semi合集-English.pdf - 第6179页

SEMI G38-0996 © SEMI 1987, 2004 4 measuring current, I M , used during the calib ration procedure). The DUT shall then be operated with heating power (P H ) applied. The temperature-sensitive parameter, V MH , shall be m…

100%1 / 7923
SEMI G38-0996 © SEMI 1987, 2004 3
thermocouple beneath the DUT. For purposes of
measuring forced air junction-to-ambient thermal
resistance in a wind tunnel, the ambient temperature
should be measured with a thermocouple upstream of
the DUT in the section of the tunnel that experiences
fully developed flow.
6.3 Thermal Resistance, Junction to Specified
Reference Point, R
θJR
.
6.3.1 General Considerations — The thermal
resistance of a semiconductor device is a measure of the
ability of its carrier, or package and mounting technique
to provide for heat removal from the semiconductor
junction. The thermal resistance of a microelectronic
device can be calculated when the ambient temperature
and power dissipation in the device and a measurement
of the junction temperature are known. When making
the indicated measurements, the package shall be
considered to have achieved thermal equilibrium when
halving the time between the application of power and
the taking of the reading causes no error in the indicated
results within the required accuracy of measurement.
6.3.2 Indirect Measurement of Junction Temperature
for the Determination of R
θJA
— The purpose of the test
is to measure the thermal resistance of integrated
circuits by using particular semiconductor elements on
the chip to indicate the device junction temperature. In
order to obtain a realistic estimate of the operating
junction temperature, the whole chip in the package
should be powered in order to provide the proper
internal temperature distribution. During measurement
of the junction temperature, the chip heating power
(constant voltage source) shall remain constant while
the junction calibration current remains stable. It is
assumed that the calibration current will not be affected
by the circuit operation during the application of
heating power.
6.3.3 The temperature-sensitive device parameter is
used as an indicator of an average (weighted) junction
temperature of the semiconductor element for
calculations of thermal resistance. The measured
junction temperature is indicative of the temperature
only in the immediate vicinity of the element used to
sense the temperature.
6.3.4 The temperature-sensitive electrical parameters
generally used to indirectly measure the junction
temperature are the forward voltage of diodes and the
emitter-base voltage of bipolar transistors. Other
appropriate temperature-sensitive parameters may be
used for indirectly measuring junction temperature for
fabrication technologies that do not lend themselves to
sensing the active junction voltages.
6.3.4.1 Steady-State Technique for Measuring T
J
—
The following symbols shall apply for the purpose of
these measurements:
I
M
Measuring current in milliamperes.
V
MH
Value of temperature-sensitive parameters in
millivolts, measured at I
M
, and corresponding to
the temperature of the junction heated by P
H
.
T
MC
Calibration temperature in degrees Celsius,
measured at the reference point.
V
MC
Value of temperature-sensitive parameter in
millivolts, measured at I
M
and specific value of
T
MC
.
6.3.4.2 The measurement of T
J
, using junction forward
voltage as the TSP, is made in the following manner:
6.3.4.2.1 Step 1 — Measurement of the temperature
coefficient of the TSP (calibration).
6.3.4.2.2 The coefficient of the temperature-sensitive
parameter is generated by measuring the TSP as a
function of the reference point temperature, for a
specified constant measuring current, I
M
, by externally
heating the device under test in a controlled temperature
oven or fluid bath. The reference point temperature
range used during calibration shall encompass the
temperature range encountered in the power application
test (see Step 2). The measuring current is generally
chosen such that the TSP decreases linearly with
increasing temperature over the range of interest and
that negligible internal heating occurs in the silicon and
metal traces. For determining the optimum TSP
calibration or measuring current, V
MC
vs. log I
M
curves
for two temperature levels that encompass the
calibration temperature range of interest should be
blotted. The optimum measuring current, I
M
, is then
selected such that it resides on the linear portion of the
two V
MC
vs. log I
M
curves that were generated. A
measuring current ranging from 0.05 to 5 mA is
generally used, depending on the specifications and
operating conditions of the device under test for
measuring the TSP. The value of the TSP temperature
coefficient, V
MC
/T
MC
, for the particular measuring
current used in the test, is calculated from the
calibration curve, V
MC
vs. T
MC
. At least three points
should be used to generate the voltage vs. temperature
curve for the determination of the TSP temperature
coefficient.
