新型碱性抛光液各组分对铜化学机械平坦化性能的影响

随着集成电路特征尺寸的减小、晶圆尺寸的增大以及布线层的逐渐增多,加工晶圆过程中实现较高的材料去除速率、较小的片内非一致性(WIWNU)及较小的表面粗糙度已经成为铜化学机械抛光工艺的几大难点.采用正交实验法选取5组抛光液进行Cu CMP实验,系统研究了含有双氧水、脂肪醇聚氧乙烯醚(AEO)、FA/O Ⅰ型螯合剂与苯骈三氮唑(BTA)的碱性抛光液化学组分对铜去除速率、WIWNU的影响,并对铜CMP的各种变化规律做出机理分析.结果表明:采用pH值约为8.6,体积分数为3％的H202,质量分数为0.08％的非离子表面活性剂AEO与体积分数为1.5％的螯合剂的碱性抛光液,在12英寸(1英寸=2.54 cm)铜镀膜片抛光后有助于去除速率达到629.1 nm/min,片内非一致性达到4.7％,粗糙度达到1.88 nm.

Effect of Components of Novel Alkaline Slurry on Performance of Copper Chemical Mechanical Planarization

As integrated circuit feature size decreases,wafer size increases and wiring layers increase gradually,higher material removal rate,smaller within-wafer non-uniformity (WIWNU) and less surface roughness on the polished wafer have become major difficulties in copper mechanical polishing (CMP) process.Five groups of polishing solutions were selected for copper CMP experiment by orthogonal experiment method.The effects of chemical composition of the alkaline polishing solution containing hydrogen peroxide (H2O2),nonionic surfactant fatty alcohol polyoxyethylene ether (AEO),FA/OⅠchelating agent and inhibitor benzotriazole (BTA) on copper removal rate and WIWNU were systemically studied.The mechanism of various changes of c.opper CMP was analyzed.The results show that after polishing by the alkaline polishing solution with the pH value of 8.6,the H2O2 volume fraction of 3％,the AEO mass fraction of 0.08％ and the chelating agent volume fraction of 1.5％,the 12 inches (1 inch =2.54 cm) copper coating film wafer achieves a removal rate of 629.1 nm/min,WIWNU of 4.7％ and roughness of 1.88 nm.