CMP浆料SiO_2水溶胶纯化稳定性技术的研究

Research of CMP Slurry Silica Sol Purification Stability Technology

介绍了CMP浆料SiO2水溶胶的Na+含量过高对集成电路可靠性的影响,讨论了硅溶胶纯化制备过程中容易凝胶的不稳定现象。中试实验中,采用阳离子交换的方法,去除Na+等金属离子。改变SiO2水溶胶pH值,测量其Zeta电位,得到最稳定SiO2水溶胶pH值在10左右。分析一次阳离子交换和两次阳离子交换过程,得到Na+浓度、pH值和Zeta电位变化规律。加入有机碱调节pH值,并起到螯合金属离子的作用。最后得到Na+浓度为1×10-6～2×10-6 mol/L、pH值在10～10.5、Zeta电位在-40～-45 mV的稳定碱性硅溶胶。为碱性CMP浆料SiO2水溶胶工业化纯化制备生产提供了理论依据。

The effect of the high concentration of Na＋ in the CMP colloidal silica sol on the relia- bility of IC was introduced, and the instability phenomenon of the gel during the silicon sol purifi- cation preparation process was discussed. In pilot test, the Na＊ metal ions were removed by the method of cationic exchange. After changing the pH value of the silicon sol and measuring the Zeta potential, the most stable pH value of about to for the silica sol was achieved. The change rules of the Na＋ concentration, pH value and Zeta potential were obtained through analyzing the process of the first cationic exchange and the second cationic exchange. The organic base was added to adjust the pH value, and played the role of chelating metal ions. Finally, the conclu- sions show that the concentration of Na＋ is l ×10^-6 - 2 ×10^-6 mol/L, while the pH value is 10- 10.5 and the Zeta potential is from - 40 to 45 mV in a stable alkaline silicon sol. The theory basis is provided for the industrial purification preparation process of the CMP colloidal silica sol.