背照式CMOS图像传感器中氧化铝薄膜的研究

Study on Aluminam Oxide Film in Back-Illuminated CMOS Image Sensor

为提高背照式图像传感器在减薄工艺后引入氧化铝钝化层的质量,从表面钝化及原子层淀积过程的原理分析出发,设计一套实验,详细考查了温度对薄膜形貌及均匀性的影响,验证反应物之一的三甲基铝的通入时间及生成物吹扫时间对薄膜表面粗糙度的改善效果,并对炉体不同区域形成薄膜的质量差异进行对比分析,总结其规律性。通过实验优化了工艺条件,在实际流片中得到了致密均匀的氧化铝薄膜,确保了器件的量产及可靠性。

In order to improve the quality of aluminum oxide passivation layer introduced into backilluminated image sensor after thinning process,based on analyzing the principle of surface passivation and Atomic Layer Deposition process,a set of experiments are designed.The effects of temperature on film morphology and uniformity are examined in detail,and the effect of introducing time of TMA as one of reactants and purging time of products on improving film surface roughness is verified.The quality differences of films formed in different areas of the equipment are compared and analyzed,and their regularity is summarized.Through experiments,the process conditions are optimized,and the dense and uniform alumina film is obtained in the actual tape out,which ensured the mass production and reliability of the device.