目的 探究BK7光学玻璃在化学机械抛光（Chemical mechanical polishing, CMP）过程中,相关因素对BK7光学玻璃抛光表面的材料去除率（MRR）、粗糙度（Ra）的影响规律,揭示BK7光学玻璃在二氧化铈（CeO2）抛光液中的化学机械抛光机理,获得高效、低损伤的表面抛光质量。方法 采用单因素实验法进行CMP实验,比较不同抛光时间、抛光盘转速、CeO2含量、抛光液pH和柠檬酸含量下的抛光效果,分析不同条件对抛光效果的影响规律,通过正交实验得到最优参数组合。结果 在最优参数组合（抛光时间50 min、抛光盘转速60 r/min、抛光液pH 6、CeO2磨粒的质量分数0.5%、柠檬酸的质量分数2.0%）下,抛光后表面无明显磨粒残留,MRR值为139.6 µm/h,Ra为2 nm。结合XPS、EDS、纳米压痕测试表征结果,提出了BK7光学玻璃化学机械抛光去除机理,柠檬酸作为还原剂,将CeO2磨粒表面的Ce4+还原为Ce3+,形成了氧空位。随着Ce3+浓度的增加,CeO2磨粒与硅酸盐离子间的化学吸附增加,形成了Ce—O—Si,Ce3+中的自由电子向SiO2表面迁移,促进Si—O断裂,有利于CeO2磨粒机械去除抛光表面的软化层,从而提高了抛光效率。结论 通过加入柠檬酸,提高了CeO2磨粒表面Ce3+的浓度,加速了CeO2磨粒与抛光表面的反应速率,促进了Si—O的断裂,有效提高了抛光效率,对于获得高质量表面的BK7光学玻璃抛光工艺优化及揭示材料去除机理具有一定指导意义。
Abstract
BK7 optical glass is an excellent material in the optical industry due to its low dispersion and high transmittance. However, its surface polishing still remains a serious challenge. BK7 optical glass is a typical hard-brittle material with high hardness, high brittleness, low fracture toughness, and good chemical stability. Traditional mechanical processing methods are difficult to meet the technical requirements of modern industry. CMP (Chemical Mechanical Polishing) can achieve an extremely low roughness on the surface of BK7 glass while causing minimal surface and subsurface damage. The work aims to explore the effect of various factors during the chemical mechanical polishing (CMP) process on the removal rate (MRR) and surface roughness (Ra) of BK7 optical glass materials, to reveal the chemical mechanical polishing mechanism of BK7 optical glass in a polishing liquid containing nano-scale cerium dioxide (CeO2) abrasive particles, and improve the efficiency and achieve low-damage surface polishing of BK7 optical glass.
By the single-factor experimental method, CMP experiments were conducted on BK7 optical glass to compare the polishing effects under different polishing time, platen speed, CeO2 contents, slurry pH values, and citric acid contents, to analyze the effect of these conditions on the polishing performance of BK7 optical glass, and the optimal parameter combination was determined through orthogonal experiments. The variations in the concentration of Ce3+ on the surface of CeO2 abrasive particles were investigated through energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), as well as the aggregation and adsorption behavior of CeO2 under different conditions.
Through orthogonal experimental design, the optimal combination of polishing parameters was determined: the polishing time of 50 min, the polishing disc speed of 60 r/min, the slurry pH value of 6, the CeO2 abrasive concentration of 0.5%, and the citric acid concentration of 2%. Under these conditions, the best MRR of 139.6 µm/h and a Ra of 2 nm were achieved, with a 99.6% reduction in surface roughness. No obvious abrasive residues were observed on the polished surface of the BK7 optical glass. Based on the characterization results obtained from X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), and nanoindentation testing, the material removal mechanism of BK7 optical glass during CMP was proposed. Citric acid acted as a reducing agent, reduced Ce4+ ions on the surface of CeO2 abrasive particles to Ce3+. This reduction process increased the surface concentration of Ce3+ on the CeO2 particles, forming oxygen vacancies. With the increase in Ce3+ concentration, the chemical adsorption between CeO2 abrasive particles and silicate ions increased, forming Ce—O—Si bonds. Meanwhile, free electrons in Ce3+ migrated to the surface of SiO2, which promoted the breaking of Si—O bonds. This facilitated the mechanical removal of the softened layer on the polished surface of BK7 optical glass by CeO2 abrasives, thereby improving the polishing efficiency.
