CN114473891A - Grinding block for grinding semiconductor plastic package body and preparation method of grinding wheel - Google Patents
Grinding block for grinding semiconductor plastic package body and preparation method of grinding wheel Download PDFInfo
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- CN114473891A CN114473891A CN202210149589.6A CN202210149589A CN114473891A CN 114473891 A CN114473891 A CN 114473891A CN 202210149589 A CN202210149589 A CN 202210149589A CN 114473891 A CN114473891 A CN 114473891A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
- B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
- B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
- B24D3/14—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic ceramic, i.e. vitrified bondings
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
- B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
- B24D18/0009—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for using moulds or presses
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Abstract
The invention discloses a grinding block for grinding a semiconductor plastic package body and a preparation method of a grinding wheel, wherein the preparation method of the grinding block for grinding the semiconductor plastic package body comprises the following steps: 1) drying the raw materials; 2) sieving the diamond powder; 3) preparing materials; 4) pressing and forming; 5) heat treatment and deburring; 6) and sintering the grinding block. A preparation method of a grinding wheel for grinding a semiconductor plastic package body comprises the following steps: 1) bonding and finishing; bonding the grinding block prepared by the method on an aluminum alloy matrix matched with the grinding block in size by using AB glue to obtain a grinding wheel; 2) testing dynamic balance; 3) cleaning; 4) checking; 5) marking and packaging. The grinding wheel prepared by the method has the advantages that the surface of the product is not scratched in the grinding process, so that the service life of the grinding wheel is prolonged, the production cost of a customer is reduced, and the industrial application of the grinding wheel product is realized.
Description
Technical Field
The invention relates to a semiconductor processing technology, in particular to a grinding block for grinding a semiconductor plastic package body and a preparation method of a grinding wheel.
Background
Electronic packaging is an important component of the semiconductor industry, and is a back-end process of the semiconductor industry, and the main processes are Wafer back grinding (Wafer back grinding), Wafer saw (Wafer saw), Die attach (Die attach), Wire bond (Wire bond), plastic package (Compound molding), plastic package grinding (Compound grinding), plastic package cutting (Compound sintering), Marking (Marking), Testing (Testing), and the like. The basic method for grinding the plastic package body comprises the steps of installing a special grinding wheel on a full-automatic precision grinding machine, grinding redundant materials on the back surface of the plastic package body by using the grinding wheel according to requirements to reach the expected thickness, and simultaneously ensuring the surface roughness and the smoothness of a grinding surface. Due to the difference of the model number and the thickness of the plastic packaging material, the online grinding condition is extremely harsh, and the requirement on the grinding quality index is extremely high.
At present, almost all grinding wheels for grinding semiconductor plastic packages depend on importation, and the grinding wheels for the plastic packages are basically monopolized by manufacturers of Japan and Korea, and the technology is strictly sealed. The grinding wheel enterprise in China basically does not relate to the field of grinding of semiconductor plastic package bodies, and the reasons are that the threshold of semiconductor packaging technology is high, the industry information is relatively blocked, and manufacturers rarely invest in the grinding process across rows.
The basic structure of the grinding wheel is a grinding block and an aluminum alloy matrix, wherein the grinding block is the core of the grinding wheel and is really involved in grinding. In general, a grinding block is a ceramic-based diamond composite material, in which ceramic is used as a binder for containing and holding diamond particles, and diamond is used as a grinding unit for removing an object to be ground.
The plastic-encapsulated grinding wheel has different shapes according to the types of grinding machines, and the most common shape on the market is a bowl-shaped structure. The grinding block of the bowl-shaped grinding wheel is a plurality of identical small units, and each unit grinding block is bonded in the mounting groove of the end face of the aluminum alloy matrix in a cementing mode.
