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As the proliferation of modern-day electronics continues to drive miniaturization and functionality, electronic designers and assemblers face the issue of environmental exposure and uncommon applications never previously contemplated.
This reality, coupled with the goal of reducing the environmental and health implications of the production and disposal of these devices, has forced manufacturers to reconsider the materials used in production.
Furthermore, the need to increase package density and reduce costs has led to the rapid deployment of leadless packages such as the QFN, POP, LGA, and micro-BGA. In many cases, the manufacturers of these devices will recommend the use of no-clean fluxes due to concerns over the ability to consistently remove flux residues from under and around these devices.
These concerns, along with the need to implement a tin whisker mitigation strategy and/or increase environmental tolerance, have led to the conundrum of applying conformal coating over no-clean residues.
The AIM R&D team has united with OEM electronics and conformal coating manufacturers in an attempt to characterize the different coating technologies currently available. In this study, various coating materials were tested with different chemistries of no-clean fluxes. Results demonstrate possible combinations meeting the mission profile of the assembly with consideration for the assemblers’ capabilities and cost objectives.Read the full article here.Editor's Note: This article originally appeared in the April 2014 issue of SMT Magazine.