A New Technique for Monitoring Metallic Contamination During Aqueous Semiconductor Wafer Processing

水性半导体晶圆加工过程中监测金属污染的新技术

• 批准号: 9634058
• 负责人: Ian Suni
• 金额: $ 19.31万
• 依托单位: Clarkson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 2000-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9634058&HistoricalAwards=false
• 关键词: New; Technique; Monitoring; Metallic; Contamination

9634058 Suni As device and interconnect sizes continuously shrink, the microelectronics industry faces a number of serious technological challenges. One important challenge is to decrease the level of metallic contamination on wafer surfaces during processing. This is evidenced both by the tolerance limit of 1010 metal atoms/crn2 during fabrication of 16-MB dynamic random access memory(DRAM) and by the ability of metallic contaminants to short-circuit ultrathin((40() gate oxides . The level of contamination on the wafer surface is determined to a large extent by the tradeoff between deposition and dissolution of trace metallic impurities in aqueous chemical process solutions. This tradeoff involves a number of fundamental physical and chemical processes, including surface electroless reaction, bulk diffusion and convection. The potential sources, deposition mechanism(s) and transport of contaminants are still poorly understood despite their critical importance. Study of these problems has been hampered by analytical difficulties in measuring the level of surface contamination. We propose to develop a new in situ technique for indirect monitoring of metal contaminant deposition and dissolution in aqueous chemical process solutions. This employs spatially resolved absorption spectroscopy to detect concentration gradients in the boundary layer near the wafer surface with sensitivity limits in the ppb range. We will employ this technique to monitor the rate of Cu(( deposition from a buffered oxide etchant(BOE) and to monitor the rate of Cu dissolution in a standard chemical process solution SC-1. The experimental measurements will be complemented by computer modeling of metal contaminant deposition and dissolution during aqueous wafer processing using realistic process geometries. The proposed model will include diffusion, convection and electroless surface processes using time-dependent, three-dimensional finite difference solution of the governing momentum and mass transport equation s. Experimental determination of the rates of surface electroless processes and bulk transport are essential to correctly predict rates of metal contaminant deposition and dissolution. Besides potential applications as an in situ sensor, the experimental technique can be employed in a variety of studies of the fundamental physical and chemical processes occurring during metal contaminant deposition and dissolution. By illuminating the surface with ultraviolet light and controlling the surface electrochemically, the potential at which deposition is initiated can be measured. This will allow determination of the applicability of the Nernst equation to the prediction of metal contaminant deposition by electroless processes. ***

9634058 Suni随着设备和互连尺寸不断缩小，微电子行业面临着一些严重的技术挑战。 一个重要的挑战是在处理期间降低晶片表面上的金属污染水平。 在16-MB动态随机存取存储器（DRAM）的制造过程中，1010个金属原子/cm 2的容限和金属污染物使半导体（40）栅极氧化物短路的能力都证明了这一点。晶片表面上的污染水平在很大程度上取决于痕量金属杂质在含水化学工艺溶液中的沉积和溶解之间的权衡。 这种折衷涉及许多基本的物理和化学过程，包括表面无电反应、体扩散和对流。 尽管污染物的潜在来源、沉积机制和迁移至关重要，但对它们的了解仍然很少。 对这些问题的研究一直受到测量表面污染水平的分析困难的阻碍。 我们建议开发一种新的原位技术，间接监测金属污染物的沉积和溶解在水化学工艺解决方案。 这采用了空间分辨吸收光谱法来检测在晶片表面附近的边界层中的浓度梯度，灵敏度限制在ppb范围内。 我们将采用这种技术来监测铜（从缓冲氧化物蚀刻剂（BOE）的沉积速率，并监测铜在标准化学工艺溶液SC-1中的溶解速率。 实验测量结果将通过计算机模拟的金属污染物的沉积和溶解过程中使用现实的工艺几何水处理晶片。 所提出的模型将包括扩散，对流和无电表面过程中使用的时间依赖性，三维有限差分解决方案的控制动量和质量传输方程。 实验测定的表面无电过程和散装运输的速率是必不可少的，以正确地预测金属污染物的沉积和溶解速率。 除了作为原位传感器的潜在应用外，该实验技术还可用于金属污染物沉积和溶解过程中发生的基本物理和化学过程的各种研究。 通过用紫外光照射表面并以电化学方式控制表面，可以测量沉积开始时的电位。 这将允许确定能斯特方程的适用性，以预测金属污染物沉积的无电工艺。 ***