電子封裝領域中回焊過程的氧化會嚴重影響接點的潤濕表現，從而損害電子封裝的可靠度。本研究透過常壓電漿清潔的方法取代傳統助焊劑用於去除金屬表層之氧化物以實現可靠的焊接，探討常壓電漿對銅基板及焊球的清潔效果，並觀察電漿去除氧化層後的潤濕行為。
透過掃描電子顯微鏡（SEM）的橫截面分析顯示，經過電漿前處理和後處理的樣品表現出最佳的潤濕性。電漿前處理過程促進了界面處的金屬間化合物形成，而電漿後處理則有效地去除了焊料表層的氧化層。結合前處理及後處理能使焊球和銅基板達到最低的潤濕角，顯示出優越潤濕表現。電子微探儀（EPMA）進一步證實了電漿處理後錫球和銅表面上的氧化層能被完全去除，應證了氧化對潤濕表現的影響。同時為了瞭解回焊階段的電漿清潔效率，本研究計算了電漿還原與氧化層形成速率之間的差異。透過SEM觀察的氧化層厚度變化顯示，該電漿系統中氧化層的去除速率超過了回焊溫度下氧化層的生成速率。這表明在回焊過程中進行的電漿處理仍能有效維持去除氧化層的效果。
綜觀上述內容本研究強調常壓電漿處理能去除銅基板表層的氧化層，同時抑制焊球表面氧化層在回焊過程中的生成以提升整體的潤濕表現。此外也驗證電漿在回焊過程中去除氧化層的效率。透過上述的實驗結果能更深入理解並優化電漿表面處理製程，進而開發較可靠的焊點接合。

The challenge of solder pad oxidation is crucial in electronic packaging, as it detrimentally affects solder wettability, thereby compromising solderability and overall reliability. This study is committed to achieving reliable solder joints through the plasma cleaning methodology, focusing on the effectiveness of atmospheric-pressure plasma (APP) for plasma pre-treatment and post-treatment. The APP system utilizes a mixture of Argon gas and 5% Hydrogen to minimize the presence of metallic oxides during the reflow process.
Cross-sectional analysis using Scanning Electron Microscopy (SEM) revealed that Groups subjected to plasma pre-treatment following post-treatment exhibited optimal wettability. The plasma pre-treatment process facilitated the formation of intermetallic compounds (IMCs) at the interface, while the plasma post-treatment effectively removed the solder oxide shell. This combination resulted in the lowest contact angle of 29.5° between the solder balls and copper substrates, indicating superior wetting behavior. Electron Probe Micro-Analyzer (EPMA) analysis further confirmed the absence of continuous oxide layers on the tin balls and copper surfaces after plasma treatment, supporting the wettability performance observed in the cross-sectional analysis and establishing a significant correlation between oxide layer presence and wettability.
To better understand plasma cleaning efficiency during the reflow stage, the study further investigated the differences in plasma reduction and oxide layer formation rates. SEM analysis showed that the oxide removal rate exceeded that during reflow. This suggests that plasma treatment can maintain a low oxygen level at the bonding interface, which promotes wetting and achieves an ideal balanced wetting angle.
In summary, this study emphasizes the enhancement of solder wettability through APP treatment while reducing the formation of oxide layers on copper and solder ball surfaces during reflow. It also validates the efficiency of oxide layer removal by plasma during the reflow process and examines the final wettability performance after plasma treatment. These findings significantly contribute to understanding and optimizing plasma cleaning approach for achieving reliable solder joints.

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