鑽石修整器參數最佳化對化學機械研磨墊之改善

Abstract

化學機械研磨主要是用來研磨晶圓薄膜的製程，當晶圓經過薄膜製 成後，表面厚度的平整性無法達到全面性的均勻，所以利用化學機械 研磨製程，可以改善晶圓薄膜的均勻性，有利於下一次薄膜的成長。 研磨墊會隨著研磨過程慢慢地被消耗掉。透過鑽石碟刮除研磨墊 劣化區域，可以再生並活化研磨墊表面的孔洞，因此如何在相同的鑽 石碟下，利用研磨機台控制鑽石碟的程式( Pad Condition Recipe) ， 來達成研磨墊最佳的平坦化，並觀察研磨墊表面多孔性的分佈行為。 此實驗主要是探討在不同的鑽石碟模擬方程式下，藉由得到最平坦 化的研磨墊耗損量，並且比較與鑽石碟模擬方程式的結果是否一致， 並且驗證晶圓移除率、移除率波形範圍以及移除率均勻性之比較，和 晶圓缺陷的相關性。 本實驗總共有四個對照組來比較，分別將研磨墊分成十三個區域來 表示，根據鑽石碟模擬方程式在各個不同區域的停留時間，比較各個 區域間，研磨墊耗損量的多寡，藉由不同的耗損量可以得到不同的晶 圓研磨結果，透過結果的證明，可以得到鑽石碟模擬方程式是否與實 驗結果一致。最終實驗結果顯示，當鑽石碟對研磨墊十三個區域的耗 損量愈一致性，可以得到最佳化的晶圓研磨結果和製程的穩定性

Chemical mechanical polishing (CMP) is an integrated circuit fabrication process for smoothing a solid surface using the combination of chemical and mechanical erosion methods. CMP can improve the uniformity of thin films for better control of subsequent processes. The polishing pad will degrade over time in CMP operations and requires continuing conditioning during the CMP process. To regenerate the surface condition of the polishing pad, a diamond disk are used to continuously remove debris left on the surface of the polishing pad and to reactivate pores of the pad. The diamond disk requires an optimized pad condition receipt (PCR) to achieve the desired conditioning quality of the polishing pad. The study focuses the dependence of CMP processes on the optimization of PCR. The success of a PCR is evaluated by the quality of Si wafers under the CMP operation and the polishing pad in terms of the removal rate of the polished material and the defect distribution on the wafers. Four PCRs were designed for the study, in which the polishing pad were evenly divided into 13 areas. The optimized PCR is determined by the dependence of the consumption of the polishing pad and the quality of the polished wafer on the moving course and the duration time of the diamond disk in each divided areas. The study demonstrates that satisfactory silicon polishing performance is achieved when the individual divided areas of the 3

polishing pad are uniformly consumed by the diamond disk conditioning.