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Solder Bond Integrity Via Thermal Transfer Function Analysis Methodology

IP.com Disclosure Number: IPCOM000102714D
Original Publication Date: 1990-Dec-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 6 page(s) / 506K

Publishing Venue

IBM

Related People

Flake, RH: AUTHOR [+4]

Abstract

This article describes a method summarized from a study reported in (*) for characterizing the integrity of a solder bond by the development of a thermal transfer function methodology.

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This is the abbreviated version, containing approximately 52% of the total text.

Solder Bond Integrity Via Thermal Transfer Function Analysis Methodology

       This article describes a method summarized from a study
reported in (*) for characterizing the integrity of a solder bond by
the development of a thermal transfer function methodology.

      From thermodynamics, thermal energy flows from a region of high
temperature to a region of lower temperature.  When a solder bond
structure, (component lead, circuit trace, via or land), is locally
heated, there is a local rise in temperature, with a corresponding
flow of thermal energy to lower temperature regions.  The
characteristics of this flow are affected by the thermal parameters
of the solder bond structure.  A transfer function relates the output
to the input of a system in terms of the system properties. The
transfer function describing the thermal transmission properties of
the solder bond gives the dynamic relationship between a transient
thermal output and the transient thermal input for the system (joint
structure).

      When the measurement parameter of the system is temperature,
Fig.  1 illustrates the temperature input and output transient
responses for bonded and non-bonded configurations.  The thermal
input is a heat source pulse applied to the system.  The input is the
temperature transient pulse measured at a heat source input.  The
output measurement location is on the other side of the solder bond,
so that the thermal energy must flow through the joint structure to
arrive at the output location.  The measured temperature transient
pulse at the output location is identified as the output for the
system (Fig. 2).

      The dynamic thermal input output system across the solder bond
can be modeled as a nth order system as described in equation 1.

                            (Image Omitted)

 .
                c(n)+...+a1c+a0c=bu                   (1)
where u is the input temperature pulse and c is the output
temperature pulse.  The thermal resistance and capacitance properties
of the system are described by the coefficients of equation 1 which
can also be given in the transfer function form of equati...