深沟槽工艺产品晶片周边硅针缺陷的解决方法

Solution to Wafer Edge Silicon Grass Defect of Deep Trench Process

在功率金属氧化物半导体器件生产中,有些为了达到特殊的器件性能,采用深沟槽工艺,其沟槽深度可达几十微米,该类产品在关键的深沟槽刻蚀中,晶片边缘经常会有硅针缺陷产生,该缺陷在后续湿法清洗过程中,会成为颗粒的主要来源,影响晶片良率和污染湿法清洗机台。文章阐述了两种通过优化沟槽光刻工艺来解决此种缺陷的方法,一种为沟槽层光刻采用倒梯形工艺,另一种为沟槽层光刻采用负光阻工艺,两种方法旨在将晶片周边保护起来,在深沟槽刻蚀中下层材质不被损伤,解决深沟槽工艺产品周边硅针缺陷问题。

In power MOS microelectronic device design and manufacture,deep trench process is used for some special request.The trench depth reaches to scores of micrometer,some often in deep trench etch step,wafer edge generates silicon grass defect.It becomes the major particle resource during the post wet clean steps,which impact line yield and contaminate wet tools.The thesis states two solutions for this defect by optimizing trench-photo process,one is inverted trapezoid process,another is negative resist process,both solutions in lithography are aimed at wafer edge protection,when in deep trench etch step to protect the underground material from being damaged,and results to solve the wafer edge silicon grass defect of deep trench process.