電子元件可靠度評估－以通訊用連接器為例

吳文方臺灣大學:機械工程學研究所陳耀鍾Chen, Yao-ChungYao-ChungChen2010-06-302018-06-282010-06-302018-06-282009U0001-2707200919014200http://ntur.lib.ntu.edu.tw//handle/246246/187186一般而言，產業界對於通訊用電子產品穩態期之失效率評估，常是以Telcordia SR-332可靠度預估模型來做估算，其基本假設是產品壽命分佈符合指數分佈且失效率為一定值。儘管此方式可快速預估產品的平均失效時間與失效率等相關可靠度指標，但在現實使用環境中，產品仍會受到眾多因素影響，導致模型評估的結果不一定符合該產品之特性。因此，本研究藉由失效模式及影響性分析與失效樹分析，釐清本研究對象－2-mm Hard Metric Connector（以下簡稱連接器）最關鍵之潛在失效因子，並針對分析結果擬定加速試驗與插拔試驗規劃，最後再透過試驗數據，依可靠度工程原理找出最符合產品特性之可靠度指標。研究結果顯示，此型連接器端子的活化能為0.26 eV，若以阿列尼厄斯(Arrhenius)模型分析連接器端子在40 ℃環境下之壽命，在幾種常見的機率密度函數中，對數常態機率密度函數為其最適分配，平均失效時間為69,734小時；若以艾林(Eyring)模型分析端子在40 ℃與40 ℃/30％ RH環境下之壽命，對數常態機率密度函數亦為其最適分配，其中在40 ℃的使用環境下，平均失效時間為74,634小時，而在40 ℃/30％ RH的使用環境下，其平均失效時間則為70,725小時。以上顯示此類電子產品的壽命分配並非恆為指數分佈、且失效率並非恆為定值。同樣的試驗數據若依Telcordia SR-332可靠度預估模型計算，其失效率為1.79 FITs (Failures Per Billion Device Hours)，換算平均失效時間為558,659,218小時，相較於前述分析結果存有極大之差異，所以在解讀Telcordia模型的分析結果時，務必要格外謹慎、小心。本研究插拔試驗之分析結果則同樣顯示對數常態機率密度函數為插拔壽命之最適分配，平均失效次數為41,771次。綜合以上分析結果可知，此型連接器對於外在環境與反覆插拔均具相當的可靠度。The steady-state failure rates of electronic products applied to telecommunication are frequently estimated based on Telcordia SR-332 Reliability Prediction Model. Its basic assumptions are that product lives follow the exponential distribution and failure rates are constants. Although this approach provides us an easy way to estimate the failure rate, mean time to failure (MTTF) and other quantities related to product reliability, it may not be able to reflect complicated environmental conditions a product may be subjected to. In practical applications, products are affected by many environmental factors causing reliabilities predicted by the model inconsistent with characteristics of the products. Therefore, in the present study, Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA) are used to identify the most relevant failure modes of a particular electronic product - a two-mm hard metric connector. Based on results from FMEA and FTA, a series of accelerated test and durability test are designed and performed for the studied connectors. Detailed reliability analyses are carried out. The result shows that the activation energy is 0.26 eV for pins of this type of connector. Among the fitted probability distribution functions, the pin life follows the lognormal distribution the best, and its MTTF is 69,734 hours under the condition of 40 ℃ if Arrhenius model is adopted. If Eyring model is considered instead, the lognormal distribution is also the best fit to the tested data. Its MTTFs are 74,634 hours under the condition of 40 ℃, and 70,725 hours under the condition of 40 ℃/30％ RH, respectively. The above results show that the pin life does not follow the exponential distribution and the failure rate is not a constant as reflected by Telcordia model. If Telcordia SR-332 Reliability Prediction Model is applied, the failure rate is found to be 1.79 FITs (Failures per Billion Device Hours), which has a MTTF of 558,659,218 hours. As for the plug-in-and-out durability test, the result from analyzing the test data indicates the pin life may be fitted by a lognormal distribution, and its MTTF is 41,771 cycles. In summary, with its rather strong pins, the tested and analyzed type of connector is quite reliable.致謝 I要 IIbstract III錄 V目錄 VIII目錄 XI號說明 XV一章緒論 1-1 研究背景與動機 1-2 文獻回顧 2-3 研究流程 3-4 本文架構 3二章連接器介紹 6-1 設計流程 6-2 發展趨勢 6-3 連接器特性 8-3-1 機械特性 8-3-2 電氣特性 10三章應用理論概述 13-1 可靠度基本理論 13-1-1 失效模式及影響性分析 13-1-2 失效樹分析 16-1-3 可靠度與機率函數 17-1-4 機率點圖 24-1-5 卡方適合度檢定 26-1-6 蒙地卡羅模擬 27-2 Telcordia SR-332可靠度預估模型 27-2-1 沿革 28-2-2 元件可靠度預估方式 28-2-3 單元可靠度預估方式 29-2-4 系統可靠度預估方式 31-3 加速試驗 31-3-1 阿列尼厄斯模型 32-3-2 派克模型 33-3-3 羅森模型 34-3-4 艾林模型 35-4 迴歸分析 36-4-1 迴歸分析簡介 36-4-2 簡單線性迴歸 37-4-3 簡單非線性迴歸 43四章失效模式及影響性分析與失效樹分析 50-1 失效模式及影響性分析 50-1-1 操作環境與可靠度模式建立 50-1-2 各細部構件之失效模式分析 51-1-3 失效影響性與機率性分析 53-1-4 失效關鍵性評估 53-2 失效樹分析 54-3 小結 54五章可靠度試驗規劃 63-1 溫濕加速試驗 63-1-1 試驗目的 63-1-2 試驗內容 63-2 插拔試驗 64-2-1 試驗目的 64-2-2 試驗內容 65六章數據分析與結果 79-1 加速試驗數據 79-2 阿列尼厄斯模型之分析結果 80-2-1 阿列尼厄斯模型之加速因子 80-2-2 以阿列尼厄斯模型分析產品可靠度 81-3 艾林模型之分析結果 81-3-1 艾林模型之加速因子 82-3-2 以艾林模型分析產品可靠度 83-4 Telcordia SR-332可靠度預估模型之計算結果 83-5 插拔試驗之分析結果 84-6 小結 85七章結論與未來展望 139-1 結論 139-2 未來展望 140考文獻 1422022367 bytesapplication/pdfen-USTelcordia SR-332失效模式及影響性分析連接器加速試驗插拔試驗活化能Failure Mode and Effect Analysis (FMEA)connectoraccelerated testdurability testactivation energy電子元件可靠度評估－以通訊用連接器為例Reliability Assessment of Electronic Devices - A Case Study of Connectors Applied to Telecommunicationthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/187186/1/ntu-98-R96522531-1.pdf