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Design of Polymer Matrix Composite Chip Carrier to Achieve Predictable Solder Joint (C4) Reliability

IP.com Disclosure Number: IPCOM000101036D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Ingraham, A: AUTHOR [+4]

Abstract

Disclosed is a methodology for the design of composite chip carriers with controllable solder joint (C4) reliability. Traditionally, C4 attachment of semiconductor chips has used ceramic as the substrate material, thereby restricting any variability in the modulus or coefficient of thermal expansion (CTE) of the system. The success of direct chip attachment, using C4 technology, to polymeric/polymer matrix composite structures depends on defining and predicting the solder joint reliability. This must be done in relation to the thermophysical characteristics of the materials (such as CTE, elastic moduli and thermal stability) as well as the design of different structural layers in the composite board.

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Design of Polymer Matrix Composite Chip Carrier to Achieve Predictable Solder Joint (C4) Reliability

       Disclosed is a methodology for the design of composite
chip carriers with controllable solder joint (C4) reliability.
Traditionally, C4 attachment of semiconductor chips has used ceramic
as the substrate material, thereby restricting any variability in the
modulus or coefficient of thermal expansion (CTE) of the system.  The
success of direct chip attachment, using C4 technology, to
polymeric/polymer matrix composite structures depends on defining and
predicting the solder joint reliability.  This must be done in
relation to the thermophysical characteristics of the materials (such
as CTE, elastic moduli and thermal stability) as well as the design
of different structural layers in the composite board.

      This disclosure outlines the theoretical and experimental data
that makes prediction of C4 reliability possible.  From Fig. 1 it is
evident that a low modulus substrate will significantly reduce the C4
solder strain for a given delta alpha (Wx) and distance from the
neutral point (DNP)  The product of the Wx, DNP and modulus for a
given substrate CTE, as shown in Fig. 2, can be used to predict total
C4 solder strain which in turn can be related to C4 reliability by
the Coffin-Manson equation N50 = C x strain - 1.9.  Experimental data
using different modulus  dielectric substrates has shown good
correlation with the predicted C4 life.  The ability...