Methods for vacuum assisted underfilling

摘要

Methods for applying an underfill with vacuum assistance. The method may include dispensing the underfill onto a substrate proximate to at least one exterior edge of an electronic device attached to the substrate. A space between the electronic device and the substrate is evacuated through at least one gap in the underfill. The method further includes heating the underfill to cause the underfill to flow into the space. Because a vacuum condition is supplied in the open portion of the space before flow is initiated, the incidence of underfill voiding is lowered.

主权项

1. A method of providing an underfill on a substrate having a surface to which an electronic device is mounted by electrically conductive joints and is separated from the substrate by a space, the space having an open portion that is unoccupied by the electrically conductive joints, the method comprising:
cooling the underfill; receiving the substrate with the surface in a plasma-treated condition; providing, after cooling the underfill, the underfill on the substrate along an exterior edge of the electronic device; evacuating the space to provide a vacuum condition in the open portion of the space; and after evacuating the space to provide the vacuum condition and while the vacuum condition is being maintained, causing flow of the underfill toward the exterior edge and into the open portion of the space, wherein the plasma-treated condition of the surface reduces trapping of gas under the underfill provided on the substrate.