硅晶片表面污染物去除的关键工艺

硅晶片的清洗通常是在一个“过流(overflow)”清洗槽中进行,其中流过晶片的水流平均速度为1cm蛐s,而在晶片表面的速度则为零。清洗效率受到污染物从硅片表面扩散出并进入到水流速率的限制。报告了清洗效率的提高熏通过对初次将污染物扩散进停滞层的1min循环进行重复,然后“倾倒”清洗槽,从而去除大部分污染的停滞层。通过旋转晶片,并利用离心力去除更大部分的停滞层,每个清洗循环可将清洗效率再提高10倍眼1演。与目前的浸泡式清洗技术相比,本方法可以完全去除可溶性污染物,而使用的水量降低20倍。

Rinsing:A Critical Process in Contamination Removal

The rinsing process of silicon wafers is normally carried out in an ″overflow″ bath in which water flows past the wafers at average velocity of 1 cm/s. But the velocity is zero at the wafer surface. The efficiency of rinsing is limited by the rate at which contaminants diffuse away from the silicon surface, and into the flow stream. This paper reports the improvement in rinsing efficiency gained by repeating a one-minute cycle of first allowing the contaminants to diffuse into the stagnant layer and then ″dumping″ the rinse tank to remove most of the contaminated stagnant layer. A further 10 fold improvment in rinsing efficiency per rinse cycle can be achieved by spinning the wafer and using centrifugal force to remove a greater fraction of the stagnant layer (1). This allows the complete removal of soluble contaminants with a 20 fold reduction in water usage compared to present immersion techniques.