CN116141215B - Preparation method of soft rubber polishing pad containing rare earth compound - Google Patents

Abstract

The invention discloses a preparation method of a soft rubber polishing pad containing rare earth compounds. A polyester mesh structure is selected for skeleton support so that the processing time can be sufficiently guaranteed. In addition, the invention can adopt a multi-layer structure design so that a higher material removal rate can be obtained in the initial stage of a diamond grinding and polishing process, and better surface quality can be obtained in subsequent grinding and polishing processes. Titanium-plated diamond abrasive grains/iron-plated diamond abrasive grains are used, which can not only improve the holding force of the polishing pad base on the diamond abrasive grains, but also participate in the diamond graphitization reaction. La _0.6 Sr _0.4 Co ₃ powder plays a role similar to a catalyst in the diamond graphitization during the diamond grinding and polishing process, so that the processing efficiency is better, and the polishing pad can also be optimized.

Description

A method for preparing a soft rubber polishing pad containing rare earth compounds

Technical Field

The invention belongs to the technical field of ultra-precision polishing tools, and in particular relates to a method for preparing a soft rubber polishing pad containing a rare earth compound.

Background Art

Diamond is one of the hardest materials known in nature. And because of its good physical, chemical and electrical properties, diamond has become the best choice for the fourth generation of semiconductor materials. However, as a semiconductor material, diamond has very strict requirements on surface quality. Any tiny defect may cause the diamond product to fail to achieve the use accuracy. Due to the high brittleness of diamond, it is easy to collapse or other surface processing defects during the processing. Therefore, the use of flexible materials in the grinding and polishing of diamond can obtain better surface quality.

Chemical mechanical polishing is an ultra-precision polishing method that uses chemical reactions to assist mechanical polishing and improve polishing efficiency. Chemical mechanical polishing is currently widely used in diamond grinding and polishing, and can achieve ultra-smooth, low-damage processing. At the same time, the sub-surface damage problem of diamond products can also be well solved.

For hard and brittle materials used in the field of information and precision engineering, it is generally difficult to simultaneously achieve high processing efficiency and high processing quality with free abrasive processing. Therefore, in theory, the sol-gel method for preparing SG polishing pads can be used to fix the abrasive in the binder. Specifically, the diamond abrasive can be fixed in the binder by drawing on the principle that sodium alginate solution reacts with calcium ions to form colloidal silica. However, when polishing soft-based materials, as the processing time increases, the abrasive particles on the semi-consolidated abrasive will fall off, and the subsequent processing quality cannot be guaranteed.

Summary of the invention

The purpose of the present invention is to overcome the defects of the prior art and provide a method for preparing a soft rubber polishing pad containing a rare earth compound.

The technical solution of the present invention is as follows:

A method for preparing a soft rubber polishing pad containing a rare earth compound comprises the following steps:

(1) adding titanium-coated diamond abrasive grains/iron-coated diamond abrasive grains and La _0.6 Sr _0.4 Co ₃ powder into a sodium alginate solution containing sucrose and uniformly dispersing them;

(2) dripping the material obtained in step (1) into a calcium salt solution dropwise to obtain gel spheres;

(3) mixing the polyester material and the wax balls evenly, and then heating to melt the wax balls to obtain a mesh polyester;

(4) filling the gel balls obtained in step (2) into the holes of the mesh polyester obtained in step (3);

(5) soaking the material obtained in step (4) in a sodium alginate solution containing sucrose to fully infiltrate the sodium alginate solution, and then placing it in a calcium salt solution to obtain a wet polishing pad;

(6) freeze-drying the wet polishing pad to obtain the soft gel polishing pad.

In a preferred embodiment of the present invention, the particle size of the titanium-coated diamond abrasive grains/iron-coated diamond abrasive grains is W5-W10.

In a preferred embodiment of the present invention, the particle size of the La _0.6 Sr _0.4 Co ₃ powder is 1000-5000 mesh.

In a preferred embodiment of the present invention, the mass ratio of the titanium-coated diamond abrasive grains/iron-coated diamond abrasive grains and the La _0.6 Sr _0.4 Co ₃ powder is 1-5:1.

In a preferred embodiment of the present invention, in the sodium alginate solution, the concentration of sodium alginate is 3-5wt%, and the concentration of sucrose is 7-10wt%.

In a preferred embodiment of the present invention, the concentration of the calcium salt solution is 1.5-2.5 wt%.

In a preferred embodiment of the present invention, the diameter of the wax ball is 200-300 μm.

In a preferred embodiment of the present invention, the freeze-drying time is 1-2 hours.

In a preferred embodiment of the present invention, the step (5) is as follows: stacking the materials obtained in the steps (4) and immersing them in a sodium alginate solution containing sucrose to allow the sodium alginate solution to fully infiltrate the materials, and then placing them in a calcium salt solution to obtain a wet polishing pad.

