THE INFLUENCE OF STORAGE TIME ON MOISTURE MIGRATION IN POLYMERIC ENCAPSULANTS
Authors: Charles J. Koehler and Martin A. Seitz Company: Marquette University Date Published: 6/12/2001
Advanced Packaging Technology
Abstract: An important attribute of an encapsulant is to act as a barrier to moisture migration in electronic packaging. While moisture permeation information may be provided by a manufacturer or tested when received, this ability may deteriorate during storage. This deterioration may not be detected under normal processing. In order to examine any changes in the moisture permeation rate, an impedance spectroscopy methodology was implemented. A typical encapsulant was subdivided and stored at the suggested storage temperature for varying periods of time then cured using the specifications suggested by the manufacture. These test coupons were then evaluated in an 85 oC / 85 % humidity chamber. The results of these studies indicate that the ability of a polymeric encapsulant to resist the migration of moisture is significantly impacted by the time of storage.