Browse Prior Art Database

Integrated Circuit Leadframe Design to Prevent Plastic Package Cracking

IP.com Disclosure Number: IPCOM000115509D
Original Publication Date: 1995-May-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Ikeda, H: AUTHOR [+2]

Abstract

Disclosed is an Integrated Circuit (IC) leadframe design method to prevent cracking of the plastic encapsulant in packages that use the die pad design. The proposed design separates the die pad into two or more sections onto which the silicon chip is attached. By separating the die pad into smaller section, this reduces the impact by the difference in Coefficient of Thermal Expansion (CTE) between the leadframe and the chip or the leadframe and mold compound is reduced, thus preventing package warpage and internal stress of the package.

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Integrated Circuit Leadframe Design to Prevent Plastic Package Cracking

      Disclosed is an Integrated Circuit (IC) leadframe design method
to prevent cracking of the plastic encapsulant in packages that use
the die pad design.  The proposed design separates the die pad into
two or more sections onto which the silicon chip is attached.  By
separating the die pad into smaller section, this reduces the impact
by the difference in Coefficient of Thermal Expansion (CTE) between
the leadframe and the chip or the leadframe and mold compound is
reduced, thus preventing package warpage and internal stress of the
package.

      The Figure demonstrates this separated die pad concept as it
relates to the chip and the plastic body.

      In the past, packages using the standard die pad design
utilized square chips mounted onto square die pads.  However,
recently rectangular chips are required to be mounted in this kind of
package also.  The stresses generated by these rectangular chips/die
pads can cause the mold compound to crack due to mismatches in the
CTE of the various packaging materials.  Using the die pad separation
concepts presented in this invention disclosure, it has been
demonstrated that the package can be designed and produced without
the problem of plastic cracking.

      So far, the ideas described in this invention disclosure have
not been described in any reports or theses for semiconductor
packaging.

      This invention can be applied...