The beneficial effects of the present invention are:

1. The present invention selects a mesh structure made of polyester for skeleton support, so that the processing time can be sufficiently guaranteed, and the present invention can adopt a multi-layer structure design, so that a higher material removal rate can be obtained in the early stage of the diamond grinding and polishing process, and better surface quality can be obtained in the subsequent grinding and polishing process.

2. The present invention uses titanium-plated diamond abrasive grains/iron-plated diamond abrasive grains, which can not only improve the holding force of the polishing pad base on the diamond abrasive grains, but also participate in the diamond graphitization reaction.

3. The La _0.6 Sr _0.4 Co ₃ powder in the present invention plays a role similar to a catalyst in the graphitization of diamond during the diamond grinding and polishing process, thereby improving the processing efficiency and optimizing the polishing pad; the La _0.6 Sr _0.4 Co ₃ powder has very excellent redox properties. During the diamond grinding and polishing process, it reacts with diamond through valence change, promotes reaction removal, and achieves the effect of high-efficiency diamond grinding and polishing; and adding La _0.6 Sr _0.4 Co ₃ powder to the polishing pad can also effectively reduce the surface defects of the diamond abrasive in the polishing pad, and play a role in purifying the grain boundaries. At the same time, it can also reduce the plated metal of the diamond abrasive and improve the reaction performance of the abrasive.

4. The present invention adopts biological substrates, and various materials have little pollution to the environment. At the same time, it is easy to make, takes a short time, and can be processed in batches.

5. The present invention can control the size of wax balls when sintering the polyester skeleton, and then select silica gel balls of the same size, so that the processing effect of the contact position during the processing is as uniform as possible.

6. The present invention has a supporting frame. Compared with the previous soft rubber polishing pad, the present invention is more solid and can be used as a medium or large polishing pad.

7. The present invention can be provided with a multi-layer structure, which can simultaneously obtain higher processing efficiency and better surface quality compared to normal soft rubber polishing pads.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a cross-sectional view of a polyester mesh structure according to Example 1 of the present invention.

FIG2 is a cross-sectional view of the soft rubber polishing pad obtained in Example 1 of the present invention.

FIG. 3 is a graph showing the surface quality of the polished diamond according to Example 1 of the present invention.

FIG. 4 is a graph showing the surface quality of diamond polished in comparative experiment in Comparative Example 1 of the present invention.

DETAILED DESCRIPTION

The technical solution of the present invention is further illustrated and described below through specific implementation modes in combination with the accompanying drawings.

Example 1

A soft rubber polishing pad comprises two layers of polyester mesh structure, the lower polyester mesh structure has a gap of 300 μm, and the upper polyester mesh structure has a gap of 200 μm. The polishing pad is freeze-dried at 0°C for 1 hour. The abrasive particles are titanium-coated diamond abrasive particles. The preparation method of the soft rubber polishing pad comprises the following steps:

(1) Titanium-coated diamond abrasive (particle size: W5) and La _0.6 Sr _0.4 Co ₃ powder (particle size: W0.5) were added to a sodium alginate solution and stirred to make the abrasive and rare earth compound uniformly distributed in the solution. The composition of the sodium alginate solution was: sodium alginate concentration 3wt%, sucrose concentration 7wt%.

(2) The solution obtained in step (1) is slowly and evenly dripped into the calcium salt solution intermittently to obtain two batches of gel spheres of similar size (particle sizes of 200 μm and 300 μm, respectively). Calcium salt solution composition: calcium chloride concentration 2%.

(3) Using polyester material, pores were formed by filling with 200 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 min. The wax balls were melted by heating (temperature: 60°C; duration: 1 h) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure (as shown in FIG1 ).

(4) Using polyester material, pores were formed by filling with 300 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 min. The wax balls were melted by heating (temperature: 60°C; duration: 1 h) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure with a diameter of 170 mm.

(5) placing the gel balls prepared in step (2) in the polyester mesh structure prepared in steps (3) and (4), and vibrating the mesh structure so that a uniform layer of gel balls is filled therein.

(6) The mesh structure prepared in step (5) is placed and coated on a substrate disk having a diameter of 180 mm, and the above-mentioned sodium alginate solution is added so that the solution covers the mesh structure.

(7) Place the base disc prepared in step (6) into a large-capacity beaker and pour in the calcium salt solution to obtain a wet polishing pad after gel reaction and solidification.

(8) The wet polishing pad obtained in step (7) is freeze-dried at 0° C. for 1 h to obtain the soft gel polishing pad (as shown in FIG. 2 ).