The commonly existing problems of the imported plastic package body grinding wheel used in the market at present are that the service life of the grinding wheel is short due to the scratch of the surface of a product in the grinding process, the price of the grinding wheel is high, the production cost of a client is high, and the product competitiveness is influenced.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a grinding block for grinding a semiconductor plastic package body and a preparation method of a grinding wheel, wherein the grinding block can avoid the surface of a product from being scratched.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of a grinding block for grinding a semiconductor plastic package body comprises the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow sphere in a drying box for drying;
2) sieving the diamond powder; selecting a screen with two standard grades larger than the granularity of the selected diamond powder, and sieving the diamond powder by using a vibrating sieving machine to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 35-50% of ceramic bond, 35-50% of diamond powder, 10-20% of alumina hollow sphere and 5-10% of auxiliary agent for wetting the ceramic bond according to the mass percentage, filling the materials into a mixing tank, and putting the materials into a three-dimensional mixer to be fully and uniformly mixed to obtain a raw material mixture;
4) pressing and forming; weighing the raw material mixture, pouring the raw material mixture into a grinding block forming die, performing compression forming on a press, and taking out the grinding block after demolding;
5) heat treatment and deburring; placing the pressed grinding block in a drying oven for heat treatment at 60-100 ℃ for 4-8h, and removing scraps and burrs on the surface of the grinding block after the heat treatment;
6) sintering the grinding block; placing the grinding block in a sintering furnace, heating to 300 ℃ from room temperature at the heating rate of 1-2 ℃/min, preserving heat for 2-4h, then heating to 750 ℃ at the heating rate of 3-5 ℃/min, preserving heat for 3-5h, then cooling to room temperature along with the furnace, and taking out to obtain the finished grinding block.
Further, the ceramic binder in the step 1) comprises, by mass, 50-70% of silicon dioxide, 5-15% of boron trioxide, 5-15% of aluminum oxide, 5-10% of calcium oxide, 1-5% of sodium oxide and 1-5% of magnesium oxide, and the particle size of the ceramic binder is 10-50 μm.
Further, the diamond powder in the step 1) is original ecological polycrystalline or single crystal diamond with 600-1300 meshes.
Further, the diameter of the inner sphere of the alumina hollow sphere in the step 1) is 30-60 μm, and the wall thickness is 3-5 μm.
Further, the drying temperature in the step 1) is 85-100 ℃, and the drying time is 8-12 h.
Further, the diamond powder is sieved for 3 times by using a vibrating sieving machine in the step 2).
Further, the auxiliary agent in the step 3) is a dextrin aqueous solution, a polyacrylamide aqueous solution or a methylcellulose aqueous solution with the mass percentage concentration of 10%.
Further, the rotating speed of the three-dimensional mixer in the step 3) is set to be 200-.
Further, the pressure of the compression molding in the step 4) is 60-80MPa, and the dwell time is 30-45 s.
The invention also relates to a preparation method of the grinding wheel for grinding the semiconductor plastic package body, which comprises the following steps:
1) bonding and finishing; bonding the grinding block prepared by the method on an aluminum alloy matrix matched with the aluminum alloy matrix in size by using AB glue to obtain a grinding wheel, and finishing the grinding block on the grinding wheel by using No. 200 green silicon carbide or white corundum grinding wheel on a numerical control external grinding machine to ensure that the flatness of the grinding block is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning stains and water stains on the surface of the grinding wheel;
4) checking; checking the size, flatness and dynamic balance of the grinding wheel;
5) marking and packaging.
Compared with the prior art, the invention has the following technical effects:
1) the problem of scratching the surface of a product is solved; the alumina hollow ball is used as a pore forming agent, the hollow ball is not deformed and does not generate any gas in the sintering process, the hollow core in the alumina hollow ball is used as a final micropore, the micropore is spherical, and irregular sharp corners do not appear in the subsequent grinding process of a grinding wheel, so that the surface of a product cannot be scratched, the quality problem of scratching is avoided, and the grinding wheel cannot be abnormally failed.
2) The problem of low service life of the grinding wheel in the prior art is solved; the grinding wheel prepared by adopting the alumina hollow sphere as the pore-forming agent does not generate surface scratches in the grinding process, avoids the problem of surface scratches caused by midway replacement of a new grinding wheel, ensures that each grinding wheel can reach the normal service life, indirectly improves the effective service time of the grinding wheel, and can grind more products by using a single grinding wheel, thereby reducing the grinding wheel cost of a single product and reducing the production cost of customers.
