雙氧水與銅離子於電化學電鍍製程應用之反應性研究

Reactivity Research of Hydrogen Peroxide and Copper Ions at Electrochemical Plating Process

王承賢(Cheng-Shyan Wang)

指導教授 ： 李崑池

崑山科技大學/工程學院/環境工程研究所/碩士(2005年)

摘要

由於近年來銅製程因為元件特性需求而大量量產，雙氧水與銅離子的使用量也隨之增加。因此本研究進行雙氧水與銅離子於半導體電化學電鍍製程應用之反應相容性研究，分別探討雙氧水及銅離子共存系統放熱反應行為受銅離子濃度、雙氧水溶液濃度、溶液pH值、硫酸根離子濃度、氯離子濃度及添加劑濃度等因素的影響。並配合電化學電鍍製程配方、製程機台硬體設計(包含廢液配管)及研究結果提出製程機台化學品廢液桶爆炸的可能原因，以提升製程機台整體安全性。
實驗結果顯示，CuSO4/H2O2系統在較低溶液pH值範圍下，溶液pH值降低會抑制銅離子與分子態H2O2平衡生成Cu2+(HO2－)離子的反應，進而降低系統的放熱速率，因此CuSO4/H2O2系統的TMR（Time to Maximum Rate）值隨著溶液pH值降低而增加。
於CuSO4/H2O2/Chloride系統中，由於添加氯離子會捕捉系統中產生的氫氧自由基，使系統中氫氧自由基的反應途徑由主要與銅一價離子反應改變為部分與氯離子反應，進而使得溶液中的銅一價離子部分與H2O2反應，進而增加系統的放熱速率；另外可能由於氯離子的添加會加速Cu2+(HO2－)離子形成CuCl及OH?的反應速率，進而增加系統的放熱速率，因此氯離子的添加會明顯降低系統的TMR值。
於CuSO4/H2O2/Citrate系統中，由於在低pH值下，所添加的檸檬酸根離子部份以CuCit－型式存在，部份以H2Cit－存在，會捕捉CuSO4/H2O2/Citrate系統中產生的氫氧自由基，使系統中氫氧自由基的主要反應途徑由主要與銅一價離子反應改變為部分與檸檬酸根離子反應，進而使得溶液中的銅一價離子部分與H2O2反應，進而增加系統的放熱速率；且由於EDTA與銅離子的螯合平衡常數為1018.8，遠大於檸檬酸根離子與銅離子的螯合平衡常數106.1，因此EDTA抑制生成Cu2+(HO2－)的效應大於Cit3－抑制生成Cu2+(HO2－)，所以系統放熱速率為Cu/Cit > Cu/EDTA。
配合本研究之實驗結果及結合相關文獻，可以架構性說明CuSO4/H2O2系統中，系統放熱行為受溶液特性（溶液pH值、銅離子濃度、雙氧水濃度、添加劑）之影響。

關鍵字

雙氧水 ； 電化學電鍍 ； 相容性 ； 氯離子 ； 溶液pH值 ； 銅離子

並列摘要

The usage of hydrogen peroxide and copper ions were increased with the mass production of the copper integration process for improving the devices performance in semiconductor industry. The compatibility of hydrogen peroxide and copper ions at electrochemical plating process was studied under various concentrations of copper ions, hydrogen peroxide, sulfate ions, chloride ions, additives and solution pH values. The root causes of explosion of waste ECP chemicals drum tank were identified by integration of this research results, process recipes and hardware configuration.
Experimental results demonstrated that the heat generation rate was decreased in more acidic solution conditions which repressed the generation of Cu2+(HO2－) ions at CuSO4/H2O2 system. The concentrations of Cu2+(HO2－) ion could be enhanced by the addition of chloride ions. And cuprous ions might not just react with hydroxyl free radical but partly react with hydrogen peroxide to generate heat source which resulted from hydroxyl free radical was partly scavenged by chloride ions. Consequently, the TMR (Time to Maximum Rate) was found to be decreased significantly with increasing chloride ion concentrations at CuSO4/H2O2/Chloride system.
The heat generation rate in lower concentration of citrate ions was larger than that without the chelating agent additions. These might be because hydroxyl free radical was scavenged by organic species like as citrate ions, and then changed the parts of reaction ways of cuprous ion at CuSO4/H2O2/citrate system. The TMR at CuSO4/H2O2/citrate system was lower than that at CuSO4/H2O2/EDTA system due to copper-EDTA complex ion with higher stability constant to reduce the concentrations of Cu2+(HO2－) ions. The behaviors of heat generation could be explained by introducing the concepts of species distribution and free radical reaction mechanisms in aqueous solution at CuSO4/H2O2/additive system.

並列關鍵字

copper ions ； hydrogen peroxide ； solution pH values ； ECP ； chloride ions ； compatibility

參考文獻

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