Compared with the chemical mechanical polishing method that prepares complex CeO2 core-shell structures and adds low-valent metal ions to CeO2 abrasive particles, this study employs the addition of citric acid to enhance the surface concentration of Ce3+ on CeO2 abrasive particles. This method accelerates the reaction rate between CeO2 abrasives and the polished surface of BK7 optical glass, thereby facilitating the cleavage of Si—O bonds and significantly improving the polishing efficiency of BK7 optical glass surfaces. It can also be applied to ultra-precision machining with high accuracy, which provides guidance for optimizing polishing process parameters and elucidating the material removal mechanism to achieve high-quality surfaces on BK7 optical glass.
关键词
BK7光学玻璃 /
化学机械抛光 /
CeO2 /
材料去除机理 /
pH /
材料去除率
Key words
BK7 optical glass /
chemical mechanical polishing /
CeO2 /
material removal mechanism /
pH /
material removal rate
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参考文献
[1] LI C, HU Y X, WEI Z Z, et al.Damage Evolution and Removal Behaviors of GaN Crystals Involved in Double- Grits Grinding[J]. International Journal of Extreme Manufacturing, 2024, 6(2): 025103.
[2] 梁赢东, 牛俊开, 张超, 等. 超声振动辅助抛光BK7过程中聚氨酯抛光垫磨损行为[J]. 东北大学学报(自然科学版), 2023, 44(1): 82-88.
LIANG Y D, NIU J K, ZHANG C, et al.Wear Behavior of Polyurethane Polishing Pads Used in BK7 Ultrasonic Vibration-Assisted Polishing[J]. Journal of Northeastern University (Natural Science), 2023, 44(1): 82-88.
[3] GUO Y F, YIN S H, OHMORI H, et al.A Novel High Efficiency Magnetorheological Polishing Process Excited by Halbach Array Magnetic Field[J]. Precision Engineering, 2022, 74: 175-185.
[4] 白倩, 马浩, 殷景飞. 基于偏振激光共聚焦的研磨石英玻璃亚表面损伤检测[J]. 光学精密工程, 2021, 29(8): 1795-1803.
BAI Q, MA H, YIN J F.Polarized Laser Confocal Technique for Subsurface Damage of Lapped Quartz Glass[J]. Optics and Precision Engineering, 2021, 29(8): 1795-1803.
[5] LEE H, KIM H, JEONG H.Approaches to Sustainability in Chemical Mechanical Polishing (CMP): A Review[J]. International Journal of Precision Engineering and Manufacturing-Green Technology, 2022, 9(1): 349-367.
[6] LI W, XIN Q, FAN B, et al.A Review of Emerging Technologies in Ultra-Smooth Surface Processing for Optical Components[J]. Micromachines, 2024, 15(2): 178.
[7] 朱子俊, 刘顺, 韩冰, 等. 超声振动复合研磨K9光学玻璃工艺研究[J]. 表面技术, 2020, 49(4): 74-80.
ZHU Z J, LIU S, HAN B, et al.Study on Hybrid Technology of Ultrasonic Vibration Assisted Abrasive Lapping K9 Optical Glass[J]. Surface Technology, 2020, 49(4): 74-80.
[8] QI H, SHI L W, TENG Q, et al.Subsurface Damage Evaluation in the Single Abrasive Scratching of BK7 Glass by Considering Coupling Effect of Strain Rate and Temperature[J]. Ceramics International, 2022, 48(6): 8661-8670.
[9] HUANG Y H, WANG M C, LI J M, et al.Effect of Abrasive Particle Shape on the Development of Silicon Substrate during Nano-Grinding[J]. Computational Materials Science, 2021, 193: 110420.