Drawings
FIG. 1 is a schematic structural view of a grinding wheel prepared in example 1 of the present invention;
FIG. 2 is a pictorial representation of an abrasive wheel made in accordance with example 1 of the present invention;
FIG. 3 is a surface effect graph of a product ground by the grinding wheel prepared in example 1 of the present invention;
FIG. 4 is an SEM image of a grinding block made using a conventional pore-forming agent;
FIG. 5 is an SEM photograph of a grinding block prepared in example 1 of the present invention;
FIG. 6 is a surface effect diagram of a product after grinding by a grinding block prepared by using a conventional pore-forming agent;
FIG. 7 is a front view of a fingerprint chip package adopted in embodiment 2 of the present invention;
FIG. 8 is a surface effect graph of a product ground by the grinding wheel prepared in example 2 of the present invention.
Detailed Description
The present invention will be explained in further detail with reference to examples.
Referring to fig. 1 to 8, this embodiment provides a method for preparing a polishing pad for polishing a semiconductor plastic package, comprising the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow sphere in a drying box for drying;
2) sieving the diamond powder; selecting a screen with two standard grades larger than the granularity of the selected diamond powder, and sieving the diamond powder by using a vibrating sieving machine to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 35-50% of ceramic bond, 35-50% of diamond powder, 10-20% of alumina hollow sphere and 5-10% of auxiliary agent for wetting the ceramic bond according to the mass percentage, filling the materials into a mixing tank, and putting the materials into a three-dimensional mixer to be fully and uniformly mixed to obtain a raw material mixture;
4) pressing and forming; weighing the raw material mixture, pouring the raw material mixture into a grinding block forming die, performing compression forming on a press, and taking out the grinding block after demolding;
5) heat treatment and deburring; placing the pressed grinding block in a drying oven for heat treatment at 60-100 ℃ for 4-8h, and removing scraps and burrs on the surface of the grinding block after the heat treatment;
6) sintering the grinding block; placing the grinding block in a sintering furnace, heating to 300 ℃ at the temperature rise rate of 1-2 ℃/min from room temperature, preserving heat for 2-4h, then heating to 750 ℃ at the temperature rise rate of 3-5 ℃/min, preserving heat for 3-5h, then cooling to room temperature along with the furnace, and taking out to obtain the finished grinding block.
The embodiment also relates to a preparation method of the grinding wheel for grinding the semiconductor plastic package body, which comprises the following steps:
1) bonding and finishing; bonding the grinding block prepared by the method on an aluminum alloy matrix matched with the aluminum alloy matrix in size by using AB glue to obtain a grinding wheel, and finishing the grinding block on the grinding wheel by using No. 200 green silicon carbide or white corundum grinding wheel on a numerical control external grinding machine to ensure that the flatness of the grinding block is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning stains and water stains on the surface of the grinding wheel;
4) checking; checking the size, flatness and dynamic balance of the grinding wheel;
5) marking and packaging.
To further illustrate the technical solution of the present invention, the following detailed description is made with reference to specific data.
Example 1
The embodiment provides a preparation method of a grinding block for grinding a semiconductor plastic package body, which comprises the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow spheres in a drying oven, and drying for 12 hours at 85 ℃; wherein the ceramic bond comprises 65 mass percent of silicon dioxide, 10 mass percent of boron trioxide, 10 mass percent of aluminum oxide, 5 mass percent of calcium oxide, 5 mass percent of sodium oxide and 5 mass percent of magnesium oxide, and the particle size of the ceramic bond is 15 mu m; the diamond powder is 1300 meshes of original ecological polycrystalline diamond; the inner sphere diameter of the pore-forming agent alumina hollow sphere is 50 μm, and the wall thickness is 3 μm;
2) sieving the diamond powder; selecting a screen with the specification of 1000 meshes, and carrying out sieving treatment on the diamond powder for 3 times by using a vibrating sieving machine so as to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 40% of ceramic bond, 40% of diamond powder, 15% of alumina hollow spheres and 5% of auxiliary agent for wetting the ceramic bond according to the mass percentage, putting into a mixing tank, and then putting into a three-dimensional mixer to mix for 16h at the rotating speed of 250r/min to obtain a raw material mixture; wherein the auxiliary agent is polyacrylamide aqueous solution with the mass percentage concentration of 10%;
4) pressing and forming; weighing the raw material mixture according to the requirement, pouring the raw material mixture into a forming die of a grinding block 1, and performing compression forming on a press, wherein the pressure is set as follows: 60 +/-5 MPa, pressure maintaining time: 45s, taking out the grinding block 1 after demolding;
5) heat treatment and deburring; placing the pressed grinding block 1 in a drying oven for heat treatment at 65 ℃, keeping the temperature for 5 hours, and removing scraps and burrs on the surface of the grinding block 1 after the heat treatment;
6) sintering the grinding block 1; placing the grinding block 1 in a sintering furnace, heating to 300 ℃ from room temperature at a heating rate of 2 ℃/min, preserving heat for 4 hours, fully discharging carbon dioxide and water vapor, heating to 690 ℃ at a heating rate of 4 ℃/min, preserving heat for 4 hours, cooling to room temperature along with the furnace, opening a furnace door, and taking out the grinding block 1.
