新型抛光后晶片表面金属离子清洗工艺

本文提出了一种新型的利用金刚石膜电极电化学氧化进行抛光后晶片金属离子污染的清洗方法。金刚石膜电极电化学氧化，可以制备氧化性强的过氧焦磷酸盐，过氧焦磷酸盐可以有效的氧化表面有机物，同时过氧焦磷酸盐被还原成的焦磷酸盐具有很强的配合力，它能与铜等金属离子络合。将三块晶片在0.01mol/L的CuSO4溶液中进行金属离子污染后进行清洗对比实验。对比实验有三部分，一是采用金刚石膜电化学氧化制备的过氧焦磷酸盐进行清洗，二是传统的RCA清洗方法，三是去离子水清洗。XPS测试结果表明，过氧焦磷酸盐清洗与RCA清洗方法对金属离子的去除效果均小于ppm级。过氧焦磷酸盐清洗对有机物的清洗效果优于传统的RCA清洗方法。因此金刚石膜电化学氧化清洗方法可以有效去除有机污染以及金属离子污染，实现了一剂多用，减少清洗步骤，达到节能环保的目的。

A new cleaning process for the metallic contaminants on a post-CMP wafer's surface

This paper presents a new cleaning process using boron-doped diamond (BDD) film anode electrochemical oxidation for metallic contaminants on polished silicon wafer surfaces. The BDD film anode electrochemical oxidation can efficiently prepare pyrophosphate peroxide, pyrophosphate peroxide can oxidize organic contaminants, and pyrophosphate peroxide is deoxidized into pyrophosphate. Pyrophosphate, a good complexing agent, can form a metal complex, which is a structure consisting of a copper ion, bonded to a surrounding array of two pyrophosphate anions. Three polished wafers were immersed in the 0.01 mol/L CuSO₄ solution for 2 h in order to make comparative experiments. The first one was cleaned by pyrophosphate peroxide, the second by RCA (Radio Corporation of America) cleaning, and the third by deionized (DI) water. The XPS measurement result shows that the metallic contaminants on wafers cleaned by the RCA method and by pyrophosphate peroxide is less than the XPS detection limits of 1 ppm. And the wafer's surface cleaned by pyrophosphate peroxide is more efficient in removing organic carbon residues than RCA cleaning. Therefore, BDD film anode electrochemical oxidation can be used for microelectronics cleaning, and it can effectively remove organic contaminants and metallic contaminants in one step. It also achieves energy saving and environmental protection.