覆晶球柵陣列構裝元件於不同溫度及振動環境與結合兩者之高加速壽命測試結果比較

Comparison among Various Thermal and Vibration Loadings as well as the Combined Test for Flip Chip Ball Grid Array Components

李洋欣(Yang-Sin Li)

指導教授 ： 陳永樹

元智大學/工程學院/機械工程學系/碩士(2012年)

摘要

摘要
電子設備無論用於汽車或航空產業，都同時受到振動和熱環境負荷之影響。而這些電子產品的可靠度測試往往是熱和振動測試分別進行，其測試結果顯然與真實負載情況有別，因為未考慮溫度與振動之間的相互影響。高加速壽命測試（Highly Accelerated Life Test , HALT）試驗機的發展，可同時結合熱和振動進行測試，更接近真實的應用環境。
本研究的重點為經由一系列測試，包括熱循環，振動和HALT測試，研究覆晶球柵陣列電子元件（FCBGA）受力最大之角落錫球的應力與應變在這些測試條件下之變化，以做為可靠度研究之基礎，並同步以商業軟體ANSYS進行相關之有限元素分析(FEA)。
研究結果顯示，在不同溫度下進行振動試驗，因為溫度所產生的熱應力會導致錫球的楊氏係數改變，進而會影響其振動測試結果。本研究以有限元分析將溫度所產生的熱應力作為一個預應力當初始條件代入模型，然後再加入振動求解，而當我們在溫度循環(-55℃~150℃)加入30G振動時，其應變會較單獨溫度循環之應變高170μstrain。另一項則是探討不同溫度下其自然頻率會隨溫度增加而略為上升。透過本研究，能了解不同溫度及振動值對於錫球、自然頻率以及應變造成影響。其結果，有助於提高電子產品的壽命估計的準確性。
關鍵詞：FCBGA、HALT、壽命、可靠度、熱循環、振動

關鍵字

FCBGA ； HALT ； 壽命 ； 可靠度 ； 熱循環 ； 振動

並列摘要

Abstract
The electronic devices such as those used in automotive or avionic industries, all subjected to vibration and thermal environmental loadings. These electronics were tested for their reliabilities with thermal and vibration test conducted separately in the past. These kinds of test were considered as not precise enough since they didn’t consider the mutual effects between these two loadings. Thanks to the development of Highly Accelerated Life Test (HALT) test machine, it is possible to conduct test closer to the real world applications by combining both thermal and vibration test simultaneously.
This study focuses on examining the resulting stresses of the most vulnerable to damage corner solder ball of today’s sophisticated flip chip ball grid array components (FCBGA) through a series of tests including thermal cycling, vibration, and HALT tests. Meanwhile, the finite element analysis (FEA) with the commercial ANSYS software was also performed for all the foregoing test conditions. It is then feasible to investigate the coupling effects between individual thermal and vibration tests by checking with results from the HALT test.
The results showed that if conducting vibration test under the temperature other than room temperature, the generated thermal stress will cause the dynamic properties of the test vehicle as well as the Young's modulus of the solder balls be changed. Similar results were verified though the FEA by finding the thermal stress firstly, and put them as an initial stress on a pre-stressed model to compare with the experimental data. When we add 30Grms vibration into -55~150℃thermal cycling test ,it adds another 170 μstrain(about 15% more strain and can’t be ignored. )Both of these two methods were then varied for the test temperature to explore the effects on the vibration testing results. It was found that with the increase of temperature, the natural frequency also increases too. However, with elevated temperature that softens the solder balls, the observation then differs a bit. Through this study, some of the unexplored data in the dynamic performance and life of the today’s advanced electronic components under combined dynamic loading environments were revealed. The corresponding results were helpful in improving the life estimation accuracy of electronic products.

Keywords: FCBGA, HALT, Life, Reliability, Thermal Cycling, Vibration

並列關鍵字

FCBGA ； HALT ； Life ； Reliability ； Thermal Cycling ； Vibration

參考文獻

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