The embodiment also relates to a preparation method of the grinding wheel for grinding the semiconductor plastic package body, which comprises the following steps:
1) bonding and finishing; bonding the grinding block 1 prepared in the embodiment on an aluminum alloy matrix 2 which is processed according to the size requirement in advance by using AB glue to obtain a grinding wheel, and finely trimming the grinding block 1 on the grinding wheel by using No. 200 green silicon carbide or white corundum grinding wheel on a numerical control cylindrical grinding machine to ensure that the flatness of the grinding block 1 is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning the grinding wheel to ensure that the surface is free from stains, water stains and dirt;
4) checking; inspecting various sizes, planeness, dynamic balance, appearance and the like of the grinding wheel;
5) marking and packaging; and (5) laser marking and packaging according to the specified position and requirements. The grinding wheel structure prepared in this example is shown in fig. 1 and 2.
The grinding wheel prepared in this example was tested on-line:
this example grinds the molded bodies on a fully automatic grinder to evaluate grinding quality and grinding wheel life.
Grinder model: korean SUHWOO corporation full-automatic SD2000D grinder;
an object to be polished: a fingerprint chip plastic package body;
plastic package material: korean KCC corporation model number is KTMC-5600 epoxy resin;
grinding parameters:
| number of stages | First stage | Second section | Third stage | Fourth stage |
| Grinding thickness (μm) | 80 | 18 | 1 | 1 |
| Cutting quantity (mum/knife) | 3 | 2 | 1 | 0.5 |
| Feed rate (mm/s) | 100 | 80 | 50 | 5 |
| Spindle speed (RPM) | 3000 | 3000 | 1500 | 1500 |
And (3) grinding results: the surface has no scratch, the grinding is not abnormal, and the grinding wheel is replaced after reaching the service life. The surface (back) effect of the product after grinding is shown in fig. 3.
In the prior art, the grinding block 1 of the ceramic-based diamond grinding wheel used at present selects walnut powder, graphite and other materials as pore-forming agents, the pore-forming agents volatilize or carbonize in the sintering process to form carbon dioxide gas, and required micropores are prepared through gas expansion, the micropores are basically irregular shapes, such as the grinding block 1 of the ceramic-based diamond grinding wheel with the model of NP-S2-180D5W10-1300-VP-E002, the microstructure of a scanning electron microscope of the grinding block is shown in figure 4, in the subsequent grinding process of the grinding wheel, sharp corners in the irregular shapes can easily scratch the surface of the product, the surface effect of the ground product (the model of the product is the same as that adopted in the grinding wheel test in the embodiment) is shown in figure 6, the quality problem is caused, the grinding wheel is abnormally ineffective, and the grinding wheel has to be replaced by a new grinding wheel.
In the method, the alumina hollow spheres are used as pore-forming agents to prepare the grinding block 1, the hollow spheres are not deformed and do not generate any gas in the sintering process, the 'hollow' inside the alumina hollow spheres are used as final micropores, the micropores are spherical, the microstructure of a scanning electron microscope of the micropores is shown in figure 5, irregular sharp corners do not appear in the subsequent grinding process of the grinding wheel, the surface of the product cannot be scratched, the surface effect of the ground product is shown in figure 3, the quality problem of scratching is avoided, and the grinding wheel cannot be abnormally disabled.
