化學機械研磨製程之控片與樣片之移除率及不平坦度預測與分析

Abstract

化學機械研磨(Chemical-Mechanical Polish, CMP)是一個極為複雜的製程，其中包括物理、化學及機械的研究領域[1]；而其研磨的過程，主要是靠機械手臂上的晶圓載具吸起晶圓置於研磨墊上，同時旋轉晶圓載具的吸盤及研磨墊來研磨晶圓。在研磨的過程中，研磨墊會因為研磨晶圓而不斷的耗損；當研磨墊耗損到一定程度的時候，就必須手動使用刷子刷研磨墊，恢復研磨墊的摩擦率；或更換新的研磨墊，使晶圓的移除率維持在一定的標準內。 目前的晶圓廠測試研磨墊的磨擦率的方法，大致為：在研磨過數千至數萬片的樣片(pattern wafer)之後，研磨一片控片(blanket wafer)，並觀察控片的移除率，來確定研磨墊的摩擦率是否過低。 本實驗是以控片的移除率(Material Remove Rate)及不平坦度(Non-Planarization Index)的模型(Model)為基礎模型，再以最小平方法(The Least Square Method)，來求出NDL常用的樣片的移除率及不平坦度的模型，使可以在用同樣的條件進行研磨的時候，以控片的移除率及不平坦度，推得樣片的移除率及不平坦度；或反之，以樣片的移除率及不平坦度，推得控片的移除率及不平坦度，進而達到節省控片使用之目的。

Chemical-Mechanical Polish is an extremely complicated process because it involves physical, chemical, and mechanical field [1].And the process of polishing is using carrier on the mechanical arm to get wafers. Then Carrier put the wafer on the pad, and polish wafer with turning itself and pad. With this process, pad could be fewer, because of polishing wafers. When the frictional forces of the pad is too low, we have conditioning the pad or changing another new pad. Nowadays, when many factories want to check the pad, always after polishing thousands of pattern wafers then polish one blanket wafer. And check blanket wafer to make shore that the frictional forces of the pad is ok or not. This experiment is used the model of the material remove rate and the non-planarization index of the blanket wafer to predict the model of the material remove rate and the non-planarization index of the pattern wafer. Then we can use the material remove rate and the non-planarization index of the pattern wafer to predict the material remove rate and the non-planarization index of the blanket wafer, and check the frictional forces of the pad is ok or not. And then we can reduce the wasting of the blanket wafer.