File name gxebgapkg_issue.pdf
AMD GeodeTM Solutions
EBGA Package Clarification
Some AMD GeodeTM devices are available in an EBGA As a result of the cavity size tolerance in addition to the
(Enhanced Ball Grid Array) package. This document pro- assembly process controls, it is possible for the die attach
vides clarification on the EBGA package. The data book(s) epoxy to bridge the die edge and heat sink to the sidewall,
do not specify any electrical condition pertaining to the and short the die backside and heat sink to VSS. The vol-
metal top. Through the epoxy die attach process used for ume resistivity of the die attach epoxy is ~ 0.3 -cm.
the Geode devices, the metal top (heat sink) of the EBGA
In summary, the epoxy bridging is inherent to the manufac-
package can be electrically open or connected to VSS.
turing process. Some devices have been in high-volume
production for well over two years. Furthermore, AMD's
dynamic operational-life results (1,600 units representing
2.0 Discussion over 75,000 device-hours) along with the Customer DPPM
The Geode devices are packaged in 352-terminal and 432- performance does not suggest that the epoxy bridging
terminal cavity-down EBGA substrates. Each has separate adversely affects product quality or reliability. If any ques-
planes for VSS, VIO, and VCORE. Signal traces are micros- tions arise, contact you local AMD support representative.
tripline with VSS as the reference plane. The VSS ring is
connected to the VSS plane using the plated sidewall of the
cavity. In order to allow for adequate thermal dissipation, a
conductive (silver-impregnated) die attach epoxy is used to
connect the die directly to the heat sink.
Revision 2.0 - January 2001 - Confidential 1