The diamond sheet was polished for 0.5 hours using the prepared soft rubber polishing pad and then tested. The results are shown in Figure 3. It is found that the surface quality of the diamond sheet after polishing with the polishing pad with La _0.6 Sr _0.4 Co ₃ is better, and the surface quality can reach 0.54Ra, with relatively few scratches and surface defects. And the material removal efficiency is greatly improved. The reason is that La _0.6 Sr _0.4 Co ₃ promotes the chemical reaction in the diamond polishing process, optimizes the abrasive interface and refines the grains, and the multi-layer structure makes the material removal efficiency higher in the initial stage of diamond polishing, and can also ensure that the subsequent polishing process can obtain better surface quality.

Comparative Example 1

A soft rubber polishing pad without adding La _0.6 Sr _0.4 Co ₃ and without using a multi-layer structure and using diamond abrasive particles, and a preparation method thereof comprises the following steps:

(1) Add diamond abrasive powder (particle size: W5) into sodium alginate solution and stir to make the abrasive evenly distributed in the solution. The composition of the sodium alginate solution is: sodium alginate concentration 3wt%, sucrose concentration 7wt%.

(2) The solution obtained in step (1) is slowly and evenly dripped into the calcium salt solution intermittently to obtain gel spheres of similar size with a particle size of about 200 μm. Calcium salt solution composition: calcium chloride concentration 2 wt%.

(3) Place the gel balls prepared in step (2) on a base plate with a diameter of 180 mm, and add sodium alginate solution so that the solution covers the mesh structure.

(4) Place the base disc prepared in step (3) into a large-capacity beaker and pour in the calcium salt solution to obtain a wet polishing pad after gel reaction and solidification.

(5) freeze-drying the wet polishing pad obtained in step (4) at 0° C. for 1 h to obtain the soft gel polishing pad.

By using this polishing pad to grind and polish diamond, it was found that the strength of this soft glue polishing pad was poor. After 10 minutes of processing, the soft glue polishing pad had ulcerated. After using multiple sets of soft glue polishing pads to continuously process the diamond surface for 1 hour and finally detecting the surface, the results are shown in Figure 4. It was found that compared with the soft glue polishing pad prepared in Example 1, the processing time was longer, the surface removal was slower, the scratches were obvious, and the surface quality could only reach 1.08Ra.

Example 2

A soft rubber polishing pad comprises three layers of polyester mesh structure, wherein the gap of the lower polyester mesh structure is 300 μm, the gap of the middle polyester mesh structure is 250 μm, and the gap of the upper polyester mesh structure is 200 μm. The polishing pad is freeze-dried at 0° C. for 1 hour. The abrasive grains are titanium-coated diamond abrasive grains.

The method for preparing the soft rubber polishing pad comprises the following steps:

(1) Titanium-coated diamond abrasive (particle size: W5) and La _0.6 Sr _0.4 Co ₃ powder (particle size: W0.5) were added to a sodium alginate solution and stirred to make the abrasive and rare earth compound uniformly distributed in the solution. The composition of the sodium alginate solution was: sodium alginate concentration 3wt%, sucrose concentration 7wt%.

(2) The solution obtained in step (1) was slowly and evenly dripped into the calcium salt solution to obtain three batches of gel spheres of similar size (particle sizes were 200 μm, 250 μm and 300 μm, respectively). Calcium salt solution composition: calcium chloride concentration 2 wt%.

(3) Using polyester material, pores were formed by filling with 200 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 minutes. The wax balls were melted by heating (temperature: 60°C; duration: 1 hour) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure with a diameter of 170 mm.

(4) Using polyester material, pores were formed by filling with 250 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 min. The wax balls were melted by heating (temperature: 60°C; duration: 1 h) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure with a diameter of 170 mm.

(5) Using polyester material, pores were formed by filling with 300 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 min. The wax balls were melted by heating (temperature: 60°C; duration: 1 h) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure with a diameter of 170 mm.

(6) placing the gel balls prepared in step (2) in the polyester mesh structure prepared in steps (3), (4) and (5), and vibrating the mesh structure so that a uniform layer of gel balls is filled therein.

(7) The mesh structure prepared in step (6) is placed and coated on a substrate disk with a diameter of 180 mm, and sodium alginate solution is added so that the solution covers the mesh structure.

(8) Place the base disc prepared in step (7) into a large-capacity beaker and pour in the calcium salt solution to obtain a wet polishing pad after gel reaction and solidification.

(9) freeze-drying the wet polishing pad obtained in step (8) at 0° C. for 1 h to obtain the soft gel polishing pad.

Example 3

A soft rubber polishing pad comprises three layers of polyester mesh structure, wherein the gap of the lower polyester mesh structure is 350 μm, the gap of the middle polyester mesh structure is 300 μm, and the gap of the upper polyester mesh structure is 250 μm. The polishing pad is freeze-dried at 0° C. for 1 hour. The abrasive grains are iron-plated diamond abrasive grains.

