removal, improve the polishing efficiency, reduce the edge collapse phenomenon and reduce the product cracking risk.

Description

Planarization method for large-size sapphire wafer
Technical Field
The application relates to the field of wafer grinding, in particular to a planarization method of a large-size sapphire wafer.
Background
The existing large-size (8 inches and above) sapphire wafer planarization process steps and defects are as follows: firstly, a cast iron plate is matched with a boron carbide solution with a certain concentration ratio to thin and flatten, and TTV (total thickness variation, total thickness deviation) is controlled within 15-20 um. And secondly, improving the surface effect by copper disc matched with diamond polishing solution copper grinding with the particle size of 3-5um, wherein TTV is controlled to be 10-15um. And thirdly, improving the internal stress change of the sapphire by atmospheric annealing at 1650 ℃ for 12 hours, and controlling warp (warping degree) to be between 70 and 90 mu m. And fourthly, matching a non-woven fabric polishing pad with a silica sol polishing solution with the thickness of 90-120nm to obtain a fine surface effect, wherein TTV is controlled to be 10-13 mu m.
The existing cast iron disc is matched with a boron carbide solution with a certain concentration ratio for thinning, the hardness of the cast iron disc is higher, broken edge fragments are easily generated in the product, boron carbide is easy to precipitate, the cutting rate is greatly attenuated, meanwhile, the disc shape of the cast iron disc is always changed, the disc surface is required to be corrected in a time-consuming manner, the good TTV is difficult to control, and only thinning and poor flatness trimming can be achieved. The existing copper disk processing is limited by a machine table, and the processing is assisted by adhering wax, so that the large-size sapphire cannot be uniformly diffused due to large area, and bubbles exist to influence the processing effect of the copper disk; secondly, the copper plate machine is required to have a good pressure regulating system and a frozen water temperature control system, and the machine cost is high; repeated dewaxing is needed for the re-waxing and the matching processing, and the processing time is long; finally, the copper disc is processed in a split way, the removal amount of the two sides cannot be guaranteed to be equal, certain internal stress exists, and the next annealing process is not facilitated. The existing polishing uses a non-woven fabric polishing pad matched with a 90-120nm silica sol polishing solution, and the product is easy to collapse due to lower hardness of a non-woven fabric polishing skin, so that planarization of the product is affected.
Disclosure of Invention
The technical problem to be solved by the application is to provide a large-size sapphire wafer planarization method aiming at the defects in the prior art.
The technical scheme adopted for solving the technical problems is as follows: a planarization method for a large-size sapphire wafer is constructed, which comprises the following steps of:
a primary rough grinding step: performing first double-sided rough grinding on the sapphire wafer by using a grinding pad and a green silicon carbide solution to control TTV within 10 um;
and (3) a secondary rough grinding step: performing second double-sided rough grinding on the sapphire wafer by using a double-sided fine grinding pad and matching with diamond polishing liquid to control TTV to be 5-7um;
and (3) a high-temperature annealing step: taking out the sapphire wafer to perform high-temperature annealing;
fine grinding: and (3) carrying out double-sided fine grinding on the sapphire wafer by using a polyurethane polishing pad and an alumina polishing solution to control TTV within 5um.
Further, in the planarization method of the large-size sapphire wafer, the temperature during high-temperature annealing is not more than 1400 degrees.
Further, in the large-size sapphire wafer planarization method of the present application, the sapphire wafer is placed in an off-center cavity of the star wheel.
Further, in the large-size sapphire wafer planarization method of the present application, the method further comprises: before each polishing, the sapphire wafers are grouped into thickness groups according to the interval of 5-10um by using a height gauge, and the sapphire wafers which are grouped into the same group are polished simultaneously.
Further, in the large-size sapphire wafer planarization method of the present application, the method further comprises: and in each grinding process, when the processing is performed until the set time is half, stopping the machine to turn over the sapphire wafer and then continuing to process.
