Green, environment-friendly and efficient sapphire polishing solution

Abstract

The invention discloses a green, environment-friendly and efficient sapphire polishing solution, and relates to the technical field of polishing solutions, the green, environment-friendly and efficient sapphire polishing solution comprises an abrasive material, a pH regulator, a surfactant and deionized water, the abrasive material is colloidal SiO2, the pH regulator is an arginine solution, the surfactant is ammonium dodecyl sulfate, and the balance is deionized water; the polishing solution is green and environment-friendly, the components do not contain metal ions, the organic alkali arginine not only can be used as an alkaline pH regulator, but also can play a role of a complexing agent, the anionic surfactant ammonium dodecyl sulfate can improve the surface quality of polished sapphire, the stability of the polishing solution can be effectively improved, and the polishing solution is suitable for polishing sapphire. The polishing solution provided by the invention has a good CMP (Chemical Mechanical Polishing) effect on sapphires with three crystal faces of C, A and R, and the material removal rate and the surface quality are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of polishing liquid, in particular to a green, environment-friendly and efficient sapphire polishing liquid. Background Art

[0002] Sapphire is often used as an important optical material due to its excellent physical and chemical properties. It is widely used in many fields such as LED, optical instruments, semiconductor devices, etc. However, due to its high hardness and good chemical stability, the processing of sapphire has always been a technical problem. Polishing is an important process in the processing of sapphire, aiming to achieve the flattening of the sapphire surface. Chemical mechanical polishing (CMP) technology perfectly combines the advantages of mechanical polishing and chemical polishing, and is currently one of the most effective technologies for achieving global flattening in ultra-precision machining. Among the many factors that affect the performance of sapphire CMP, the optimization of the components of the polishing liquid is more likely to improve the performance of sapphire CMP, and is less affected by other factors and has universal applicability. However, there are still some problems with the existing sapphire polishing liquid: the chemical composition of the polishing liquid is complex and the cost is high; the metal ions contained in the polishing liquid will cause certain harm to people and the environment, and it is not environmentally friendly; the stability of the polishing liquid is poor, the abrasive is easy to agglomerate, and it is not easy to store for a long time; most of the polishing liquids are only suitable for sapphires with a single crystal face, not for sapphires with multiple crystal faces, and the universality is poor and the polishing efficiency is not high enough. Therefore, developing a sapphire polishing liquid with simple ingredients, green and environmental protection, good stability and high efficiency is of great significance to improving the processing efficiency and product quality of sapphire. Summary of the invention

[0003] The purpose of the present invention is to provide a green, environmentally friendly and efficient sapphire polishing liquid to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A green, environment-friendly and efficient sapphire polishing liquid comprises an abrasive, a pH regulator, a surfactant and deionized water, wherein the abrasive is colloidal SiO2, the pH regulator is an arginine solution, the surfactant is dodecyl ammonium sulfate, and the remaining components are deionized water.

[0006] As a further solution of the present invention: the average particle size of the abrasive is in the range of 80nm to 100nm, and the concentration is 20wt%.

[0007] As a further solution of the present invention: the pH value of the polishing liquid adjusted by the pH adjuster is in the range of 10.0-10.5.

[0008] As a further solution of the present invention: the concentration range of the ammonium dodecyl sulfate is 0.01wt%-0.03wt%.

[0009] As a further solution of the present invention: the polishing process parameters of the polishing liquid are: polishing lower pressure is 0.1MPa, polishing upper pressure is 0.06MPa, polishing head speed is 50r / min, polishing disk speed is 45r / min, polishing time is 30min, polishing liquid flow rate is 160mL / min, and temperature is 25-29°C.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The polishing liquid of the present invention is green and environmentally friendly, and does not contain metal ions in its ingredients. The organic base arginine can not only serve as an alkaline pH regulator, but also play the role of a complexing agent.

