大直径硅单晶的制备与数值分析

发布时间：2018-01-30 07:41

本文关键词： 硅单晶直拉法大直径晶体生长数值分析传热传质热场　出处：《北京有色金属研究总院》2017年博士论文　论文类型：学位论文

【摘要】：大直径硅单晶是微电子工业的基础材料,广泛应用于集成电路备件和硅片制造领域,是现今信息社会的基石。根据国际半导体设备材料产业协会(SEMI)的报告,全球大直径硅单晶的需求依然旺盛,450mm硅单晶要继续开发研究。当前主流集成电路设备用部件急需400mm硅单晶并提出低成本的要求,开发400mm硅单晶和研究晶体制备的工艺过程,无疑具有重要的理论意义和现实需求。同时,开发下一代450mm集成电路用硅晶体、研究外加磁场对改善晶体质量的作用,对于我国未来制造450mm硅片具有重要的战略意义。本文从晶体生长物理基础和流体力学的基本理论出发,结合硅单晶制备过程中热质输运的分析,采用实验和数值分析相结合的方法,以大直径硅单晶制备为主要研究对象,研究热场结构、控制参数和外加磁场对大直径硅单晶生长的影响。通过数值分析的手段,研究了结构参数和控制参数对晶体生长特性的影响,确定了晶体制备的工艺条件;采用28inch和32inch热场制备出400mm和450mm无位错硅单晶;通过分析单晶样片的电学性质和化学成分,研究了晶体的生长特性及晶体生长的影响因素。具体如下:(1)利用数值分析技术研究了热屏对晶体生长的影响。结果表明,直壁式热屏在降低晶体内应力和熔体中氧含量方面具有一定的优势,但直壁式热屏的使用会极大增加熔体边缘区域过冷的风险,在后续的计算和实验中均使用斜壁式热屏。此外,计算了液面位置对晶体生长的影响。结果表明,随着液面位置的升高,晶体内热应力增加,固液界面更加凸向熔体,界面上的v/G比值略有下降。(2)利用数值分析技术研究了控制参数(提拉速率、氩气流量、晶体转速和坩埚转速)对晶体制备的影响。拉速的变化将改变炉体内的温场分布和加热器功率。加热器功率的下降不仅是因为结晶潜热释放的增加,还与固液界面上的热平衡及三相点的温度有关。氩气流量的变化直接影响晶体内的温度分布以及熔体内的氧含量。晶体转速和坩埚转速的变化直接影响熔体内流场和温场的分布,精确控制晶体转速和坩埚转速的比值可以在晶体生长的各个阶段获得平坦的固液界面。(3)应用优化过的热场和工艺控制参数进行了晶体制备实验并进行氧、电阻率、微缺陷类型的测试。结果表明,利用28inch热场可制备400mm直径,轻掺硼,100硅单晶。该热场的采用不仅可以节约能源消耗,而且降低硅单晶制备成本。氧含量径向分布的实验值与计算值的变化趋势能很好地吻合,为进一步优化热场结构及控制参数指明方向。缺陷分析测试表明,晶体中未发现氧化诱生层错;通过FPDs及铜坠饰实验结果表明晶体内部为富空位型缺陷。(4)利用32inch热场和磁场拉晶工艺制备出450mm无位错单晶。整根硅单晶电阻率与预期值相符,晶体的生长过程完全可控。通过对比分析不同磁场条件下硅单晶内氧含量的实验值,在等径末期磁场对降低晶体内氧含量的作用更加明显。进一步计算了磁场强度和等高斯面的位置对晶体生长的影响,随着磁场强度的增加,熔体湍流程度大幅度降低,但当磁场强度超过500Gs后,磁场强度对熔体对流抑制作用的边际效应开始体现出来,需要平衡磁场拉晶的效果与能耗之间的关系。在磁场强度增加到1OOOGs的过程中,熔体中氧含量的最小值下降了 27.4%,固液界面上氧浓度的平均值下降了 25%,固液界面上氧含量的径向均匀性提高了 35%。等高斯面的位置对熔体中的温场、流场和浓度场影响较小,等高斯面在熔体自由液面上方时固液界面上氧含量及其径向均匀性都达到最佳值。
[Abstract]:Large diameter silicon single crystal material is the foundation of the microelectronics industry, widely used in integrated circuit parts and wafer manufacturing field, is the cornerstone of today's information society. According to the international semiconductor equipment and Materials Industry Association (SEMI) report, the global large diameter silicon single crystals are in high demand, continued research and development of 450mm single crystal silicon integrated circuit to the mainstream. Urgent need for components of 400mm silicon crystal and put forward the requirements of low cost, process development and research of 400mm silicon crystal crystal preparation, undoubtedly has important theoretical significance and realistic demand. At the same time, the development of next generation 450mm integrated circuit silicon crystal, study the effect of magnetic field to improve the quality of the crystal, which has a strategic significance for the the manufacturing of 450mm chip in our country in the future. The basic theory of growth physics and fluid mechanics from the crystal, the preparation process of combined heat and mass transport in silicon single crystal The analysis, by means of experiment and numerical analysis are combined, with large diameter silicon single crystal preparation as the main research object, research on thermal field structure, effect of control parameters and external magnetic field on the growth of large diameter silicon single crystal. By the means of numerical analysis, the influence of structural parameters and control parameters on the crystal growth characteristics the process conditions of crystal preparation, determination of 28Inch and 32inch; the thermal field of prepared 400mm and 450mm dislocation free silicon single crystal; the electrical properties and chemical composition analysis of single crystal samples, the crystal growth characteristics and the effects of growth factors. The details are as follows: (1) studied the effect of heat on the screen the crystal growth by using numerical analysis technology. The results show that the straight wall heat shield has certain advantages in reducing