Methods of fabricating leadless packages are described that provide good
solder joint reliability. In most respects, the packages are fabricated in a manner
similar to current lead frame based leadless packaging techniques. However, at
some point in the process, the contacts are provided with undercut regions that
are left exposed during solder plating so that the solder plating also covers the
exposed side and undercut segments of the contacts. When the resultant devices
are soldered to an appropriate substrate (after singulation), each resulting solder
joint includes a fillet that adheres very well to the undercut portion of contact.
This provides a high quality solder joint that can be visually inspected from the
side of the package.