[0012] 2. The anionic surfactant ammonium dodecyl sulfate provided in the present invention can not only improve the surface quality of sapphire after polishing, but also effectively improve the stability of the polishing liquid, prevent abrasive agglomeration, and enable the polishing liquid to be stored for a long time.

[0013] 3. The polishing liquid of the present invention has a good CMP effect on sapphire with three crystal planes, C, A and R, and the material removal rate and surface quality are greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Figure 2 shows the distribution of sapphires embedded in wax-free adsorption pads.

[0015] Figure 2 Surface morphologies of sapphires with different crystal faces after polishing: (a) C-face sapphire, (b) A-face sapphire, and (c) R-face sapphire.

[0016] Figure 3 The morphology, size and aggregation state of SiO2 particles in SEM tests at different scales: (a) 1μm, (b) 200nm.

[0017] Figure 4 This is a graph showing the changing trend of pH value and Zeta potential of the polishing solution within 7 days.

[0018] Figure 5 This is the surface morphology of sapphire after CMP using the control group polishing solution.

[0019] Figure 6 It is a CMP performance data comparison chart, where A is the control group and B is the present application. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1

[0022] The polishing equipment is a single-sided polishing machine produced by Suzhou Heruit Company, model X62S82×305-DS, the polishing pad model is Suba 600, and the process parameters are shown in Table 1.

[0023] Table 1 Sapphire CMP process parameters:

[0024]

[0025] The components and parameters of the polishing liquid are as follows: the abrasive is colloidal SiO2 (average particle size is about 85nm, concentration is 20wt%), the pH adjuster is arginine solution (the pH value of the polishing liquid is adjusted to 10.25), the surfactant is anionic ammonium dodecyl sulfate (concentration is 0.02wt%) and deionized water. The sapphire samples are 2-inch diameter C-side, A-side and R-side sapphire single crystals. Before the experiment, the three sapphire wafers were cleaned with deionized water, and then each sapphire wafer was embedded in the hole of the wax-free adsorption pad on the alumina ceramic disk to ensure that the wafer would not fall off. In order to make the pressure uniform, the three wafers are distributed in a regular triangle, such as Figure 1 As shown. Then, the alumina ceramic disc was mounted on the polishing head, and after setting the program, polishing began. After polishing, the material removal rates of the C-side, A-side, and R-side sapphires were 5.78μm / h, 3.00μm / h, and 3.62μm / h, respectively, and the surface roughness Sq reached 0.182nm, 0.153nm, and 0.158nm, respectively (the detection range was 5×5μm 2 ), the surface flatness is good, and there are no scratches, pits and other defects, such as Figure 2 shown. Figure 3 The morphology and aggregation state of the colloidal SiO2 abrasive in the polishing liquid are shown in the SEM test. There is no obvious difference in the average particle size of the SiO2 abrasive, and no obvious agglomeration occurs. Figure 4 The results show that when the initial pH value of the polishing liquid is 10.25, the pH value and Zeta potential change trend with the increase of days. The results show that the pH value and Zeta potential fluctuate very little with the increase of days, and the absolute value of Zeta potential is greater than 30mV within 7 days. The polishing liquid is in a stable state, indicating that the polishing liquid can be stable for at least 7 days and meet the requirements of industrial production.

[0026] Control group:

[0027] The difference from Example 1 is that:

[0028] The control group used conventional polishing liquid component configuration. The components and parameters of the control group polishing liquid were as follows: the abrasive was SiO2 (average particle size was 50nm, concentration was 15wt%), the pH adjuster was sodium metasilicate nonahydrate (the pH value of the polishing liquid was adjusted to 10), the chelating agent was sorbitol (concentration was 0.8wt%), and the remaining components were deionized water.

