危害性物質限制指令(Restriction of Hazardous Substances Directive; RoHS)於2006年正式實施後,促使業界使用無鉛環保焊料生產消費性產品比例逐年攀升。由於消費性產品生命週期甚短,相關研究皆採用加速壽命試驗(Accelerated Life Testing, ALT)以縮短產品測試及上市時間。運用阿氏模型(Arrhenius)中之參數推估加速因子,當中指前因子與波茲曼常數為常數,僅活化能隨溫度的改變而不同。因此溫度的改變對活化能值影響甚大,如從經驗或軟體求算對推估加速因子及正常使用環境下之壽命容易造成偏差,因此不合適用於新興的產品上。此外,產品上市時間緊迫而無法測試至失效以估計其壽命,由於測試之加嚴條件之決定仍屬主觀,故建立一系統化的方法來決定合適之加嚴條件得以在有限的時間內完成測試是業界重視的課題。本研究運用阿氏模型推估產品活化能值,以三個溫度水準及蒐集樣本失效數據,計算各溫度水準下之加速因子分別為32.0、67.3、135.8;相對應之產品正常使用下壽命則分別為50,523、48,508、66,761小時,與依照MIL-HDBK-217給定活化能值計算得之產品壽命呈現約42%的差異。訂定產品測試之加嚴條件,於容許時間內完成驗證產品具備保固規範之可靠度水準。經加嚴溫度57℃執行500小時測試後,受測樣本未發生失效現象,確認該產品具有保固期限一年之最短壽命。
The Restriction of Hazardous Substances Directive (RoHS) was implemented in 2006. The lead-free soldering materials are increasingly used in the electronics industry. Due to the reduction of product life cycle, the Accelerated Life Testing (ALT) is commonly used to reduce the time to market. In the Arrhenius model for estimation of product life time, the product’s activation energy depends on the operating temperature. Considering activation energy as a constant may lead to the error in estimation result. Also, short time to market may limit the possibility to test the samples till failure occurs. The determination of the test condition used to verify the product’s reliability level within limited time frame is critical in the industry. This research estimates the lead-free product’s activation energy through the failure data of samples tested under three distinct temperature environments. The acceleration factors are determined. The estimated life times are different from that estimated based on the activation energy provided by MIL-HDBK-217. The appropriate test temperature is proposed. After 500 hours of test at 57℃, no failure occurs. The samples are therefore verified with reliability level of minimal one year of warranty life.