田口方法應用於無鉛迴銲製程參數優化

Using the Taguchi Method to Optimize a Lead-Free Reflow Soldering Process

黃乾怡(Chien-Yi Huang) ； 林宜鋒(Yi-Feng Lin) ； 紀勝財(Sheng-Chai Chi) ； 蘇彥衍(Yann-Yean Su)

《科學與工程技術期刊》 3卷2期 (2007/06) Pp. 99-111

https://doi.org/10.7117/JSET.200706.0099

摘要

為因應電子產品量產更迅速，更輕化且更低成本的需求，表面黏著技術(surface mount technology, SMT)成為電子構裝中最為重要的製程技術之一，而SMT迴銲製程中，多以63/37錫鉛合金作為電子元件與印刷電路板(printed circuit board, PCB)間之接合銲料。然而，自2006年7月1日起，電子產品將全面禁止使用含鉛物質，此將影響印刷電路板組裝製程。鑒於導入無鉛過程中，對迴流銲接製程影響甚鉅，且製程參數尚未明確，業界缺乏一個廣為接受的標準。
首先，本研究運用田口方法規劃無鉛迴銲溫度曲線實驗，觀察錫珠發生情況並針對被動元件進行推力測試，再利用主成分分析法中特徵向量概念決定最佳溫度曲線。其次，針對迴銲環境中含氧量對銲接品質的影響，觀察錫珠、空洞與銲點表面光澤程度，再進行推力測試以決定銲點強度。實驗結果發現，迴銲尖鋒溫度越高，錫珠發生情況越明顯，但呈現較佳之銲點強度；另一影響銲點強度因子為恆溫時間，於98秒之恆溫時間表現最佳。主成分分析法整合結果指出，最佳製程參數為恆溫溫度範圍150℃~180℃，恆溫時間90秒～100秒，迴銲尖鋒溫度245℃~250℃，冷卻速度3℃/秒～4℃/秒。業者則可依良率或可靠度需求，選擇適合之溫度曲線。含氧量實驗結果顯示，1000ppm以上含氧量對錫珠與銲點強度並無影響；當含氧量降至310ppm以下時，銲點強度則明顯提升。

關鍵字

電子構裝 ； 迴銲製程 ； 田口方法 ； 主成分分析法

並列摘要

In electronics packaging, Surface Mount Technology (SMT) helps to achieve the realization of an end product at a lower production cost. However, beginning July 1, 2006, electronic products containing lead ingredients will be prohibited to the European market. This prohibition will have a major impact on the electronics industry, since the solder paste used in the SMT process is typically a tin-lead alloy.
This research is conducted to characterize and optimize the reflow soldering process as lead-free materials are used. A Taguchi-based experimental design is employed to determine the desired reflow profile and investigate the influences of oxygen content during the reflow. The occurrence of solder balls and voids and the appearance of solder joints and shear-test values are quality performances being considered. Use of the Eigen vector concept in the principle component analysis helps to determine the optimal profile when considering multiple response variables.
The optimal reflow profile is characterized by a soaking temperature of 150~180℃, a soaking time of 90~100 seconds, a peak temperature of 245~250℃ and a cooling rate of 4oC/second. A peak temperature above 250℃ results in server solder balls as well as superior shear strength in the solder joints. There is a significant improvement in the reliability of a solder joint as the oxygen content is reduced from 1000ppm to 310ppm. Finally, the reduction of the oxygen content helps to reduce the voiding only for a solder joint around the periphery of Chip Scale Package (CSP) components.

並列關鍵字

electronics packaging ； Taguchi experimental design ； reflow soldering process ； principle component analysis