The IMAPS National meeting was recently held in Orlando FLA.
Lets first take a look at some of the materials papers that were presented.
Namics
Namics presented their latest data on available underfill solutions
for 2.5/3DIC. Below we see several opportunities for epoxy underfill materials.
Vacuum underfilling is replacing CUF due to decreased
voiding which improves reliability. Underfill must have a high enough Tg to
insure the modulus is high enough to protect bumps during thermal cycling but
low enough not to crack the die.
Namics proposes that in the near future it might be possible
for substrate suppliers to apply a B staged underfill prior to shipping. The
customer would then perform a thermocompression bond.
Despite the obvious benefits, the drawbacks of both NCP (non
conductive paste) and NCF (non conductive film) at present include required
additional capital, cost more and have a longer bonding time.
Application methods
for Various Underfill Solutions
Towa – Compression
Molding for High End Packaging Solutions
Traditional transfer molding has been challenged to mold 2.5/3D stacked die
structures since these structures have limited space for resin flow. It is also
difficult to transfer mold large wafer or panel substrates.
Compression molding was developed to mold packages with
minimum resin flow. The blue layer, in the figure below , is a release film
which is sucked down flat to the mold. A vacuum is subsequently pulled to
remove air, gas and moisture from the cavity and
molding cmpd.
Dow Chemical –
toughened BCB
BCB has been commercially used by the packaging community
for more than 20 years. Although it has various superior properties such as low
curing temp, low water absorption and low dielectric constant, being a
thermoset resin, toughness and elongation are not one of them. A toughened BCB has been a “holy grail” in
the BCB user community.
A new toughened BCB product has now been described by Dow.
Comparative properties are shown below. As one can see most properties have
been maintained while elongation has been improved 3X and shows a 2X increase
in fracture toughness from 0.3 to 0.4 to 0.6 – 0.9 MPa m1/2 vs standard BCB.
A cross section of a via in this toughened BCB is shown below.
Volume 3 of 3D
Integration Handbook being readied
It was 2008 when the Handbook of 3D Integration was
published by Wiley VCH. Since then it
has been the most referenced 3D treatis on the market. Much has happened since
2008 and we, the editors, felt that rather than update the first two volumes , we
would rather issue further volumes updating some chapters and adding others as
required and Wiley VCH agreed.
Volume 3, due to be published 1st quarter of 2014
will be focused on processing and will include chapters on 2.5D interposers,
TSV formation, bond/debond, thin, reveal and backside processing, reliability
and metrology. Authors in this volume, in addition to the editors, include Eric Beyne (IMEC), (EVG);
Hiroaki Ikeda (ASET); James Lu (RPI); Thorsten Matthias (EVG); Rama
Pulligadda (Brewer); Sesh Ramaswami (Applied Materials); Fred Roozeboom (TNO);
Rao Tummala (GaTech); Larry Smith (Sematech); Doug Yu (TSMC) .
For all the latest in 3DIC and advanced packaging, stay linked to IFTLE………………….
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