本論文之目的在於研究銅、擴散阻障層TaSix和TaN與犧牲層的製程整合，配合damascene技術，製作Cu/TaSix or TaN/SiO2 air-gap damascene平行導線結構，探討其漏電流機制。
在犧牲層(sacrificial layer)方面，以旋轉塗佈的方式將調配不同稀釋比例的HSQ(hydrogen silsesquioxane，precursor : Fox15)和MIBK塗佈在晶圓上，來得到所需的膜厚。在預烤350℃時，HSQ可承受CMP的研磨且浸泡在BOE溶液內可快速被去除，為一個良好的犧牲層。
擴散阻障層(TaSix、TaN)方面，以濺鍍方式沉積之TaSix薄膜，經由歐傑電子顯微鏡之縱深分佈圖得知其原子組成比例約為Si/Ta=0.52。
將犧牲層HSQ、擴散阻障層TaSix、TaN和有電極電鍍銅配合化學機械研磨製程完成Cu/TaSix or TaN/SiO2 air-gap damascene平行導線結構，量測其導線與導線間之漏電流。Cu/TaN(200Å)/SiO2 air-gap damascene structures的崩潰電壓為0.94~1.1 MV/cm，崩潰前漏電流大小為1.02×10-4~2.27×10-4 A/cm2；Cu/TaSix(200Å)/SiO2 air-gap damascene structures的崩潰電壓為0.73 MV/cm，崩潰前漏電流大小為5.9×10-6 A/cm2；Cu/TaSix(100Å)/SiO2 air-gap damascene structures的崩潰電壓為大於1.3 MV/cm，崩潰前漏電流大小為6.6×10-4~2.89×10-3 A/cm2。在漏電流傳導機制方面，我們將漏電流量測結果，由J v.s. V2之作圖發現可以分成兩類：一為當電壓上升至某個電壓時，漏電流密度(J)與V2成線性關係；另一為在電壓為0V時，漏電流密度(J)與V2成線性關係。由J v.s. V2為線性關係確認了Cu/TaSix or TaN/SiO2 air-gap Damascene結構之漏電流傳導機制主要為space charge limited。由SEM圖觀察結果發現，damascene structures 的溝槽沒有完完全填滿，使得在CMP後造成導線兩側的阻障層受到影響，而影響到漏電流和崩潰電壓。

The integration of copper, diffusion barrier TaSix or TaN and sacrificial layer HSQ were investigated. We fabricated diffusion barrier layer, TaSix or TaN, sacrificial layer HSQ, develop the processes integration for Cu metallization and investigated the conduction mechanism of line-to-line leakage current for air-gap damascene structure.
In order to get various thicknesses, we mixed solution with different ratio of HSQ and MIBK after spin on. The HSQ film is a good sacrificial layer with pre-bake temperature 350℃. It has a good mechanical strength during metal CMP and can be removed by BOE solution quickly and easily.
The Cu air-gap damascene structures with diffusion barrier TaSix or TaN and sacrificial layer HSQ were fabricated. From leakage current measurements, the breakdown electric field of the Cu/TaN(200Å)/SiO2 air-gap damascene structures is 0.94~1.1 MV/cm and the leakage current is about 1.02×10-4~2.27×10-4 A/cm2 before the breakdown occurring. The breakdown electric field of Cu/TaSix(200Å)/SiO2 air-gap damascene structures is 0.73 MV/cm and the leakage current is about 5.9×10-6 A/cm2 before the breakdown occurring. The breakdown electric field of Cu/TaSix(100Å)/SiO2 air-gap damascene structures is higher than 1.3 MV/cm and the leakage current is about 6.6×10-4~2.89×10-3 A/cm2 before the breakdown occurring. From the SEM pictures, we observed the trenches of damascene structures being not filled with the copper. Meanwhile, CMP will remove or shake the barrier layers. The breakdown electric field and the leakage current were enhanced. From various electrical leakage current analyses, we find that the dominant conduction mechanism of the Cu/TaSix or TaN/SiO2 air-gap damascene structures is space charge limited.

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