[10] CUI X X, ZHANG Z Y, SHI C J, et al.Atomic Surface Induced by Novel Green Chemical Mechanical Polishing for Aspheric Thin-Walled Crucibles with Large Diameters[J]. Journal of Manufacturing Processes, 2024, 117: 59-70.
[11] STREY N F, SCANDIAN C.Abrasive Polishing Load Effect on Surface Roughness and Material Removal Rate of Al2O3, ZTA and SiC[J]. Wear, 2021, 477: 203787.
[12] KENCHAPPA N B, POPURI R, CHOCKKALINGAM A, et al.Soft Chemical Mechanical Polishing Pad for Oxide CMP Applications[J]. ECS Journal of Solid State Science and Technology, 2021, 10(1): 014008.
[13] 余青, 刘德福, 陈涛. 单晶蓝宝石衬底晶片的化学机械抛光工艺研究[J]. 表面技术, 2017, 46(3): 253-261.
YU Q, LIU D F, CHEN T.Chemico-Mechanical Polishing Technique of Monocrystal Sapphire Substrate Wafer[J]. Surface Technology, 2017, 46(3): 253-261.
[14] 许宁, 马家辉, 刘琦. CeO2基磨粒在化学机械抛光中的研究进展[J]. 中国稀土学报, 2022, 40(2): 181-193.
XU N, MA J H, LIU Q.Research Progress of CeO2-Based Abrasive Particles in Chemical Mechanical Polishing[J]. Journal of the Chinese Society of Rare Earths, 2022, 40(2): 181-193.
[15] XIAN W H, ZHANG B G, LIU S T, et al.The Mechanism of Ceria Slurry on Chemical Mechanical Polishing Efficiency and Surface Quality of Gallium Nitride[J]. Materials Science in Semiconductor Processing, 2025, 188: 109208.
[16] 程佳宝, 石芸慧, 牛新环, 等. CMP抛光液中SiO2磨料分散稳定性的研究进展[J]. 微纳电子技术, 2024, 61(2): 31-41.
CHENG J B, SHI Y H, NIU X H, et al.Research Progress on Dispersion Stability of SiO2 Abrasive in CMP Slurry[J]. Micronanoelectronic Technology, 2024, 61(2): 31-41.
[17] 朱玉广, 王子睿, 马服辉, 等. pH条件对铝合金化学机械抛光过程中纳米摩擦化学行为的影响[J]. 表面技术, 2025, 54(2): 173-181.
ZHU Y G, WANG Z R, MA F H, et al.Effect of pH on Nano-Tribochemical Behavior in Chemical Mechanical Polishing of Aluminum Alloy[J]. Surface Technology, 2025, 54(2): 173-181.
[18] 贾慧灵, 徐阳, 吴锦绣, 等. 制备条件对二氧化铈稀土抛光粉性能的影响[J]. 稀土, 2022, 43(4): 37-45.
JIA H L, XU Y, WU J X, et al.Effect of Preparation Conditions on the Properties of Cerium Oxide Polishing Powder[J]. Chinese Rare Earths, 2022, 43(4): 37-45.
[19] MA J H, XU N, HU J R, et al.Doping Strategy on Properties and Chemical Mechanical Polishing Performance of CeO2 Abrasives: A DFT Assisted Experimental Study[J]. Applied Surface Science, 2023, 623: 156997.
[20] 王旭, 李鑫, 邱名健, 等. 纳米CeO2磨料在化学机械抛光中的研究进展[J]. 有色金属材料与工程, 2025, 46(2): 1-8.
WANG X, LI X, QIU M J, et al.Research Progress on Nano-CeO2 Abrasive in Chemical Mechanical Polishing[J]. Nonferrous Metal Materials and Engineering, 2025, 46(2): 1-8.
[21] SEO J, KIM K, KANG H, et al.Perspective - Recent Advances and Thoughts on Ceria Particle Applications in Chemical Mechanical Planarization[J]. ECS Journal of Solid State Science and Technology, 2022, 11(8): 084003.
[22] 姜峰, 钱善华, 屈克松, 等. 不同粒径氧化铈磨料对K9玻璃化学机械平坦化性能的影响[J]. 中国表面工程, 2025, 38(5): 107-118.
