Soft Probing for Direct Chip Cell Burn-in

Soft Probing for Direct Chip Cell Burn-in

       This article describes a technique to test, to burn-in,
and to re-test a device at the lowest cost before module assembly.

      By using existing available techniques (low cost TAB tape), it
is required that a soft contact be established between the device and
the tester.  To that end, different implementations are suggested
below.  Burn-in socket for C4 devices (Fig. 1)

      The probe is of the C4-TAB tape type.  The probe is centered by
its own sprocket holes (TAB process alignment punched holes) in the
burn-in fixture.  Next, the chip is placed thereon (manually or using
an automatic chip-placement machine) and self-aligned in the TAB tape
C4 holes window. To ensure a good electrical contact, the chip is
pressed onto the C4 TAB land area by the compression plate.  This C4
TAB land area is itself supported by an elastic compression pad.  The
compression plate can be temperature controlled at the burn-in set
point
Burn-in socket for wire-bonding devices (Fig. 2)

      The probe proposal is of the Ball-TAB (B-TAB) tape type.  The
probe is still centered by its own sprocket holes (TAB process
alignment punched holes) in the burn-in fixture.  Chip centering is
obtained by using a second tape, punched at the external chip
dimensions, centered above the probe tape by its sprocket holes in
the burn-in fixture. The chip is then placed onto the B-TAB probes,
centered by the chip dimensioned punched tape...