Further, in the planarization method of a large-sized sapphire wafer of the present application, the primary rough polishing step specifically includes:
placing an upstream star wheel on a millstone of a double-sided grinder attached with a grinding pad, adding a prepared green silicon carbide solution to moisten the grinding pad, and performing air compression for 5-10s to grind the upstream star wheel; wherein, the proportion of the green silicon carbide solution is that 8L of water is mixed with 300g of green silicon carbide;
sequentially placing the sapphire wafer into a cavity of the planetary wheel to smooth, and starting processing according to set processing parameters; wherein, the processing pressure is 200-250kg, and the rotating speeds of the upper disc, the lower disc and the planetary wheel are 15-25rpm;
when the processing is carried out until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
and taking out the sapphire wafer after processing, and testing TTV after ultrasonic cleaning.
Further, in the planarization method of a large-sized sapphire wafer, the secondary rough polishing step specifically includes:
putting a star wheel on a millstone of a double-sided grinder attached with a double-sided fine grinding pad, and adding a prepared diamond polishing solution to moisten the double-sided fine grinding pad; wherein, the granularity of the diamond polishing solution is 3-5um;
sequentially placing the sapphire wafer into a cavity of the planetary wheel to smooth, and starting processing according to set processing parameters; wherein, the processing pressure is 200-250kg, and the rotating speeds of the upper disc, the lower disc and the planetary wheel are 15-25rpm;
when the processing is carried out until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
and taking out the sapphire wafer after processing, and testing TTV after ultrasonic cleaning.
Further, in the planarization method of a large-sized sapphire wafer according to the present application, the fine polishing step specifically includes:
after the line is drawn on the polyurethane polishing pad, the polyurethane polishing pad is stuck to a millstone of a double-sided grinder for trimming, so that uniform and no writing residue of the line is ensured on the polyurethane polishing pad after trimming;
placing a star wheel on a machine platform on which the polyurethane polishing pad is stuck, and adding the prepared alumina polishing solution to moisten the polyurethane polishing pad; wherein, the proportion of the polishing solution is 3L of water and 1L of alumina;
sequentially placing the sapphire wafer into a cavity of the planetary wheel to smooth, and starting processing according to set processing parameters; wherein, the processing pressure is 600kg, and the rotating speed is 33rpm of an upper disc, 17rpm of a lower disc and 5rpm of a star wheel;
when the processing is carried out until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
and taking out the sapphire wafer after processing, cleaning with water, and testing TTV.
Further, in the planarization method of a large-sized sapphire wafer, the high-temperature annealing step specifically includes:
wiping the wafer clean, placing the wafer into a clamping groove clamp in a vertical mode, and pushing the periphery of the wafer into an annealing furnace in a sealing way by using a baffle;
setting processing parameters, heating 7-9H to 1400 DEG, keeping the temperature at 12H, and taking out the wafer when the temperature is naturally reduced to room temperature;
and checking whether the annealed wafer has breakage/edge breakage.
The planarization method of the large-size sapphire wafer has the following beneficial effects: the grinding pad is used for replacing the cast iron disc, the green silicon carbide is used for replacing the boron carbide solution, and the green silicon carbide can repair the grinding pad and keep the grinding pad flat, so that the processing auxiliary material cost can be reduced, and the warping problem of a cutting part can be optimized; the double-sided accurate grinding pad is used for replacing the single-sided processing of the copper disc, so that the internal stress generated by uneven removal can be reduced; the polyurethane polishing pad is matched with the alumina polishing solution, so that the polishing efficiency can be improved, and the edge collapse phenomenon can be reduced;
further, when the product is annealed, the temperature is reduced to 1400 DEG, so that the risk of cracking the product can be reduced; in detail, the offset design of the planet wheel and the reduction of the processing pressure/rotation speed can be adopted, the problem of uneven removal inside and outside the part can be neutralized, and the TTV can be further ensured to be controlled within 5um by matching with the low pressure parameter.
