氮化鋁與銅接合之性質研究

Abstract

本實驗主要研究氮化鋁與銅接合之微結構、強度與熱傳導性質之間的關係。因氮化鋁與銅在鍵結上的差異，導致兩者無法直接接合，必須先在表面生成一薄層氧化物 (分別為氧化鋁及氧化銅)做為過渡層，再利用直接接合銅 (direct bond copper)的技術，並藉由共晶接合法 (eutectic bonding process)於銅/氧化亞銅共晶溫度 (1065oC)以上形成共晶液相來潤濕氮化鋁/銅之界面，而得到良好之界面強度。 在本實驗中，將不同預氧化處理之氮化鋁以及銅分別在氮氣下升溫至1070oC進行接合，經微結構觀察、座滴實驗 (sessile drop test)測量潤濕情形、四點彎曲強度測試以及閃光導熱儀測量熱傳導係數，來探討不同預氧化程度試片接合造成結果之差異。 由微結構觀察可發現氮化鋁預氧化的機制為由氮化鋁表面向內部成長，而氧化鋁的厚度隨氧化溫度增加而增加。在熱傳導實驗以及強度的結果，可觀察到：若固定氮化鋁的氧化程度，當銅的氧含量越高，所測得的熱傳導係數越小，但強度越高；若固定銅的氧化程度，當氮化鋁的氧含量越高，所測得的熱傳導係數越小，且強度越低。而導致此結果皆與界面的性質息息相關。

In the present study, the microstructure, strength and thermal properties relationships of AlN/Cu samples are investigated. Due to the different bond characteristics of AlN and Cu, the pre-oxidation treatment is needed to form a thin oxide layer (aluminum oxide and copper oxide) on the substrate first. In order to join AlN with Cu, the direct bond copper process is used to form a Cu-Cu2O eutectic liquid above 1065oC. The Cu-Cu2O eutectic liquid wets the interface between AlN and Cu to form a strong bonding. Various pre-oxidation routes of AlN and Cu are adopted in this experiment, then join AlN with Cu at 1070oC in a flowing nitrogen. Combining the experimental results from microstructure observation, sessile drop test, four-point bending test and thermal properties analyses, the relationships between the surface conditions and performances can then be established. The increase of strength and the decrease in thermal conductivity of AlN/Cu assemble can be found by increasing the oxygen concentration of Cu. Nevertheless, the decrease of strength and the decrease in thermal conductivity of AlN/Cu assemble can be observed by increasing the oxidation extent of AlN.