Smart Chemistry Towards Highly Efficient Soldering Material FormulationAuthors: Yanrong Shi, Ph.D, Xiang Wei, Ph.D, Bruno Tolla, Ph.D
Company: Kester Inc.
Date Published: 9/28/2014 Conference: SMTA International
Activator choices are critical parameters in the design of paste and flux formula in order to achieve outstanding performance in lead-free and halogen-free soldering processes. For an efficient printed circuit boards (PCBs) soldering operation, the fluxing mechanism requires the right chemistry coupled with a proper initial heat cycle to remove the oxide and surface contamination. A synergetic combination between chemistry and processing will promote a clean and solder-wettable metal surface, which is a prerequisite to achieve good metallurgical bonding. Meanwhile, the activator itself has to remain inert at mild temperatures to guarantee an acceptable shelf-life while leaving non-corrosive and non-conductive residues to ensure a high-reliability in the no-clean categories.
Here, we report a systematic study of a series of innovative activator systems applied in new solder paste and liquid flux platforms. Analytical methods such as thermogravimetric analysis (TGA) are applied to characterize the thermal behavior of these activators. Solder pastes are formulated using these activator packages. The solderabilities, physical properties and stabilities of the pastes and fluxes are evaluated. This fundamental understanding may provide some scientific guidance for future formulation work.
Lead-free, halogen-free, formulation, activator, fluxing chemistry
Members download articles for free:
Not a member yet?
What else do you get when you join SMTA? Read about all of the benefits that go along with membership.
Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.