【作者】 张冰；

【导师】 赵继； 李志来；

【作者基本信息】 吉林大学 ， 机械工程（专业学位）， 2018， 硕士

【摘要】 随着国家汽车工业、电子信息、航空航天和军事等领域的不断发展,碳化硅材料由其优异性能得到广泛的应用。然而,碳化硅材料硬度高,脆性大,具有难加工的特性。化学机械抛光(CMP)针对硬脆性材料可以提高材料去除率,缩短产品的生产周期,同时基于“软磨硬”原理,使得抛光后工件具有较好的表面质量。因此,CMP获得各国研究学者的广泛关注。化学机械抛光技术包括化学作用和机械作用。因此,抛光过程中不仅需要考虑化学作用和机械作用单独作用效果,还要研究化学机械的协同作用效果。本文分别研究化学作用、机械作用及化学机械协同作用对碳化硅材料去除率的影响。本文主要研究工作如下:(1)研究化学改性机理。改性为利用化学试剂与工件表面层材料发生反应,来改变工件表面层机械性能。其中,改性层厚度和硬度会影响机械去除时磨粒去除深度,进而影响CMP的材料去除率。因此,为分析化学作用对改性层厚度的影响,基于表面扩散原理和氧化模型建立化学改性速率模型,获得改性速率先线性后抛物线变化规律。并进行过氧化氢改性碳化硅实验,研究分别改变时间、浓度和温度等参数时的改性层厚度。基于薄膜力学原理,对改性层进行纳米压痕实验,获得改性层硬度随压头压入深度变化曲线,与后期机械作用的磨粒压入工件深度建立联系,从而分析改性过程对材料去除率的影响。(2)研究机械作用去除机理。机械去除过程中,抛光垫和磨粒性质均会对工件材料去除产生影响。对抛光垫表面进行特征高度建模,对磨粒进行受力分析,研究抛光垫性质、磨粒粒径和法向压力对单颗磨粒压入工件深度的影响。建立上下抛光盘的相对速度模型,研究单颗磨粒去除体积模型。计算抛光去除过程中的瞬时有效磨粒数,将单颗磨粒去除深度按瞬时有效磨粒数进行累加,获得多颗磨粒材料去除深度,对其进行积分可得材料去除率。此模型不只预测压力和速度等工艺参数对材料去除的影响,还真实的反应了抛光过程中抛光垫表面廓形、抛光垫承载磨粒能力、磨粒粒径、磨粒体积比浓度以及工件表面硬度对材料去除的影响。通过改变抛光过程的压力和速度,对碳化硅材料进行去除实验,获得压力和转速对材料去除的影响,从而验证模型准确性。(3)材料去除仿真研究。单颗磨粒去除为材料去除的基础,本文采用ABAQUS软件对单颗磨粒作用的材料去除过程进行仿真。分别用残余应力、等效塑性应变(PEEQ)和剖面高度来描述抛光后工件表面强度、材料去除量和抛光后工件表面质量,获得了压力、转速、磨粒粒径和种类等因素对残余应力,PEEQ和剖面高度的影响。进行NiP抛光实验,获得压力、转速和粒径等参数对抛光后表面质量的影响,从而验证仿真的准确性。(4)化学机械协同作用实验。在化学和机械作用基础上,通过实验研究化学机械协同作用影响效果。改性过程可有效降低工件表面硬度,使得磨粒压入工件改性层的深度变大,导致材料去除率增加。研究改性层生成速率与单位时间内磨粒去除厚度的关系,探索在化学作用下,抛光去除层材料为改性层或碳化硅基体。通过实验研究磨粒性质、抛光液中离子添加剂种类、浓度和抛光液的化学性质等对材料去除率的影响。获得在最佳抛光压力和转速下,化学机械协同作用的最优抛光液组分。更多还原

【Abstract】 As the rapid and continuous development of national industries,especially the automobile,electronic information,aerospace and military filed.Si C material is deeply and widely used.However,it is quite hard,fragile and difficult to polish.Traditional polishing method shows low polishing efficiency,high cost and poor polishing roughness.Aimed at SiC material,CMP technology can promote polishing efficiency,shorten the production cycle and cut the cost.What’s more,CMP can get better polishing surface quality.CMP technology consists of ehemism and mechanism.Therefore,during polishing process,should consider not only chemical and mechanical separately,but also the synergistic effect of them.The main research contents in this dissertation are as follows:(1)Principle of chemical modification.Using hydrogen peroxide to modify the surface of SiC workpiece.Changing the material properties to promote mechanical removal rate.Based on the principle of surface diffusion and the oxidation model to establish the chemical reaction rate model.Getting the changing regulations and affecting factors of chemical reaction rate.Through the experiment to obtain the hardness and depth of modified layer.(2)Principle of mechanical removal.traditional Preston model considers effects of pressure and velocity,it shows no effects of abrasive particles,polishing pad and some other factors.Aimed at this problem,based on the properties of polishing pad,considering the removal depth model of single abrasive particle and active particles numbers.Combined with velocity,establish removal model of single particle.Then,whole material removal explained as a superposition of single particle removal.getting removal depth and profile of whole active abrasive particles act.then integrate this profile will get the material removal rate.This model can predict the influence of pressure and velocity on the material removal.also indicated the effects of abrasive particle,polishing pad.At the same time,considered the particle distortion and concentration makes the model reasonable.(3)It is important to verify the accuracy of single abrasive paticle removal.prefer using simulation to verify the accuracy rather than doing experiment because of the limitation of conditions.ABAQUS is choosen.Analyse the residual stress remained on surface after polishing can suggest the influence of polishing condition on the property of SiC.Analyse the PEEQ profile can suggest the influence of polishing condition on the material removal.analyse the section depth can suggest the influence of polishing condition on the surface roughness.Doing the experiment to verify the rules of surface roughness,and getting good consistency with the results of simulation.(4)Through experiment to obtain the effect of chemical and mechanical synergistic polishing.observed that removal rate on the modified layer obviously higher than SiC layer.And then analysing the influence of polishing slurry on the material removal rate,getting the optimized polishing condition.更多还原