[0029] Taking surface roughness and material removal rate as evaluation indicators, orthogonal experiment and single factor experimental method were used to optimize the polishing process parameters and polishing liquid composition parameters, and a new sapphire polishing liquid was studied. The polishing equipment is UNIPOL-1200S automatic pressure grinding and polishing machine produced by Shenyang Kejing Automation Equipment Co., Ltd., and the polishing pad is a frosted leather polishing pad. The optimized polishing process parameters are: polishing pressure of 35.5kPa, polishing speed of 90rpm, polishing time of 1h, polishing liquid flow rate of 15mL / min; the sapphire sample is a 2-inch C-face sapphire wafer, which is cut into many 10×10mm wafers using a diamond wire saw. 2 For small samples, use anhydrous ethanol to ultrasonically clean them after cutting, and then blow dry them with compressed air. During the experiment, clean the surface of the aluminum alloy carrier plate and place it on a heating table for heating. Apply paraffin evenly on the carrier plate, take three samples and place them on the carrier plate. The samples are evenly distributed around the circumference, and then a weight is placed on the weighing paper to compact the three samples. After natural cooling, remove the weight, wipe the surface of the sapphire sample clean with a non-woven cloth soaked in anhydrous ethanol, and start polishing. Figure 5 As shown in Figure 2, the surface roughness Ra of the polished sapphire reaches 0.169nm (the detection range is 868.148×868.148μm 2 ), and there are no defects such as scratches and pits on the surface. The material removal rate during polishing reaches 3.238μm / h.

[0030] Table 2: CMP performance data comparison

[0031]

[0032] Control group: C-surface sapphire material removal rate is 3.238μm / h, and surface roughness Ra is 0.169nm. This application: C-surface sapphire material removal rate is 5.780μm / h, surface roughness Sq is 0.182nm, and Ra is 0.007nm. From the results, the performance of the sapphire polishing liquid developed in this application far exceeds that of the sapphire polishing liquid in the control group. Note: Surface roughness Sq and Ra are two different evaluation parameters. Sq (root mean square height roughness) usually refers to surface roughness, which is defined as the standard deviation of the surface profile height. It is used to describe the average deviation of the surface micromorphology. It can reflect the roughness and smoothness of the surface. The larger the value, the rougher the surface, and the smaller the value, the smoother the surface. Ra (arithmetic mean roughness) usually refers to line roughness, which is defined as the arithmetic mean deviation of the surface profile relative to the measurement baseline within a certain measurement length range. The smaller the Ra value, the smoother the surface; conversely, the larger the Ra value, the rougher the surface.

[0033] Table 3: 7-day stability data of the polishing liquid in this application

[0034]

[0035] It can be seen that the polishing liquid of the present application has good stability and can be stored for more than 7 days, meeting the requirements of industrial production.

[0036] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Although this specification is described in accordance with the implementation modes, not every implementation mode includes only one technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A green, environmentally friendly and efficient sapphire polishing liquid, characterized by: The invention comprises abrasive, pH regulator, surfactant and deionized water, wherein the abrasive is colloidal SiO2, the pH regulator is arginine solution, the surfactant is dodecyl ammonium sulfate, and the remaining components are deionized water.

2. The green, environmentally friendly and efficient sapphire polishing liquid according to claim 1, characterized in that: The average particle size of the abrasive is in the range of 80 nm to 100 nm, and the concentration is 20 wt %.

3. The green, environmentally friendly and efficient sapphire polishing liquid according to claim 1, characterized in that: The pH adjuster adjusts the pH value of the polishing liquid to a range of 10.0-10.

5.

4. The green, environmentally friendly and efficient sapphire polishing liquid according to claim 1, characterized in that: The concentration of the ammonium dodecyl sulfate is in the range of 0.01 wt % to 0.03 wt %.

5. The green, environmentally friendly and efficient sapphire polishing liquid according to claim 1, characterized in that: The polishing process parameters of the polishing liquid are: polishing lower pressure is 0.1MPa, polishing upper pressure is 0.06MPa, polishing head speed is 50r / min, polishing disk speed is 45r / min, polishing time is 30min, polishing liquid flow rate is 160mL / min, and temperature is 25-29℃.

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