A chemical mechanical polishing liquid containing dissolved silk suitable for fused quartz, its preparation method and application

Abstract

The present invention relates to a chemical mechanical polishing liquid, specifically a chemical mechanical polishing liquid containing dissolved silk suitable for fused quartz, and its preparation method and application. The polishing liquid of the present invention comprises cerium dioxide, sodium alginate and silk solution. The polishing liquid comprises 0.005wt% - 0.05wt% cerium dioxide, 0.0005wt% - 0.04wt% sodium alginate, 0.005wt% - 0.05wt% silk solution, and the balance is water. The components of the polishing liquid of the present invention are derived from natural products, which are green and environmentally friendly. The polishing liquid is simple to prepare, has good dispersibility, and the polishing efficiency (MRR) is as high as 28.222μm / h. At the same time, the surface roughness (Sa) is greatly reduced, the Sa value is 0.098nm, and the polished surface is smooth and flat without defects.

Description

Technical Field

[0001] The present invention relates to a chemical mechanical polishing liquid, specifically a chemical mechanical polishing liquid containing dissolved silk suitable for fused quartz, and its preparation method and application. Background Art

[0002] Fused quartz is widely used in various optical precision devices due to its high hardness, high transparency, heat resistance and dimensional stability, such as aerospace, detection systems, spectroscopy instruments and optical fiber communication, etc. Subsurface damage introduced during the pure mechanical processing directly reduces important performance indicators such as the strength, long-term stability, imaging quality, coating quality and laser damage threshold of optical parts. Therefore, it is of great significance to construct a damage-free surface. Chemical mechanical polishing (CMP) is a finishing process for planarizing fused quartz substrates. In a typical CMP process, a strongly corrosive polishing liquid containing abrasives is used, and the chemical products formed on the material surface can be removed by the abrasives at the same time, and a flat surface is obtained through the synergistic effect of chemistry and mechanics.

[0003] Currently, some prior arts have disclosed some fused quartz polishing liquids and polishing methods, which are specifically as follows:

[0004] CN115093829A discloses a fused quartz hybrid abrasive polishing liquid, which contains a composite abrasive of diamond and metal oxide. In addition, the polishing liquid contains a dispersant, a pH regulator, a complexing agent, a wetting agent, etc. The dispersant has a high molecular alcohol structure and can form a large steric hindrance with the wetting agent, effectively preventing the agglomeration between particles and increasing the dispersion stability of the system, thereby further reducing the roughness. However, the alcohol dispersants are polyvinyl alcohol, isomeric alcohol polyoxyethylene ether, etc.; the complexing agents are diethylenetriamine pentacarboxylate, sodium dimercaptopropanesulfonate, N,N-dicarboxyamino-2-hydroxypropylsulfonic acid, methyl thymol blue and calcein, etc.; the pH regulators are potassium hydroxide, sodium hydroxide, hydrochloric acid and sulfuric acid, etc. The above components in the polishing liquid will cause harm to the environment, operators and equipment.

[0005] CN115433520A discloses a green and environmentally friendly polishing liquid for fused quartz, and its components include: nano-powder abrasive, pH regulator, dispersant, defoamer, moisturizer, oxidant and deionized water. This polishing liquid has high polishing efficiency, strong dispersion ability, good long-lasting defoaming effect, and the surface after polishing can reach the sub-nanometer level, which can meet the commercial requirements. However, the preparation process of this polishing liquid is complex, and the mechanical stirring and ball milling time are long.

[0006] Therefore, the existing fused quartz polishing liquids and processes need to be further improved, and it is expected to obtain a chemical mechanical polishing liquid with green and environmentally friendly components and simple preparation. Summary of the Invention

[0007] The object of the present invention is to provide a chemical mechanical polishing liquid containing dissolved silk suitable for fused quartz, its preparation method and application.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a chemical mechanical polishing liquid, and the polishing liquid includes cerium dioxide, sodium alginate and silk solution.

[0010] In the above technical solution, further, the polishing liquid includes 0.005wt% - 0.05wt% cerium dioxide, 0.0005wt% - 0.04wt% sodium alginate, 0.005wt% - 0.05wt% silk solution, and the rest is water.

