Intel Pentium 4 Processor 478-Pin Socket (mPGA478) Design Guidelines

Intel® Pentium® 4 Processor 478-Pin Socket (mPGA478)
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(d) Check to ensure calibration successfully performed
(e) Measure the inductance by probing on the solder ball side of the socket with the test fixture mounted on
it. (Figure 4-6 –
Inductance Measurement Fixture Cross-section).
(i) Call this
assemblysocket
L .
(ii) Export data into MDS/ADS or (capture data at frequency specified in item 6 of Table 4-1 –
Electrical Requirements)
(f) Measure the inductance by probing on the shoulder of the test fixture with the pins cut (Figure 4-6 –
Inductance Measurement Fixture Cross-section).
Call this
sandwich
L .
(i) Measure 30 units.
The package for 30 units must be chosen from different lots. Use 5 different lots, 6 units from each
lot.
(ii) Export data into MDS/ADS or (capture data at frequency specified in item 7 of Table 1).
(iii) Calculate
sandwich
L .
(iv) For each socket unit, calculate
sandwich
assemblysocketsocket
LLL −=
It means
sandwich
L will be subtracted from each
assemblysocket
L and the result will be compared
with spec value for each individual socket unit.
4.6.2. Correlation of measurement and model data Inductance
To correlate the measurement and model data for loop inductance, one unit of measured socket assembly
(socket and shorted test fixture) and one unit of measured sandwich (shorted test fixture) will be chosen for
cross sectioning. Both units will be modeled based on data from cross sectioning using Ansoft* 3D. The
sandwich inductance will be subtracted from socket assembly inductance for both measured and modeled
data. This procedure results in loop inductance for socket pin + interposer pin. This final result can be
compared with the loop inductance from the supplier model for the socket. The shoulder of the interposer is
not included in the electrical modeling. If there is any difference between them, it will be called the de-
embedded correction factor. Adding the interposer to the socket and then eliminating the contribution of the
fixture creates this correction factor because inductance is not linear.
4.7. Pin-to-Pin Capacitance:
Pin-to-pin capacitance shall be measured using the top fixture (test vehicle) shown in Figure 4-8 – Test fixture
mounted bottom view with the pins cut
–, which contains pins that will connect to the socket. Figure 4-9 –
Top view of the Test vehicle – shows the capacitance measurement fixture cross-section and the capacitance
measurement methodology. The first figure shows the entire assembly. The second figure shows the
assembly without the socket, pins cut on the test vehicle. This is used to calibrate out the fixture contribution.
Figure 4-10 –
Capacitance measurement fixture cross section – represents the capacitance fixture design and