Authored By:
Master Bond, Inc.
With circuit board real estate at a premium, a constant drive to increase production rates and ensure reliable long term performance, one of the options designers are turning to are glob-tops.
A glob-top is a precisely measured and applied drop of specially formulated epoxy that is applied over a microelectronic circuit and its connecting wires. Most notably, glob-tops are used in chip-on-board applications to protect the circuit from contaminants, facilitate thermal dissipation, and minimize the thermal mismatch between the chip and substrate.
In addition, glob-tops provide dielectric insulation for the circuit as well as mechanical support. Glob-top adhesives are available as two part epoxies, one part heat curable epoxies, and as UV curing systems.
Glob-top adhesives are typically thixotropic materials; while they are flowable during application, their viscosity becomes great enough that they do not flow or move after placement. This assures that the epoxy is present at the necessary locations while at the same time preventing deposits of adhesive from gathering in areas where it could affect the function of delicate assemblies.
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