大面阵内线转移CCD二次金属铝刻蚀残留研究

Study on Etching Residue of the Second-layer Al in Large Array Interline Transfer CCD

分析了引起大面阵内线转移CCD直流短路的原因,确认了二次金属铝刻蚀残留是引起器件失效的主要原因。利用扫描电子显微镜技术,研究了刻蚀工艺参数对内线转移CCD二次金属铝刻蚀残留的影响。优化了预刻蚀、主刻蚀和过刻蚀三个阶段的工艺条件,消除了金属铝刻蚀残留。采用优化的工艺参数进行二次金属铝刻蚀,器件直流成品率提高了30%。

The cause of the DC short-circuit of the large array interline transfer CCD is analyzed in this paper,and confirms that the etching residues of the second-layer Al are the main cause of the device failure.The scanning electron microscopy（SEM）is used to investigate the influence of etching process parameters on the etching residue of the second-layer Al in interline transfer CCD.The process conditions of pre etching,primary etching and over etching are optimized,and the etching residue of metal aluminum is eliminated in the three stages.With the optimized process parameters,the second-layer Al etching is carried ou,and the DC yield of the device is increased by 30%.