Corrosion reliability is a severe concern related no-clean flux (NCF) residue. It results in a decreased life span of electronic devices, specially fine pitch assemblies. NCFs are formulated from various organic/inorganic components viz. activator, solvent, surfactant, and additive. Each constituent of a flux has specific functions, and its advantages and limitations. The first part of this review paper describes the constituents of NCF, their characteristics and their compositional ranges. The effects of process parameters such as soldering process and soldering temperature on the performance of NCF are then presented in the second part. Finally, the effects of flux residue on the underfill and reliability of flip-chip packaging are discussed. Carboxylic acid containing less number of carboxyl functional group, lower decomposition temperature, lower solubility, higher acid dissociation constant and higher chain length can increase the cleaning efficiency of NCF. Hybrid activators (amine+carboxylic acid) are advantageous in terms of improving the cleaning action and also increasing interactions with underfill. Lower boiling point solvents are preferable as they are the main evaporating constituent. Reflow soldering has been proven as a better choice for NCF at the soldering temperature range of 200–250 °C, as it leaves minimum flux residue. Besides, incompatible residue on solder mask or die surface can hinder the flow of underfill and flux residue outgassing during curing generates voids and delamination. Therefore, to formulate an efficient NCF, the characteristics of its constituents need to be understood and the flux composition optimized.

腐蚀可靠性是与免清洗助焊剂 (NCF) 残留物相关的一个严重问题。它会导致电子设备的寿命缩短，特别是细间距组件。NCF 由各种有机/无机成分配制而成，即。活化剂、溶剂、表面活性剂和添加剂。助焊剂的每种成分都有特定的功能，以及其优点和局限性。本综述论文的第一部分描述了 NCF 的成分、特征和组成范围。第二部分介绍了焊接工艺和焊接温度等工艺参数对 NCF 性能的影响。最后，讨论了助焊剂残留对倒装芯片封装的底部填充和可靠性的影响。含有较少羧基官能团的羧酸，分解温度较低，较低的溶解度、较高的酸解离常数和较高的链长可以提高 NCF 的清洗效率。混合活化剂（胺+羧酸）在改善清洁作用以及增加与底部填料的相互作用方面是有利的。低沸点溶剂是优选的，因为它们是主要的蒸发成分。回流焊接已被证明是 NCF 在 200–250 °C 焊接温度范围内的更好选择，因为它留下的助焊剂残留量最少。此外，阻焊层或芯片表面上不相容的残留物会阻碍底部填充胶的流动，助焊剂残留物在固化过程中会产生空隙和分层。因此，要制定有效的 NCF，需要了解其成分的特性并优化助焊剂成分。较高的酸解离常数和较长的链长可以提高 NCF 的清洗效率。混合活化剂（胺+羧酸）在改善清洁作用以及增加与底部填料的相互作用方面是有利的。低沸点溶剂是优选的，因为它们是主要的蒸发成分。在 200–250 °C 的焊接温度范围内，回流焊接已被证明是 NCF 的更好选择，因为它留下的助焊剂残留量最少。此外，阻焊层或芯片表面上不相容的残留物会阻碍底部填充胶的流动，助焊剂残留物在固化过程中会产生空隙和分层。因此，要制定有效的 NCF，需要了解其成分的特性并优化助焊剂成分。较高的酸解离常数和较长的链长可以提高 NCF 的清洗效率。混合活化剂（胺+羧酸）在改善清洁作用以及增加与底部填料的相互作用方面是有利的。低沸点溶剂是优选的，因为它们是主要的蒸发成分。回流焊接已被证明是 NCF 在 200–250 °C 焊接温度范围内的更好选择，因为它留下的助焊剂残留量最少。此外，阻焊层或芯片表面上不相容的残留物会阻碍底部填充胶的流动，助焊剂残留物在固化过程中会产生空隙和分层。因此，要制定有效的 NCF，需要了解其成分的特性并优化助焊剂成分。