The method for preparing the soft rubber polishing pad comprises the following steps:

(1) Add iron-plated diamond abrasive grains (particle size: W5) and La _0.6 Sr _0.4 Co ₃ powder (particle size: W0.5) into a sodium alginate solution and stir to make the abrasive grains and rare earth compound uniformly distributed in the solution. The composition of the sodium alginate solution is: sodium alginate concentration 3wt%, sucrose concentration 7wt%.

(2) The solution obtained in step (1) was slowly and evenly dripped into the calcium salt solution to obtain three batches of gel spheres of similar size (particle sizes were 250 μm, 300 μm and 350 μm, respectively). Calcium salt solution composition: calcium chloride concentration 2 wt%.

(3) Using polyester material, pores were formed by filling with 250 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 min. The wax balls were melted by heating (temperature: 60°C; duration: 1 h) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure with a diameter of 170 mm.

(4) Using polyester material, pores were formed by filling with 300 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 min. The wax balls were melted by heating (temperature: 60°C; duration: 1 h) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure with a diameter of 170 mm.

(5) Using polyester material, pores were formed by filling with 350 μm wax balls, and the pores were pressed by a cold press (pressure: 10 N) for 15 min. The wax balls were melted by heating (temperature: 60°C; duration: 1 h) to obtain a mesh structure. The polyester mesh structure was modified to obtain a finished polyester mesh structure with a diameter of 170 mm.

(6) placing the gel balls prepared in step (2) in the polyester mesh structure prepared in steps (3), (4) and (5), and vibrating the mesh structure so that a uniform layer of gel balls is filled therein.

(7) The mesh structure prepared in step (6) is placed and coated on a substrate disk with a diameter of 180 mm, and sodium alginate solution is added so that the solution covers the mesh structure.

(8) Place the base disc prepared in step (7) into a large-capacity beaker and pour in the calcium salt solution to obtain a wet polishing pad after gel reaction and solidification.

(9) freeze-drying the wet polishing pad obtained in step (8) at 0° C. for 1 h to obtain the soft gel polishing pad.

The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of implementation of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims (9)

1. A method for preparing a soft rubber polishing pad containing a rare earth compound, characterized in that it comprises the following steps: (1) adding titanium-coated diamond abrasive grains/iron-coated diamond abrasive grains and La _0.6 Sr _0.4 Co ₃ powder into a sodium alginate solution containing sucrose and uniformly dispersing them; (2) dripping the material obtained in step (1) into a calcium salt solution dropwise to obtain gel spheres; (3) mixing the polyester material and the wax balls evenly, and then heating to melt the wax balls to obtain a mesh polyester; (4) filling the gel balls obtained in step (2) into the holes of the mesh polyester obtained in step (3); (5) soaking the material obtained in step (4) in a sodium alginate solution containing sucrose to fully infiltrate the sodium alginate solution, and then placing it in a calcium salt solution to obtain a wet polishing pad; (6) freeze-drying the wet polishing pad to obtain the soft gel polishing pad. 2. The method for preparing a soft rubber polishing pad containing rare earth compounds as described in claim 1, characterized in that the particle size of the titanium-coated diamond abrasive grains/iron-coated diamond abrasive grains is W5-W10. 3. The method for preparing a soft rubber polishing pad containing rare earth compounds according to claim 1, characterized in that the particle size of the La _0.6 Sr _0.4 Co ₃ powder is 1000-5000 mesh. 4. The method for preparing a soft rubber polishing pad containing rare earth compounds as claimed in claim 1, characterized in that the mass ratio of the titanium-coated diamond abrasive grains/iron-coated diamond abrasive grains and the La _0.6 Sr _0.4 Co ₃ powder is 1-5:1. 5. The method for preparing a soft rubber polishing pad containing rare earth compounds as claimed in claim 1, characterized in that: in the sodium alginate solution, the concentration of sodium alginate is 3-5wt%, and the concentration of sucrose is 7-10wt%. 6. The method for preparing a soft rubber polishing pad containing a rare earth compound as claimed in claim 1, characterized in that the concentration of the calcium salt solution is 1.5-2.5wt%. 7. The method for preparing a soft rubber polishing pad containing rare earth compounds as claimed in claim 1, characterized in that the diameter of the wax ball is 200-300 μm. 8. The method for preparing a soft-gel polishing pad containing a rare earth compound as claimed in claim 1, characterized in that the freeze-drying time is 1-2 hours. 9. A method for preparing a soft rubber polishing pad containing rare earth compounds as claimed in any one of claims 1 to 8, characterized in that: the step (5) is: stacking the materials obtained in the steps (4) and immersing them in a sodium alginate solution containing sucrose to allow the sodium alginate solution to fully infiltrate the materials, and then placing them in a calcium salt solution to obtain a wet polishing pad.