Example 2
The embodiment provides a preparation method of a grinding block for grinding a semiconductor plastic package body, which comprises the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow sphere in a drying oven, and drying for 10 hours at 100 ℃; wherein the ceramic bond comprises 62 percent of silicon dioxide, 12 percent of boron trioxide, 8 percent of alumina, 5 percent of calcium oxide, 5 percent of sodium oxide and 5 percent of magnesium oxide according to mass percentage, and the granularity of the ceramic bond is 15 mu m; the diamond powder is 1200 mesh original ecological polycrystalline diamond; the inner sphere diameter of the pore-forming agent alumina hollow sphere is 40 mu m, and the wall thickness is 5 mu m;
2) sieving the diamond powder; selecting a screen with the specification of 800 meshes, and carrying out sieving treatment on the diamond powder for 3 times by using a vibrating sieving machine to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 42% of ceramic bond, 40% of diamond powder, 12% of alumina hollow spheres and 6% of auxiliary agent for wetting the ceramic bond according to the mass percentage, putting the materials into a mixing tank body, and then putting the materials into a three-dimensional mixer to mix for 12 hours at the rotating speed of 300r/min to obtain a raw material mixture; wherein the auxiliary agent is a methyl cellulose aqueous solution with the mass percentage concentration of 10 percent;
4) pressing and forming; weighing the raw material mixture according to the requirement, pouring the raw material mixture into a grinding block forming die, and performing compression forming on a press, wherein the pressure is set as follows: 60 +/-5 MPa, pressure maintaining time: 45s, taking out the grinding block after demolding;
5) heat treatment and deburring; placing the pressed grinding block in a drying oven for heat treatment at 65 ℃, keeping the temperature for 5 hours, and removing scraps and burrs on the surface of the grinding block after the heat treatment;
6) sintering the grinding block; placing the grinding block in a sintering furnace, heating to 250 ℃ from room temperature at a heating rate of 2 ℃/min, preserving heat for 3h, fully discharging carbon dioxide and water vapor, heating to 650 ℃ at a heating rate of 4 ℃/min, preserving heat for 4h, cooling to room temperature along with the furnace, opening a furnace door, and taking out the grinding block.
The embodiment also relates to a preparation method of the grinding wheel for grinding the semiconductor plastic package body, which comprises the following steps:
1) bonding and finishing; bonding the grinding block prepared in the embodiment on an aluminum alloy matrix which is processed in advance according to the size requirement by using AB glue to obtain a grinding wheel, and finishing the grinding block on the grinding wheel by using No. 200 green silicon carbide or white corundum grinding wheel on a numerical control external grinding machine to ensure that the flatness of the grinding block is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning the grinding wheel to ensure that the surface is free from stains, water stains and dirt;
4) checking; inspecting various sizes, planeness, dynamic balance, appearance and the like of the grinding wheel;
5) marking and packaging; and (5) laser marking and packaging according to the specified position and requirements.
The grinding wheel prepared in this example was tested on-line:
this example grinds the molded bodies on a fully automatic grinder to evaluate grinding quality and grinding wheel life.
Grinder model: korean SUHWOO corporation full-automatic SD2000D grinder;
an object to be polished: a fingerprint chip plastic package body;
plastic package material: japanese sumitomo corporation model number G750N epoxy resin;
grinding parameters:
| number of stages | First stage | Second section |
| Grinding thickness (μm) | 140 | 10 |
| Cutting quantity (mum/knife) | 10 | 5 |
| Feed rate (mm/s) | 200 | 200 |
| Spindle speed (RPM) | 3000 | 3000 |
And (3) grinding results: the surface has no scratch, the grinding is not abnormal, and the grinding wheel is replaced after reaching the service life. The front surface of the chip plastic package and the surface (back surface) of the plastic package after grinding have the effects shown in fig. 7 and 8, respectively.
