功率元件具有顯著的能源損耗效率，故在觸及能源轉換與高密度功率相關產業中， 扮演電路控制與能源轉換處理系統中之核心要件，其廣泛應用於車用電子、航太工程與5G通訊等。相較於傳統消費性電子產品，功率元件多處於嚴苛與高溫環境下工作，然而鮮少有接合技術能與其高溫工作環境匹配。為了使功率元件的發展與應用能夠快速擴張，開發一具有高熱穩定性的接合材料與製程以符合功率元件於電子構裝中的需求勢在必行。 本研究添加少量錫銀銅粉於銅膠中，成功開發出一新式銅錫膠。此接合材料能以固 態擴散方式於低溫無壓下達成銅對銅接合。本研究系統性地探討銅錫膠中錫含量與銅顆粒大小對整體銅接合性質之影響與機制。銅錫膠經固態擴散接合後會生成銅相鑲嵌於脆 性銅錫介金屬化合物中之特殊雙相球殼結構。此結構能改善並提升純介金屬化合物接合之機械性質，其機械強度可達19.5 MPa。於GIXRD與EDS分析中可得知，銅錫膠中之 錫已完全反應生成Cu3Sn，故此結構符合高熱穩定性的需求;在TEM的觀察中亦可發 現球殼結構的交界處有一穩定之界面。 本研究證明了除孔洞生成會降低整體銅接合機械強度外，球殼結構中介金屬化合物 其厚度與分佈面積亦會影響接合性質。此外，本研究建立一模型量化銅錫膠反應後介金屬化合物的生長行為，其結果與實驗相符，顯示此模型可用於預測與設計開發銅錫膠系統。;A power device is a promising technology for high energy density applications, including automobile, aerospace, and 5G telecommunication. However, traditional bonding processes cannot meet the requirements of the interconnects for such applications because of the severe working temperature. Consequently, a material that can sustain at high-temperature is essential to address the demands for electronic packaging in power devices for high-end products. In this study, a pressureless, low-temperature Cu-embedded intermetallic joint for interconnects was achieved using a Cu–SAC305 (Cu–SAC) hybrid paste under solid-state interdiffusion. The effects of the SAC weight fractions and Cu-particle sizes in the Cu–SAC hybrid paste were systematically investigated. The strength of the joint can reach an average of 19.5 MPa, which is high compared with other pressureless solid-state bonding methods. After a solid-state interdiffusion bonding process, the joint composed of an intermetallic compound (IMC) shell and Cu core particles, namely a ductile Cu phase combined with brittle IMC, exhibited exceptional microstructure and enhanced strength. GIXRD and EDS results showed that the SAC completely transforms into thermodynamically stable Cu3Sn. Alternatively, TEM examination indicated a coherent interface between the Cu3Sn/Cu interface. This study validated that void fraction in the joints is not the only factor that affects the joint performance. A mathematical model proved that the IMC thickness and IMC interfacial areas make significant contributions for robust interconnects. The results in this study demonstrate a potential material for interconnects in high-temperature applications.
