| Summary: | 碩士 === 國立交通大學 === 工學院半導體材料與製程設備學程 === 100 === This thesis studied the delamination failure of the interface of polyimide with the underfiller layerand other neighboring layers in Flip Chip IC assembly. We first studied process factors affecting the interface property of the polyimide and performed surface treatment for the polyimide to improve the interfacial quality. We also carried out the bump integration process to investigate the correlation of various assembly process stages with the delamination failure and to improve the process yield. We performed reliabity tests after the assembly process to verify the feasibility of the adopted process modifications. In this study, C-mode scanning acoustic microscope (C-SAM) and scanning electron microscope(SEM) were used to study the interface falure between the polyimide and neighboring layers.
From the study, we found that, after the nitrogen plasma bombardment on thesurface of the polyimide, the best obtained adhesion strength of the polyimide with the Ti/Cu under-bump-metal (UBM) layer was about 72 Mpa with a satisfactory electrical resistance. The polyimide treated with the N2 plasma bombardment was much less liable to delaminaiton failure as compred with other plasma processes.Moreover, integration of the plasma treatment with other processes, such as UBM etching and PI surface cleaning, could significantly reduce metal residues on the polyimide surface. As a result,metal bridge, solder extrusion deformation and polyimide interface delamination were greatly alleviated, and electrical reliability was improved.
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