Example 3
The embodiment provides a preparation method of a grinding block for grinding a semiconductor plastic package body, which comprises the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow sphere in a drying oven, and drying for 8 hours at 90 ℃; wherein the ceramic bond comprises 66% of silicon dioxide, 15% of boron trioxide, 5% of alumina, 10% of calcium oxide, 1% of sodium oxide and 3% of magnesium oxide in percentage by mass, and the particle size of the ceramic bond is 30 μm; the diamond powder is 600-mesh original ecological polycrystalline diamond; the inner sphere diameter of the pore-forming agent alumina hollow sphere is 30 mu m, and the wall thickness is 4 mu m;
2) sieving the diamond powder; selecting a screen with the specification of 450 meshes, and carrying out sieving treatment on the diamond powder for 3 times by using a vibrating sieving machine to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 35% of ceramic bond, 50% of diamond powder, 10% of alumina hollow spheres and 5% of auxiliary agent for wetting the ceramic bond according to the mass percentage, putting into a mixing tank, and then putting into a three-dimensional mixer to mix for 15 hours at the rotating speed of 500r/min to obtain a raw material mixture; wherein the auxiliary agent is a methyl cellulose aqueous solution with the mass percentage concentration of 10 percent;
4) pressing and forming; weighing the raw material mixture according to the requirement, pouring the raw material mixture into a grinding block forming die, and performing compression forming on a press, wherein the pressure is set as follows: 80 +/-5 MPa, pressure maintaining time: 30s, taking out the grinding block after demolding;
5) heat treatment and deburring; placing the pressed grinding block in a drying oven for heat treatment at 60 ℃, keeping the temperature for 8h, and removing scraps and burrs on the surface of the grinding block after the heat treatment;
6) sintering the grinding block; placing the grinding block in a sintering furnace, heating to 200 ℃ from room temperature at a heating rate of 1 ℃/min, preserving heat for 2h, fully discharging carbon dioxide and water vapor, heating to 750 ℃ at a heating rate of 3 ℃/min, preserving heat for 3h, cooling to room temperature along with the furnace, opening a furnace door, and taking out the grinding block.
The embodiment also relates to a preparation method of the grinding wheel for grinding the semiconductor plastic package body, which comprises the following steps:
1) bonding and finishing; bonding the grinding block prepared in the embodiment on an aluminum alloy matrix which is processed in advance according to the size requirement by using AB glue to obtain a grinding wheel, and finishing the grinding block on the grinding wheel by using No. 200 green silicon carbide or white corundum grinding wheel on a numerical control external grinding machine to ensure that the flatness of the grinding block is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning the grinding wheel to ensure that the surface is free from stains, water stains and dirt;
4) checking; inspecting various sizes, planeness, dynamic balance, appearance and the like of the grinding wheel;
5) marking and packaging; and (5) laser marking and packaging according to the specified position and requirements.
Example 4
The embodiment provides a preparation method of a grinding block for grinding a semiconductor plastic package body, which comprises the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow sphere in a drying oven, and drying for 11 hours at 95 ℃; wherein the ceramic bond comprises 50% of silicon dioxide, 15% of boron trioxide, 15% of aluminum oxide, 10% of calcium oxide, 5% of sodium oxide and 5% of magnesium oxide by mass percent, and the particle size of the ceramic bond is 10 mu m; the diamond powder is original ecological polycrystalline diamond of 800 meshes; the inner sphere diameter of the pore-forming agent alumina hollow sphere is 60 mu m, and the wall thickness is 5 mu m;
2) sieving the diamond powder; selecting a screen with the specification of 600 meshes, and sieving the diamond powder for 3 times by using a vibrating sieving machine to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 50% of ceramic bond, 35% of diamond powder, 10% of alumina hollow spheres and 5% of auxiliary agent for wetting the ceramic bond according to the mass percentage, putting into a mixing tank, and then putting into a three-dimensional mixer to mix for 14 hours at a rotating speed of 200r/min to obtain a raw material mixture; wherein the auxiliary agent is polyacrylamide aqueous solution with the mass percentage concentration of 10%;
4) pressing and forming; weighing the raw material mixture according to the requirement, pouring the raw material mixture into a grinding block forming die, and performing compression forming on a press, wherein the pressure is set as follows: 70 +/-5 MPa, pressure maintaining time: 40s, taking out the grinding block after demolding;
5) heat treatment and deburring; placing the pressed grinding block in a drying oven for heat treatment at 100 ℃, keeping the temperature for 4 hours, and removing scraps and burrs on the surface of the grinding block after the heat treatment;
6) sintering the grinding block; placing the grinding block in a sintering furnace, heating to 280 ℃ from room temperature at a heating rate of 1 ℃/min, preserving heat for 2h, fully discharging carbon dioxide and water vapor, heating to 720 ℃ at a heating rate of 5 ℃/min, preserving heat for 5h, cooling to room temperature along with the furnace, opening a furnace door, and taking out the grinding block.