Drawings
For a clearer description of an embodiment of the application or of a technical solution in the prior art, the drawings that are needed in the description of the embodiment or of the prior art will be briefly described, it being obvious that the drawings in the description below are only embodiments of the application, and that other drawings can be obtained, without inventive effort, by a person skilled in the art from the drawings provided:
FIG. 1 is a flow chart of a method for planarizing a large-sized sapphire wafer according to the present application;
fig. 2 is a schematic view of the structure of the double-sided grinder.
Detailed Description
In order that the application may be readily understood, a more complete description of the application will be rendered by reference to the appended drawings. Exemplary embodiments of the present application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, and not limited to the technical solutions of the present application, and the embodiments of the present application and the technical features in the embodiments may be combined with each other without conflict.
Referring to fig. 1, the planarization method of a large-sized sapphire wafer according to the present application can control TTV to be within 5um after polishing the large-sized sapphire wafer, and the method of the present application mainly comprises the steps of:
primary rough grinding step S101: performing first double-sided rough grinding on the sapphire wafer by using a grinding pad and a green silicon carbide solution to control TTV within 10 um;
referring to fig. 2, the machine includes a rotating shaft and a grinding disc sleeved on the rotating shaft, the grinding disc is divided into an upper disc and a lower disc, a ring of external teeth 1 is formed on the inner side of the circular periphery of the lower disc, a ring of internal teeth 2 is arranged outside the rotating shaft, a planetary wheel 4 is positioned on the lower disc and simultaneously runs with the external teeth 1 and the internal teeth 2 through tooth-type meshing, and the interaction of the internal teeth and the external teeth forms the rotation and revolution of the planetary wheel 4. The polishing pad 3 is attached to the upper and lower plates for polishing.
Preferably, the star wheel is of an offset design, i.e. the sapphire wafer is placed in an off-center cavity of the star wheel. The effect is better when the cavity of the sapphire wafer product is placed by the star wheel and deviates from the center of the star wheel farther.
Preferably, the size of the polishing pad is adjusted, mainly the inner diameter is changed, the outer diameter is changed to be smaller, and the purpose is to enable the sapphire wafer in the star wheel to leak out and balance the inner and outer removal amount.
Preferably, during each grinding process, when the processing is performed until the set time is half, the machine is stopped to turn over the sapphire wafer, and then the processing is continued.
In the step, the grinding pad is used for replacing the cast iron disc, the green silicon carbide solution is used for replacing the boron carbide solution, the processing auxiliary material cost can be reduced, and the TTV and the warping problem of the cutting part can be optimized; secondly, the grinding pad is provided with a fixed abrasive, the self-sharpening property is guaranteed, the processing and removing rate is stable, the green silicon carbide solution cannot thin the sapphire, and the effect is to repair the grinding pad so that the grinding pad is kept flat; the problem of poor internal and external removal rates of the neutralization mill can be solved by changing the internal and external diameter sizes of the grinding pad and the offset design of the free star wheel, so that TTV is effectively reduced, and the planarization effect is good; finally, through optimization of processing parameters, such as pressure reduction and rotation speed matching with the grinding pad, the warping problem of the cutting part can be optimized, and TTV is controlled within 10 um.
Secondary rough grinding step S102: performing second double-sided rough grinding on the sapphire wafer by using a double-sided fine grinding pad and matching with diamond polishing liquid to control TTV to be 5-7um;
the double-sided accurate grinding pad is used for replacing the single-sided processing of the copper disc, so that the waxing auxiliary station is reduced, and the processing efficiency is improved; the double-sided accurate grinding pad is matched with the diamond polishing solution with the size of 3-5um, so that two sides can be thinned and processed simultaneously, and the double sides can be removed consistently by turning during processing, so that the internal stress generated by uneven removal can be reduced. Through the offset design of the star wheel and the reduction of the processing pressure/rotation speed, the problem of uneven removal inside and outside a part can be neutralized, and the TTV is controlled to be 5-7um.
High temperature annealing step S103: taking out the sapphire wafer to perform high-temperature annealing;
preferably, the temperature at high temperature annealing is not more than 1400 °, which reduces the risk of product breakage.
