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采用低介电常数材料(低k介质)作为Cu布线中的介质层,已经成为集成电路技术发展的必然趋势。由于低k介质的低耐压性,加工的机械强度必须降低,这对传统化学机械抛光(CMP)工艺提出了挑战。通过对CMP过程的机理分析,提出了影响低机械强度下Cu布线CMP速率的主要因素,详细分析了CMP过程中磨料体积分数、氧化剂体积分数、FA/O螯合剂体积分数等参数对去除速率的影响。在4.33 kPa的低压下通过实验得出,在磨料体积分数为20%,氧化剂体积分数为3%,FA/O螯合剂体积分数为1.5%时可以获得最佳的去除速率及良好的速率一致性。
The use of low dielectric constant material (low-k dielectric) as the dielectric layer in Cu wiring has become an inevitable trend in the development of integrated circuit technology. Due to the low pressure resistance of low-k dielectrics, the mechanical strength of the process must be reduced, which poses challenges to traditional chemical mechanical polishing (CMP) processes. Based on the mechanism analysis of CMP process, the main factors affecting the CMP rate of Cu wiring under low mechanical strength were proposed. The effects of abrasive volume fraction, oxidant volume fraction and FA / O chelating agent volume fraction on the removal rate influences. At a low pressure of 4.33 kPa, it was experimentally found that the best removal rate and good rate consistency were obtained with an abrasive volume fraction of 20%, an oxidizer volume fraction of 3% and a FA / O chelator volume fraction of 1.5% .