The embodiment also relates to a preparation method of the grinding wheel for grinding the semiconductor plastic package body, which comprises the following steps:
1) bonding and finishing; bonding the grinding block prepared in the embodiment on an aluminum alloy matrix which is processed in advance according to the size requirement by using AB glue to obtain a grinding wheel, and finishing the grinding block on the grinding wheel by using No. 200 green silicon carbide or white corundum grinding wheel on a numerical control external grinding machine to ensure that the flatness of the grinding block is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning the grinding wheel to ensure that the surface is free from stains, water stains and dirt;
4) checking; inspecting various sizes, planeness, dynamic balance, appearance and the like of the grinding wheel;
5) marking and packaging; and (5) laser marking and packaging according to the specified position and requirements.
Example 5
The embodiment provides a preparation method of a grinding block for grinding a semiconductor plastic package body, which comprises the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow spheres in a drying oven, and drying for 9 hours at 85 ℃; wherein the ceramic bond comprises 70 percent of silicon dioxide, 5 percent of boron trioxide, 15 percent of alumina, 8 percent of calcium oxide, 1 percent of sodium oxide and 1 percent of magnesium oxide according to mass percentage, and the granularity of the ceramic bond is 50 mu m; the diamond powder is 1000 meshes of original ecological single crystal diamond; the inner sphere diameter of the pore-forming agent alumina hollow sphere is 40 mu m, and the wall thickness is 3 mu m;
2) sieving the diamond powder; selecting a screen with the specification of 700 meshes, and carrying out sieving treatment on the diamond powder for 3 times by using a vibrating sieving machine to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 35% of ceramic bond, 35% of diamond powder, 20% of alumina hollow spheres and 10% of auxiliary agent for wetting the ceramic bond according to the mass percentage, putting into a mixing tank body, and then putting into a three-dimensional mixer to mix for 13 hours at the rotating speed of 400r/min to obtain a raw material mixture; wherein the auxiliary agent is a dextrin water solution with the mass percentage concentration of 10%;
4) pressing and forming; weighing the raw material mixture according to the requirement, pouring the raw material mixture into a grinding block forming die, and performing compression forming on a press, wherein the pressure is set as follows: 70 +/-5 MPa, pressure maintaining time: 40s, taking out the grinding block after demolding;
5) heat treatment and deburring; placing the pressed grinding block in a drying oven for heat treatment at 80 ℃, keeping the temperature for 6h, and removing scraps and burrs on the surface of the grinding block after the heat treatment;
6) sintering the grinding block; placing the grinding block in a sintering furnace, heating to 220 ℃ from room temperature at a heating rate of 2 ℃/min, preserving heat for 4h, fully discharging carbon dioxide and water vapor, heating to 700 ℃ at a heating rate of 4 ℃/min, preserving heat for 5h, cooling to room temperature along with the furnace, opening a furnace door, and taking out the grinding block.
The embodiment also relates to a preparation method of the grinding wheel for grinding the semiconductor plastic package body, which comprises the following steps:
1) bonding and finishing; bonding the grinding block prepared in the embodiment on an aluminum alloy matrix which is processed in advance according to the size requirement by using AB glue to obtain a grinding wheel, and finishing the grinding block on the grinding wheel by using No. 200 green silicon carbide or white corundum grinding wheel on a numerical control external grinding machine to ensure that the flatness of the grinding block is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning the grinding wheel to ensure that the surface is free from stains, water stains and dirt;
4) checking; inspecting various sizes, planeness, dynamic balance, appearance and the like of the grinding wheel;
5) marking and packaging; and (5) laser marking and packaging according to the specified position and requirements.
