| 摘要: | 因半導體科技日新月異，需開發如三維構裝、生物感測器、可撓性平面顯示器以及分子機械等，然而無論何種技術與概念都需透過電子構裝技術以產品化，因此電子構裝技術在未來的產業將扮演重角色。然而多元化的產品將對電子構裝技術帶來更大的挑戰，如高分子基板的低玻璃轉化溫度、生物元件的生物可耐溫度以及分子機械的分子裂解溫度，都嚴格的限制電子構裝的溫度，而現行的無鉛銲錫構裝溫度並不符合需求，因此發展新式的低溫銲料將至關重要。在本研究中提出Sn-In-Bi與In-Bi兩種低溫合金系統，在兩個系統中分別挑選三個具有合適熔點的成分組成。與Cu基板接合界面反應研究、推力測試以及電遷移用以評估六種銲料於應用上之合適性。16.5Sn-51In-32.5Bi、17Sn-26In-57Bi和53Sn-10In-37Bi 之熔點分別為56.30、82.14與106.21 oC。三種合金與Cu界面的介金屬化合物皆為Cu6(In, Sn)5；In-Bi之68In-32Bi熔點為75.80 oC，合金界面產生之介金屬化合物為CuIn2；50In-50Bi之熔點為95.72 oC合金界面所產生之介金屬化合物為Cu11In9；33In-67Bi之熔點為116.03 oC合金界面所產生之介金屬化合物為Cu2In。推力測試結果顯示，17Sn-26In-57Bi在Sn-In-Bi系統中有最好的剪應力，而於In-Bi系統中，50In-50Bi有最好的剪應力值，17Sn-26In-57Bi的剪應力值略高於50In-50Bi，但由破斷面可知17Sn-26In-57Bi在三次迴焊後具遠高於50In-50Bi合金之延性破裂比例，因此17Sn-26In-57Bi擁有最佳之推力性質。若上述兩種合金做成晶片以比較電遷移之抗性時，50In-50Bi的生存時間大約是17Sn-26In-57Bi的三倍。;Over the past several decades, devices and technologies that entail substrate applications have been widely developed for use in the semiconductor industry. Some new technologies are receiving a lot of attention from researchers, including three-dimensional integrated circuits (3D-IC), biosensors, flexible flat-panel displays, and molecular machinery. All of these new technologies require product assembly before they can become widely available. However, many obstacles must be overcome with respect to these assembling processes. One of the most important technological issues is the low thermal budget. The 200–300 °C temperatures used in conventional lead-free-solder assembling and manufacturing presents challenges to the functionality of these technologies. As such, it is necessary to develop low-melting solders with processing temperatures low enough for these innovative technologies to maintain their functionality during the soldering process. In this study, we investigated two low-melting alloy systems, Sn-In-Bi and In-Bi. In the Sn-In-Bi system, we used 16.5Sn-51In-32.5Bi, 17Sn-26In-57Bi, and 53Sn-10In-37Bi compositions with melting peak temperatures of 56.30 °C, 82.14 °C, and 106.21 °C, respectively. In the In-Bi system, we used 68In-32Bi, 50In-50Bi, and 33In-67Bi compositions with melting peak temperature of 75.80 °C, 95.72 °C, and 116.03 °C, respectively.
In this paper, we present the interfacial reaction on the Cu substrate for each alloy with different numbers of reflow cycles and temperatures. In the Sn-In-Bi system, we found the only intermetallic compound (IMC) formed at the interface to be Cu6(In, Sn)5, with different percentages for the In substitution. In the In-Bi system, we found the IMCs formed at the interfaces of 68In-32Bi/Cu, 50In-50Bi/Cu, and 33In-67Bi/Cu to be CuIn2, Cu11In9, and Cu2In, respectively. We found the growth rate of the Cu11In9 IMC formed between the 50In-50Bi alloy and Cu substrate to be quite slow. In addition, we used the shear test to analyze the reliability of these low-melting alloys. Our shear test results indicate that the 17Sn-26In-57Bi and 50In-50Bi alloys have the best shear strengths in the Sn-In-Bi and In-Bi systems, respectively. Compared with the shear strength results and fracture modes of the 17Sn-26In-57Bi and 50In-50Bi alloys, 17Sn-26In-57Bi exhibited a higher shear strength value and ductile fracture percentage than the 50In-50Bi alloy. We utilized samples made with the 17Sn-26In-57Bi and 50In-50Bi solders in an electromigration analysis and found the lifetimes of the 50In-50Bi samples to be around three times longer than those of 17Sn-26In-57Bi. However, compared with other low-melting alloys, 17Sn-26In-57Bi exhibits the best shear test results and 50In-50Bi the greatest electromigration resistivity. |
