阻挡层浆料特性对CMP后清洗效力的影响

摘要

铜化学机械平面化不同阻挡层浆料的应用引起了铜CMP后清洗的问题.阻挡层浆料的差异包含但不限于pH、研磨剂粒子材料和尺寸及铜腐蚀的抑制剂.为观察阻挡层浆料对清洗工艺的影响进行了清洗实验.阻挡层浆料不同于pH和所有作为铜抑制剂的BTA材料.抑制性BTA溶液的pH值将确定BTA与铜复合物的特性和随后在清洗工艺中去除这种膜的条件.因此,为了研究pH、化学成份以及阻挡层浆料留在铜表面的BTA与铜的复合物去除的化学程序的影响而改变了清洗工艺.从而发现阻挡层浆料的pH值对各种清洗设备的效力均有影响,而且,某些添加剂和两步化学清洗工艺的使用,改进了可变pH值阻挡层浆料的清洗性能.这种工作的结果表明,在最佳结果中,清洗工艺应该致力于阻挡层浆料方面.%The use of different barrier slurries for copper chemical mechanical planarization (CMP) creates a challenge for post-CMP cleaning. Differences in barrier slurries include, but are not limited to, pH, the abrasive particle material and size, and copper corrosion inhibitor(s). Cleaning tests were conducted to observe the interaction between the barrier slurry and the cleaning process. The barrier slurries differed in pH and all contained benzotriazole (BTA) as a copper inhibitor. The pH of a solution containing BTA will detemine the properties of the BTA-Cu complex and the subsequent conditions for removing this film in the cleaning process. Therefore, the cleaning process was varied to study the effect of pH, chemical components, and chemical sequence on the removal of the BTA-Cu complexes left by the barrier slurry on copper surfaces. It was found that the pH of the barrier slurry did affect the efficacy of various cleaners.Also, the use of certain additives and 2-step chemical cleaning improved cleaning performance on barrier slurries of varying pH. The results of this work indicate that, for optimum results, the cleaning process should be tuned to the barrier slurry.