Fine grinding step S104: and (3) carrying out double-sided fine grinding on the sapphire wafer by using a polyurethane polishing pad and an alumina polishing solution to control TTV within 5um.
The polyurethane polishing pad is matched with the alumina polishing solution, so that the polishing efficiency can be improved, the polyurethane polishing pad is high in hardness, and the edge collapse phenomenon can be reduced. The product is turned over in the processing process by matching with low pressure parameters, so that TTV can be further ensured to be controlled within 5um.
Because a plurality of star wheels can be arranged between the upper disc and the lower disc, and each star wheel is provided with a plurality of cavities, a plurality of sapphire wafers can be processed at one time. In order to avoid too great a difference in the thickness of the incoming material for each process, the method preferably further comprises: before each polishing, the sapphire wafers are grouped into thickness groups according to the interval of 5-10um by using a height gauge, and the sapphire wafers which are grouped into the same group are polished simultaneously. Here, the grouping of thicknesses by the interval of 5-10um means that the sapphire wafers having the height difference of 5-10um are grouped into one group.
The following describes in detail a specific example, the processing procedure of this example is:
1) The sapphire wafers are grouped according to the thickness of the interval of 5-10um by using a height gauge, and the sapphire wafers which are grouped into the same group are ground according to the following process:
1.1 Preparing a green silicon carbide solution according to the proportion, wherein the proportion is that 8L of water is mixed with 300g of green silicon carbide;
1.2 Placing 5pc of planetary wheels on a millstone of a double-sided grinder attached with the grinding pad, opening a peristaltic pump to pump the prepared green silicon carbide solution to moisten the grinding pad, and performing air compression for 5-10s to grind the planetary wheels;
1.3 Sequentially placing the sapphire wafer into the cavity of the planetary wheel to smooth, ensuring autorotation, and starting processing according to set processing parameters. Wherein, the set processing parameters are mainly that the processing pressure is 200-250kg, the rotating speed of the upper disc, the lower disc and the free star wheel is 15-25rpm, and the disc surface temperature is 28-32 degrees. In the processing process, attention is paid to whether the liquid flow and the machine shake to produce abnormal sound.
1.4 When the processing is performed until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
1.5 Taking out the sapphire wafer after processing, and testing TTV after ultrasonic cleaning.
And grinding each group of sapphire wafers according to the steps until all the sapphire wafers are ground for one time according to the steps.
2) The sapphire wafers are grouped according to the thickness of the interval of 5-10um by using a height gauge, and the sapphire wafers which are grouped into the same group are ground according to the following process:
2.1 Placing a planetary wheel on a millstone of a double-sided grinder attached with the double-sided fine grinding pad, and opening a peristaltic pump to pump the prepared diamond polishing solution to moisten the double-sided fine grinding pad; wherein, the granularity of the diamond polishing solution is 3-5um;
2.2 Sequentially placing the sapphire wafer into the cavity of the planetary wheel to smooth, ensuring autorotation, and starting processing according to set processing parameters. Wherein, the processing pressure is 200-250kg, the rotating speed of the upper disc, the lower disc and the planetary wheel is 15-25rpm, and the disc surface temperature is 28-32 degrees. In the processing process, attention is paid to whether the liquid flow and the machine shake to produce abnormal sound.
2.3 When the processing is performed until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
2.4 Taking out the sapphire wafer after processing, and testing TTV after ultrasonic cleaning.
And grinding each group of sapphire wafers according to the steps until all the sapphire wafers are ground for one time according to the steps.
3) High-temperature annealing:
and wiping the wafer clean, placing the wafer into a clamping groove clamp in a vertical mode, and pushing the periphery of the wafer into an annealing furnace in a sealing way by using a baffle plate. Setting processing parameters, heating to 1400 degrees by 7-9H, keeping the temperature at 12H, and naturally cooling. And closing the hearth, naturally cooling to room temperature after the processing is finished, carrying out the sapphire wafer, and checking whether the annealed wafer has cracking/edge breakage.
