Investigation on the control of silicon whisker generation during dichlorosilane-based WSi deposition process

Semiconductor industry faces a continuous challenge to increase the production yield by eliminating defect sources. The majority of the defect is caused by synthesized nano-materials in the process chamber. So analysis and removal of these nano-materials are important to prevent defect. In this paper, the prevention method of silicon whisker generation during dichlorosilane-based WSi ₂ deposition process has been studied by analysis and modification of equipment. First, silicon whiskers were formed to observe the shape, distribution, and composition at general dichlorosilane-based WSi ₂ deposition conditions. These distributed as a ring with a diameter between 0.2 μm and 2 μm on the graphite susceptor surface. Second, experiments according to gas flow rate, susceptor material, and susceptor structure were studied systematically to remove these silicon whiskers. Silicon whisker generation and transportation are defined as a major reason of wafer contamination in this study. And it has also been revealed that silicon whisker generation can be effectively controlled by an Aluminum Nitride coated susceptor with modified structure.