SEMI G30-88 TEST METHOD FOR JUNCTION-TO-CASE THERMAL RESISTANCE.pdf

SEMI G30-88
TEST METHOD FOR JUNCTION-TO-CASE THERMAL RESISTANCE
MEASUREMENTS OF CERAMIC PACKAGES
1 Purpose
d. power dissipation, PH, in watts, is the heating
The purpose of this test is to determine the thermal
power applied to the device causing a junction-to-
resistance of ceramic packages using thermal test
reference point temperature difference
chips. This test method deals only with junction-
e. thermal resistance, iunction-to-specified reference
case or mounting surface measurements of thermal
point, Reik, in degrees Celsius/watt. The thermal
resistance and iits itself to heat sink and fluid bath
resistance of the microcircuit is the temperature dif-
testing environments. Following the guidelines out-
ference from the junction to some reference point
lined in this test method, junction-to-case thermal
on the package divided by the power dissipation
resistance measurements of ceramic packages usin
the heat sink and fiuid bath methods should give the
same results only under certain limited conditions(.e
f. lemperalure-sensitive parameter, TSP, is the tem
under conditions that approximate unidirectional heat
perature-dependent electrical characteristic of the
flow through the chip and substrate to the preferred
junction under test which can be calibrated with
heat removal surface). If discrepancies occur. the heat
respect to temperature and subsequently used to
detect the iunction temperature of interest
sink mounting technique shall be considered as the ref-
eree test method. The heat sink mounting method for
measuring junction-to-case thermal resistance will be, 2 Apparatus
conservative measure of the package's ability to trans-2. I The apparatus required for these tests shall
fer heat to the ambient environment because heat sink- include the following as applicable to the specified test
ing is provided only on one side of the package, procedures
whereas the fluid bath mounting method has the poten
a. Thermocouple material shall be copper-constan
tial for equally cooling both sides of the package
tan(type T) or equivalent, for the temperature
I Defimitions-the following definitions and sym
range -100 to +300C. The wire size shall be no
bols shall apply for the purpose of this test
larger than A WG size 30. The junction of the ther
mocouple shall be welded to form a bead rather
a. ca
e, Tc, in degrees Celsius. The case
than soldered or twisted. The accuracy of the ther
temperature is the temperature at a specified acces
mocouple and associated measuring system shall
sible reference point on the package in which the
be士0.5°C.
microelectronic chip is mounted
b. Suitable electrical equipment as required to provide
b. mounting surface temperalure, TM, in degrees Cel
controlled levels of conditioning power and to
sius. The mounting surface temperature is the tem
make the specified measurements. The instrument
perature of a specified point at the device-heat sink
used to electrically measure the temperature-senst
mounting interface (or primary heat removal sur
tive parameter shall be capable of resolving a volt
age change of0.5 mv
c. junction temperature, TL, in degrees Celsius. The
C. Controlled temperature chamber, fiuid