4) The sapphire wafers are grouped according to the thickness of the interval of 5-10um by using a height gauge, and the sapphire wafers which are grouped into the same group are ground according to the following process:
4.1 After the polyurethane polishing pad is painted (such as painting cross lines), the polyurethane polishing pad is attached to a millstone of a double-sided grinder for trimming, so that uniform and non-painted writing residue on the polyurethane polishing pad is ensured after trimming is finished; simultaneously processing a small wafer test piece on the upper disc, and completely pressing and flattening the polyurethane polishing pad;
4.2 After the cleaning machine is completed, setting the temperature of a disc surface and preparing an alumina polishing solution, wherein the proportion of the polishing solution is 3L of water and 1L of alumina;
4.3 Placing a star wheel on a machine table on which the polyurethane polishing pad is stuck, and opening a peristaltic pump to pump the prepared alumina polishing solution to moisten the polyurethane polishing pad;
4.4 Sequentially placing the sapphire wafer into the cavity of the planetary wheel to smooth, ensuring autorotation, and starting processing according to set processing parameters. Wherein, the processing pressure is 600kg, the rotating speed is 33rpm of an upper disc, 17rpm of a lower disc, 5rpm of a star wheel and the disc surface temperature is 28-32 degrees. In the processing process, attention is paid to whether the liquid flow and the machine shake to produce abnormal sound.
4.5 When the processing is performed until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
4.6 Taking out the sapphire wafer after processing, cleaning the sapphire wafer with water, checking the appearance of the product, and testing TTV.
In summary, the planarization method of the large-size sapphire wafer of the present embodiment has the following advantages: the grinding pad is used for replacing the cast iron disc, the green silicon carbide is used for replacing the boron carbide solution, and the green silicon carbide can repair the grinding pad and keep the grinding pad flat, so that the processing auxiliary material cost can be reduced, and the warping problem of a cutting part can be optimized; the double-sided accurate grinding pad is used for replacing the single-sided processing of the copper disc, so that the internal stress generated by uneven removal can be reduced; the polyurethane polishing pad is matched with the alumina polishing solution, so that the polishing efficiency can be improved, and the edge collapse phenomenon can be reduced; when the product is annealed, the temperature is reduced to 1400 DEG, so that the product cracking risk can be reduced; through the offset design of the star wheel and the reduction of the processing pressure/rotation speed, the problem of uneven removal inside and outside a part can be neutralized, and the TTV can be further ensured to be controlled within 5um by matching with low pressure parameters.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
The terms including ordinal numbers such as "first", "second", and the like used in the present specification may be used to describe various constituent elements, but these constituent elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first component may be termed a second component, and, similarly, a second component may be termed a first component, without departing from the scope of the present application.
The embodiments of the present application have been described above with reference to the accompanying drawings, but the present application is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present application and the scope of the claims, which are to be protected by the present application.

Claims (9)

1. A planarization method for a large-size sapphire wafer is characterized by comprising the following steps of:
a primary rough grinding step: performing first double-sided rough grinding on the sapphire wafer by using a grinding pad and a green silicon carbide solution to control TTV within 10 um;
and (3) a secondary rough grinding step: performing second double-sided rough grinding on the sapphire wafer by using a double-sided fine grinding pad and matching with diamond polishing liquid to control TTV to be 5-7um;
and (3) a high-temperature annealing step: taking out the sapphire wafer to perform high-temperature annealing;
fine grinding: and (3) carrying out double-sided fine grinding on the sapphire wafer by using a polyurethane polishing pad and an alumina polishing solution to control TTV within 5um.
2. The method of claim 1, wherein the high temperature anneal is performed at a temperature not exceeding 1400 °.
3. The method of claim 1, wherein the sapphire wafer is placed in an off-center cavity of a star wheel.
4. The method of planarizing a large-scale sapphire wafer of claim 1, further comprising: before each polishing, the sapphire wafers are grouped into thickness groups according to the interval of 5-10um by using a height gauge, and the sapphire wafers which are grouped into the same group are polished simultaneously.
