Abstract
近來，氮化鋁陶瓷基板金屬化之技術在微電子構裝工業上之應用已受到非常廣泛的注意，因此，本實驗的主要目的在研究氮化鋁陶瓷基板在各種腐蝕環境下之抗腐蝕性，氮化鋁陶瓷基板無電鍍鎳之金屬化行為和評估無電鍍鎳後之氮化鋁陶瓷基板與銅熱壓接合之可行性。在腐蝕實驗中，氮化鋁在鹼性溶液中的重量損失，經五天後可達70％，並導致三天後表面粗糙度由10毫米增至7微米 。但是，在酸性溶液中腐蝕的重量損失則僅為鹼性腐蝕情形的1/700。 相對而言，在酸性與中性溶液中，氮化鋁表面僅數個原子層的厚度被侵蝕。在鹼性環境下的主要作用為氮化鋁與水反應，氫氧化鈉具催化作用，而氧化鈉及其水和物則為中間產物。在金屬化實驗中，準備不同表面形態的氮化鋁基板，包括未處理，研磨拋光和鹼性侵蝕等三種試片進行無電鍍鎳實驗。無電鍍鎳後的氮化鋁基板則在真空中經熱壓法與銅箔接合，形成AlN/EN/Cu/EN/AlN三明治形態之試片。此接合試片之機械強度 ，主要決定於EN/AlN和EN/Cu兩個界面的接合強度。銅箔與無電鍍鎳膜之間主要是靠銅與鎳之擴散所形成之固溶液層而接合；然而無電鍍鎳與氮化鋁之間則是藉氮化鋁表面的粗糙度，侵蝕孔洞和燒結孔洞之作用而形成機械鍵鎖之接合機構。適當的接合強度發生於接合溫度在600至700℃之間。 其值高於10MPa。接合強度與界面形態，元素分布和殘留應力之間的關係在本文中將有詳細的探討。Metallization of AlN substrates has attracted more attentionfor the application in microelectronic packaging industry. Inthis study, the etching resistance of AlN in various corrosiveenvironments and the metallization of AlN by the electroless Ni-P (EN) plating and hot-pressed Cu methods are investigated. Inthe corrosion experiments, the weight loss of AlN corroded inalkali aqueous reaches 70% and results in an increase insurface roughness from 10 nm to 7 μm after 3 days corrosion.However, the weight loss in acid solution is only 1/700 of thealkali case. The violent chemical reactions in basic solutionsare observed. Na2O, or Na2Al2O4*6H2O, is the intermediateproduct, and NaOH is an catalytic agent in the reaction. Incontrast, only several atomic layers of AlN surface are etchedoff in acid solutions and in deionized water. In themetallization experiments, the AlN ceramics with differentsurface morphologies, including the as-received, polished andetched, are prepared for the EN plating. The EN-plated AlNsubstrate is bonded with the Cu foil to form a sandwich-likeAlN-EN/Cu/EN-AlN assembly by hot pressing method in vacuum.The bonding strength of the joint is determined by the adhesiveabilities of EN/AlN and EN/Cu interfaces. Bonding between theCu foil and the EN film is achieved by the interdiffusion of Cuand Ni atoms to form a solid solution interlayer, while the ENfilm is adhered on the AlN substrate mainly by the mechanicalinterlocking through the rough interface, etching holes andopen pores. An optimum adhesion strength higher than 10 MPa isfound at the bonding temperatures of 600-700℃. The relationsof adhesion strengths, the interfacial morphologies, elementaldistribution and calculated residual stresses are proposed.