| Summary: | 碩士 === 國立交通大學 === 電機資訊國際學程 === 105 === 3D integrated circuit (IC) is recognized as one of the promising approach in keeping up with Moore’s law in the semiconductor field. Some of the key technologies of the approach include bonding, through silicon via (TSV), thinning and handling. The focused key technology in this thesis is polymer-metal hybrid bonding, a bonding approach to achieve electrical connection and structural enhancement simultaneously. In this thesis, polyimide is used for polymer bonding while Cu and Sn are used for metal bonding. Since hybrid bonding is often carried out on top of a passivation layer, to ensure the success of hybrid bonding, the adhesion of the materials used respective to the passivation layer is important. Thus the first research topic aims to study on the adhesion strength of polyimide against various possible passivation layers. The respective adhesion strengths are quantified using the Four Point Bending system (4PB).
On the other hand, to ensure the success of hybrid bonding, low temperature metal bonding is always preferred. Copper-tin (Cu-Sn) metal bonding has recently been widely researched on because of its low bonding temperature requirement. However, the disadvantage of direct Cu-Sn bonding is the formation of intermetallic compound (IMC) thus an ultra-thin buffer layer (UBL) is required in between the Cu and Sn layer to delay or prevent the IMC formation. The UBL material researched in this thesis is Cobalt (Co) since Co has recently been widely used as a wetting layer for the TSV process thus this research is conducted with the aim to identify the possibility of utilizing Co as the UBL. A comparison between Cu-Sn with and without UBL is conducted. It is found that 10nm Co is capable of improving the Cu-Sn bonding quality.
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