苯並環丁烯在鋁上的黏著性研究

Abstract

在多晶片模組構裝中, 介電絕緣層與金屬的黏著性, 為評估產品可靠度 的要素之一 . 聚亞醯氨(Polyimide , PI)為最普遍使用的介電材料, 而 苯並環丁烯(Benzocyclobutene,BCB)為Dow Chemivals公司新開發之介電 絕緣材料, 它有更低的介電常數與低吸水性, 故極具應用潛力. 本實驗 以90度剝離試驗研究苯並環丁烯與鋁膜間的黏著性實驗結果顯示, 剝離強 度會隨苯並環丁烯厚度增加而增加, 至一最大值後, 便開始下降. 苯並環 丁烯厚度固定, 剝離速率越快時, 剝離強度越大. 在環境測試方面, 基 板溫度上升時, 剝離強度亦隨著上升, 當溫度達100C以上時, 剝離強度的 增加則漸趨平緩. 在85C, 一小時不同濕度環境測試及85C/85%RH長時間濕 度環境測試中得知 環境濕度會使界面黏著性質劣化 變更鋁膜厚度的基 板效應實驗顯示, 鋁膜越厚時, 剝離強度越小. 本實驗以橫截面穿透式電 子顯微鏡(XTEM)觀察苯並環丁烯與鋁膜間的界面形貌, 並使用原子力顯微 鏡(AFM)觀察不同厚度鋁膜的表面型態以評估其表面粗糙度對黏著性質的 影響. Adhesion of dielectric layer on metal is one of the most important factorsaffecting the reliability of multilayer interconnection substrate for multi-chip module (MCM) packaging. Benzocyclobutene (BCB) is a new polymeric insulating material developed by Dow Chemicals with lower dielectric constant and water absorption properties. In this work, a 90-peel test was used to evaluate the adhesion between BCB and aluminum. It was found that the peel strength varied with film thickness. It reached a peak value at some intermediate thickness then decreased as the film thickness further increased. On the other hand, at fixed film thickness the peel strength increased as the peel rate increased. The peel strength also increased as the peel rate increased, and gradually reached a saturated value above 100C. In 85C/1hr and 85C/85%RH storage test, the deterioration of peel strength was observed. The effect of aluminum film thickness on peel strength was also investigated. It was found that the peel strength of BCB decreased as the thickness of aluminum film increased. Cross-sectional transmission electron microscopy (XTEM) and the atomic force microscopy (AFM) was employed to examine the morphology of BCB/ Al interface and the roughness change of aluminum film at different thickness, respectively.