鋁與氧化鋁接合與其界面性質之研究

Abstract

直接接合鋁基板被廣泛運用在電子電路基板與能源模組上，然而鋁的氧化層在其與陶瓷基板接合時形成阻礙。本研究的研究目的是瞭解金屬鋁與氧化鋁接合界面的微結構、機械性質與導熱性。金屬鋁/氧化鋁界面的接合是藉由高於金屬鋁熔點(660C)之接合溫度使鋁與氧化鋁進行液態接合，接合過程在氮氣環境下進行以減少鋁的氧化，並嘗試不同的接合溫度來獲得接合良好的界面。 本研究對不同接合溫度下所得到之金屬鋁/氧化鋁的接合界面進行相分析與微結構觀察，並使用四點彎曲測試以及閃光法來評估接合後的性質。由於接合過程在金屬鋁層中產生大量的孔洞，因此本研究也探討了孔洞的形成機制以及孔洞對接合性質的影響。這些孔洞的存在會大幅降低界面的接合面積，因而降低了界面的接合強度與熱傳導性質。雖然較高的接合溫度才能得到接合良好的界面，但孔洞的面積也會隨接合溫度提高而增加。因此對於得到金屬鋁/氧化鋁的良好接合界面，接合溫度的選擇十分重要。

Direct bonded aluminum (DBA) substrates can serve as carriers for power electronic components. However, the aluminum is easily oxidized. The oxide layer formed on the metallic aluminum surface prevents the formation of a strong bonding between aluminum and ceramic. The aim of the present study provides a detailed characterization on the processing and interfacial characterization of Al/Al2O3 joints. The bonding process was held above the melting temperature of Al, so the Al could be bonded to Al2O3 at its liquid state. The microstructure observation and phase analysis were carried out on the interface between Al and Al2O3. The interfacial strength of Al/Al2O3 interfaces and the flexural strength of Al2O3/Al/Al2O3 joints were determined by a four-point bending test. The thermal conductivities of the bilayer and trilayer bonding specimens was measured by flash method. After bonding at elevated temperatures, many pores were observed at the interface. The presence of pores seriously damaged the properties of bonding specimens. The relationships between interfacial properties and mechanical properties or thermal conductivity are established and the mechanism for pore formation is proposed.