refer to the
various ways in which the marking on a device package fails to meet its
required visual/physical and chemical specifications.
The more commonly encountered marking failure attributes encountered in
the industry are presented below.
of a package to be marked in accordance with applicable specifications
is known as 'markability.'
Poor markability is the condition wherein the package is difficult or
impossible to mark correctly and/or the mark on the
package exhibits insufficient permanence. Ink markability problems are
often due to the inability of the ink to adhere to the surface of the
package. Laser markability problems are often due to improper branding
equipment set-up, but may sometimes be due to textural problems on the
surface of the package as well.
of ink marks or brands on the package is usually caused by the presence
of a thin film or layer of
or foreign material on the package surface. For
instance, packages with excessive amounts of mold release agent on their
surfaces are likely to exhibit poor markability. It may also be due to
the use of an incorrect, incompatible, or expired ink.
Common marking failure
attributes which are applicable to both ink and laser marking include
the following: 1)
mark, wherein the entire mark is absent from
the package; 2)
mark or missing character, wherein only a
part of the mark is absent from the package; 3)
mark, wherein a mark appears in incorrect orientation with respect to
the package; 4)
mark, wherein a mark is in incorrect location with respect to the
wherein a mark has a different style or character arrangement than what
is prescribed; and 6)
poor mark contrast.
is also widely used in the semiconductor industry, but this term can
often be described more specifically as either an incomplete mark or as
a mark with poor contrast.
failure, or the failure of a package to retain the quality of its ink
mark over a prescribed period of time, is also a critical failure
attribute of the ink marking process. The
permanency test (MPT), which is described by
Mil-Std-883 Method 2015, is performed to test the mark permanency of a
sample. The MPT subjects the package marking to a set of chemicals
which, under normal circumstances, should not be able to erase the mark
or a part thereof.
markability is usually caused by incorrect laser branding settings. Packages
with textural problems or defects may likewise exhibit poor contrast
after laser marking. For example, reworked packages that have undergone
sand blasting generally exhibit marks with poor legibility.
Failure Mechanisms; Failure Analysis
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