[0011] In the above technical solution, further, the polishing liquid includes 0.01wt% - 0.03wt% cerium dioxide, 0.001wt% - 0.002wt% sodium alginate, 0.01wt% - 0.03wt% silk solution, and the rest is water.

[0012] In the above technical solution, further, it is characterized in that the polishing liquid includes 0.02wt% cerium dioxide, 0.0015wt% sodium alginate, 0.02wt% silk solution, and the rest is water.

[0013] In the above technical solution, further, the particle size range of the CeO2 abrasive grains is 0.2 - 0.7μm, preferably 0.4 - 0.5μm;

[0014] The molecular weight range of the complexing agent sodium alginate is 200 - 400, preferably 216.

[0015] In the above technical solution, further, the silk solution includes 10wt% - 20wt% silk, 20wt% - 40wt% urea, 10wt% - 25wt% sodium hydroxide.

[0016] In the above technical solution, further, the silk solution includes 10wt% - 15wt% silk, 35wt% - 38wt% urea, 20wt% - 23wt% sodium hydroxide;

[0017] Preferably, the silk solution includes 12wt% silk, 36wt% urea, 21wt% sodium hydroxide.

[0018] In the above technical solution, further, the preparation method of the silk solution is: after mixing silk, urea, sodium hydroxide and deionized water evenly, freeze at -12°C for 24h, and thaw at room temperature to obtain a silk solution with uniform dissolution.

[0019] The present invention also provides the application of the aforementioned chemical mechanical polishing liquid in the polishing of fused quartz.

[0020] In the above technical solution, further, the application is to improve the polishing efficiency of fused quartz and reduce the surface roughness of fused quartz.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention first adds silk components to the polishing liquid. The components of the polishing liquid are derived from natural products, which are green and environmentally friendly. Moreover, the polishing liquid is simple to prepare, has good dispersibility, and the polishing efficiency (MRR) is as high as 28.222 μm / h. At the same time, the surface roughness (Sa) is greatly reduced, and the Sa value is 0.098 nm. Description of the Drawings

[0022] Figure 1 is the Sa value of the initial fused quartz surface (measurement range 200×200 μm 2 ).

[0023] Figure 2 is the Sa value of the fused quartz surface after polishing in Example 3 (measurement range 200×200 μm 2 ).

[0024] Figure 3 is the Sa value of the fused quartz surface after polishing in Example 3 (measurement range 20×20 μm 2 ).

[0025] Figure 4 is the optical photograph of the initial fused quartz surface.

[0026] Figure 5 is the optical photograph of the fused quartz surface after polishing in Example 3.

[0027] Figure 6 The effects of different CeO2, sodium alginate, and silk solutions on MRR and Sa. Detailed Embodiments

[0028] The following further illustrates the present invention with specific embodiments, but does not limit the present invention in any way.

[0029] The polishing process includes the following steps:

[0030] Step 1: After weighing the fused quartz (1×1 cm 2 ) (accurate to four decimal places), stick it on the counterweight plate with paraffin, place it on the polishing machine, and polish it with the prepared polishing liquid;

[0031] Step 2: After polishing, heat to remove the fused quartz, clean the wax with ethanol, then clean it with deionized water, air dry it naturally, and weigh it again.

[0032] The MRR is calculated using the following formula:

[0033]

[0034] Δm is the difference in weight between two weighings (g), ρ is the density of optical quartz glass (g / cm 3 ), t is the polishing time (h), and A is the area of the optical quartz glass.

[0035] Step 3: Select a total of 5 points around the fused silica sheet and at its center, and use a white light interferometer to measure the Sa value. Each point is measured 3 times, and the average value is taken.

[0036] The polishing application of the present invention will be further described in combination with the following examples:

[0037] Prepare a silk solution: Add 12 g of silk, 36 g of urea, and 21 g of sodium hydroxide to deionized water, freeze at -12°C for 24 h, and after melting at room temperature, a uniformly dissolved silk solution is obtained.

[0038] Mix and stir CeO2 abrasive grains, sodium alginate, and the silk dissolving solution according to the ratio. Stir until uniformly dissolved at a rotation speed of 500 rpm, and ultrasonically treat for 30 min to prepare 500 mL of polishing solution. Examine the surface quality Sa value and MRR value of the polished samples under different ratios. The polishing pressure is 10 KPa, the rotation speed of the polishing disc is 80 rpm, the polishing temperature is 50°C, and the polishing time is 30 min. The measurement range is 800×800 μm 2 .