Claims (10)
1. A preparation method of a grinding block for grinding a semiconductor plastic package body is characterized by comprising the following steps:
1) drying the raw materials; placing the ceramic bond, the diamond powder and the pore-forming agent alumina hollow sphere in a drying box for drying;
2) sieving the diamond powder; selecting a screen with two standard grades larger than the granularity of the selected diamond powder, and sieving the diamond powder by using a vibrating sieving machine to remove large-particle diamonds in the diamond powder;
3) preparing materials; weighing 35-50% of ceramic bond, 35-50% of diamond powder, 10-20% of alumina hollow sphere and 5-10% of auxiliary agent for wetting the ceramic bond according to the mass percentage, filling the materials into a mixing tank, and putting the materials into a three-dimensional mixer to be fully and uniformly mixed to obtain a raw material mixture;
4) pressing and forming; weighing the raw material mixture, pouring the raw material mixture into a grinding block forming die, performing compression forming on a press, and taking out the grinding block after demolding;
5) heat treatment and deburring; placing the pressed grinding block in a drying oven for heat treatment at 60-100 ℃ for 4-8h, and removing scraps and burrs on the surface of the grinding block after the heat treatment;
6) sintering the grinding block; placing the grinding block in a sintering furnace, heating to 300 ℃ at the temperature rise rate of 1-2 ℃/min from room temperature, preserving heat for 2-4h, then heating to 750 ℃ at the temperature rise rate of 3-5 ℃/min, preserving heat for 3-5h, then cooling to room temperature along with the furnace, and taking out to obtain the finished grinding block.
2. The method for preparing a grinding block for grinding a semiconductor plastic package body according to claim 1, wherein the ceramic binder in the step 1) comprises 50-70% by mass of silica, 5-15% by mass of diboron trioxide, 5-15% by mass of alumina, 5-10% by mass of calcium oxide, 1-5% by mass of sodium oxide and 1-5% by mass of magnesium oxide, and the particle size of the ceramic binder is 10-50 μm.
3. The method for preparing a grinding block for grinding a semiconductor plastic package body as claimed in claim 1, wherein the diamond powder in the step 1) is original polycrystalline or single crystal diamond of 600-1300 meshes.
4. The method for preparing a grinding block for grinding a semiconductor plastic package body according to claim 1, wherein the alumina hollow sphere in the step 1) has an inner sphere diameter of 30 to 60 μm and a wall thickness of 3 to 5 μm.
5. The method of claim 1, wherein the drying temperature in step 1) is 85-100 ℃ and the drying time is 8-12 h.
6. The method of manufacturing a grinding block for grinding a semiconductor plastic package according to claim 1, wherein the diamond powder is sieved 3 times by using a vibrating sieving machine in the step 2).
7. The method of claim 1, wherein the adjuvant in the step 3) is an aqueous dextrin solution, an aqueous polyacrylamide solution or an aqueous methylcellulose solution having a concentration of 10% by mass.
8. The method as claimed in claim 1, wherein the rotation speed of the three-dimensional blender in step 3) is set to 200-500r/min, and the mixing time is 12-16 h.
9. The method of claim 1, wherein the pressure for compression molding in the step 4) is 60 to 80MPa and the pressure holding time is 30 to 45 s.
10. A preparation method of a grinding wheel for grinding a semiconductor plastic package body is characterized by comprising the following steps:
1) bonding and finishing; bonding the grinding block prepared by the method according to claim 1 on an aluminum alloy matrix with the size matched with the grinding block by using AB glue to obtain a grinding wheel, and finishing the grinding block on the grinding wheel on a numerical control cylindrical grinding machine by using a No. 200 green silicon carbide or white corundum grinding wheel to ensure that the flatness of the grinding block is within 0.05 mm;
2) testing dynamic balance; testing the dynamic balance of the grinding wheel on a dynamic balancing instrument, and drilling holes at specified positions by using a radial drilling machine to ensure that the degree of unbalance is less than 0.1 g.cm;
3) cleaning; cleaning stains and water stains on the surface of the grinding wheel;
4) checking; checking the size, flatness and dynamic balance of the grinding wheel;
5) marking and packaging.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210149589.6A CN114473891A (en) | 2022-02-18 | 2022-02-18 | Grinding block for grinding semiconductor plastic package body and preparation method of grinding wheel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210149589.6A CN114473891A (en) | 2022-02-18 | 2022-02-18 | Grinding block for grinding semiconductor plastic package body and preparation method of grinding wheel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114473891A true CN114473891A (en) | 2022-05-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210149589.6A Withdrawn CN114473891A (en) | 2022-02-18 | 2022-02-18 | Grinding block for grinding semiconductor plastic package body and preparation method of grinding wheel |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114473891A (en) |
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2022
- 2022-02-18 CN CN202210149589.6A patent/CN114473891A/en not_active Withdrawn
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Application publication date: 20220513 |