以鋁鍺薄膜研究銅質接合之微通道的特性

Study on the Properties of Microchannels with Copper Bonded by Al-Ge Thin Films

李志文(Chin-Wen Lee)

指導教授 ： 陳文瑞

國立虎尾科技大學/電機資訊學院/電子工程系碩士班/碩士(2017年)

摘要

在雷射光學引擎模組中，常以微通道致冷器(MCC)作為散熱的基板，一般是使用多片薄銅片直接加熱接合而成，本研究為求降低銅片接合之加熱溫度及製造成本，後續得以採用異質金屬接合作為微通道致冷器之最頂層，所以採用真空熱蒸鍍之鋁鍺薄膜作為銅片接合之銲料，其鋁鍺銲料共晶接合溫度約需424℃。
關於鍵合製程，於銅箔上雙面沉積鋁鍺薄膜，並作為子母銅塊中間的焊料層，形成三明治的結構，後續在真空環境下進行熱壓合，然後以推力計進行剪應力強度分析並以光學顯微鏡探討表面微結構，實驗結果發現，銅箔表面過於粗糙，影響鋁鍺擴散，導致剪應力強度不穩。後續研究重點放在電解拋光處理，結果發現，表面粗糙度有明顯改善的現象。
關於自行開發微通道致冷器，將每一層水道圖案轉印於PCB基版上，後續電鍍300µm銅箔於有圖案之PCB基版上，然後使用超音波震盪讓電鍍銅箔與PCB分離，最後將五層設計的電鍍銅箔，在真空中升至一定溫度執行組合與鍵結壓合，自行開發MCC樣品即完成。

關鍵字

鋁鍺薄膜 ； 表面粗糙度 ； 微通道

並列摘要

In the laser optics engine module, the microchannel cooler (MCC) was often used as the heat dissipation of the substrate. Generally, it is using multiple pieces of thin patterned copper plates directly to form the joints. In this study, in order to reduce the heating temperature of the bonding joints as well as the manufacturing thermal budgets, the heterogeneous metal bonding joints were adopted to bond the copper-based micro-channel cooler. The AlGe films were deposited onto the patterned copper plates by using the thermal evaporation. The bonding temperature of the aluminum-germanium eutectic was about 424 ℃.
For the bonding process, the AlGe films were deposited on the 25µm-thick copper foil on both sides. Here we have prepared mother and son copper blocks, and inserted the 25µm-thick copper foil into the mother and son copper blocks for form a sandwich structure. Then bonding process was performed in a vacuum chamber. After that the amplitude of shear stress was measured, and the surface topography was examined by the optical microscopy. The results showed that the surface roughness was too large and resulted in the poor diffusion between the aluminum and germanium. So, it is difficult to obtain the reliable shear stress for these bonding joints. The further study was focused on the electrolytic polishing process. It was found that the surface roughness was obviously improved.
For the development of the home-made MCC, the patterns used here were transferred to the copper-based PCB substrate. Subsequently, the 300µm-thick copper layer was electroplated on the patterned PCB substrate. Then the electroplated copper plate was separated from the PCB by using the ultrasonic vibration. Finally, five above designed copper plates were assembled and bonded in the vacuum chamber at a desire temperature. The self-made MCC was thus completed.

並列關鍵字

aluminum-germanium film ； surface roughness ； MCC

參考文獻

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