[0039] Table 1

[0040]

[0041]

[0042] After adding the silk solution to the present invention, there is no need to use components that are harmful to the environment and human body such as strong acids, and the polishing solution system and preparation are simple. The polishing efficiency MRR value is high, and the surface roughness Sa value is reduced. Taking Example 12 as an example, when the measurement range is 200×200 μm 2 , the Sa value is 0.466 nm( Figure 2 ), when the measurement range is 20×20 μm 2 , the Sa value is only 0.098 nm, and the polished surface is smooth and flat without any defects (see Figure 5 ).

[0043] In this polishing liquid, the CeO2 abrasive has a low hardness and can achieve the effect of "soft polishing on hard materials", and it is not easy to produce scratches on the surface of fused quartz. The complexing agent sodium alginate contains a large number of free hydroxyl and carboxyl groups distributed along the polymer chain backbone. After dissolution, protonation occurs and hydrogen bonds are formed, which are easy to crosslink with other organic and inorganic materials. The silk dissolving solution contains groups with lone pair electrons such as N atoms and benzene rings. As a coordination center, it is extremely easy to form coordination bonds and complexes with fused quartz, forming a softening layer on its surface. In addition, high shear force is easily generated after the protein and sodium alginate are mixed. The reactants can be removed by using a small mechanical force and the mass transfer effect of the CeO2 abrasive, which can improve the surface quality of fused quartz and increase the MRR.

[0044] The above embodiments are intended to illustrate the embodiments disclosed in the present invention and should not be construed as limiting the present invention. In addition, various modifications listed herein and changes in the methods and compositions of the invention are obvious to those skilled in the art without departing from the scope and spirit of the present invention. Although the present invention has been specifically described in conjunction with various specific preferred embodiments of the present invention, it should be understood that the present invention should not be limited to these specific embodiments. In fact, all obvious modifications to those skilled in the art as described above to obtain the invention should be included within the scope of the present invention.

Claims

1. A chemical mechanical polishing liquid, characterized in that, The polishing liquid comprises 0.005 wt% - 0.05 wt% cerium dioxide, 0.0005 wt% - 0.04 wt% sodium alginate, 0.005 wt% - 0.05 wt% silk solution, and the balance is water; The silk solution comprises 10 wt% - 20 wt% silk, 20 wt% - 40 wt% urea, 10 wt% - 25 wt% sodium hydroxide; the preparation method of the silk solution is: mixing silk, urea, sodium hydroxide and deionized water evenly, freezing at -12°C for 24 h, and thawing at room temperature to obtain a uniformly dissolved silk solution.

2. The chemical mechanical polishing liquid according to claim 1, wherein The polishing liquid comprises 0.01 wt% - 0.03 wt% cerium dioxide, 0.001 wt% - 0.002 wt% sodium alginate, 0.01 wt% - 0.03 wt% silk solution, and the balance is water.

3. The chemical mechanical polishing liquid according to claim 1, characterized in that The polishing liquid comprises 0.02 wt% cerium dioxide, 0.0015 wt% sodium alginate, 0.02 wt% silk solution, and the balance is water.

4. The chemical mechanical polishing liquid according to claim 1, wherein, The particle size range of the cerium dioxide abrasive grains is 0.2 - 0.7 μm; The molecular weight range of the sodium alginate is 200 - 400.

5. The chemical mechanical polishing liquid according to claim 4, characterized in that, The particle size range of the cerium dioxide abrasive grains is 0.4 - 0.5 μm; the molecular weight of the sodium alginate is 216.

6. The chemical mechanical polishing liquid according to claim 1, wherein The silk solution comprises 10 wt% - 15 wt% silk, 35 wt% - 38 wt% urea, 20 wt% - 23 wt% sodium hydroxide.

7. The chemical mechanical polishing liquid according to claim 6, wherein The silk solution comprises 12 wt% silk, 36 wt% urea, 21 wt% sodium hydroxide.

8. Application of the chemical mechanical polishing liquid according to any one of claims 1 - 7 in the polishing of fused silica.

9. The application according to claim 8, wherein The application is to improve the polishing efficiency of fused silica and reduce the surface roughness of fused silica.

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