6.3.4.3 Step 2 — Power application test
6.3.4.3.1 The power application test is performed in
two parts. For both portions of the test, the reference
point temperature and the specified air velocity are held
constant at a preset value. The first measurement to be
made is that of the temperature-sensitive parameter
(i.e., V
MC
, under operating conditions with the
SEMI G38-0996 © SEMI 1987, 2004 4
measuring current, I
M
, used during the calibration
procedure). The DUT shall then be operated with
heating power (P
H
) applied. The temperature-sensitive
parameter, V
MH
, shall be measured with constant
measuring current, I
M
, that was applied during the
calibration procedure (see Step 1).
6.3.4.3.2 The heating power, P
H
, shall be chosen such
that the calculated junction-to-reference point
temperature difference as measured at V
MH
is greater
than or equal to 20°C. In accomplishing this, the device
under test should not be operated at such a high heating
power level that the on-chip temperature sensing and
heating circuitry is no longer electrically isolated. Care
should also be taken not to exceed the design ratings of
the package-interconnect system, as this may lead to an
overestimation of the power being dissipated in the
active area of the chip due to excessive power losses in
the package leads and wire bonds. The values of V
MH
,
V
MC
, and P
H
are recorded during the power application
test.
6.3.4.3.3 The following data shall be recorded for these
test conditions:
a. Temperature-sensitive electrical parameters (V
F
,
V
EB
, or other appropriate TSP).
b. Junction temperature, T
J
, is calculated from the
equation:
T
J
= T
R
+ V
MH
− V
MC
()
∆V
MC
∆T
MC
−
1
where T
R
= T
A
c. Ambient (air) temperature, T
A
.
d. Ambient (air) velocity, v
A
, (v
A
= 0 for still-air
enclosure).
e. Power dissipation, P
H
.
f. Mounting arrangement (including offset from test
board).
6.4 Calculations of R
θJR
6.4.1 Calculation of Package Thermal Resistance —
The thermal resistance of a microelectronic device can
be calculated when the junction temperature, T
J
, has
been measured in accordance with procedures outlined
in Sections 6.1 through 6.3. With the data recorded
from each test, the thermal resistance shall be
determined from:
R
θ
JR
=
T
J
−
T
R
P
H(Package)
where : R
θ
JR
=
R
θ
JA
and T
R
=
T
A
.
SEMI G38-0996 © SEMI 1987, 2004 5
7 Summary Report
7.1 The following details shall be specified:
1. Description of Package
1.1 Package Type
Package Name ________________ (per JEDEC or EIAJ)
Pin Counts ________________ pins
Special Specification ________________ Yes ________________ No
If Yes, describe the detail specification.
1.2 Test Chip
Chip per SEMI G32 ________________ Yes ________________ No
Chip Size ________________ mm x ________________ mm
Chip Thickness ________________ mm
1.3 Leadframe
Leadframe Material Fe/Ni Alloy, Cu, Cu Alloy, Other (____________ )
Leadframe Thickness ________________ mm
Die Pad Size ________________ mm x ________________ mm
1.4 Package Dimension & Compound
Package Size ________________ mm x ________________ mm
Package Thickness ________________ mm
Compound Material ___________________________________________
1.5 Others
Die Attach Material ____________________________________________
Heat Sink/Spreader ________________ Yes ________________ No
If yes, describe the configuration, dimension, method of attachment, location, etc.
2. Description of Test Board
Test Board per SEMI G42 ________________ Yes ________________ No
No. of Layers ___________________________________________
If test board is specified, describe the specification of the following items:
Dimension ________________ mm x ________________ mm x ________________mmt
No. of Layers ___________________________________________
Material ___________________________________________