Investigation of material removal characteristics of Si (100) wafer during linear field atmospheric-pressure plasma etching

Atmospheric-pressure (AP) plasma etching provides an alternative method for mechanical grinding to realize wafer thinning of Si wafer. It can avoid the damages and micro-cracks that would be introduced by mechanical stress during the grinding process. In this study, the material removal characteristics of Si (100) wafer processed by linear field AP plasma generated using carbon tetrafluoride (CF₄) as the reactive source were analyzed. This linear field plasma etching tool has a typical removal profile and the depth removal rate that can reach up to 1.082 μm/min. The effect of O₂ concentration on the removal rate was discussed and the surface morphology during the process was characterized using scanning electron microscopy. It is shown that the subsurface damage layer was gradually removed during the etching process and the surface was observed to be smoothened with the increase of the etching depth. This present work contributes a basic understanding of the linear field AP plasma etching performance with different gas composition and the typical characteristics would be further applied to damage-free precision removal of Si.