JIANG F, QIAN S H, QU K S, et al.Effect of Cerium Oxide Abrasives with Different Particle Sizes on the Chemical Mechanical Planarization Performance of K9 Glass[J]. China Surface Engineering, 2025, 38(5): 107-118.
[23] MA J H, XU N, LUO Y X, et al.Enhancing the Polishing Efficiency of CeO2 Abrasives on the SiO2 Substrates by Improving the Ce3+ Concentration on Their Surface[J]. ACS Applied Electronic Materials, 2023, 5(1): 526-536.
[24] BRUGNOLI L, MIYATANI K, AKAJI M, et al.New Atomistic Insights on the Chemical Mechanical Polishing of Silica Glass with Ceria Nanoparticles[J]. Langmuir, 2023, 39(15): 5527-5541.
[25] FAN Y Y, JIAO J, ZHAO L, et al.Nd-Doped Porous CeO2 Abrasives for Chemical Mechanical Polishing of SiO2 Films[J]. Materials Science in Semiconductor Processing, 2024, 175: 108265.
[26] ZHANG Y S, LEI H, ZHANG J H, et al.Dual Impact of Nd3+ Doping on CeO2 Abrasives: Enhancing Chemical and Mechanical Effects in Chemical-Mechanical Polishing[J]. Surface Science and Technology, 2025, 3(1): 6.
[27] KIM K, YI D K, PAIK U.Increase in Ce3+Concentration of Ceria Nanoparticles for High Removal Rate of SiO2 in Chemical Mechanical Planarization[J]. ECS Journal of Solid State Science and Technology, 2017, 6(9): 681-685.
[28] ZHU C Z, WANG Y T, JIANG Z F, et al.CeO2 Nanocrystal-Modified Layered MoS2/g-C3N4 as 0D/2D Ternary Composite for Visible-Light Photocatalytic Hydrogen Evolution: Interfacial Consecutive Multi-Step Electron Transfer and Enhanced H2O Reactant Adsorption[J]. Applied Catalysis B: Environmental, 2019, 259: 118072.
[29] HANCOCK M L, YOKEL R A, BECK M J, et al.The Characterization of Purified Citrate-Coated Cerium Oxide Nanoparticles Prepared via Hydrothermal Synthesis[J]. Applied Surface Science, 2021, 535: 147681.
[30] KONG J J, XIANG Z W, LI G Y, et al.Introduce Oxygen Vacancies into CeO2 Catalyst for Enhanced Coke Resistance during Photothermocatalytic Oxidation of Typical VOCs[J]. Applied Catalysis B: Environmental, 2020, 269: 118755.
[31] JIANG F, WANG S S, LIU B, et al.Insights into the Influence of CeO2Crystal Facet on CO2Hydrogenation to Methanol over Pd/CeO2Catalysts[J]. ACS Catalysis, 2020, 10(19): 11493-11509.
[32] BARTH C, LAFFON C, OLBRICH R, et al.A Perfectly Stoichiometric and Flat CeO2(111) Surface on a Bulk-Like Ceria Film[J]. Scientific Reports, 2016, 6: 21165.
[33] YE J H, YU J X, HE H T, et al.Effect of Water on Wear of Phosphate Laser Glass and BK7 Glass[J]. Wear, 2017, 376: 393-402.
[34] VOSKRESENSKAYA O O, SKORIK N A.Thermodynamics of the Formation of Intermediate Complexes in the Oxidation of Citric Acid with Cerium(IV) and the Kinetics of Their Intramolecular Redox Decomposition[J]. Russian Journal of Physical Chemistry A, 2023, 97(4): 663-671.
[35] VOSKRESENSKAYA O O, SKORIK N A.The Kinetics of Cerium(IV) Sulfate Reaction with Citrate and the Thermodynamic Characteristics of Formation of Intermediate Complexes[J]. Russian Journal of Physical Chemistry A, 2009, 83(6): 945-950.
基金
国家自然科学基金（52265056）; 甘肃省自然科学基金青年科技基金（23JRRA776）; 兰州青年人才项目（2023-QN-38）; 温州市基础性公益科研项目（G20240035）
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