Research on Abrasive Free Electrochemical Mechanical Polishing (AF-ECMP) Process of Copper Film
碩士 === 國立臺灣科技大學 === 機械工程系 === 97 === Chemical mechanical planarization (CMP) process is an important technology to achieve overall planarization in integrated circuit (IC) fabrication process. However, there are some problems including residual stress, scratch and post CMP-cleaning in the manufactur...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2009
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| Online Access: | http://ndltd.ncl.edu.tw/handle/62857437638010261147 |
| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 97 === Chemical mechanical planarization (CMP) process is an important technology to achieve overall planarization in integrated circuit (IC) fabrication process. However, there are some problems including residual stress, scratch and post CMP-cleaning in the manufacturing of multi-layer interconnect that containing copper metal and low-k dielectric should be solved. The electrochemical mechanical polishing (ECMP) has been proposed and it can be controlled with current control and voltage control. In this study, an abrasive free electrochemical mechanical polishing system (AF-ECMP) has been developed with voltage control mode. The potentiodynamic polarization curve (PD Curve) has been measured by potentiodynamic scan and X-ray photoelectron spectroscope is used to analyze the oxide layer on copper surface after different electrolyte (KOH based and H3PO4 based) and difference bias voltage. It shows the material removal rate (MRR) in H3PO4 based electrolyte is higher than that in KOH base electrolyte because the existence of copper oxide (Cu2O). The MRR is calculated based on the Faraday’s law as the workpiece contacts or noncontacts with pad. The MRR is observed to be very low when the workpiece noncontacts with pad. The surface roughness Ra of copper film is 1.274 nm measured by atomic force microscopy (AFM) after AF-ECMP process. Moreover the residual stress of copper film after Cu-CMP and AF-ECMP process have been investigated and the residual stress of copper film after AF-ECMP process with politex pad is lower than that of Cu-CMP. Future study can focus on the effects of pad design and slurry for AF-ECMP of copper film.
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