高分子奈米顆粒應用於晶圓平坦化技術之缺陷改善及研磨拋光材料移除速率趨勢

Abstract

化學機械研磨拋光製程技術（Chemical Mechanical Polishing, CMP）是一種濕式的晶圓表面拋光平坦化技術，該技術結合了化學和機械力的作用，使矽晶圓上的沈積成長材料及半導體材料完全平坦化，使晶圓表面上之積體電路(Integrated Circuit, IC)的微電子元件產生更高更好的堆疊密集化。達到實現具有奈米尺寸、缺陷少、晶圓良率好的元件對於積體電路晶圓製造商提高利潤和提高競爭力至關重要。化學機械研磨拋光(CMP)技術用於生產許多IC世代的奈米尺寸生產節點(generation node)，在更窄的線寬，以獲得更好的性能和製造可行性。研磨拋光漿料(Slurry)是化學機械研磨拋光過程中的重要原料。在研磨拋光漿料之中，最關鍵的成分是研磨拋光顆粒，而研磨拋光顆粒是研磨拋光過程中產生機械力的來源。它會影響晶圓表面材料的移除速率、非均勻性、缺陷種類及數量和材料移除速率的選擇比。傳統的研磨拋光顆粒是由膠體型二氧化矽，燒結型二氧化矽或其他無機型奈米顆粒所組成。我們首先系統地研究了應用於化學機械研磨拋光漿料中使用聚合物類型的奈米顆粒，並在拋光性能方面比較了傳統的無機和聚合物奈米顆粒。我們亦進行研究聚合物奈米顆粒的尺寸大小、顆粒形狀、顆粒固含量比例和高分子共聚物的不同類型，並根據研磨拋光材料移除速率、總缺陷數和非均勻性來評估其平坦化研磨效果，發現聚合物奈米顆粒顯著改善了總缺陷數和非均勻性。儘管高分子型奈米顆粒研磨拋光材料移除速率低於使用無機奈米顆粒的研磨拋光材料移除速率，然而，聚合物奈米顆粒的較低研磨速率是可以接受的，因為用於更小的製造世代在低於10nm以下的線寬，其製程沈積成長的薄膜材料更薄更小。從數據結果發現，聚合物奈米顆粒的物理性質，就其尺寸，形狀和不同類型的共聚物高分子而言，會導致拋光性能的差異。同時，我們使用統計分析軟體對研磨拋光材質移除速率和研磨拋光缺陷總數的數據進行分析。該方法有助於確定最適合用作研磨拋光漿料的聚合物奈米顆粒，並改善降低缺陷總數的可靠性趨勢研究。

Abstract Chemical mechanical planarization (CMP) is a wafer-surface-polishing planarization technique based on a wet procedure that combines chemical and mechanical forces to fully flatten materials for semiconductors to be mounted on the wafer surface. The achievement of devices of a small nano-size with few defects and good wafer yields is essential in enabling IC chip manufacturers to enhance their profits and become more competitive. The CMP process is applied to produce many IC generations of nanometer node, or those of even narrower line widths, for a better performance and manufacturing feasibility. Slurry is a necessary supply for CMP. The most critical component in slurry is an abrasive particle which affects the removal rates, uniformity, defects, and removal selectivity for the materials on the wafer surface. The polishing abrasive is the source of mechanical force. Conventional CMP abrasives consist of colloidal silica, fume silica or other inorganic pol-ishing particles in the slurries. I am the first to systematically study nanoparticles of the polymer type applied in CMP, and to compare traditional inorganic and polymer nanoparticles in terms of polishing performance. In particular, the polymer nanoparticle size, shape, solid content dosing ratio, and molecular types were examined. The polishing performance was measured for the polishing removal rates, total defect counts, and uniformity. I found that the polymer nanoparticles significantly improved the total defect counts and uniformity, although the removal rates were lower than the rates obtained using inorganic nanoparticles. However, the lower removal rates of the polymer nanoparticles are acceptable due to the thinner film materials used for smaller IC device nodes, which may be below 10 nm. I also found that the physical properties of polymer nanoparticles, in terms of their size, shape, and different types of copolymer molecules, cause differences in the polishing performance. Meanwhile, we used statistical analysis software to analyze the data on the polishing removal rates and defect counts. This method help to determine the most suitable polymer nanoparticle for use as a slurry abrasive, and improves the reliability trends for defect counts.