低介電常數材料在積體電路上之應用研究

Abstract

隨著元件尺寸縮小，元件速度主要受限於訊號在金屬連線間傳送的時間延遲，為了改善此問題，本論文主要針對利用低介電常數材質來降低金屬連線中的電容值。本篇論文研究的低介電常數材料MSQ為一種旋轉式塗佈介電材質。其為含碳氫鍵結的有機旋塗式低介電材質，在旋塗的過程中，富良好的流動性，因此，有極佳的局部平坦化能力，並能填入高高寬比的孔洞中。且因有機官能基之存在而具低介電常數，此材料的介電常數在理想狀態下約為2.7。內容主要針對其基本特性、熱穩定性、各種電漿處理後的特性與對銅金屬接觸的效應做詳細的探討。結論發現此材料的熱穩定性佳，經電漿處理之後，介電常數值變化不大，漏電流有顯著下降趨勢。對銅金屬接觸方面，銅金屬對此材料之特性無明顯的劣化影響。綜上所述，此低介電常數材料於現今銅金屬連線製程整合應用上具有極大潛力。

Interconnect delay is a performance-liming factor for ULSI circuits when feature size is scaled into the deep sub-micron region. Using low dielectric constant material for the interlayer insulator is an effective way to solve the problem. We study a low dielectric constant material, methylsilsesquioxane spin on polymer, with permittivity lower than silicon dioxide interlevel dielectric. The low-k SOG is an organic material containing carbon-hydrogen bonds. The spin on glass can offer low dielectric constant (~2.7) on the optimal conditions. The intrinsic properties and thermal stability of this spin on glass are investigated. We also study the properties of the SOG film with plasma treatment and the effect on copper induced. We found that the thermal stability of methylsilsesquioxane is good because of its silicon-carbon bonds. After plasma treatment, the dielectric constant of MSQ film has little change. The leakage current density reduces obviously for the plasma treated MSQ film. As for the copper issue, it seems no degradation for the film integrated with copper.