AIM Announces One-Step Underfill 688

Cranston, Rhode Island, USA - AIM is pleased to announce the development of One-Step Underfill 688, a non-odorous, low surface tension, reworkable one component epoxy resin designed as a one-step underfill for flip chip, CSP, BGA and µBGA assemblies.

One-Step Underfill 688 is a novel product that acts as a flux and an underfill. Historically, the underfill dispense and cure processes have taken place after the SMT reflow process. However, One-Step Underfill 688 may be applied directly after the SMT printing process and then cured during the standard lead-free reflow process. By eliminating the second assembly step and a second cure cycle, the One-Step Underfill 688 does it all in one step through excellent capillary action, faster reflow characteristics, rapid cure speeds, and good fluxing action. The results are fewer process steps and increased throughput.

One-Step Underfill 688 also can be used in mixed alloy solutions, such as a lead-free BGA on a tin lead board. As lead is not desired in lead-free applications, One-Step Underfill 688 can be used on a lead-free BGA, and the balance of the products can be printed with Sn63. This way, the BGA remains lead-free, and the board can be run through a lead-free profile to insure BGA collapse.

One-Step Underfill 688 offers superior reliability through high Tg, low CTE, and good fill with no voiding. Though flux is not required, One-Step Underfill 688 is compatible with no-clean flux residues and provides excellent adhesion.

One-Step Underfill 688 may be reworked at 120° C and the viscosity of the product remains stable throughout its shelf life. Additionally, One-Step Underfill 688 wets solder to OSP, ENG immersion silver and immersion tin board surfaces.

Headquartered in Montreal, Canada, AIM is a leading global manufacturer of assembly materials for the electronics industry. The company produces solder paste, liquid flux, cored wire, bar solder, adhesives, performs, and specialty alloys such as indium and gold for electronics assembly, PC fabrication, component manufacturing and other industries. For more information, visit AIM on the web at, or contact us through email at

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