[[alternative]]System Level Reliability Test of Flip Chip BGA -Power Cycling

碩士電子工程學系[[abstract]]系統層級電力溫度循環試驗對於「覆晶封裝」為一新型式的信賴性試驗，也是最為接近實際應用狀態的一項實驗；主要用以驗證GPU-圖形處理器 (繪圖晶片卡上的覆晶封裝)的各元件與搭配不同材質時之可靠度。本試驗架設程序、故障分析比傳統溫度循環試驗更為繁瑣困難；因此，失效分析的方向由大範圍至小範圍、高階往低階進行。此外，先執行「非破壞」分析再「破壞性」也是一個必要原則。第三階的失效時，若螢幕所顯示都是文字敘述，通常屬於電腦系統問題；而當出現異常鮮艷的畫面，則多為繪圖晶片卡已產生故障。第二階的失效原因，大多是由於「錫球斷裂」造成開路。主要分佈於晶片加熱區正下方。第一階的失效分析，「凸塊氣洞」、「填充物的氣洞」通常並不是造成失效的原因。由超音波斷層攝影發現的「脫層」都從角落開始發生，但是最先發生「白凸塊」則不一定從角落，而可能位於晶片中間某主要I/O 通過之處。由低玻璃轉換溫度值的填充物搭配合金凸塊是目前為止效能最優的材料表組合。[[abstract]]System Level Power Cycling Test is a whole new kind of reliability test for FCBGA (Flip Chip Ball Grid Array). The test can simulate the condition of actual application. It's a test used on verifying GPU(Graphic Process Unit, assembly in the type of FCBGA), and studying different kinds of material. The setup procedure and failure analysis procedure are much more difficult than traditional temperature cycle test. Therefore, we go analysis from wide range to narrow range; go from high level to low level; and go from 「non-destructive」 to 「destructive」. For the 3rd analysis, if the display shows a lot of narrative sentences, it may be the system problems. If there is a colorful picture on the display, it may be the graphic card broken. For the 2nd level analysis, the major failure mode is 「Solder ball crack」, which happens underneath the die region. For the 1st level analysis, 「Bump Void」 & 「Underfill Void」 won't cause to failure. Through SAT(Scanning Acoustic Tomography), 「Delamination」 is found at the die corner. However, 「White Bump」 does not necessary occur at the die corner, and it can be found at the middle of the die, where we suspect it could be the key I/O. Low Tg underfill goes with eutectic bump is the best BOM selection so far