用于EMC-Si-Cu复合界面平坦化的CMP抛光液的研究

在后摩尔定律时代，先进封装成为延续摩尔定律的重要手段，而在先进封装硅通孔化学机械抛光（CMP，Chemical Mechanical Polishing）中，如何实现EMC-Si-Cu复合界面处的材料均匀去除成为先进封装工艺面临的一个关键问题。其中环氧模塑料（EMC，Epoxy Molding Compound）是一种环氧基复合封装材料，Cu是先进封装中采用的高导电、低迁移的布线材料。目前CMP抛光液对EMC、Si、Cu材料的去除选择比较高，暂无法实现复合界面处的均匀去除，同时，其酸/碱体系对于设备、工装的损耗较大，因而开发绿色环保，且具备较低EMC-Si-Cu去除选择比的抛光液，实现EMC-Si-Cu复合界面处的材料均匀去除，对先进封装工艺的发展具有重要意义。

鉴于Cu在先进封装中的重要应用和目前复合界面CMP抛光液对Cu的高抛光要求。本文以Cu的CMP抛光液为切入点，围绕Cu CMP抛光液核心成分中的络合剂、缓蚀剂和表面活性剂，引入肌氨酸作为辅助络合剂，腺嘌呤和壳聚糖作为混合缓蚀剂，羧甲基纤维素作为表面活性剂，提出了一种高效可靠、全成分绿色环保的中性抛光液，实现了对Cu高于600 nm/min的材料去除速率和低于1 nm的表面粗糙度。为适应EMC-Si-Cu复合界面平坦化，提出硅溶胶和胶体型氧化铈复合磨料抛光液体系，通过对氧化铈的改性和SiO₂@CeO₂核壳结构复合磨料合成的研究，实现了对Si抛光后低于0.4 nm的表面粗糙度，并控制Cu/Si材料选择比至1.5左右，Cu与EMC近1:1去除，有效保证了EMC中填料SiO₂的完整性，取得了理想的平坦化效果，为高密度、高可靠性封装中CMP抛光液提供了新的研究思路。

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