the oxygen content in the melt and crystal stress, but the use of straight wall heat shield will greatly increase the edge weld area The risk is too cold, use inclined wall heat shield in calculation and subsequent experiments. In addition, effects of surface position on crystal growth were calculated. The results show that with increasing the liquid level, the heat stress increases, the solid-liquid interface is more convex to melt, the ratio of v/G on the interface (2) decreased slightly. Study on the technical analysis by numerical control parameters (pull rate, argon flow rate, crystal and crucible rotation speed) influence on the crystal preparation. The change of casting speed will change the temperature distribution inside the furnace and heater power. The power of the heater is not only decreased because of the increased latent heat release, and heat balance on the solid-liquid interface and the triple point temperature. Direct effects of temperature distribution inside the crystal and melt in the oxygen argon flow. The rotation of crystal and crucible rotation speed changes directly affect the distribution of flow field and temperature field in the melt, fine The ratio accurately control the rotate of crystal and crucible can obtain flat solid-liquid interface in various stages of crystal growth. (3) thermal field and process parameters are optimized for the application of crystal preparation experiment and oxygen, resistivity, test micro defect types. The results show that the diameter of 400mm can be prepared using the 28Inch light field, boron doped silicon crystal, 100. The thermal field can not only save energy consumption, but also reduce the cost of preparation of single crystal silicon. The oxygen content of the radial distribution of experimental values and the calculated values of the trend are in good agreement, to further optimize the thermal structure and control parameters of defect analysis tests show that the direction., OSFs was not found in the crystal by FPDs; and the experimental results show that the crystal pendant copper rich vacancy type defects. (4) using 32inch thermal field and magnetic field pulling technology to prepare 450mm dislocation free single crystal silicon single whole. The crystal resistivity is consistent with the expected value, fully controllable crystal growth process. Through the comparative analysis of the oxygen content of silicon in different magnetic field conditions, etc. in the end diameter magnetic field on reducing the oxygen content in the crystal effect more obvious. Further calculation of magnetic field intensity and the position of the Gauss effect on crystal growth, with the increase of the magnetic field strength, melt turbulence is greatly reduced, but when the field strength exceeds 500Gs, the magnetic field strength to reflect marginal effect on the inhibition of melt convection between the magnetic field and the effect of pulling the need to balance the energy consumption between. Increased to 1OOOGs in the process of magnetic field strength, the minimum value of the oxygen content in melt down 27.4%, on the solid-liquid interface the average oxygen concentration decreased by 25%, the radial oxygen content on the solid-liquid interface uniformity improves the position of Gauss 35%. in the melt temperature The field, the flow field and the concentration field have little influence, and the oxygen content and the radial uniformity at the solid liquid interface of the Gauss surface all reach the best value when the melt surface is above the melt surface.

【学位授予单位】：北京有色金属研究总院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TN304.12

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