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Tokozások termikus tesztje, minősítése

Tokozások termikus tesztje, minősítése. Termikus tranziens tesztelés. The measured a ( t ) response function is characteristic to the package. The features of the chip + package + environment structure can be extracted from it. Numerical derivation. Numerical deconvolution.

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Tokozások termikus tesztje, minősítése

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  1. Tokozások termikus tesztje, minősítése

  2. Termikus tranziens tesztelés • The measureda(t) response function is characteristic to the package. • The features of the chip + package + environment structure can be extracted from it.

  3. Numerical derivation Numerical deconvolution Derivative of the thermal impedance curve Discretization Structure function Measured thermal impedance curve Time-constant spectrum Foster model of the impedance Cauer model of the impedance Transformation Az ún. struktúrafüggvények

  4. ambient junction ambient Struktúrafüggvény:

  5. P(t) Die attach t Junction Grease We measure the thermal transient at the junction... T(z) heat-flow z = ln t Cold-plate: infiniteheat-sinking (Cth ) Grease:large Rth/Cthratio Base: small Rth/Cthratio Junction:is always in the origin Die attach: large Rth/Cthratio Chip:small Rth/Cthratio Struktúrafüggvény • thermal Capacitance vs. thermal Resistance Chip (Si) Base (Cu) Cold-plate ...and we convert it into the cumulative structure function and a compact model: Allows structural analysis and modeling…

  6. Junction Junction Grease Grease Die attach Die attach Unknown device with suspected DA voids Chip Chip Base Base Cold-plate Cold-plate Copy the reference structure function into this plot Grease Base Die attach Chip This increase suggests DA voids Chip rögzítés minősítése Reference device with good DA Identify its structure function: Identify its structure function:

  7. Thermal transient testing of IC packages T3Ster: RECORD=B1D 35 "B01d.MR1" "B02d.mr1" "B03d.mr1" 30 "B04d.mr1" "B05d.mr1" "B06d.mr1" 25 20 Temperature rise [Cels] 15 10 T3Ster: differential structure function 5 1000 0 1e-06 1e-05 0.0001 0.001 0.01 0.1 1 10 100 Time [s] 100 10 K [W2s/K2] 1 0.1 "C08D.stf" "C02D.stf" "C05D.stf" "C17D.stf" 0.01 0 1 2 3 4 5 Rth [K/W] Példa: tranzisztor modul Identification of properties of the chip-to-ambient heat-conduction path based on thermal transient measurements The so called structure functions provide the required information

  8. Measurement of a power BJT mount: failure analysis Rth=3.2 K/W The "good" structure function

  9. Die attach delamination inside the package Imperfect soldering of the package Measurement of a power BJT mount: failure analysis

  10. Top die 2.54×2.54 mm Bottom die 3.81×3.81 mm Mould 1st die attach 2nd die attach Leadframe Két működő chip 44L LLP tokban

  11. We can see what was invisible even for X-ray microscopy. Non-destructive analysis without using extra elements: delamination/voiding in the 2nd DA Stacked dietokok tesztelése For the last 15 K/W section the thermal wave propagates in the far region of the board and in the chamber, the structures fit perfectly (the blue curve is the shifted copy of the black curve) Failure between package body and the test board: solder delamination

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