5. The method of planarizing a large-scale sapphire wafer of claim 1, further comprising: and in each grinding process, when the processing is performed until the set time is half, stopping the machine to turn over the sapphire wafer and then continuing to process.
6. The method for planarizing a large-sized sapphire wafer of claim 5, wherein the primary rough grinding step comprises:
placing an upstream star wheel on a millstone of a double-sided grinder attached with a grinding pad, adding a prepared green silicon carbide solution to moisten the grinding pad, and performing air compression for 5-10s to grind the upstream star wheel; wherein, the proportion of the green silicon carbide solution is that 8L of water is mixed with 300g of green silicon carbide;
sequentially placing the sapphire wafer into a cavity of the planetary wheel to smooth, and starting processing according to set processing parameters; wherein, the processing pressure is 200-250kg, and the rotating speeds of the upper disc, the lower disc and the planetary wheel are 15-25rpm;
when the processing is carried out until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
and taking out the sapphire wafer after processing, and testing TTV after ultrasonic cleaning.
7. The method for planarizing a large-sized sapphire wafer of claim 5, wherein the secondary rough grinding step comprises:
putting a star wheel on a millstone of a double-sided grinder attached with a double-sided fine grinding pad, and adding a prepared diamond polishing solution to moisten the double-sided fine grinding pad; wherein, the granularity of the diamond polishing solution is 3-5um;
sequentially placing the sapphire wafer into a cavity of the planetary wheel to smooth, and starting processing according to set processing parameters; wherein, the processing pressure is 200-250kg, and the rotating speeds of the upper disc, the lower disc and the planetary wheel are 15-25rpm;
when the processing is carried out until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
and taking out the sapphire wafer after processing, and testing TTV after ultrasonic cleaning.
8. The method for planarizing a large-sized sapphire wafer of claim 5, wherein said fine polishing step comprises:
after the line is drawn on the polyurethane polishing pad, the polyurethane polishing pad is stuck to a millstone of a double-sided grinder for trimming, so that uniform and no writing residue of the line is ensured on the polyurethane polishing pad after trimming;
placing a star wheel on a machine platform on which the polyurethane polishing pad is stuck, and adding the prepared alumina polishing solution to moisten the polyurethane polishing pad; wherein, the proportion of the polishing solution is 3L of water and 1L of alumina;
sequentially placing the sapphire wafer into a cavity of the planetary wheel to smooth, and starting processing according to set processing parameters; wherein, the processing pressure is 600kg, and the rotating speed is 33rpm of an upper disc, 17rpm of a lower disc and 5rpm of a star wheel;
when the processing is carried out until the set time is half, stopping the machine to turn over the sapphire wafer and continuing to process the sapphire wafer;
and taking out the sapphire wafer after processing, cleaning with water, and testing TTV.
9. The method for planarizing a large-sized sapphire wafer of claim 1, wherein the high-temperature annealing step comprises:
wiping the wafer clean, placing the wafer into a clamping groove clamp in a vertical mode, and pushing the periphery of the wafer into an annealing furnace in a sealing way by using a baffle;
setting processing parameters, heating 7-9H to 1400 DEG, keeping the temperature at 12H, and taking out the wafer when the temperature is naturally reduced to room temperature;
and checking whether the annealed wafer has breakage/edge breakage.
CN202310645416.8A 2023-06-01 2023-06-01 Planarization method for large-size sapphire wafer Pending CN116598191A (en)

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Publication number Priority date Publication date Assignee Title
CN117359435A (en) * 2023-12-05 2024-01-09 福建荣德光电科技有限公司 Numerical control plane precision milling and grinding machine for optical lens processing

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117359435A (en) * 2023-12-05 2024-01-09 福建荣德光电科技有限公司 Numerical control plane precision milling and grinding machine for optical lens processing
CN117359435B (en) * 2023-12-05 2024-03-05 福建荣德光电科技有限公司 Numerical control plane precision milling and grinding machine for optical lens processing

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