表面電漿處理對HSQ及銅導線電致遷移的影響

Abstract

在此利用FTIR及TDS來觀察HSQ於熱處理過程中之鍵結變化及因化學反應所釋收出的氣體成份。於不同固化溫度下觀察厚度和折射係數之關係發現HSQ於較高的固化溫度下結構會變得近似於二氧化矽。不同固化溫度下的化學鍵變化量亦隨之觀察。氫氣電漿處理可以增強受損的HSQ之抗吸水性。而因氧氣電漿灰化所造成的Si-OH增加也可以前置的氫氣電漿處理來減少其影響。另外由電漿處理後測得拉伸應力的增加表示出電漿處理會令HSQ薄膜更加緻密並可防止後續製程的傷害。二次離子質譜儀的結果顯示電漿處理可以改善對銅擴散的抵抗性。然而電漿處理會對HSQ的表面造成物理性及化學性的傷害，而較為粗糙的表面會令沉積於上面之銅膜優選之(111)結晶程度降低且獲得較為鬆散的結構。在電漿處理後的HSQ上所沉積的較劣銅膜對電致遷移的抵抗性會有所降低。

The bond structure change and gas desorption from chemical reaction of HSQ during thermal process was observed by FTIR and TDS. The thickness and refractive index of different curing temperature were investigated and it was found that HSQ would become more silica like with higher curing temperature. The chemical bond structure change with different curing temperatures was also observed. The H2 plasma treatment can enhance the water resistance of damaged HSQ film. The Si-OH bond increment due to O2 plasma damage was also reduced by H2 plasma pre-treatment. The tensile stress increment after plasma treatment shows the plasma treatment would make HSQ films denser and avoid the injuries from subsequent processes. The SIMS depth profiles show the resistance of copper diffusion into HSQ was improved by plasma treatment. The surface of HSQ is roughened by H2 plasma treatment. The rougher surface makes the upper copper film has worse degree of preferred (111) crystallization and a loose structure. The poor quality of copper film deposited on plasma treated HSQ degrades the electromigration performance.