Interfacial Reactions Between Copper Substrates and Tin

本研究有二組實驗，第一組使用二種銅基材(塊材銅及電鍍銅)與純錫銲料進行界面反應 第二組使用 Sn-xCu(x=0.7, 2, 3wt％Cu)合金與，銅基材進行界面反應。實驗結果顯示在空氣冷卻的條件下，第一組塊材銅迴銲 30~90 秒時生成棱柱狀的 Cu6Sn5 具有規則排列性，同樣反應時間電鍍銅生成的 Cu6Sn5 不具有規則排列性且表面具有許多孔洞。第二組 Sn-0.7Cu 迴銲 15~30 秒時生成棱柱狀的 Cu6Sn5 但不具有規則排列性，Sn-2Cu 及 Sn-3Cu 則為卵狀結構但晶粒大小不同。在冰水冷卻條件下二種基材及三種銲料生成的 Cu6Sn5 晶粒並未有明顯的差異性。在溫度 200℃反應時，Cu6Sn5 晶粒隨著熱處理時間增加而變大，電鍍銅生成的 Cu3Sn 會有許多的孔洞產生，這些孔洞會影響 Cu 元素的擴散，並且誘發產生大量的 IMC 結構，影響到銲點的可靠度。在 Sn-xCu銲料中 含銅量較高的 Sn-2Cu 及 Sn-3Cu 可以降低反應時對銅的需求，達到抑制 Cu6Sn5 的析出。There are two groups in this study the first group uses two kinds of copper substrates (bulk copper and plated copper) and pure tin solder for interfacial reactions, the second group uses Sn-xCu (x = 0.7, 2, 3 wt% Cu) alloys and copper substrate for interfacial reactions. The results showed that bulk copper formed prism Cu6Sn5 after reflow for 30~90s and the Cu6Sn5 grains aligned regularly in air-cooled samples, the plated copper formed Cu6Sn5 didn’t present specific texture and there were many void existing on the Cu6Sn5 surface. The second group of Sn-0.7Cu formed prism Cu6Sn5 after reflow for 15~30s and Cu6Sn5 didn’t present specific texture, the Sn-2Cu and Sn-3Cu formed ovate Cu6Sn5 and different grain size. In icewater-cooling condition, the IMC exterior didn’t have significant differences. The Cu6Sn5 grains became bigger with aging time at 200℃, the Cu3Sn formed by plated copper produced many voids, these voids would restrain the Cu diffusion and then induced more IMC formation and bad influence on the solder joints reliability. In the Sn-xCu solders, the Sn-2Cu and Sn-3Cu have higher copper content and the reaction can be reduced demand for copper elements and restrain the Cu6Sn5 formation.誌謝 ........................................... I 中文摘要 .................................. II Abstract ................................ III 目次 .......................................IV 表目次 ....................................VI 圖目次 .................................. VII 1.前言 ....................................... 1 2.文獻回顧 ................................ 2 2.1 電子構裝層級簡介 .......................... 2 2.2 界面反應 .....................................4 2.3 無鉛銲料 .................................... 5 2.4 錫/銅界面反應............................ 6 3. 實驗方法 .............................. 13 3.1 原料製備方法 ..................................... 13 3.1.1 合金銲料製備...................................13 3.1.2 界面反應基材製備................................ 13 3.1.2.1 塊材銅基材製備...............................13 3.1.2.2 電鍍銅基材製備.............................. 14 3.2 銅/錫液/固界面反應 .................................. 16 3.2.1 塊材銅與合金銲料液/固界面反應 ................................. 16 3.2.2 塊材銅、電鍍銅與純錫銲料液/固界面反應 ................. 17 3.3 銅/錫固/固界面反應 ............................... 17 3.4 金相樣品之製備與分析.............................. 17 3.4.1 上視結構金相界面觀察........................... 18 3.4.2 橫截面金相界面觀察........................... 18 4.結果與討論 ....................................... 19 4.1 純錫銲料與銅基材之界面反應............................ 19 4.1.1 純錫銲料與不同銅基材之迴銲液/固反應 ...................... 19 4.1.2 純錫銲料與不同銅基材 200℃熱處理固/固反應 ......... 33 4.2 合金銲料與塊材銅基材之界面反應......................... 43 4.2.1 合金銲料與銅基材之迴銲液/固反應 .............................. 43 4.2.2 合金銲料與銅基材 200℃熱處理固/固反應 ................... 53 5.結論 ..................................... 61 6.參考文獻 ................................. 6